Patent Application
20240082327
This application claims the benefit of priority to United Kingdom Patent Application No. GB 2212472.1, filed Aug. 26, 2022, hereby incorporated by reference in its entirety.
The instant application contains a Sequence Listing which has been submitted in XML format and is hereby incorporated by reference in its entirety. Said XML copy, created on Aug. 25, 2023, is named “MSIP.P0030US Sequence Listing” and is 210 kilobytes in size.
The present invention relates to retroviral vectors, particularly lentiviral vectors, comprising a modified retroviral RNA sequence that is codon-substituted and comprises a reduced number of retroviral open-reading frames, and wherein the retroviral vector is pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus, methods of making the same and uses thereof.
Retroviruses are a family of RNA viruses (Retroviridae) that encode the enzyme reverse transcriptase. Lentiviruses are a genus of the Retroviridae family, and are characterised by a long incubation period. Retroviruses, and lentiviruses in particular, can deliver a significant amount of viral RNA into the DNA of the host cell and have the unique ability among retroviruses of being able to infect non-dividing cells, so they are one of the most efficient methods of a gene delivery vector.
Pseudotyping is the process of producing viruses or viral vectors in combination with foreign viral envelope proteins. As such, the foreign viral envelope proteins can be used to alter host tropism or an increased/decreased stability of the virus particles. For example, pseudotyping allows one to specify the character of the envelope proteins. A frequently used protein to pseudotype retroviral and lentiviral vectors is the glycoprotein G of the Vesicular stomatitis virus (VSV), short VSV-G.
Lentiviral vectors, especially those derived from HIV-1, are widely studied and frequently used vectors. The evolution of the lentiviral vectors backbone and the ability of viruses to deliver recombinant DNA molecules (transgenes) into target cells have led to their use in many applications. Two possible applications of viral vectors include restoration of functional genes in genetic therapy and in vitro recombinant protein production.
When designing retroviral/lentiviral vectors suitable for use as gene delivery vectors, one key driver is to make the vector as safe as possible for patients. A second key driver is the need to produce sufficient quantities of the vector not just to treat an individual patient, but to allow wider clinical access to the therapy for all patients who could benefit from the therapy. These two drivers can find themselves in conflict, as modifications which improve vector safety are often associated with decreased yield during vector production.
One example of a clinical setting which would benefit from gene transfer to the airway epithelium is treatment of Cystic Fibrosis (CF). CF is a fatal genetic disorder caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, which acts as a chloride channel in airway epithelial cells. CF is characterised by recurrent chest infections, increased airway secretions, and eventually respiratory failure. In the UK, the current median age at death is ˜25 years. For most genotypes, there are no treatments targeting the basic defect; current treatments for symptomatic relief require hours of self-administered therapy daily. Gene therapy, unlike small molecule drugs, is independent of CFTR mutational class and is thus applicable to all affected CF individuals. However, to date there are no viral vectors approved for clinical use in the treatment of CF, and the same applies to other diseases, particularly many other respiratory tract diseases.
In addition to patient safety and yield issues, there are other difficulties conventionally associated with gene transfer to the airway epithelium.
Gene transfer efficiency to the airway epithelium is generally poor, at least in part because the respective receptors for many viral vectors appear to be predominantly localised to the basolateral surface of the airway epithelium. As such, prior to the inventors' research, the use of lentiviral pseudotypes required disruption of epithelial integrity to transduce the airways, for example by the use of detergents such as lysophosphatidylcholine or ethylene glycol bis(2-aminoethyl ether)-N,N,N′N′-tetraacetic acid, has been linked to an increased risk of sepsis. In addition, conventional gene transfer vectors struggle to penetrate the respiratory tract mucus layer, which also reduces gene transfer efficiency. The ability to administer conventional viral vectors repeatedly, mandatory for the life-long treatment of a self-renewing epithelium, is limited, because of patients' adaptive immune responses, which prevent successful repeat administration.
Administration of the vectors for clinical application is another pertinent factor. Therefore, viral stability through use of clinically relevant devices (e.g. bronchoscope and nebuliser) must be maintained for treatment efficacy.
There is accordingly a need for a gene therapy vector that is able to circumvent one or more of the problems described above. In particular, it is an object of the invention to provide a method for producing a pseudotyped retroviral or lentiviral (e.g. SIV) vector, and the means for carrying out said method, wherein the resulting vector is safe and adapted for improved gene transfer efficiency across the airway epithelium, and is produced at clinically relevant scale.
The present inventors have previously developed a lentiviral vector, which has been pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus, comprising a promoter and a transgene. Typically, the backbone of the vector is from a simian immunodeficiency virus (SIV), such as SIV1 or African green monkey SIV (SIV-AGM). Preferably the backbone of a viral vector of the invention is from SIV-AGM. The HN and F proteins function, respectively, to attach to sialic acids and mediate cell fusion for vector entry to target cells. The present inventors discovered that this specifically F/HN-pseudotyped lentiviral vector can efficiently transduce airway epithelium, resulting in transgene expression sustained for periods beyond the proposed lifespan of airway epithelial cells. Importantly, the present inventors also found that re-administration does not result in a loss of efficacy. These features make the vectors of the present invention attractive candidates for treating diseases via their use in expressing therapeutic proteins: (i) within the cells of the respiratory tract; (ii) secreted into the lumen of the respiratory tract; and (iii) secreted into the circulatory system.
However, there were potential safety concerns with this lentiviral vector. In particular, the lentiviral vector includes a significant number of retroviral (i.e., non-transgene) open reading frames (ORFs). There is a theoretical risk that said retroviral ORFs may be expressed following administration to a patient. Expression of retroviral ORFS represents a safety risk to the patient, particularly if said patient were to have an immune response against the expressed retroviral sequences.
Further, a significant degree of sequence homology between the retroviral vector and the GagPol plasmid used in the production creates a further theoretical risk that a replication competent lentivirus (RCL) could be generated either during manufacture, or in clinical use following administration to a patient. This represents an additional safety risk to the patient. The risk of generating replication competent viral particles is an issue for other retroviral/lentiviral vectors as well.
Whilst it would be desirable to mitigate these risks, it is not straightforward to do so, or at least not without eliciting other unacceptable disadvantages. On the one hand, modifications to reduce the number of ORFs, particularly the reduction of the number of ORFs 5′ to the promoter transgene, risks affecting the expression of the downstream transgene. Furthermore, other modifications to the retroviral genome, for example, codon substitutions with the aim of introducing STOP codons to reduce retroviral ORF length can also have deleterious effects, for example on vector yield and/or transgene expression. In addition, it is known in the art that modifications aimed at reducing the risk of RCL, such as codon-optimisation of the manufacturing gag-pol genes typically negatively impacting the titre or yield of the vector. Given the large titres of vector required to treat even a single patient, such a reduction in yield has the potential to render its production commercially unviable.
Described herein, the present inventors have designed and produced a retroviral vector, particularly a SIV vector, comprising a retroviral RNA sequence that has been modified to reduce the number of retroviral ORFs and to introduce specific codon-substitution modifications. The modified retroviral vectors of the invention comprising these newly described retroviral RNA sequences mitigate one or more of the above risks, providing a clinically advantageous product. Furthermore, the inventors have demonstrated that benefits can surprisingly be obtained without the expected disadvantages, such as reduced transgene expression and/or reduction in vector yield. Whilst such modifications had previously been considered in the context of the proviral DNA, the present application is the first to elucidate these modifications within the retroviral/lentiviral RNA sequence itself, rather than within the manufacturing platform. Further, the present application is the first to demonstrate the benefits conferred by particular modifications to the retroviral/lentiviral RNA sequence, and to show that not only does this extend to beneficial effects on vector yield, but also on transgene expression and integration of the retroviral/lentiviral RNA sequence into the host/target cell.
In particular, the inventors identified potential SIV ORFs within the SIV RNA sequence. The SIV RNA sequence was modified to remove one or more SIV ORFs. In particular, the inventors removed one or more SIV ORFs located 5′ to the transgene promoter, one or more SIV ORFs encoding polypeptides greater than or equal to 100 amino acids in length, one or more ORFs that were comprised (at least in part) in a partial RRE sequence and/or one or more ORFs that were comprised (at least in part) in a partial Gag sequence. Removal of the SIV ORFs was achieved by removing the start codon (ATG) of the selected SIV ORFs. To determine which SIV ORFs (and combinations thereof) could be removed without affecting the expression of the downstream transgene, the inventors produced a number of different SIV vectors. Each SIV vector was assessed to quantify vector yield, and transgene expression of the modified SIV vector with the corresponding unmodified vector.
The aforementioned modifications (both codon substitutions and modifications to reduce the number of SIV ORFs) were demonstrated not negatively impact transgene expression by the SIV vector pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus, and can even result in increased transgene expression by the vector. This is surprising, given that it generally accepted that such modifications, whilst addressing potential safety issues, can give rise to detrimental effects on transgene expression.
In addition, the aforementioned mutations (both codon substitutions and modifications to reduce the number of SIV ORFs) did not have negative impact on integration of SIV vector pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus into a host/target cell, and can even result in increased integration. Again, this is surprising, given that it generally accepted that such modifications, whilst addressing potential safety issues, can give rise to detrimental effects on vector integration.
Furthermore, the aforementioned mutations (both codon substitutions and modifications to reduce the number of SIV ORFs) did not have negative impact on the yield of SIV vector pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus, and can even result in increased titre of the vector. Again, this is surprising, given that it generally accepted that such modifications, whilst addressing potential safety issues, can give rise to detrimental effects on vector yield.
Accordingly, the present invention provides a retroviral vector comprising a modified retroviral RNA sequence that is (i) codon-substituted and (ii) comprises a reduced number of retroviral open reading frames (ORFs) compared with the non-modified retroviral RNA sequence from which the modified retroviral RNA sequence is derived; and wherein: (a) the retroviral RNA sequence comprises a promoter and a transgene; and (b) the retroviral vector is pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus.
Also disclosed is a method for the production of a retroviral, particularly a lentiviral vector, such as SIV, comprising a retroviral RNA sequence that is codon-substituted and comprises a reduced number of retroviral ORFs compared with the non-modified plasmid genome vector from which the modified retroviral genome RNA sequence is derived, and wherein (a) the retroviral RNA sequence comprises a promoter and a transgene, and (b) the retroviral vector is pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus which, when administered to a patient, has a reduced risk of immune response, without negatively affecting transgene expression.
The modified retroviral genome RNA sequence may lack: (a) one or more retroviral ORFs 5′ of the promoter; (b) one or more retroviral ORF encoding a polypeptide of ≥100 amino acids in length; (c) one or more retroviral ORF comprised (at least in part) in a partial RRE sequence; and/or (d) one or more retroviral ORF comprised (at least in part) in a partial Gag sequence.
The respiratory paramyxovirus may be a Sendai virus.
The promoter may be selected the group consisting of a hybrid human CMV enhancer/EF1a (hCEF) promoter, a cytomegalovirus (CMV) promoter, and elongation factor 1a (EF1a) promoter. Preferably the vector may comprise a hybrid human CMV enhancer/EF1a (hCEF) promoter.
The transgene may be selected from: (a) CFTR, ABCA3, DNAH5, DNAH11, DNAI1, and DNAI2; or (b) a secreted therapeutic protein, optionally Alpha-1 Antitrypsin (A1AT), Factor VIII, Surfactant Protein B (SFTPB), Factor VII, Factor IX, Factor X, Factor XI, von Willebrand Factor, Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) and a monoclonal antibody against an infectious agent. Preferably the transgene may encode: (a) CFTR; (b) A1AT; or (c) FVIII.
The promoter may be a hCEF promoter and the transgene may encode CFTR. The promoter may be a hCEF promoter and the transgene may encode A1AT. The promoter may be a hCEF or CMV promoter and the transgene may encode FVIII.
The retroviral vector may be a lentiviral vector; optionally wherein a lentiviral vector selected from the group consisting of a SIV vector, a Human immunodeficiency virus (HIV) vector, a Feline immunodeficiency virus (FIV) vector, an Equine infectious anaemia virus (EIAV) vector, and a Visna/maedi virus vector. Preferably the retroviral vector may be an SIV vector.
The modified retroviral RNA sequence may be (i) less than 9,000 bases in length and/or (ii) comprise or consist of a nucleic acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% identity to SEQ ID NO: 1. Preferably the modified retroviral RNA sequence may be (i) less than 9,000 bases in length and (ii) comprise or consist of a nucleic acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% identity to SEQ ID NO: 1. More preferably, the modified retroviral RNA sequence may comprise or consist of a nucleic acid sequence of SEQ ID NO: 1, still more preferably the modified retroviral RNA sequence may consist of a nucleic acid sequence of SEQ ID NO: 1.
The retroviral vector may further comprise one or more of: (a) a p17 protein comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 2; (b) a p24 protein comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 3; (c) a p8 protein comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 4; (d) a protease comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 5; (e) a p51 protein comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 6; (f) a p15 protein comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 7; and/or (g) a p31 protein comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 8. Optionally the vector may comprise each of (a) to (g).
The retroviral vector may further comprise one or more of: (a) a Gag protein comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 9; and or (b) a Pol protein comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 10.
The invention also provides a SIV vector pseudotyped with Sendai virus hemagglutinin-neuraminidase (HN) and fusion (F) proteins, wherein: (a) said vector comprises a modified retroviral RNA sequence which comprises or consists of a nucleic acid sequence of SEQ ID NO: 1, preferably wherein the modified retroviral RNA sequence consists of a nucleic acid sequence of SEQ ID NO: 1; and (b) the F protein comprises a first subunit which comprises or consists of an amino acid sequence of SEQ ID NO: 14 and a second subunit which comprises or consists of an amino acid sequence of SEQ ID NO: 15. Said vector may further comprise one or more of: (a) a p17 protein comprising or consisting of an amino acid sequence of SEQ ID NO: 2; (b) a p24 protein comprising or consisting of an amino acid sequence of SEQ ID NO: 3; (c) p8 protein comprising or consisting of an amino acid sequence of SEQ ID NO: 4; (d) a protease comprising or consisting of an amino acid sequence of SEQ ID NO: 5; (e) a p51 protein comprising or consisting of an amino acid sequence of SEQ ID NO: 6; (f) a p15 protein comprising or consisting of an amino acid sequence of SEQ ID NO: 7; (g) a p31 protein comprising or consisting of an amino acid sequence of SEQ ID NO: 8; (h) a Gag protein comprising or consisting of an amino acid sequence of SEQ ID NO: 9; and/or (i) a Pol protein comprising or consisting of an amino acid sequence of SEQ ID NO: 10; wherein optionally the vector comprises each of (a) to (g).
Also disclosed is a method for the production of a retroviral, particularly a lentiviral vector, such as SIV, comprising a retroviral RNA sequence that is codon-substituted and comprises a reduced number of retroviral ORFs compared with the non-modified plasmid genome vector from which the modified retroviral genome RNA sequence is derived, and wherein (a) the retroviral RNA sequence comprises a promoter and a transgene, and (b) the retroviral vector is pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus, wherein the method has a reduced risk of RCL, without negatively affecting, or even increasing vector titre, vector integration and/or transgene expression. Thus, the methods of the invention provide for safer vectors produced at commercially desirable yields.
Accordingly the invention also provides a method of producing a retroviral vector which is codon-substituted and comprises a reduced number of ORFs compared with the non-modified retroviral RNA sequence from which the modified retroviral RNA sequence is derived and wherein the retroviral RNA sequence comprises a promoter and a transgene and which is pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus. The method of the invention may comprise or consist of the following steps: (a) growing cells in suspension; (b) transfecting the cells with one or more plasmids; (c) adding a nuclease; (d) harvesting the lentivirus; (e) adding trypsin (or an enzyme with the same cleavage specificity); and (d) purification.
Steps (a)-(f) of the method may be carried out sequentially. The cells may be HEK293 cells (such as HEK293F or HEK293T cells) or 293T/17 cells. The addition of the nuclease may be at the pre-harvest stage. The addition of trypsin (or enzyme with the same cleavage specificity) may be at the post-harvest stage. The purification step may comprise one or more chromatography step.
The invention further provides a retroviral vector which is codon-substituted and comprises a reduced number of ORFs compared with the non-modified retroviral RNA sequence from which the modified retroviral RNA sequence is derived and wherein the retroviral RNA sequence comprises a promoter and a transgene and which is pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus which is obtainable by a method of the invention.
The invention also provides a composition comprising a retroviral vector and a pharmaceutically acceptable excipient or diluent, wherein said retroviral vector comprises a modified retroviral RNA sequence which is codon-substituted and comprises a reduced number of ORFs compared with the non-modified retroviral RNA sequence from which the modified retroviral RNA sequence is derived and wherein the retroviral RNA sequence comprises a promoter and a transgene and the retroviral vector is pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus. Said composition may be formulated for administration to the lungs; optionally wherein the administration is by intratracheal or intranasal instillation, aerosol delivery, intravenous injection, direct injection into the lungs.
The invention also provides a retroviral vector for use in a method of treatment, wherein the retroviral vector comprises a modified retroviral RNA sequence which is codon-substituted and comprises a reduced number of ORFs compared with the non-modified retroviral RNA sequence from which the modified retroviral RNA sequence is derived and wherein the retroviral RNA sequence comprises a promoter and a transgene and the retroviral vector is pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus. The invention also provides a method of treating a disease comprising administering a retroviral vector to a subject in need thereof, wherein the retroviral vector comprises a modified retroviral RNA sequence which is codon-substituted and comprises a reduced number of ORFs compared with the non-modified retroviral RNA sequence from which the modified retroviral RNA sequence is derived and wherein the retroviral RNA sequence comprises a promoter and a transgene and the retroviral vector is pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus. The disease to be treated may be a lung disease, preferably cystic fibrosis.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Singleton, et al., DICTIONARY OF MICROBIOLOGY AND MOLECULAR BIOLOGY, 20 ED., John Wiley and Sons, New York (1994), and Hale & Marham, THE HARPER COLLINS DICTIONARY OF BIOLOGY, Harper Perennial, NY (1991) provide the skilled person with a general dictionary of many of the terms used in this disclosure. The meaning and scope of the terms should be clear; however, in the event of any latent ambiguity, definitions provided herein take precedent over any dictionary or extrinsic definition. It should be understood that this invention is not limited to the particular methodology, protocols, and reagents, etc., described herein and as such can vary.
This disclosure is not limited by the exemplary methods and materials disclosed herein, and any methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of this disclosure. The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention, which is defined solely by the claims.
The description of embodiments of the disclosure is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. While specific embodiments of, and examples for, the disclosure are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the disclosure, as those skilled in the relevant art will recognize. For example, while method steps or functions are presented in a given order, alternative embodiments may perform functions in a different order, or functions may be performed substantially concurrently. The teachings of the disclosure provided herein can be applied to other procedures or methods as appropriate. The various embodiments described herein can be combined to provide further embodiments. Aspects of the disclosure can be modified, if necessary, to employ the compositions, functions and concepts of the above references and application to provide yet further embodiments of the disclosure. Moreover, due to biological functional equivalency considerations, some changes can be made in protein structure without affecting the biological or chemical action in kind or amount. These and other changes can be made to the disclosure in light of the detailed description. All such modifications are intended to be included within the scope of the appended claims.
Unless otherwise indicated, any nucleic acid sequences are written left to right in 5′ to 3′ orientation; amino acid sequences are written left to right in amino to carboxy orientation, respectively.
The headings provided herein are not limitations of the various aspects or embodiments of this disclosure.
As used herein, the term “capable of” when used with a verb, encompasses or means the action of the corresponding verb. For example, “capable of interacting” also means interacting, “capable of cleaving” also means cleaves, “capable of binding” also means binds and “capable of specifically targeting . . . ” also means specifically targets.
Other definitions of terms may appear throughout the specification. Before the exemplary embodiments are described in more detail, it is to be understood that this disclosure is not limited to particular embodiments described, and as such may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present disclosure will be defined only by the appended claims.
Numeric ranges are inclusive of the numbers defining the range. Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limits of that range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is encompassed within this disclosure. The upper and lower limits of these smaller ranges may independently be included or excluded in the range, and each range where either, neither or both limits are included in the smaller ranges is also encompassed within this disclosure, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in this disclosure.
As used herein, the articles “a” and “an” may refer to one or to more than one (e.g. to at least one) of the grammatical object of the article. Further, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular. In this application, the use of “or” means “and/or” unless stated otherwise. Furthermore, the use of the term “including”, as well as other forms, such as “includes” and “included”, is not limiting.
“About” may generally mean an acceptable degree of error for the quantity measured given the nature or precision of the measurements. Exemplary degrees of error are within 20 percent (%), typically, within 10%, and more typically, within 5% of a given value or range of values. Preferably, the term “about” shall be understood herein as plus or minus (±) 5%, preferably ±4%, ±3%, ±2%, ±1%, ±0.5%, ±0.1%, of the numerical value of the number with which it is being used.
The term “consisting of” refers to compositions, methods, and respective components thereof as described herein, which are exclusive of any element not recited in that description of the invention.
As used herein the term “consisting essentially of” refers to those elements required for a given invention. The term permits the presence of elements that do not materially affect the basic and novel or functional characteristic(s) of that invention (i.e. inactive or non-immunogenic ingredients).
Embodiments described herein as “comprising” one or more features may also be considered as disclosure of the corresponding embodiments “consisting of” and/or “consisting essentially of” such features.
Concentrations, amounts, volumes, percentages and other numerical values may be presented herein in a range format. It is also to be understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited.
As used herein, the terms “vector”, “retroviral vector” and “retroviral F/HN vector” are used interchangeably to mean a retroviral vector comprising a retroviral RNA sequence and pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus, unless otherwise stated. The terms “lentiviral vector” and “lentiviral F/HN vector” are used interchangeably to mean a lentiviral vector pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus, unless otherwise stated. All disclosure herein in relation to retroviral vectors of the invention applies equally and without reservation to lentiviral vectors of the invention and to SIV vectors that are pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus (also referred to herein as SIV F/HN or SIV-FHN).
As defined herein, the term “retroviral RNA sequence” refers to the nucleic acid molecule that is contained within a retroviral vector. A retroviral RNA sequence comprises long terminal repeat (LTR) elements, nucleic acid sequences necessary for incorporation of the retroviral RNA sequence into retroviral particles, and the transgene expression cassette. The transgene expression cassette is comprised of a suitable enhancer/promoter element, the transgene cDNA and a posttranscriptional regulatory element. The retroviral RNA sequence essentially starts with a 5′ LTR R sequence and essentially ends with a 3′ LTR R sequence. The 5′ region retroviral RNA sequence typically comprises or consists of a retroviral LTR R sequence followed by a retroviral LTR U5 sequence (in 5′ to 3′ order). The 3′ region retroviral RNA sequence typically comprises or consists of a retroviral LTR U3 sequence followed by a retroviral LTR R sequence (in 5′ to 3′ order).
The terms “DNA provirus” or “DNA provirus sequence” and “DNA proviral sequence” refer interchangeably to the DNA sequence which is integrated into the genome of cells transduced with the retrovirus. The DNA provirus sequence contains additional regions of nucleic acid that are not found within the retroviral RNA sequence, including a 5′ LTR U3 sequence and a 3′ LTR U5 sequence. Therefore, the sequences of the DNA provirus and the retroviral RNA sequence are not identical, but rather the sequence of the retroviral RNA sequence is shorter than the proviral DNA sequence from which it is derived. The precise 5′ and 3′ limits of the retroviral RNA sequence compared with the proviral DNA sequence from which it is derived cannot readily and reliably be determined by simple analysis of the proviral DNA sequence.
The retroviral vectors of the invention comprise codon-substituted retroviral RNA sequences. One of ordinary skill in the art will appreciate that codon substitution is a technique to impart advantageous properties on the resulting retroviral RNA sequence, for example, to reduce retroviral ORF length, and/or maximise protein expression. For example, codon substitution includes methods to reduce the length of retroviral ORFs and hence reduce the length of any encoded retroviral (poly)peptides, and/or to increase the translational efficiency of an encoding gene. Translational efficiency may be increased by modification of the nucleic acid sequence. Codon substitution is routine in the art, and it is within the routine practice of one of ordinary skill to devise a codon-substituted version of a given nucleic acid sequence. However, what is not straightforward is predicting the effect of codon substitution on other parameters. By way of non-limiting example, as described herein, conventional wisdom teaches that under normal manufacturing conditions, codon-substitution can decrease vector yield and/or transgene expression.
In addition to codon substitution, the retroviral RNA sequences of the invention additionally comprise modifications to reduce the number of retroviral open reading frames (ORFs). One of ordinary skill in the art appreciates that an open reading frame is a span of DNA or RNA sequence between a start and a stop codon. ORFs can be readily identified using standard techniques known in the art, such as by using software tools such as ORFfinder (ORffinder Home—NCBI (nih.gov)) from the NIH. Standard methods for testing the effect of ORFs on, e.g. vector yield and/or transgene expression are also within the routine skill of one of ordinary skill in the art and exemplary methods are described herein. A retroviral ORF is an ORF that is present in the (unmodified) retroviral RNA sequence that could potentially be expressed in a patient to give rise to a retroviral protein. Partially or fully overlapping ORFs often occur on the same nucleic acid strand. Further, competing ORFs are commonly present on different nucleic acid strands. Following administration of a retroviral vector, expression of one or more retroviral open reading frames (ORFs) to produce a retroviral protein may theoretically trigger an immune response. Specifically, in this context, the terms “ORF reduction”, “ORF elimination” and “ORF disruption” refer interchangeably to the removal of open reading frames, i.e. decreasing the number of ORFs that are translated to express a retroviral protein, peptide or polypeptide sequence. This can be achieved by any appropriate technique, for example, by the deletion of the start codon (otherwise known as an initiation codon) of said ORF. Alternatively, the nucleotides in said start codon may be substituted, or one or more additional nucleotides added to disrupt the start codon. One of ordinary skill in the art will further appreciate that the start codon in a retroviral RNA sequence is AUG. The start codon in the DNA sequence of the corresponding provirus is ATG.
STOP codons signal the termination of translation. One of ordinary skill in the art will appreciate that the standard STOP codons in a retroviral RNA sequence may be selected from UAG, UAA and UGA. Standard STOP codons in the DNA sequence of the corresponding provirus are TAG, TAA and TGA.
The retroviral vectors of the invention may additionally comprise codon-optimised retroviral RNA sequences. One of ordinary skill in the art will appreciate that codon optimisation is a technique to maximise protein expression. For example, codon optimisation can increase the translational efficiency of an encoding gene. Translational efficiency may be increased by modification of the nucleic acid sequence. Codon optimisation is routine in the art, and it is within the routine practice of one of ordinary skill to devise a codon-optimised version of a given nucleic acid sequence. However, what is not straightforward is predicting the effect of codon optimisation on other parameters. By way of non-limiting example, as described herein, conventional wisdom teaches that under normal manufacturing conditions, codon-optimisation of the gag-pol genes typically decreases vector yield.
As used herein, the terms “titre” and “yield” are used interchangeably to mean the amount of lentiviral (e.g. SIV) vector produced by a method of the invention. Titre is the primary benchmark characterising manufacturing efficiency, with higher titres generally indicating that more retroviral/lentiviral (e.g. SIV) vector is manufactured (e.g. using the same amount of reagents). Titre or yield may relate to the number of vector genomes that have integrated into the genome of a target cell (integration titre), which is a measure of “active” virus particles, i.e. the number of particles capable of transducing a cell. Transducing units (TU/mL also referred to as TTU/mL) is a biological readout of the number of host cells that get transduced under certain tissue culture/virus dilutions conditions, and is a measure of the number of “active” virus particles. The total number of (active+inactive) virus particles may also be determined using any appropriate means, such as by measuring either how much Gag is present in the test solution or how many copies of viral RNA are in the test solution. Assumptions are then made that a lentivirus particle contains either 2000 Gag molecules or 2 viral RNA molecules. Once total particle number and a transducing titre/TU have been measured, a particle:infectivity ratio calculated. Amino acids are referred to herein using the name of the amino acid, the three-letter abbreviation or the single letter abbreviation.
As used herein, the terms “protein” and “polypeptide” are used interchangeably herein to designate a series of amino acid residues, connected to each other by peptide bonds between the alpha-amino and carboxyl groups of adjacent residues. The terms “protein”, and “polypeptide” refer to a polymer of amino acids, including modified amino acids (e.g., phosphorylated, glycated, glycosylated, etc.) and amino acid analogues, regardless of its size or function. “Protein” and “polypeptide” are often used in reference to relatively large polypeptides, whereas the term “peptide” is often used in reference to small polypeptides, but usage of these terms in the art overlaps. The terms “protein” and “polypeptide” are used interchangeably herein when referring to a gene product and fragments thereof. Thus, exemplary polypeptides or proteins include gene products, naturally occurring proteins, homologs, orthologs, paralogs, fragments and other equivalents, variants, fragments, and analogues of the foregoing.
As used herein, the terms “polynucleotides”, “nucleic acid” and “nucleic acid sequence” refers to any molecule, preferably a polymeric molecule, incorporating units of ribonucleic acid, deoxyribonucleic acid or an analogue thereof. The nucleic acid can be either single-stranded or double-stranded. A single-stranded nucleic acid can be one nucleic acid strand of a denatured double-stranded DNA Alternatively, it can be a single-stranded nucleic acid not derived from any double-stranded DNA. In one aspect, the nucleic acid can be DNA. In another aspect, the nucleic acid can be RNA Suitable nucleic acid molecules are DNA, including genomic DNA or cDNA. Other suitable nucleic acid molecules are RNA, including siRNA, shRNA, and antisense oligonucleotides. The terms “transgene” and “gene” are also used interchangeably and both terms encompass fragments or variants thereof encoding the target protein.
The transgenes of the present invention include nucleic acid sequences that have been removed from their naturally occurring environment, recombinant or cloned DNA isolates, and chemically synthesized analogues or analogues biologically synthesized by heterologous systems.
Minor variations in the amino acid sequences of the invention are contemplated as being encompassed by the present invention, providing that the variations in the amino acid sequence(s) maintain at least 60%, at least 70%, more preferably at least 80%, at least 85%, at least 90%, at least 95%, and most preferably at least 97% or at least 99% sequence identity to the amino acid sequence of the invention or a fragment thereof as defined anywhere herein. The term homology is used herein to mean identity. As such, the sequence of a variant or analogue sequence of an amino acid sequence of the invention may differ on the basis of substitution (typically conservative substitution) deletion or insertion. Proteins comprising such variations are referred to herein as variants.
Proteins of the invention may include variants in which amino acid residues from one species are substituted for the corresponding residue in another species, either at the conserved or non-conserved positions. Variants of protein molecules disclosed herein may be produced and used in the present invention. Following the lead of computational chemistry in applying multivariate data analysis techniques to the structure/property-activity relationships [see for example, Wold, et al. Multivariate data analysis in chemistry. Chemometrics-Mathematics and Statistics in Chemistry (Ed.: B. Kowalski); D. Reidel Publishing Company, Dordrecht, Holland, 1984 (ISBN 90-277-1846-6] quantitative activity-property relationships of proteins can be derived using well-known mathematical techniques, such as statistical regression, pattern recognition and classification [see for example Norman et al. Applied Regression Analysis. Wiley-Interscience; 3rd edition (April 1998) ISBN: 0471170828; Kandel, Abraham et al. Computer-Assisted Reasoning in Cluster Analysis. Prentice Hall PTR, (May 11, 1995), ISBN: 0133418847; Krzanowski, Wojtek. Principles of Multivariate Analysis: A User's Perspective (Oxford Statistical Science Series, No 22 (Paper)). Oxford University Press; (December 2000), ISBN: 0198507089; Witten, Ian H. et al Data Mining: Practical Machine Learning Tools and Techniques with Java Implementations. Morgan Kaufmann; (Oct. 11, 1999), ISBN:1558605525; Denison David G. T. (Editor) et al Bayesian Methods for Nonlinear Classification and Regression (Wiley Series in Probability and Statistics). John Wiley & Sons; (July 2002), ISBN: 0471490369; Ghose, Arup K. et al. Combinatorial Library Design and Evaluation Principles, Software, Tools, and Applications in Drug Discovery. ISBN: 0-8247-0487-8]. The properties of proteins can be derived from empirical and theoretical models (for example, analysis of likely contact residues or calculated physicochemical property) of proteins sequence, functional and three-dimensional structures and these properties can be considered individually and in combination.
Amino acids are referred to herein using the name of the amino acid, the three-letter abbreviation or the single letter abbreviation. The term “protein”, as used herein, includes proteins, polypeptides, and peptides. As used herein, the term “amino acid sequence” is synonymous with the term “polypeptide” and/or the term “protein”. In some instances, the term “amino acid sequence” is synonymous with the term “peptide”. The terms “protein” and “polypeptide” are used interchangeably herein. In the present disclosure and claims, the conventional one-letter and three-letter codes for amino acid residues may be used. The 3-letter code for amino acids as defined in conformity with the IUPACIUB Joint Commission on Biochemical Nomenclature (JCBN). It is also understood that a polypeptide may be coded for by more than one nucleotide sequence due to the degeneracy of the genetic code.
Amino acid residues at non-conserved positions may be substituted with conservative or non-conservative residues. In particular, conservative amino acid replacements are contemplated.
A “conservative amino acid substitution” is one in which the amino acid residue is replaced with an amino acid residue having a similar side chain. Families of amino acid residues having similar side chains have been defined in the art, including basic side chains (e.g., lysine, arginine, or histidine), acidic side chains (e.g., aspartic acid or glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, or cysteine), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, or tryptophan), beta-branched side chains (e.g., threonine, valine, isoleucine) and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, or histidine). Thus, if an amino acid in a polypeptide is replaced with another amino acid from the same side chain family, the amino acid substitution is considered to be conservative. The inclusion of conservatively modified variants in a protein of the invention does not exclude other forms of variant, for example polymorphic variants, interspecies homologs, and alleles.
“Non-conservative amino acid substitutions” include those in which (i) a residue having an electropositive side chain (e.g., Arg, His or Lys) is substituted for, or by, an electronegative residue (e.g., Glu or Asp), (ii) a hydrophilic residue (e.g., Ser or Thr) is substituted for, or by, a hydrophobic residue (e.g., Ala, Leu, lie, Phe or Val), (iii) a cysteine or proline is substituted for, or by, any other residue, or (iv) a residue having a bulky hydrophobic or aromatic side chain (e.g., Val, His, Ile or Trp) is substituted for, or by, one having a smaller side chain (e.g., Ala or Ser) or no side chain (e.g., Gly).
“Insertions” or “deletions” are typically in the range of about 1, 2, or 3 amino acids. The variation allowed may be experimentally determined by systematically introducing insertions or deletions of amino acids in a protein using recombinant DNA techniques and assaying the resulting recombinant variants for activity. This does not require more than routine experiments for a skilled person.
A “fragment” of a polypeptide comprises at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 97% or more of the original polypeptide.
The polynucleotides of the present invention may be prepared by any means known in the art. For example, large amounts of the polynucleotides may be produced by replication in a suitable host cell. The natural or synthetic DNA fragments coding for a desired fragment will be incorporated into recombinant nucleic acid constructs, typically DNA constructs, capable of introduction into and replication in a prokaryotic or eukaryotic cell. Usually the DNA constructs will be suitable for autonomous replication in a unicellular host, such as yeast or bacteria, but may also be intended for introduction to and integration within the genome of a cultured insect, mammalian, plant or other eukaryotic cell lines.
The polynucleotides of the present invention may also be produced by chemical synthesis, e.g. by the phosphoramidite method or the tri-ester method, and may be performed on commercial automated oligonucleotide synthesizers. A double-stranded fragment may be obtained from the single stranded product of chemical synthesis either by synthesizing the complementary strand and annealing the strand together under appropriate conditions or by adding the complementary strand using DNA polymerase with an appropriate primer sequence.
When applied to a nucleic acid sequence, the term “isolated” in the context of the present invention denotes that the polynucleotide sequence has been removed from its natural genetic milieu and is thus free of other extraneous or unwanted coding sequences (but may include naturally occurring 5′ and 3′ untranslated regions such as promoters and terminators), and is in a form suitable for use within genetically engineered protein production systems. Such isolated molecules are those that are separated from their natural environment.
In view of the degeneracy of the genetic code, considerable sequence variation is possible among the polynucleotides of the present invention. Degenerate codons encompassing all possible codons for a given amino acid are set forth below:
One of ordinary skill in the art will appreciate that flexibility exists when determining a degenerate codon, representative of all possible codons encoding each amino acid. For example, some polynucleotides encompassed by the degenerate sequence may encode variant amino acid sequences, but one of ordinary skill in the art can easily identify such variant sequences by reference to the amino acid sequences of the present invention.
A “variant” nucleic acid sequence has substantial homology or substantial similarity to a reference nucleic acid sequence (or a fragment thereof). A nucleic acid sequence or fragment thereof is “substantially homologous” (or “substantially identical”) to a reference sequence if, when optimally aligned (with appropriate nucleotide insertions or deletions) with the other nucleic acid (or its complementary strand), there is nucleotide sequence identity in at least about 70%, 75%, 80%, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or more % of the nucleotide bases. Methods for homology determination of nucleic acid sequences are known in the art.
Alternatively, a “variant” nucleic acid sequence is substantially homologous with (or substantially identical to) a reference sequence (or a fragment thereof) if the “variant” and the reference sequence they are capable of hybridizing under stringent (e.g. highly stringent) hybridization conditions. Nucleic acid sequence hybridization will be affected by such conditions as salt concentration (e.g. NaCl), temperature, or organic solvents, in addition to the base composition, length of the complementary strands, and the number of nucleotide base mismatches between the hybridizing nucleic acids, as will be readily appreciated by those skilled in the art. Stringent temperature conditions are preferably employed, and generally include temperatures in excess of 30° C., typically in excess of 37° C. and preferably in excess of 45° C. Stringent salt conditions will ordinarily be less than 1000 mM, typically less than 500 mM, and preferably less than 200 mM. The pH is typically between 7.0 and 8.3. The combination of parameters is much more important than any single parameter.
Methods of determining nucleic acid percentage sequence identity are known in the art. By way of example, when assessing nucleic acid sequence identity, a sequence having a defined number of contiguous nucleotides may be aligned with a nucleic acid sequence (having the same number of contiguous nucleotides) from the corresponding portion of a nucleic acid sequence of the present invention. Tools known in the art for determining nucleic acid percentage sequence identity include Nucleotide BLAST (as described below).
One of ordinary skill in the art appreciates that different species exhibit “preferential codon usage”. As used herein, the term “preferential codon usage” refers to codons that are most frequently used in cells of a certain species, thus favouring one or a few representatives of the possible codons encoding each amino acid. For example, the amino acid threonine (Thr) may be encoded by ACA, ACC, ACG, or ACT, but in mammalian host cells ACC is the most commonly used codon; in other species, different codons may be preferential. Preferential codons for a particular host cell species can be introduced into the polynucleotides of the present invention by a variety of methods known in the art. Introduction of preferential codon sequences into recombinant DNA can, for example, enhance production of the protein by making protein translation more efficient within a particular cell type or species. Thus, according to the invention, in addition to the gag-pol genes any nucleic acid sequence may be codon-optimised for expression in a host or target cell. In particular, the vector genome (or corresponding plasmid), the REV gene (or corresponding plasmid), the fusion protein (F) gene (or correspond plasmid) and/or the hemagglutinin-neuraminidase (HN) gene (or corresponding plasmid, or any combination thereof may be codon-optimised.
A “fragment” of a polynucleotide of interest comprises a series of consecutive nucleotides from the sequence of said full-length polynucleotide. By way of example, a “fragment” of a polynucleotide of interest may comprise (or consist of) at least 30 consecutive nucleotides from the sequence of said polynucleotide (e.g. at least 35, 50, 75, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800 850, 900, 950 or 1000 consecutive nucleic acid residues of said polynucleotide). A fragment may include at least one antigenic determinant and/or may encode at least one antigenic epitope of the corresponding polypeptide of interest. Typically, a fragment as defined herein retains the same function as the full-length polynucleotide.
The terms “decrease”, “reduced”, “reduction”, or “inhibit” are all used herein to mean a decrease by a statistically significant amount. The terms “reduce,” “reduction” or “decrease” or “inhibit” typically means a decrease by at least 10% as compared to a reference level (e.g. the absence of a given treatment) and can include, for example, a decrease by at least about 10%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, at least about 50%, at least about 55%, at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 98%, at least about 99%, or more. As used herein, “reduction” or “inhibition” encompasses a complete inhibition or reduction as compared to a reference level. “Complete inhibition” is a 100% inhibition (i.e. abrogation) as compared to a reference level.
The terms “increased”, “increase”, “enhance”, or “activate” are all used herein to mean an increase by a statically significant amount. The terms “increased”, “increase”, “enhance”, or “activate” can mean an increase of at least 25%, at least 50% as compared to a reference level, for example an increase of at least about 50%, or at least about 75%, or at least about 80%, or at least about 90%, or at least about 100%, or at least about 150%, or at least about 200%, or at least about 250% or more compared with a reference level, or at least about a 1.5-fold, or at least about a 2-fold, or at least about a 2.5-fold, or at least about a 3-fold, or at least about a 4-fold, or at least about a 5-fold or at least about a 10-fold increase, or any increase between 1.5-fold and 10-fold or greater as compared to a reference level. In the context of a yield or titre, an “increase” is an observable or statistically significant increase in such level.
The terms “individual”, “subject”, and “patient”, are used interchangeably herein to refer to a mammalian subject for whom diagnosis, prognosis, disease monitoring, treatment, therapy, and/or therapy optimisation is desired. The mammal can be (without limitation) a human, non-human primate, mouse, rat, dog, cat, horse, or cow. In a preferred embodiment, the individual, subject, or patient is a human. An “individual” may be an adult, juvenile or infant. An “individual” may be male or female.
A “subject in need” of treatment for a particular condition can be an individual having that condition, diagnosed as having that condition, or at risk of developing that condition.
A subject can be one who has been previously diagnosed with or identified as suffering from or having a condition in need of treatment or one or more complications or symptoms related to such a condition, and optionally, have already undergone treatment for a condition as defined herein or the one or more complications or symptoms related to said condition. Alternatively, a subject can also be one who has not been previously diagnosed as having a condition as defined herein or one or more or symptoms or complications related to said condition. For example, a subject can be one who exhibits one or more risk factors for a condition, or one or more or symptoms or complications related to said condition or a subject who does not exhibit risk factors.
As used herein, the term “healthy individual” refers to an individual or group of individuals who are in a healthy state, e.g. individuals who have not shown any symptoms of the disease, have not been diagnosed with the disease and/or are not likely to develop the disease e.g. cystic fibrosis (CF) or any other disease described herein). Preferably said healthy individual(s) is not on medication affecting CF and has not been diagnosed with any other disease. The one or more healthy individuals may have a similar sex, age, and/or body mass index (BMI) as compared with the test individual. Application of standard statistical methods used in medicine permits determination of normal levels of expression in healthy individuals, and significant deviations from such normal levels.
Herein the terms “control” and “reference population” are used interchangeably.
The term “pharmaceutically acceptable” as used herein means approved by a regulatory agency of the Federal or a state government, or listed in the U.S. Pharmacopeia, European Pharmacopeia or other generally recognized pharmacopeia
The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that such publications constitute prior art to the claims appended hereto.
Disclosure related to the various methods of the invention are intended to be applied equally to other methods, therapeutic uses or methods, the data storage medium or device, the computer program product, and vice versa.
The invention relates to a retroviral/lentiviral (e.g. SIV) vector. The term “retrovirus” refers to any member of the Retroviridae family of RNA viruses that encode the enzyme reverse transcriptase. The term “lentivirus” refers to a family of retroviruses. Examples of retroviruses suitable for use in the present invention include gamma retroviruses such as murine leukaemia virus (MLV) and feline leukaemia virus (FLV). Examples of lentiviruses suitable for use in the present invention include Simian immunodeficiency virus (SIV), Human immunodeficiency virus (HIV), Feline immunodeficiency virus (FIV), Equine infectious anaemia virus (EIAV), and Visna/maedi virus. Preferably the invention relates to lentiviral vectors and the production thereof. A particularly preferred lentiviral vector is an SIV vector (including all strains and subtypes), such as a SIV-AGM (originally isolated from African green monkeys, Cercopithecus aethiops). Alternatively the invention relates to HIV vectors.
The retroviral/lentiviral (e.g. SIV) vectors of the invention are typically pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus. Preferably the respiratory paramyxovirus is a Sendai virus (murine parainfluenza virus type 1).
The F protein may be a truncated F protein, typically one in which the cytoplasmic domain is truncated. Preferably the truncated F protein is Fct4, in which 38 amino acids have been truncated from the C-terminus of the F protein, with 4 amino acids of the F protein cytoplasmic domain being retained. Thus, the F protein may comprise or consist of an Fct4 amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 12 or 13. Preferably the F protein may comprise or consist of an Fct4 amino acid sequence having at least 90%, at least 95%, or at least 99% identity to SEQ ID NO: 12 or 13.
The full length F protein, or C-terminally truncated form thereof (e.g. Fct4) is typically fusion inactive. The fusion inactive form of the F protein may be cleaved to produce two subunits, a first subunit, (also known as F2) and a second subunit (also known as F1).
The first subunit of the F protein may comprise or consist of an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 14. Preferably the first subunit may be a subunit which may comprises or consists of an amino acid sequence having at least 90%, at least 95%, or at least 99% identity to SEQ ID NO: 14. SEQ ID NO: 14 is the first subunit of Fct4.
Alternatively or in addition, preferably in addition, the second subunit of the F protein may comprise or consist of an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 15. Preferably the second subunit may be a subunit which may comprises or consists of an amino acid sequence having at least 90%, at least 95%, or at least 99% identity to SEQ ID NO: 15. SEQ ID NO: 15 is the second subunit of Fct4.
The F protein (e.g. Fct4) may comprise an N-terminal signal peptide. Alternatively, the F protein may lack such a signal peptide. The F protein signal peptide may comprise or consist of an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 16. This signal peptide may be cleaved to form the mature F protein. The signal peptide of Fct4 is SEQ ID NO: 16, which forms amino acid residues 1-25 of SEQ ID NO: 13. Thus, the mature form of Fct4 may comprise or consist of an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to amino acid residues 26-527 of SEQ ID NO: 13.
Within exemplary F protein plasmid (pDNA3a), pGM301, there is a potential alternative start codon upstream to the start codon where translation initiates to produce the Fct4 of SEQ ID NO: 12 and 13. However, according to the present invention, the F protein of the retroviral/lentiviral (e.g. SIV) vectors of the invention, does not comprise an additional amino acid sequence N-terminal to the methionine of position 1 in SEQ ID NO: 13. In particular, the F protein of the retroviral/lentiviral (e.g. SIV) vectors of the invention, typically does not comprise one or more amino acids corresponding to those encoded by bases 1645-1734 of pGM301 (SEQ ID NO: 23), which are translated as MFMPSSFSYSSWATCWLLCCLIILAKNSIA (SEQ ID NO: 46), N-terminal to the methionine of position 1 in SEQ ID NO: 13.
The HN protein may be a truncated and/or chimeric HN protein, typically one in which the cytoplasmic domain is truncated or substituted. Preferably, the HN protein is a chimeric HN protein in which (i) the cytoplasmic domain of the HN is replaced by the cytoplasmic domain of the transmembrane (TMP) protein; or (ii) the cytoplasmic domain of the TMP is added to the cytoplasmic domain of the HN protein. The HN protein may be as described in Kobayashi et al. (J. Virol. (2003) 77(4):2607-2614), which is herein incorporated by reference in its entirety.
The F/HN pseudotyping is particularly efficient at targeting cells in the airway epithelium, and as such, for therapeutic applications it is typically delivered to cells of the respiratory tract, including the cells of the airway epithelium. Accordingly, the retroviral/lentiviral (e.g. SIV) vectors of the invention are particularly suited for treatment of diseases or disorders of the airways, respiratory tract, or lung. Typically, the retroviral/lentiviral (e.g. SIV) vectors may be used for the treatment of a genetic respiratory disease.
The retroviral/lentiviral (e.g. SIV) vectors of the present invention may be pseudotyped with proteins from another virus, provided that the combination of the modified retroviral/lentiviral (e.g. SIV) RNA sequence and/or the use of codon-optimised gag-pol genes (e.g. from SIV) does not negatively impact the manufactured titre of the vector (or even results in an increased titre of the vector) and/or transgene expression (or even results in increased transgene expression). Non-limiting examples of other proteins that may be used to pseudotype retroviral/lentiviral (e.g. SIV) vectors of the present invention include G glycoprotein from Vesicular Stomatitis Virus (G-VSV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein or modified forms thereof; such as those described in UK Patent Application Nos. 2118685.3 and 2105278.2, each of which is herein incorporated by reference in its entirety.
The retroviral/lentiviral (e.g. SIV) vector of the invention further comprises Gag, Pol and/or GagPol. Typically the Gag, Pol and/or GagPol is from the desired retroviral/lentiviral (e.g. SIV) vector. By way of non-limiting example, if the retroviral vector of the invention is SIV, then typically the Gag, Pol and/or GagPol are from SIV.
The Gag, Pol and/or GagPol sequences may be codon-optimised. The inventors have previously shown that the manufactured titre of a retroviral vector comprising codon-optimised Gag protein, Pol protein and/or GagPol polyprotein from SIV is unexpectedly not negatively impacted (see International Application No. PCT/GB2022/050524, which is herein incorporated by reference in its entirety). In fact, the inventors have previously shown that the manufactured titre of a retroviral vector pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus and comprising codon-optimised Gag, Pol and/or GagPol from SIV can even be increased. This benefit of maintained/improved retroviral/lentiviral (e.g. SIV) vector yield can be combined with the benefit of the present invention in terms of providing retroviral/lentiviral (e.g. SIV) vectors with maintained/increased transgene expression and/or maintained/increased retroviral/lentiviral (e.g. SIV) RNA sequence integration, whilst addressing the potential safety risks and improving the safety profile of the retroviral/lentiviral (e.g. SIV) vectors as described herein.
In the context of Gag, Pol and/or GagPol, codon optimisation is a technique to maximise protein expression by increasing the translational efficiency of the encoding gene. Translational efficiency is increased by modification of the nucleic acid sequence. Codon optimisation is routine in the art, and it is within the routine practice of one of ordinary skill to devise a codon-optimised version of a given nucleic acid sequence. However, what is not straightforward is predicting the effect of codon optimisation on other parameters. For example, as described herein, conventional wisdom teaches that under normal manufacturing conditions (when the vector genome plasmid, rather than the gag-pol genes, is limiting), codon-optimisation of the gag-pol genes typically decreases vector yield.
The retroviral/lentiviral (e.g. SIV) vectors of the invention may comprise a codon-optimised Gag protein, a codon-optimised Pol protein, a codon-optimised GagPol polyprotein, or a combination thereof. Accordingly, the invention provides a retroviral/lentiviral (e.g. SIV) vector comprising a codon-optimised Gag protein comprising or consisting of an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% sequence identity to SEQ ID NO: 9. Preferably, the invention provides a retroviral vector comprising a codon-optimised Gag protein comprising or consisting of an amino acid sequence having at least 90%, at least 95%, or at least 99% identity to SEQ ID NO: 9. The invention provides a retroviral vector comprising a codon-optimised Pol protein comprising or consisting of an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% sequence identity to SEQ ID NO: 10. Preferably, the invention provides a retroviral vector comprising a codon-optimised Pol protein comprising or consisting of an amino acid sequence having a at least 90%, at least 95%, or at least 99% sequence identity to SEQ ID NO: 10.
GagPol is expressed as polyprotein which is processed to produce a number of smaller proteins within viral particles. The extent of processing, and hence the presence and/or concentration of GagPol or any of the constituent proteins within a retroviral/lentiviral (e.g. SIV) vector of the invention may vary with time.
Accordingly, a retroviral/lentiviral (e.g. SIV) vector of the invention may comprise one or more of a p17 protein, a p27 protein, a p8 protein, a protease, a p51 protein, a p15 protein and a p31 protein. One or more of these proteins may be present in combination with Gag, Pol and/or GagPol. Preferably, the invention provides a retroviral vector comprising a p17 protein, a p27 protein, a p8 protein, a protease, a p51 protein, a p15 protein and a p31 protein. Again, these proteins may be present in combination with Gag, Pol and/or GagPol.
The p17 protein may comprise or consist of an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% sequence identity to SEQ ID NO: 2. Preferably, the p17 protein comprises or consists of an amino acid sequence having at least 90%, at least 95%, or at least 99% sequence identity to SEQ ID NO:2.
The p24 protein may comprise or consist of an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% sequence identity to SEQ ID NO: 3. Preferably, the p24 protein comprises or consists of an amino acid sequence having at least 90%, at least 95%, or at least 99% sequence identity to SEQ ID NO: 3.
The p8 protein may comprise or consist of an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% sequence identity to SEQ ID NO: 4. Preferably, the p8 protein comprises or consists of an amino acid sequence having at least 90%, at least 95%, or at least 99% sequence identity to SEQ ID NO: 4.
The protease may comprise or consist of an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% sequence identity to SEQ ID NO: 5. Preferably, the protease comprises or consists of an amino acid sequence having at least 90%, at least 95%, or at least 99% sequence identity to SEQ ID NO: 5.
The p51 protein may comprise or consist of an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% sequence identity to SEQ ID NO: 6. Preferably, the p51 protein comprises or consists of an amino acid sequence having at least 90%, at least 95%, or at least 99% sequence identity to SEQ ID NO: 6.
The p15 protein may comprise or consist of an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% sequence identity to SEQ ID NO: 7. Preferably, the p15 protein comprises or consists of an amino acid sequence having at least 90%, at least 95%, or at least 99% sequence identity to SEQ ID NO: 7.
The p31 protein may comprise or consist of an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% sequence identity to SEQ ID NO: 8. Preferably, the p31 protein comprises or consists of an amino acid sequence having at least 90%, at least 95%, or at least 99% sequence identity to SEQ ID NO: 8.
Retroviral/lentiviral (e.g. SIV) vectors of the invention may comprise a p17 protein comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 2 (as described above), a p24 protein comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 3 (as described above), a p8 protein comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 4 (as described above), a protease comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 5 (as described above), a p51 protein comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 6 (as described above), a p15 protein comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 7 (as described above), and a p31 protein comprising or consisting of an amino acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% sequence identity to SEQ ID NO: 8 (as described above).
A retroviral/lentiviral (e.g. SIV) vector according to the invention may be integrase-competent (IC). Alternatively, the retroviral/lentiviral (e.g. SIV) vector may be integrase-deficient (ID).
Retroviral/lentiviral (e.g. SIV) vectors, such as those of the invention, can integrate into the genome of transduced cells and lead to long-lasting expression, making them suitable for transduction of stem/progenitor cells. In the lung, several cell types with regenerative capacity have been identified as responsible for maintaining specific cell lineages in the conducting airways and alveoli. These include basal cells and submucosal gland duct cells in the upper airways, club cells and neuroendocrine cells in the bronchiolar airways, bronchioalveolar stem cells in the terminal bronchioles and type II pneumocytes in the alveoli. Therefore, and without being bound by theory, it is believed that said retroviral/lentiviral (e.g. SIV) vectors bring about long term gene expression of the transgene of interest by introducing the transgene into one or more long-lived airway epithelial cells or cell types, such as basal cells and submucosal gland duct cells in the upper airways, club cells and neuroendocrine cells in the bronchiolar airways, bronchioalveolar stem cells in the terminal bronchioles and type II pneumocytes in the alveoli. As demonstrated herein, the integration of retroviral/lentiviral (e.g. SIV) vectors with modified retroviral/lentiviral (e.g. SIV) RNA sequences of the invention into target cell genomes is unexpectedly not negatively impacted, and in fact may even be increased.
Accordingly, the retroviral/lentiviral (e.g. SIV) vectors of the invention may transduce one or more cells or cell lines with regenerative potential within the lung (including the airways and respiratory tract) to achieve long term gene expression. For example, the retroviral/lentiviral (e.g. SIV) vectors may transduce basal cells, such as those in the upper airways/respiratory tract. Basal cells have a central role in processes of epithelial maintenance and repair following injury. In addition, basal cells are widely distributed along the human respiratory epithelium, with a relative distribution ranging from 30% (larger airways) to 6% (smaller airways).
The retroviral/lentiviral (e.g. SIV) vectors of the invention may be used to transduce isolated and expanded stem/progenitor cells ex vivo prior administration to a patient. Preferably, the retroviral/lentiviral (e.g. SIV) vectors of the invention are used to transduce cells within the lung (or airways/respiratory tract) in vivo.
The retroviral/lentiviral (e.g. SIV) vectors of the invention demonstrate remarkable resistance to shear forces with only modest reduction in transduction ability when passaged through clinically-relevant delivery devices such as bronchoscopes, spray bottles and nebulisers.
The retroviral/lentiviral (e.g. SIV) vectors of the present invention enable high levels of transgene expression, resulting in high levels (therapeutic levels) of expression of a therapeutic protein. The retroviral/lentiviral (e.g. SIV) vectors of the present invention typically provide high expression levels of a transgene when administered to a patient. The terms high expression and therapeutic expression are used interchangeably herein. Expression may be measured by any appropriate method (qualitative or quantitative, preferably quantitative), and concentrations given in any appropriate unit of measurement, for example ng/ml or nM.
Expression of a transgene of interest may be given relative to the expression of the corresponding endogenous (defective) gene in a patient. Expression may be measured in terms of mRNA or protein expression. The expression of the transgene of the invention, such as a functional CFTR gene, may be quantified relative to the endogenous gene, such as the endogenous (dysfunctional) CFTR genes in terms of mRNA copies per cell or any other appropriate unit.
Expression levels of a transgene and/or the encoded therapeutic protein of the invention may be measured in the lung tissue, epithelial lining fluid and/or serum/plasma as appropriate. A high and/or therapeutic expression level may therefore refer to the concentration in the lung, epithelial lining fluid and/or serum/plasma.
The retroviral/lentiviral (e.g. SIV) vectors of the invention exhibit efficient airway cell uptake, enhanced transgene expression, and suffer no loss of efficacy upon repeated administration. Accordingly, the retroviral/lentiviral (e.g. SIV) vectors of the invention are capable of producing long-lasting, repeatable, high-level expression in airway cells without inducing an undue immune response.
The retroviral/lentiviral (e.g. SIV) vectors of the present invention enable long-term transgene expression, resulting in long-term expression of a therapeutic protein. As described herein, the phrases “long-term expression”, “sustained expression”, “long-lasting expression” and “persistent expression” are used interchangeably. Long-term expression according to the present invention means expression of a therapeutic gene and/or protein, preferably at therapeutic levels, for at least 45 days, at least 60 days, at least 90 days, at least 120 days, at least 180 days, at least 250 days, at least 360 days, at least 450 days, at least 730 days or more. Preferably long-term expression means expression for at least 90 days, at least 120 days, at least 180 days, at least 250 days, at least 360 days, at least 450 days, at least 720 days or more, more preferably at least 360 days, at least 450 days, at least 720 days or more. This long-term expression may be achieved by repeated doses or by a single dose.
Repeated doses may be administered twice-daily, daily, twice-weekly, weekly, monthly, every two months, every three months, every four months, every six months, yearly, every two years, or more. Dosing may be continued for as long as required, for example, for at least six months, at least one year, two years, three years, four years, five years, ten years, fifteen years, twenty years, or more, up to for the lifetime of the patient to be treated.
Preferably, the invention relates to F/HN retroviral/lentiviral vectors comprising a promoter and a transgene, particularly SIV F/HN vectors.
Each retroviral vector particle comprises a retroviral RNA sequence. The retroviral RNA sequence comprises the LTR elements, sequences necessary for incorporation into particles, along with the transgene expression cassette. By way of non-limiting example, the retroviral RNA sequence may comprise or consist of retroviral LTR elements (typically R and U5 (read 5′ to 3′) at the 5′ end of the sequence, and U3 and R (read 5′ to 3′) at the 3′ end of the sequence), retroviral sequences necessary for incorporation into retroviral particles, along with the transgene expression cassette. The transgene expression cassette is typically comprised of a suitable enhancer/promoter element, the transgene cDNA and a posttranscriptional regulatory element. Particularly preferred is a retroviral RNA sequence which comprises SIV LTR elements, sequences necessary for incorporation into particles, along with the transgene expression cassette. By way of non-limiting example, a SIV RNA sequence may comprise or consist of SIV LTR elements (typically R and U5 (read 5′ to 3′) at the 5′ end of the sequence, and U3 and R (read 5′ to 3′) at the 3′ end of the sequence), SIV sequences necessary for incorporation into retroviral particles, along with the transgene expression cassette.
A retroviral or lentiviral RNA sequence of the invention is modified compared with the unmodified retroviral or lentiviral RNA sequence from which it is derived. Modification of the retroviral or lentiviral RNA sequence may provide advantageous properties compared with the retroviral or lentiviral RNA sequence from which it is derived. Non-limiting examples of such advantageous properties include maintained/increased transgene expression, maintained/increased retroviral/lentiviral (e.g. SIV) RNA sequence integration into a target/host cell genome, maintained/increased vector yield and/or improved patient safety compared with the unmodified retroviral or lentiviral RNA sequence from which it is derived.
The modified retroviral or lentiviral RNA sequence of the invention may be codon-substituted and/or comprise a reduced number of retroviral or lentiviral ORFs compared with the retroviral or lentiviral RNA sequence from which it is derived. For example, a modified retroviral or lentiviral RNA sequence of the invention may comprise a reduced number of retroviral or lentiviral ORFs compared with the retroviral or lentiviral RNA sequence from which it is derived. Typically the modified retroviral or lentiviral RNA sequence of the invention is codon-substituted and comprises reduced number of retroviral or lentiviral ORFs compared with the retroviral or lentiviral RNA sequence from which it is derived.
Codon-substitution of the retroviral or lentiviral RNA sequence may comprise, for example, the introduction of STOP codons and/or the introduction and/or removal of restriction enzyme cleavage sites. At least 1, at least 2, at least 3, at least 4, at least 5 or more codons may be substituted in a modified retroviral or lentiviral genome of the invention. For each codon that is substituted, the nature of the modification may independently be selected from for example, the introduction of STOP codons and/or the introduction and/or removal of restriction enzyme cleavage sites. Standard techniques for codon-substituting the retroviral or lentiviral RNA sequence in this way are known in the art. Preferably the modified retroviral/lentiviral (e.g. SIV) RNA sequence includes one or more codon-substitution to introduce a STOP codon. The introduction of a STOP codon may comprise the introduction of a frameshift.
The introduction of STOP codons can result in the early termination of translation, resulting in ORFs of reduced length compared to the corresponding unmodified ORF in which a STOP sequence has not been introduced. Thus, according to the invention a retroviral or lentiviral RNA sequence is typically modified to introduce one or more STOP codon and thus reduce the length of one or more ORF. For example, the length of one or more ORF may be reduced by the introduction of a UAG, UAA or UGA codon in the retroviral RNA sequence (or TAG, TAA or TGA codon in the pro-retroviral DNA sequence). As described herein, STOP codons may be removed by deletion or substitution of nucleotides within the retroviral RNA sequence or corresponding pro-retroviral DNA sequence to result in a STOP codon, or by the addition of one or more (e.g. 1, 2 or 3) nucleotides to introduce a STOP codon. Preferably the retroviral or lentiviral RNA sequence is modified to reduce the length of one or more retroviral or lentiviral ORF. Reducing the length of one or more retroviral or lentiviral ORF has the potential to improve the safety of the retroviral or lentiviral vector when administered to a subject. Thus, a retroviral or lentiviral vector of the invention comprising a modified retroviral or lentiviral RNA sequence may have an improved safety profile compared with a retroviral or lentiviral vector comprising the non-modified retroviral or lentiviral RNA sequence from which the modified retroviral or lentiviral RNA sequence is derived. By way of non-limiting example, reducing the length of one or more retroviral or lentiviral ORF reduces the risk of an immune response being triggered by expression of the longer polypeptide that is encoded by the corresponding unmodified one or more retroviral or lentiviral ORF. In addition, as demonstrated herein, the length of one or more retroviral or lentiviral ORF can be reduced without negatively affecting the expression of the downstream transgene, integration of the retroviral or lentiviral vector and/or the yield of the retroviral or lentiviral vector. Reduction of the length of one or more retroviral or lentiviral ORF may increase the expression of the downstream transgene, retroviral or lentiviral vector integration and/or the yield of the retroviral or lentiviral vector.
As exemplified herein, such modifications may comprise or consist of modifying the retroviral or lentiviral RNA sequence to introduce STOP codons to reduce the length of one or more viral, particularly retroviral/lentiviral (e.g. SIV) ORF in said sequence compared with the non-modified retroviral or lentiviral RNA sequence from which the modified retroviral or lentiviral RNA sequence is derived. Modification of the retroviral or lentiviral RNA sequence may be achieved by modification of the vector genome plasmid (i.e. pDNA1) as described herein that is used to produce the modified retroviral or lentiviral vector of the invention. Thus, a modified vector genome plasmid (i.e. pDNA1) may comprise one or more ORF, particularly one or more retroviral/lentiviral (e.g. SIV) ORF of reduced length compared with a corresponding non-modified plasmid genome vector (i.e., pDNA1).
By way of non-limiting example, a modified retroviral or lentiviral (e.g. SIV) RNA sequence of the invention may be modified to introduce at least 1, at least 2, at least 3, at least 4, at least 5 or more STOP codons, each of which typically reduces the length of a retroviral or lentiviral (e.g. SIV) ORF. Typically, the length of the one or more retroviral or lentiviral (e.g. SIV) ORF is reduced compared with the corresponding retroviral or lentiviral (e.g. SIV) ORF in the non-modified retroviral or lentiviral (e.g. SIV) RNA sequence from which the modified retroviral or lentiviral (e.g. SIV) RNA sequence is derived. Thus, the vector genome plasmid used to produce the modified retroviral or lentiviral (e.g. SIV) vector of the invention may comprise one or more ORF, particularly one or more retroviral/lentiviral (e.g. SIV) ORF of reduced length compared with a corresponding non-modified plasmid genome vector (i.e., pDNA1).
The retroviral or lentiviral (e.g. SIV) RNA sequence may be modified to reduce the length of one or more retroviral or lentiviral (e.g. SIV) ORFs 5′ (also referred to as upstream) of the transgene and/or the transgene promoter. One or more retroviral or lentiviral (e.g. SIV) ORFs from 5′ of the transgene and/or the transgene promoter may be reduced in length. By way of non-limiting example, at least 1, at least 2, at least 3, at least 4, at least 5 or more retroviral or lentiviral (e.g. SIV) ORFs from 5′ of the transgene and/or the transgene promoter may be reduced in length. Preferably, one or two retroviral or lentiviral (e.g. SIV) ORFs 5′ of the transgene promoter are reduced in length. The length of one or more upstream ORF may be reduced compared with length of the corresponding ORF in the non-modified retroviral or lentiviral (e.g. SIV) RNA sequence from which the modified retroviral or lentiviral (e.g. SIV) RNA sequence is derived. Thus, the vector genome plasmid used to produce the modified retroviral or lentiviral (e.g. SIV) vector of the invention may comprise one or more upstream ORF, particularly one or more upstream retroviral/lentiviral (e.g. SIV) ORF of reduced length compared with a corresponding non-modified plasmid genome vector (i.e., pDNA1).
Introduction of a STOP codon may reduce the length of the polypeptide encoded by a retroviral or lentiviral (e.g. SIV) ORFs by at least 5 amino acids, at least 10 amino acids, at least 20 amino acids, at least 40 amino acids or more.
Alternatively or in addition, each STOP codon introduced may reduce the length of the one or more retroviral or lentiviral (e.g. SIV) ORFs that encodes a polypeptide of at least 10 amino acids in length, such as at least 50 amino acids in length, at least 100 amino acids in length, at least 200 amino acids in length or more, compared with the length of the unmodified ORF prior to introduction of the STOP codon. For example, introduction of a STOP codon may reduce the length of the one or more retroviral or lentiviral (e.g. SIV) ORFs that encodes a polypeptide of at least 230 amino acids in length.
Thus, by way of non-limiting example, introduction of a STOP codon may reduce the length of the polypeptide encoded by a retroviral or lentiviral (e.g. SIV) ORFs, wherein (i) the polypeptide encoded by the (unmodified ORF) is at least 230 amino acids in length; and (ii) the length of the polypeptide encoded by said ORF is reduced by at least 40 amino acids or more.
The introduction of an individual STOP codon may reduce the length of more than one ORF, particularly one or more retroviral/lentiviral ORF. In particular, introduction of an individual STOP codon may reduce the length of 2, or 3 ORFs, particularly 2 or 3 retroviral/lentiviral ORFs, with a reduction in length of 2 ORFs being preferred.
Other codon-substitutions include the removal and/or replacement of one or more restriction enzyme site. Such codon-substitutions may be useful in the production of retroviral/lentiviral vectors of the invention.
Preferred codon-substitutions may comprise or consist of replacement of a frameshift mutation and a STOP codon into the Env ORF of the retroviral/lentiviral RNA sequence. Such substitutions typically reduce the length of the Env ORF and prevent readthrough of from the Env ORF into the cPPT sequence. As exemplified, one such preferred codon-substitution comprises the replacement of a motif corresponding to residues 2347-2352 of SEQ ID NO: 25 with the motif corresponding to residues 2354-2360 of SEQ ID NO: 19. This reduces the length of the polypeptide encoded by the Env ORF from 235 amino acids to 192 amino acids, and also reduces the length of the polypeptide encoded by an additional retroviral/lentiviral ORF from 19 amino acids to 9 amino acids. The motif corresponding to residues 2354-2360 of SEQ ID NO: 19 is found at residues 1601-1607 of SEQ ID NO: 1.
Another preferred codon-substitution that may be used alternatively or in addition to the codon-substitution of the preceding paragraph is the introduction of a SbfI restriction site, which may optionally replace an EcoR1 restriction site within the retroviral/lentiviral RNA sequence. As exemplified, one such preferred codon-substitution comprises the replacement of a motif corresponding to residues 1734-1739 of SEQ ID NO: 25 with the motif corresponding to residues 1738-1746 of SEQ ID NO: 19. The motif corresponding to residues 1738-1746 of SEQ ID NO: 19 is found at residues 985-993 of SEQ ID NO: 1.
Particularly preferred are codon-substitutions which comprise or consist of the combination of (a) replacement of a frameshift mutation and a STOP codon into the Env ORF of the retroviral/lentiviral RNA sequence; and (b) introduction of a SbfI restriction site, which may optionally replace an EcoR1 restriction site within the retroviral/lentiviral RNA sequence. As exemplified, particularly preferred codon-substitutions comprise or consist of (a) the replacement of a motif corresponding to residues 2347-2352 of SEQ ID NO: 25 with the motif corresponding to residues 2354-2360 of SEQ ID NO: 25; and (b) the replacement of a motif corresponding to residues 1734-1739 of SEQ ID NO: 25 with the motif corresponding to residues 1738-1746 of SEQ ID NO: 25.
The retroviral or lentiviral RNA sequence is typically modified to reduce the number of ORFs. For example, the number of ORFs may be reduced by removing AUG codons in the retroviral RNA sequence (or ATG codons in the pro-retroviral DNA sequence). As described herein, start codons may be removed by deletion or substitution of nucleotides within the start codon, or by the addition of one or more (e.g. 1, 2 or 3) nucleotides to disrupt the start codon. Preferably the retroviral or lentiviral RNA sequence is modified to reduce the number of retroviral or lentiviral ORFs. Removal of one or more retroviral or lentiviral ORFs has the potential to improve the safety of the retroviral or lentiviral vector when administered to a subject. Thus, a retroviral or lentiviral vector of the invention comprising a modified retroviral or lentiviral RNA sequence may have an improved safety profile compared with a retroviral or lentiviral vector comprising the non-modified retroviral or lentiviral RNA sequence from which the modified retroviral or lentiviral RNA sequence is derived. By way of non-limiting example, removal of one or more retroviral or lentiviral ORFs reduces the risk of an immune response being triggered by expression of said one or more retroviral or lentiviral ORFs. In addition, as demonstrated herein, one or more retroviral or lentiviral ORF can be removed without negatively affecting the expression of the downstream transgene, integration of the retroviral or lentiviral vector and/or the yield of the retroviral or lentiviral vector. Removal of one or more retroviral or lentiviral ORF may increase the expression of the downstream transgene, integration of the retroviral or lentiviral vector and/or the yield of the retroviral or lentiviral vector.
As exemplified herein, such modifications may comprise or consist of modifying the retroviral or lentiviral RNA sequence to remove viral, particularly retroviral/lentiviral (e.g. SIV), ORFs from said sequence compared with the non-modified retroviral or lentiviral RNA sequence from which the modified retroviral or lentiviral RNA sequence is derived. Modification of the retroviral or lentiviral RNA sequence may be achieved by modification of the vector genome plasmid (i.e. pDNA1) as described herein that is used to produce the modified retroviral or lentiviral vector of the invention. Thus, a modified vector genome plasmid (i.e. pDNA1) may comprise a reduced number of viral, particularly retroviral/lentiviral (e.g. SIV) ORFs compared with a corresponding non-modified plasmid genome vector (i.e., pDNA1). Thus, a modified retroviral or lentiviral vector of the invention comprises a reduced number of non-transgene ORFs on its retroviral or lentiviral RNA sequence.
By way of non-limiting example, a modified retroviral or lentiviral (e.g. SIV) RNA sequence of the invention may be modified to remove at least 1, at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, or more retroviral or lentiviral (e.g. SIV) ORFs, typically at least 6 or at least 7 retroviral or lentiviral (e.g. SIV) ORFs, preferably 6 or 7 retroviral or lentiviral (e.g. SIV) ORFs. Typically, the number of retroviral or lentiviral (e.g. SIV) ORFs is reduced compared with the non-modified retroviral or lentiviral (e.g. SIV) RNA sequence from which the modified retroviral or lentiviral (e.g. SIV)RNA sequence is derived. Thus, the vector genome plasmid used to produce the modified retroviral or lentiviral (e.g. SIV) vector of the invention may have a reduced number of retroviral or lentiviral (e.g. SIV) ORFs compared with the corresponding non-modified vector genome plasmid.
The retroviral or lentiviral (e.g. SIV) RNA sequence may be modified to reduce the number of retroviral or lentiviral (e.g. SIV) ORFs 5′ (also referred to as upstream) of the transgene and/or the transgene promoter. One or more retroviral or lentiviral (e.g. SIV) ORFs from 5′ of the transgene and/or the transgene promoter may be removed. By way of non-limiting example, at least 1, at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10 or more retroviral or lentiviral (e.g. SIV) ORFs from 5′ of the transgene and/or the transgene promoter may be removed, typically at least 6 or at least 7 retroviral or lentiviral (e.g. SIV) ORFs, preferably 6 or 7 retroviral or lentiviral (e.g. SIV) ORFs. Preferably, one or more retroviral or lentiviral (e.g. SIV) ORFs is removed from 5′ of the transgene promoter. The number of upstream ORFs may be reduced compared with the non-modified retroviral or lentiviral (e.g. SIV) RNA sequence from which the modified retroviral or lentiviral (e.g. SIV) RNA sequence is derived. Thus, the vector genome plasmid used to produce the modified retroviral or lentiviral (e.g. SIV) vector of the invention may have a reduced number of upstream retroviral or lentiviral (e.g. SIV) ORFs compared with the corresponding non-modified vector genome plasmid.
Alternatively, or additionally, the one or more retroviral or lentiviral (e.g. SIV) ORFs removed according to the invention may each independently encode a polypeptide of greater than or equal to 10 amino acids in length, greater than or equal to 20 amino acids in length, greater than or equal to 30 amino acids in length, greater than or equal to 40 amino acids in length, greater than or equal to 50 amino acids in length, greater than or equal to 60 amino acids in length, greater than or equal to 70 amino acids in length, greater than or equal to 80 amino acids in length, greater than or equal to 90 amino acids in length, greater than or equal to 100 amino acids in length, greater than or equal to 110 amino acids in length, greater than or equal to 120 amino acids in length, greater than or equal to 130 amino acids in length, greater than or equal to 140 amino acids in length or greater than or equal to 150 amino acids in length. Typically, the one or more retroviral or lentiviral (e.g. SIV) ORFs removed according to the invention may each independently encode a polypeptide of greater than or equal to 100 amino acids in length. Preferably, at least one retroviral or lentiviral (e.g. SIV) ORFs encoding a polypeptide of greater than or equal to 100 amino acids in length may be removed from the modified retroviral or lentiviral (e.g. SIV) RNA sequence compared with the non-modified retroviral or lentiviral (e.g. SIV) RNA sequence from which the modified retroviral or lentiviral (e.g. SIV) RNA sequence is derived. Thus, the vector genome plasmid used to produce the modified retroviral or lentiviral (e.g. SIV) vector of the invention may have one or more retroviral or lentiviral (e.g. SIV) ORFs encoding a polypeptide of greater than or equal to 100 amino acids in length removed compared with the non-modified plasmid genome vector from which the modified retroviral RNA sequence is derived.
Thus, a retroviral or lentiviral (e.g. SIV) RNA sequence of the invention may lack any ORFs (other than the transgene) encoding a polypeptide greater than or equal to 200 amino acids in length, greater than or equal to 190 amino acids in length, greater than or equal to 180 amino acids in length, greater than or equal to 170 amino acids in length, or greater than or equal to 160 amino acids in length compared with the non-modified retroviral or lentiviral (e.g. SIV) RNA sequence from which the modified retroviral or lentiviral (e.g. SIV) RNA sequence is derived. Thus, the vector genome plasmid used to produce the modified retroviral or lentiviral (e.g. SIV) vector of the invention may have lack any ORFs (other than the transgene) encoding a polypeptide greater than or equal to 200 amino acids in length as described above compared with the non-modified plasmid genome vector from which the modified retroviral RNA sequence is derived.
A retroviral or lentiviral (e.g. SIV) RNA sequence of the invention may lack any ORFs encoding a polypeptide greater than or equal to 180 amino acids in length, greater than or equal to 100 amino acids in length, greater than or equal to 90 amino acids in length, greater than or equal to 80 amino acids in length, or greater than or equal to 70 amino acids in length within the partial Gag region compared with the non-modified retroviral or lentiviral (e.g. SIV) RNA sequence from which the modified retroviral or lentiviral (e.g. SIV) RNA sequence is derived. Thus, the vector genome plasmid used to produce the modified retroviral or lentiviral (e.g. SIV) vector of the invention may have lack any ORFs (other than the transgene) encoding a polypeptide greater than or equal to 180 amino acids in length in the partial Gag region as described above compared with the non-modified plasmid genome vector from which the modified retroviral RNA sequence is derived.
A retroviral or lentiviral (e.g. SIV) RNA sequence of the invention may lack any ORFs encoding a polypeptide greater than or equal to 200 amino acids in length, greater than or equal to 170 amino acids in length, or greater than or equal to 160 amino acids in length within the partial RRE region compared with the non-modified retroviral or lentiviral (e.g. SIV) RNA sequence from which the modified retroviral or lentiviral (e.g. SIV) RNA sequence is derived. Thus, the vector genome plasmid used to produce the modified retroviral or lentiviral (e.g. SIV) vector of the invention may have lack any ORFs (other than the transgene) encoding a polypeptide of greater than or equal to 160 amino acids in length in the partial RRE region as described above compared with the non-modified plasmid genome vector from which the modified retroviral RNA sequence is derived.
Alternatively, or additionally, the one or more retroviral or lentiviral (e.g. SIV) ORF to be removed may be comprised (at least in part) in an RRE sequence. Preferably, the one or more retroviral or lentiviral (e.g. SIV) ORF is comprised (at least in part) in a partial RRE sequence. Accordingly, the retroviral or lentiviral (e.g. SIV) RNA sequence may be modified to reduce the number of ORFs comprised (at least in part) in a partial RRE sequence, compared with the non-modified retroviral or lentiviral (e.g. SIV) RNA sequence from which the modified retroviral or lentiviral (e.g. SIV) RNA sequence is derived. Thus, the vector genome plasmid used to produce the modified retroviral or lentiviral (e.g. SIV) vector of the invention may have a reduced number of ORFs comprised (at least in part) in a partial RRE sequence compared with the non-modified plasmid genome vector from which the modified retroviral RNA sequence is derived.
Alternatively, or additionally, the one or more retroviral or lentiviral (e.g. SIV) ORF may be comprised (at least in part) in a partial Gag sequence. Accordingly, the retroviral or lentiviral (e.g. SIV) RNA sequence may be modified to reduce the number of ORFs comprised (at least in part) in a partial Gag sequence, compared with the non-modified retroviral or lentiviral (e.g. SIV) RNA sequence from which the modified retroviral or lentiviral (e.g. SIV) RNA sequence is derived. Thus, the vector genome plasmid used to produce the modified retroviral or lentiviral (e.g. SIV) vector of the invention may have a reduced number of ORFs comprised (at least in part) in a partial Gag sequence compared with the non-modified plasmid genome vector from which the modified retroviral RNA sequence is derived.
References herein to an ORF that is comprised in a region of the retroviral/lentiviral (e.g. SIV) sequence, e.g. comprised in a partial Gag sequence or partial RRE sequence also apply equally and without reservation to ORFs that are partially comprised in said region of the retroviral/lentiviral (e.g. SIV) sequence, e.g. comprised in a partial Gag sequence or partial RRE sequence, unless expressly stated to the contrary. An ORF to be removed may run through different regions of the retroviral/lentiviral (e.g. SIV) sequence, and so be comprised by two or more regions of the retroviral/lentiviral (e.g. SIV) sequence. For example, an ORF to be removed may run through a partial Gag sequence into a partial RRE sequence.
Typically, the removal of the one or more retroviral or lentiviral (e.g. SIV) ORFs does not negatively affect the expression of the downstream transgene, compared to a non-modified retroviral or lentiviral (e.g. SIV) RNA sequence. The removal of the one or more retroviral or lentiviral (e.g. SIV) ORFs may increase the expression of the downstream transgene, compared with a non-modified retroviral or lentiviral (e.g. SIV) RNA sequence. The non-modified retroviral RNA sequence may be produced from the aforementioned non-modified plasmid genome vector.
Whilst a modified retroviral RNA or lentiviral (e.g. SIV) sequence may comprise no ORFs (particularly no retroviral or lentiviral (e.g. SIV) ORFs) other than the transgene, this is not essential. Rather, a modified retroviral or lentiviral (e.g. SIV) RNA sequence may still comprise ORFs (including retroviral or lentiviral (e.g. SIV)) other than the transgene, but may comprise a reduced number of non-transgene ORFs compared with the non-modified retroviral or lentiviral (e.g. SIV) RNA sequence from which the modified retroviral or lentiviral (e.g. SIV) RNA sequence is derived. Alternatively or in addition, the length of the remaining non-transgene ORFs may be reduced compared with the non-modified retroviral or lentiviral (e.g. SIV) RNA sequence from which the modified retroviral or lentiviral (e.g. SIV) RNA sequence is derived. Thus, the vector genome plasmid used to produce the modified retroviral or lentiviral (e.g. SIV) vector of the invention may have a reduced number of non-transgene ORFs compared with the unmodified plasmid genome (pDNA1) from which it is derived. Alternatively or in addition, the remaining non-transgene ORFs within the vector genome plasmid used to produce the modified retroviral or lentiviral (e.g. SIV) vector of the invention may be reduced in length compared with the non-modified retroviral or lentiviral (e.g. SIV) RNA sequence from which the modified retroviral or lentiviral (e.g. SIV) RNA sequence is derived.
Preferred modifications to reduce the number of ORFs, particularly retroviral/lentiviral (e.g. SIV) ORFs, may comprise or consist of one or more of: (i) insertion of a nucleic acid (e.g. a U in the retroviral/lentiviral RNA sequence or a T in the corresponding proviral DNA sequence) to disrupt a start codon; (ii) substitution of an A by a U in the retroviral/lentiviral RNA sequence (or an A by a T in the corresponding proviral DNA sequence) to disrupt a start codon; and/or (iii) substitution of a U by an A in the retroviral/lentiviral RNA sequence (or a T by an A in the corresponding proviral DNA sequence) to disrupt a start codon.
As exemplified, such preferred modifications to reduce the number of ORFs, particularly retroviral/lentiviral (e.g. SIV) ORFs, include: (i) introduction of a U in the retroviral/lentiviral RNA sequence or a T in the corresponding proviral DNA sequence immediately 3′ to residue 1183 of SEQ ID NO: 25 (such an insertion corresponds to residue 1184 of SEQ ID NO: 19, and residue 431 of SEQ ID NO: 1); (ii) introduction of a U in the retroviral/lentiviral RNA sequence or a T in the corresponding proviral DNA sequence immediately 3′ to residue 1287 of SEQ ID NO: 25 (such an insertion corresponds to residue 1289 of SEQ ID NO: 19, and residue 536 of SEQ ID NO: 1); (iii) introduction of a U in the retroviral/lentiviral RNA sequence or a T in the corresponding proviral DNA sequence immediately 3′ to residue 1303 of SEQ ID NO: 25 (such an insertion corresponds to residue 1306 of SEQ ID NO: 19, and residue 553 of SEQ ID NO: 1); (iv) introduction of a U in the retroviral/lentiviral RNA sequence or a T in the corresponding proviral DNA sequence immediately 3′ to residue 1625 of SEQ ID NO: 25 (such an insertion corresponds to residue 1629 of SEQ ID NO: 19, and residue 876 of SEQ ID NO: 1); (v) substitution of an A by a U in the retroviral/lentiviral RNA sequence or substitution of an A by a T in the corresponding proviral DNA sequence at residue 1787 of SEQ ID NO: 25 (corresponding to residue 1794 of SEQ ID NO: 19, and residue 1041 of SEQ ID NO: 1); (vi) substitution of a U by an A in the retroviral/lentiviral RNA sequence or a T by an A in the corresponding proviral DNA sequence at residue 2064 of SEQ ID NO: 25 (corresponding to residue 2071 of SEQ ID NO: 19, and residue 1318 of SEQ ID NO: 1); and/or (vii) substitution of a U by an A in the retroviral/lentiviral RNA sequence or a T by an A in the corresponding proviral DNA sequence at residue 2238 of SEQ ID NO: 25 (corresponding to residue 2245 of SEQ ID NO: 19, and residue 1492 of SEQ ID NO: 1).
Particularly preferred modifications to reduce the number of ORFs, particularly retroviral/lentiviral (e.g. SIV) ORFs, are modifications which comprise or consist of the combination of (i) insertion of a nucleic acid (e.g. a U in the retroviral/lentiviral RNA sequence or a T in the corresponding proviral DNA sequence) to disrupt one or more start codon (e.g. 2, 3 or 4, preferably 4, start codons); (ii) substitution of an A by a U in the retroviral/lentiviral RNA sequence (or an A by a T in the corresponding proviral DNA sequence) to disrupt one or more start codon; and/or (iii) substitution of a U by an A in the retroviral/lentiviral RNA sequence (or a T by an A in the corresponding proviral DNA sequence) to disrupt one or more start codon (e.g. 2, 3, or 4, preferably 2, start codons). As exemplified, particularly preferred modifications to remove one or more retroviral/lentiviral (e.g. SIV) ORF comprise or consist of (i) introduction of a U in the retroviral/lentiviral RNA sequence or a T in the corresponding proviral DNA sequence immediately 3′ to residue 1183 of SEQ ID NO: 25 (such an insertion corresponds to residue 1184 of SEQ ID NO: 19, and residue 431 of SEQ ID NO: 1); (ii) introduction of a U in the retroviral/lentiviral RNA sequence or a T in the corresponding proviral DNA sequence immediately 3′ to residue 1287 of SEQ ID NO: 25 (such an insertion corresponds to residue 1289 of SEQ ID NO: 19, and residue 536 of SEQ ID NO: 1); (iii) introduction of a U in the retroviral/lentiviral RNA sequence or a T in the corresponding proviral DNA sequence immediately 3′ to residue 1303 of SEQ ID NO: 25 (such an insertion corresponds to residue 1306 of SEQ ID NO: 19, and residue 553 of SEQ ID NO: 1); (iv) introduction of a U in the retroviral/lentiviral RNA sequence or a T in the corresponding proviral DNA sequence immediately 3′ to residue 1625 of SEQ ID NO: 25 (such an insertion corresponds to residue 1629 of SEQ ID NO: 19, and residue 876 of SEQ ID NO: 1); (v) substitution of an A by a U in the retroviral/lentiviral RNA sequence or substitution of an A by a T in the corresponding proviral DNA sequence at residue 1787 of SEQ ID NO: 25 (corresponding to residue 1794 of SEQ ID NO: 19, and residue 1041 of SEQ ID NO: 1); (vi) substitution of a U by an A in the retroviral/lentiviral RNA sequence or a T by an A in the corresponding proviral DNA sequence at residue 2064 of SEQ ID NO: 25 (corresponding to residue 2071 of SEQ ID NO: 19, and residue 1318 of SEQ ID NO: 1); and (vii) substitution of a U by an A in the retroviral/lentiviral RNA sequence or a T by an A in the corresponding proviral DNA sequence at residue 2238 of SEQ ID NO: 25 (corresponding to residue 2245 of SEQ ID NO: 19, and residue 1492 of SEQ ID NO: 1).
As a specific non-limiting example, the modifications to a modified retroviral or lentiviral (e.g. SIV) RNA sequence may remove retroviral or lentiviral (e.g. SIV) ORFs comprised (at least in part) within the partial Gag region of the retroviral or lentiviral (e.g. SIV) RNA sequence, and/or may reduce the size of one or more retroviral or lentiviral (e.g. SIV) ORFs within said region. Preferably, a modified retroviral or lentiviral (e.g. SIV) RNA sequence of the invention has been modified such that it does not contain any retroviral or lentiviral (e.g. SIV) ORFs encoding polypeptides of greater than 100 amino acids, typically greater than 70 amino acids within the partial Gag region. Preferably, a modified retroviral or lentiviral (e.g. SIV) RNA sequence of the invention has been modified such that it does not contain any retroviral or lentiviral (e.g. SIV) ORFs encoding polypeptides of greater than 200 amino acids, typically greater than 160 amino acids within the partial RRE region. Particularly preferred is a modified retroviral or lentiviral (e.g. SIV) RNA sequence of the invention that has been modified such that it does not contain (i) any retroviral or lentiviral (e.g. SIV) ORFs encoding polypeptides of greater than 100 amino acids, typically greater than 70 amino acids within the partial Gag region; and (ii) any retroviral or lentiviral (e.g. SIV) ORFs encoding polypeptides of greater than 200 amino acids, typically greater than 160 amino acids within the partial RRE region. The invention provides a retroviral or lentiviral (e.g. SIV) vector comprising said modified retroviral or lentiviral (e.g. SIV) RNA sequence.
Any modification or combination thereof to reduce the number of ORFs, particularly retroviral or lentiviral (e.g. SIV) ORFs within a retroviral or lentiviral (e.g. SIV) RNA sequence of the invention may be used in combination with any codon-substitution modification or combination thereof as described herein.
Thus, the invention provides a modified retroviral or lentiviral (e.g. SIV) RNA sequence that: (a) does not contain (i) any retroviral or lentiviral (e.g. SIV) ORFs encoding polypeptides of greater than 100 amino acids, typically greater than 70 amino acids within the partial Gag region; (ii) any retroviral or lentiviral (e.g. SIV) ORFs encoding polypeptides of greater than 200 amino acids, typically greater than 160 amino acids within the partial RRE region; and (b) the codon-substitutions comprise or consist of the combination of (i) replacement of a frameshift mutation and a STOP codon into the Env ORF of the retroviral/lentiviral RNA sequence; and (ii) introduction of a SbfI restriction site, which may optionally replace an EcoR1 restriction site within the retroviral/lentiviral RNA sequence, particularly the individual examples described herein. The invention provides a retroviral or lentiviral (e.g. SIV) vector comprising said modified retroviral or lentiviral (e.g. SIV) RNA sequence.
Any codon-substitution or combination thereof may be used in combination with any modification to reduce the number of ORFs, particularly retroviral/lentiviral (e.g. SIV) ORFs, or combination thereof. Preferred are retroviral/lentiviral (e.g. SIV) RNA sequences wherein (a) the codon-substitutions comprise or consist of the combination of (i) replacement of a frameshift mutation and a STOP codon into the Env ORF of the retroviral/lentiviral RNA sequence; and (ii) introduction of a SbfI restriction site, which may optionally replace an EcoR1 restriction site within the retroviral/lentiviral RNA sequence; and (b) the modifications to reduce the number of ORFs, particularly retroviral/lentiviral (e.g. SIV) ORFs, comprise or consist of the combination of (i) insertion of a nucleic acid (e.g. a U in the retroviral/lentiviral RNA sequence or a T in the corresponding proviral DNA sequence) to disrupt one or more start codon (e.g. 2, 3 or 4, preferably 4, start codons); (ii) substitution of an A by a U in the retroviral/lentiviral RNA sequence (or an A by a T in the corresponding proviral DNA sequence) to disrupt one or more start codon; and (iii) substitution of a U by an A in the retroviral/lentiviral RNA sequence (or a T by an A in the corresponding proviral DNA sequence) to disrupt one or more start codon (e.g. 2, 3, or 4, preferably 2, start codons).
Particularly preferred are retroviral/lentiviral (e.g. SIV) RNA sequences wherein (a) the codon-substitutions comprise or consist of the combination of (i) the replacement of a motif corresponding to residues 2347-2352 of SEQ ID NO: 25 with the motif corresponding to residues 2354-2360 of SEQ ID NO: 25; and (ii) the replacement of a motif corresponding to residues 1734-1739 of SEQ ID NO: 25 with the motif corresponding to residues 1738-1746 of SEQ ID NO: 25; and (b) the modifications to reduce the number of ORFs, particularly retroviral/lentiviral (e.g. SIV) ORFs, comprise or consist of the combination of (i) introduction of a U in the retroviral/lentiviral RNA sequence or a T in the corresponding proviral DNA sequence immediately 3′ to residue 1183 of SEQ ID NO: 25 (such an insertion corresponds to residue 1184 of SEQ ID NO: 19, and residue 431 of SEQ ID NO: 1); (ii) introduction of a U in the retroviral/lentiviral RNA sequence or a T in the corresponding proviral DNA sequence immediately 3′ to residue 1287 of SEQ ID NO: 25 (such an insertion corresponds to residue 1289 of SEQ ID NO: 19, and residue 536 of SEQ ID NO: 1); (iii) introduction of a U in the retroviral/lentiviral RNA sequence or a T in the corresponding proviral DNA sequence immediately 3′ to residue 1303 of SEQ ID NO: 25 (such an insertion corresponds to residue 1306 of SEQ ID NO: 19, and residue 553 of SEQ ID NO: 1); (iv) introduction of a U in the retroviral/lentiviral RNA sequence or a T in the corresponding proviral DNA sequence immediately 3′ to residue 1625 of SEQ ID NO: 25 (such an insertion corresponds to residue 1629 of SEQ ID NO: 19, and residue 876 of SEQ ID NO: 1); (v) substitution of an A by a U in the retroviral/lentiviral RNA sequence or substitution of an A by a T in the corresponding proviral DNA sequence at residue 1787 of SEQ ID NO: 25 (corresponding to residue 1794 of SEQ ID NO: 19, and residue 1041 of SEQ ID NO: 1); (vi) substitution of a U by an A in the retroviral/lentiviral RNA sequence or a T by an A in the corresponding proviral DNA sequence at residue 2064 of SEQ ID NO: 25 (corresponding to residue 2071 of SEQ ID NO: 19, and residue 1318 of SEQ ID NO: 1); and (vii) substitution of a U by an A in the retroviral/lentiviral RNA sequence or a T by an A in the corresponding proviral DNA sequence at residue 2238 of SEQ ID NO: 25 (corresponding to residue 2245 of SEQ ID NO: 19, and residue 1492 of SEQ ID NO: 1).
Of particular preference, the invention provides a SIV vector pseudotyped with Sendai virus hemagglutinin-neuraminidase (HN) and fusion (F) proteins, wherein: (a) said vector comprises a modified retroviral RNA sequence which comprises or consists of a nucleic acid sequence of SEQ ID NO: 1, preferably wherein the modified retroviral RNA sequence consists of a nucleic acid sequence of SEQ ID NO: 1; and (b) the F protein comprises a first subunit which comprises or consists of an amino acid sequence of SEQ ID NO: 14 and a second subunit which comprises or consists of an amino acid sequence of SEQ ID NO: 15. Said vector may further comprise one or more of: (a) a p17 protein comprising or consisting of an amino acid sequence of SEQ ID NO: 2; (b) a p24 protein comprising or consisting of an amino acid sequence of SEQ ID NO: 3; (c) p8 protein comprising or consisting of an amino acid sequence of SEQ ID NO: 4; (d) a protease comprising or consisting of an amino acid sequence of SEQ ID NO: 5; (e) a p51 protein comprising or consisting of an amino acid sequence of SEQ ID NO: 6; (f) a p15 protein comprising or consisting of an amino acid sequence of SEQ ID NO: 7; (g) a p31 protein comprising or consisting of an amino acid sequence of SEQ ID NO: 8; (h) a Gag protein comprising or consisting of an amino acid sequence of SEQ ID NO: 9; and/or (i) a Pol protein comprising or consisting of an amino acid sequence of SEQ ID NO: 10. Optionally said vector comprises each of (a) to (g), and may further comprise one or both of (h) and (i).
A retroviral/lentiviral (e.g. SIV) RNA sequence of the invention may comprise one or more further modifications in addition to the codon-substitutions and/or modifications to reduce retroviral/lentiviral (e.g. SIV) ORFs as described herein. By way of non-limiting example, the retroviral/lentiviral (e.g. SIV) RNA sequence may be CpG-depleted (or CpG-fee) to facilitate gene expression. Standard techniques for modifying the transgene sequence in this way are known in the art.
As exemplified herein, retroviral/lentiviral (e.g. SIV) vectors comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention have at least maintained, and potentially increased transgene expression; and/or at least maintained, and potentially increased integration of the retroviral/lentiviral (e.g. SIV) RNA sequence into target cells. Retroviral/lentiviral (e.g. SIV) vectors comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention also typically have at least maintained, and potentially increased vector yield compared with retroviral/lentiviral (e.g. SIV) vector comprising the non-modified retroviral/lentiviral (e.g. SIV) RNA sequence from which the modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived. This effect on vector yield may be further increased by the use of codon-optimised GagPol, as described herein.
The retroviral/lentiviral (e.g. SIV) vector comprises a promoter operably linked to a transgene, enabling expression of the transgene. Typically the promoter is a hybrid human CMV enhancer/EF1a (hCEF) promoter. This hCEF promoter may lack the intron corresponding to nucleotides 570-709 and the exon corresponding to nucleotides 728-733 of the hCEF promoter. A preferred example of an hCEF promoter sequence of the invention is provided by SEQ ID NO: 26. The promoter may be a CMV promoter. An example of a CMV promoter sequence is provided by SEQ ID NO: 27. The promoter may be a human elongation factor 1a (EF1a) promoter. An example of a EF1a promoter is provided by SEQ ID NO: 28. Other promoters for transgene expression are known in the art and their suitability for the retroviral/lentiviral (e.g. SIV) vectors of the invention determined using routine techniques known in the art. Non-limiting examples of other promoters include UbC and UCOE. As described herein, the promoter may be modified to further regulate expression of the transgene of the invention.
The promoter included in the retroviral/lentiviral (e.g. SIV) vector of the invention may be specifically selected and/or modified to further refine regulation of expression of the therapeutic gene. Again, suitable promoters and standard techniques for their modification are known in the art. As a non-limiting example, a number of suitable (CpG-free) promoters suitable for use in the present invention are described in Pringle et al. (J. Mol. Med. Berl. 2012, 90(12): 1487-96), which is herein incorporated by reference in its entirety. Preferably, the retroviral/lentiviral vectors (particularly SIV F/HN vectors) of the invention comprise a hCEF promoter having low or no CpG dinucleotide content. The hCEF promoter may have all CG dinucleotides replaced with any one of AG, TG or GT. Thus, the hCEF promoter may be CpG-free. A preferred example of a CpG-free hCEF promoter sequence of the invention is provided by SEQ ID NO: 26. The absence of CpG dinucleotides typically further improves the performance of retroviral/lentiviral (e.g. SIV) vectors of the invention and in particular in situations where it is not desired to induce an immune response against an expressed antigen or an inflammatory response against the delivered expression construct. The elimination of CpG dinucleotides reduces the occurrence of flu-like symptoms and inflammation which may result from administration of constructs, particularly when administered to the airways.
The retroviral/lentiviral (e.g. SIV) vector of the invention may be modified to allow shut down of gene expression. Standard techniques for modifying the vector in this way are known in the art. As a non-limiting example, Tet-responsive promoters are widely used.
A retroviral/lentiviral (e.g. SIV) vector of the invention may comprise a transgene that encodes a polypeptide or protein that is therapeutic for the treatment of such diseases, particularly a disease or disorder of the airways, respiratory tract, or lung.
Accordingly, a retroviral/lentiviral (e.g. SIV) vector of the invention may comprise a transgene encoding a protein selected from: (i) a secreted therapeutic protein, optionally Alpha-1 Antitrypsin (A1AT), Factor VIII, Surfactant Protein B (SFTPB), Factor VII, Factor IX, Factor X, Factor XI, von Willebrand Factor, Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) and a monoclonal antibody against an infectious agent; or (ii) CFTR, ABCA3, DNAH5, DNAH11, DNAI1, and DNA12. Other examples of transgenes that may be comprised in a retroviral/lentiviral (e.g. SIV) vector of the invention include genes related to or associated with other surfactant deficiencies.
The transgene included in the vector of the invention may be modified to facilitate expression. For example, the transgene sequence may be in CpG-depleted (or CpG-fee) form and/or further modified to facilitate gene expression. Standard techniques for modifying the transgene sequence in this way are known in the art.
Preferably, the transgene encodes a CFTR. An example of a CFTR cDNA is provided by SEQ ID NO: 29. Variants thereof (as described therein) are also included, particularly variants with at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 29. Preferably the CFTR transgene has at least 90%, at least 95%, or at least 99% identity to SEQ ID NO: 29.
The transgene may encode an A1AT. An example of an A1AT transgene is provided by SEQ ID NO: 30, or by the complementary sequence of SEQ ID NO: 31. SEQ ID NO: 30 is a codon-optimised CpG depleted A1AT transgene previously designed by the present inventors to enhance translation in human cells. Such optimisation has been shown to enhance gene expression by up to 15-fold. Variants of same sequence (as defined herein) which possess the same technical effect of enhancing translation compared with the unmodified (wild-type) A1AT gene sequence are also encompassed by the present invention. The polypeptide encoded by said A1AT transgene, may be exemplified by the polypeptide of SEQ ID NO: 32. Variants thereof (as described therein) are also included, particularly variants with at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 30, 31 or 32. Preferably the A1AT variants have at least 90%, at least 95%, or at least 99% identity to SEQ ID NO: 30, 31 or 32.
The transgene may encode a FVIII. Examples of a FVIII transgene are provided by SEQ ID NOs: 33 and 34, or by the respective complementary sequences of SEQ ID NO: 35 and 36. The polypeptide encoded by the FVIII transgene, may be exemplified by the polypeptide of SEQ ID NO: 37 or 38. Variants thereof (as described therein) are also included, particularly variants with at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to any one of SEQ ID NOs: 33 to 38. Preferably the FVIII variants have at least 90%, at least 95%, or at least 99% identity to any one of SEQ ID NOs: 33 to 38.
The transgene of the invention may be any one or more of DNAH5, DNAH11, DNA/1, and DNA/2, or other known related gene.
When the respiratory tract epithelium is targeted for delivery of the retroviral/lentiviral (e.g. SIV) vector, the transgene may encode A1AT, SFTPB, or GM-CSF. The transgene may encode a monoclonal antibody (mAb) against an infectious agent. The transgene may encode anti-TNF alpha. The transgene may encode a therapeutic protein implicated in an inflammatory, immune or metabolic condition.
A retroviral/lentiviral (e.g. SIV) vector of the invention may be delivered to the cells of the respiratory tract to allow production of proteins to be secreted into circulatory system. In such embodiments, the transgene may encode for Factor VII, Factor VIII, Factor IX, Factor X, Factor XI and/or von Willebrand's factor. Such a vector may be used in the treatment of diseases, particularly cardiovascular diseases and blood disorders, preferably blood clotting deficiencies such as haemophilia. Again, the transgene may encode an mAb against an infectious agent or a protein implicated in an inflammatory, immune or metabolic condition, such as, lysosomal storage disease.
The retroviral/lentiviral (e.g. SIV) vector of the invention may have no intron positioned between the promoter and the transgene. Similarly, there may be no intron between the promoter and the transgene in the vector genome (pDNA1) plasmid (for example, pGM830 as described herein, with the sequence of SEQ ID NO: 20).
In some preferred embodiments, the retroviral/lentiviral (e.g. SIV) vector comprises a hCEF promoter and a CFTR transgene, including those described herein. Optionally said retroviral/lentiviral (e.g. SIV) vector may have no intron positioned between the promoter and the transgene. Such a retroviral/lentiviral (e.g. SIV) vector may be produced by the method described herein, using a genome plasmid carrying the CFTR transgene and a promoter.
In some preferred embodiments, the retroviral/lentiviral (e.g. SIV) vector comprises a hCEF promoter and an A1AT transgene, including those described herein. Optionally said retroviral/lentiviral (e.g. SIV) vector may have no intron positioned between the promoter and the transgene. Such a retroviral/lentiviral (e.g. SIV) vector may be produced by the method described herein, using a genome plasmid carrying the A1AT transgene and a promoter.
In some preferred embodiments, the retroviral/lentiviral (e.g. SIV) vector comprises a hCEF or CMW promoter and an FVIII transgene, including those described herein. Optionally said retroviral/lentiviral (e.g. SIV) vector may have no intron positioned between the promoter and the transgene. Such a retroviral/lentiviral (e.g. SIV) vector may be produced by the method described herein, using a genome plasmid carrying the FVIII transgene and a promoter.
The retroviral/lentiviral (e.g. SIV) vector as described herein comprises a transgene. The transgene comprises a nucleic acid sequence encoding a gene product, e.g., a protein, particularly a therapeutic protein.
For example, in one embodiment, the nucleic acid sequence encoding a CFTR, A1AT or FVIII comprises (or consists of) a nucleic acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% sequence identity to the CFTR, A1AT or FVIII nucleic acid sequence respectively, examples of which are described herein. In a further embodiment, the nucleic acid sequence encoding CFTR, A1AT or FVIII comprises (or consists of) a nucleic acid sequence having at least 95% (such as at least 95, 96, 97, 98, 99 or 100%) sequence identity to the CFTR, A1AT or FVIII nucleic acid sequence respectively, examples of which are described herein. In one embodiment, the nucleic acid sequence encoding CFTR is provided by SEQ ID NO: 29, the nucleic acid sequence encoding A1AT is provided by SEQ ID NO: 30, or by the complementary sequence of SEQ ID NO: 31 and/or the nucleic acid sequence encoding FVIII is provided by SEQ ID NO: 33 and 34, or by the respective complementary sequences of SEQ ID NO: 35 and 36, or variants thereof.
The amino acid sequence of the CFTR, A1AT or FVIII transgene may comprise (or consist of) an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100%, preferably at least 90%, at least 95%, or at least 99% identity sequence identity to the functional CFTR, A1AT or FVIII polypeptide sequence respectively.
The retroviral/lentiviral (e.g. SIV) vectors of the invention may comprise a central polypurine tract (cPPT) and/or the Woodchuck hepatitis virus posttranscriptional regulatory elements (WPRE). An exemplary WPRE sequence is provided by SEQ ID NO: 39.
As described herein, the retroviral/lentiviral (e.g. SIV) RNA sequence is derived from the proviral DNA sequence. The proviral DNA sequence is itself provided during the manufacturing process by the vector genome plasmid, pDNA1. However, the retroviral/lentiviral (e.g. SIV) RNA sequence is not identical to the proviral DNA sequence (and hence not identical to the vector genome plasmid, pDNA1). Rather, the retroviral/lentiviral (e.g. SIV) RNA sequence is shorter in length than the corresponding proviral DNA sequence, and the precise limits or boundaries of the retroviral/lentiviral (e.g. SIV) RNA sequence are typically not readily determined. In other words, it is generally not possible to identify a precise retroviral/lentiviral (e.g. SIV) RNA sequence (with the 5′ and 3′ specifically identified) merely from the primary sequence of the proviral DNA sequence (and hence the vector genome plasmid, pDNA1, sequence).
The retroviral/lentiviral (e.g. SIV) vector typically comprises a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is less than 10,000 bases in length, less than 9,000 bases in length, or less than 8,000 bases in length. Preferably, the retroviral/lentiviral (e.g. SIV) vector comprises a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is less than 9,000 bases in length.
The retroviral/lentiviral (e.g. SIV) vector may comprise a modified retroviral/lentiviral (e.g. SIV) RNA sequence that comprises or consists of a nucleic acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 1. The modified retroviral/lentiviral (e.g. SIV) RNA sequence may comprise or consist of a nucleic acid sequence having at least 90%, at least 95%, or at least 99% identity to SEQ ID NO: 1. The modified retroviral/lentiviral (e.g. SIV) RNA sequence may comprise or consist of a nucleic acid sequence having at least 99% identity to SEQ ID NO: 1. The modified retroviral sequence may comprise or consist of a nucleic acid sequence of SEQ ID NO: 1.
The invention provides a retroviral/lentiviral (e.g. SIV) vector that comprises a retroviral/lentiviral (e.g. SIV) RNA sequence that consists of a nucleic acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 1. The modified retroviral/lentiviral (e.g. SIV) RNA sequence may consist of a nucleic acid sequence having at least 90%, at least 95%, or at least 99% identity to SEQ ID NO: 1. The modified retroviral/lentiviral (e.g. SIV) RNA sequence may consist of a nucleic acid sequence having at least 99% identity to SEQ ID NO: 1. The invention provides a retroviral/lentiviral (e.g. SIV) vector that comprises a retroviral/lentiviral (e.g. SIV) RNA sequence that consists of a nucleic acid sequence of SEQ ID NO: 1.
The retroviral/lentiviral (e.g. SIV) vector may comprise a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 10,000 bases in length, less than 9,000 bases in length, or less than 8,000 bases in length; and (b) comprises or consists of a nucleic acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 1.
The retroviral/lentiviral (e.g. SIV) vector may comprise a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 10,000 bases in length, less than 9,000 bases in length, or less than 8,000 bases in length; and (b) comprises or consists of a nucleic acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 1.
The retroviral/lentiviral (e.g. SIV) vector may comprise a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 10,000 bases in length, less than 9,000 bases in length, or less than 8,000 bases in length; and (b) comprises or consists of a nucleic acid sequence having at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 1.
The retroviral/lentiviral (e.g. SIV) vector may comprise a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 10,000 bases in length, less than 9,000 bases in length, or less than 8,000 bases in length; and (b) consists of a nucleic acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 1.
The retroviral/lentiviral (e.g. SIV) vector may comprise a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 10,000 bases in length, less than 9,000 bases in length, or less than 8,000 bases in length; and (b) consists of a nucleic acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 1.
The retroviral/lentiviral (e.g. SIV) vector may comprise a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 10,000 bases in length, less than 9,000 bases in length, or less than 8,000 bases in length; and (b) consists of a nucleic acid sequence having at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 1.
The retroviral/lentiviral (e.g. SIV) vector may comprise a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 9,000 bases in length, or less than 8,000 bases in length; and (b) comprises or consists of a nucleic acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 1.
The retroviral/lentiviral (e.g. SIV) vector may comprise a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 9,000 bases in length, or less than 8,000 bases in length; and (b) comprises or consists of a nucleic acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 1.
The retroviral/lentiviral (e.g. SIV) vector may comprise a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 9,000 bases in length, or less than 8,000 bases in length; and (b) comprises or consists of a nucleic acid sequence having at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 1.
The retroviral/lentiviral (e.g. SIV) vector may comprise a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 9,000 bases in length, or less than 8,000 bases in length; and (b) consists of a nucleic acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 1.
The retroviral/lentiviral (e.g. SIV) vector may comprise a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 9,000 bases in length, or less than 8,000 bases in length; and (b) consists of a nucleic acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 1.
The retroviral/lentiviral (e.g. SIV) vector may comprise a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 9,000 bases in length, or less than 8,000 bases in length; and (b) consists of a nucleic acid sequence having at least 99%, at least 99.5%, at least 99.9%, or more, up to 100% identity to SEQ ID NO: 1.
Preferably, the retroviral/lentiviral (e.g. SIV) vector comprises a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 9,000 bases in length; and (b) comprises or consists of a nucleic acid sequence having at least 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or up to 100% identity to SEQ ID NO: 1. More preferably, the retroviral/lentiviral (e.g. SIV) vector comprises a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 9,000 bases in length; and (b) comprises or consists of a nucleic acid sequence having at least 99% identity to SEQ ID NO: 1. Still more preferably, the retroviral/lentiviral (e.g. SIV) vector comprises a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 9,000 bases in length; and (b) consists of a nucleic acid sequence having at least 99% identity to SEQ ID NO: 1. Still more preferably, the retroviral/lentiviral (e.g. SIV) vector comprises a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 9,000 bases in length; and (b) comprises or consists of a nucleic acid sequence of SEQ ID NO: 1. Still more preferably, the retroviral/lentiviral (e.g. SIV) vector comprises a modified retroviral/lentiviral (e.g. SIV) RNA sequence that is (a) less than 9,000 bases in length; and (b) consists of a nucleic acid sequence of SEQ ID NO: 1.
The 5′ and/or 3′ limits of a modified retroviral/lentiviral (e.g. SIV) RNA sequence may each independently allow for some degree of flexibility, such that the 5′ end of the modified retroviral/lentiviral (e.g. SIV) RNA sequence may not correspond to the first nucleotide of SEQ ID NO: 1, and/or the 3′ end of the modified retroviral/lentiviral (e.g. SIV) RNA sequence may not correspond to the last nucleotide of SEQ ID NO: 1.
Accordingly, a modified retroviral/lentiviral (e.g. SIV) RNA sequence may comprise up to an additional 200 nucleotides, up to an additional 150 nucleotides, up to an additional 100 nucleotides, up to an additional 75 nucleotides, up to an additional 50 nucleotides, up to an additional 25 nucleotides, up to an additional 10 nucleotides, up to an additional 5, nucleotides at the 5′ and/or 3′ end, e.g. compared with SEQ ID NO: 1. The modified retroviral/lentiviral (e.g. SIV) RNA sequence may comprise an additional 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1 nucleotides at the 5′ and/or 3′ end, e.g. compared with SEQ ID NO: 1. The presence of additional nucleotides and the number thereof at the 5′ end of the modified retroviral/lentiviral (e.g. SIV) RNA sequence is independent from the presence of additional nucleotides and the number thereof at the 3′ end of the modified retroviral/lentiviral (e.g. SIV) RNA sequence. By way of non-limiting example, a modified retroviral/lentiviral (e.g. SIV) RNA sequence may comprise up to an additional 3 nucleotides at the 5′ and up to an additional 200 nucleotides at the 3′ end, e.g. compared with SEQ ID NO: 1. By way of a further non-limiting example, a modified retroviral/lentiviral (e.g. SIV) RNA sequence may comprise no additional nucleotides at the 5′ and an additional 42 nucleotides at the 3′ end, e.g. compared with SEQ ID NO: 1. Preferably, a modified retroviral/lentiviral (e.g. SIV) RNA sequence does not comprise any additional nucleotides at the 5′ end, but may comprise up to an additional 200 nucleotides at the 3′ end (as described above), e.g. compared with SEQ ID NO: 1.
A modified retroviral/lentiviral (e.g. SIV) RNA sequence may comprise up to 200 nucleotides less, up to 150 nucleotides less, up to 100 nucleotides less, up to 75 nucleotides less, up to 50 nucleotides less, up to 25 nucleotides less, up to 10 nucleotides less, up to 5 nucleotides less at the 5′ and/or 3′ end, e.g. compared with SEQ ID NO: 1. The modified retroviral/lentiviral (e.g. SIV) RNA sequence may comprise 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1 nucleotides less at the 5′ and/or 3′ end, e.g. compared with SEQ ID NO: 1. The number of deleted thereof at the 5′ end of the modified retroviral/lentiviral (e.g. SIV) RNA sequence is independent from the presence of deleted nucleotides and the number thereof at the 3′ end of the modified retroviral/lentiviral (e.g. SIV) RNA sequence. By way of non-limiting example, a modified retroviral/lentiviral (e.g. SIV) RNA sequence may comprise up to 3 nucleotides less at the 5′, e.g. compared with SEQ ID NO: 1 and up to 200 nucleotides at the 3′ end, e.g. compared with SEQ ID NO: 1. By way of a further non-limiting example, a modified retroviral/lentiviral (e.g. SIV) RNA sequence may comprise no nucleotides less at the 5′, e.g. compared with SEQ ID NO: 1 and 42 nucleotides less at the 3′ end, e.g. compared with SEQ ID NO: 1. Preferably, a modified retroviral/lentiviral (e.g. SIV) RNA sequence does not comprise any nucleotides less at the 5′ end, but may comprise up to 200 nucleotides less at the 3′ end (as described above), e.g. compared with SEQ ID NO: 1.
One end of the modified retroviral/lentiviral (e.g. SIV) RNA sequence may have additional nucleotides, e.g. compared with SEQ ID NO: 1 and the other end may have fewer nucleotides, e.g. compared with SEQ ID NO: 1. Thus, the 5′ end may have additional nucleotides, e.g. compared with SEQ ID NO: 1, and the 3′ end may have fewer nucleotides, e.g. compared with SEQ ID NO: 1. The 3′ end may have additional nucleotides, e.g. compared with SEQ ID NO: 1, and the 5′ end may have fewer nucleotides, e.g. compared with SEQ ID NO: 1. The disclosure herein in relation to the number of additional and/or deleted nucleotides applies equally and without reservation to modified retroviral/lentiviral (e.g. SIV) RNA sequence in which one end has additional nucleotides, e.g. compared with SEQ ID NO: 1 and the other end has fewer nucleotides, e.g. compared with SEQ ID NO: 1. Preferably, a modified retroviral/lentiviral (e.g. SIV) RNA sequence does not comprise any additional/missing nucleotides at the 5′ end, but may comprise additional or fewer nucleotides at the 3′ end (as described above), e.g. compared with SEQ ID NO: 1.
As described herein, retroviral/lentiviral (e.g. SIV) vectors with modified retroviral/lentiviral (e.g. SIV) RNA sequences according to the invention avoid potential safety risks as described herein, whilst: (i) maintaining or even increasing transgene expression; (ii) maintaining or even increasing retroviral/lentiviral (e.g. SIV) RNA sequence integration into a host cell genome; and/or (iii) maintaining or even increasing retroviral/lentiviral (e.g. SIV) vector yield.
Thus, the retroviral/lentiviral (e.g. SIV) vectors comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention typically exhibit high levels of transgene expression. Typically a the retroviral/lentiviral (e.g. SIV) vector with a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention is at least equivalent in terms of transgene expression compared with retroviral/lentiviral (e.g. SIV) vector which comprises the unmodified retroviral/lentiviral (e.g. SIV) RNA sequence from which the modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived (i.e. the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence).
As used herein, the term “equivalent transgene expression” may be defined such that the modified retroviral/lentiviral (e.g. SIV) RNA sequence does not significantly decrease transgene expression of the retroviral/lentiviral (e.g. SIV) vector compared with the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. By way of non-limiting example, transgene expression by a retroviral/lentiviral (e.g. SIV) vector comprising the modified retroviral/lentiviral (e.g. SIV) RNA sequence into the host/target cell genome may be no more than 2-fold lower, no more than 1.5-fold lower, no more than 1.0-fold lower, no more than 0.5-fold lower, no more than 0.25-fold lower, or less than transgene expression by the retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. The term “equivalent transgene expression” may be defined such that transgene expression by a retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence into the host/target cell genome is statistically unchanged (e.g. p<0.05, p<0.01) compared with transgene expression by the retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence.
Preferably, transgene expression by a retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence vector into the host/target cell genome is increased compared with transgene expression by the retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. Transgene expression by a retroviral/lentiviral (e.g. SIV) vector comprising the modified retroviral/lentiviral (e.g. SIV) RNA sequence into the host/target cell genome may be at least 1.5-fold, at least 2-fold, or at least 2.5-fold greater than transgene expression by the retroviral/lentiviral (e.g. SIV) vector comprising the corresponding non-modified retroviral/lentiviral (e.g. SIV) RNA sequence.
Alternatively or in addition, the retroviral/lentiviral (e.g. SIV) vectors comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention exhibit high levels of vector integration into the host/target cell genome. Typically a retroviral/lentiviral (e.g. SIV) vector with a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention is at least equivalent in terms of integration into the host/target cell genome compared with the retroviral/lentiviral (e.g. SIV) vector which comprises the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence.
As used herein, the term “equivalent integration” may be defined such that the modified retroviral/lentiviral (e.g. SIV) RNA sequence does not significantly decrease the integration of retroviral/lentiviral (e.g. SIV) vector into the host/target cell genome compared with the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. By way of non-limiting example, integration of retroviral/lentiviral (e.g. SIV) vector comprising the modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention into the host/target cell genome may be no more than 2-fold lower, no more than 1.5-fold lower, no more than 1.0-fold lower, no more than 0.5-fold lower, no more than 0.25-fold lower, or less than the integration into the host/target cell genome of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. The term “equivalent integration” may be defined such that integration of retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention into the host/target cell genome is statistically unchanged (e.g. p<0.05, p<0.01) compared with integration of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence.
Preferably, the integration of retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence vector of the invention into the host/target cell genome is increased compared with the integration of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. The integration of retroviral/lentiviral (e.g. SIV) vector comprising the modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention into the host/target cell genome may be at least 1.5-fold, at least 2-fold, or at least 2.5-fold greater than the integration of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding non-modified retroviral/lentiviral (e.g. SIV) RNA sequence.
Alternatively or in addition, the invention provides high titre purified retroviral/lentiviral (e.g. SIV) vectors comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence. Typically the titre of a retroviral/lentiviral (e.g. SIV) vector with a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention is at least equivalent to the titre of a retroviral/lentiviral (e.g. SIV) vector which comprises the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence.
As used herein, the term “equivalent titre” may be defined such that the modified retroviral/lentiviral (e.g. SIV) RNA sequence does not significantly decrease the titre of retroviral/lentiviral (e.g. SIV) vector compared with the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. By way of non-limiting example, a titre of retroviral/lentiviral (e.g. SIV) vector comprising the modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention may be no more than 2-fold lower, no more than 1.5-fold lower, no more than 1.0-fold lower, no more than 0.5-fold lower, no more than 0.25-fold lower, or less than the titre of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. The term “equivalent titre” may be defined such that titre of retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention is statistically unchanged (e.g. p<0.05, p<0.01) compared with the titre of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence.
Preferably, the titre of retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence vector of the invention is increased compared with the titre of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. The titre of retroviral/lentiviral (e.g. SIV) vector comprising the modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention may be at least 1.5-fold, at least 2-fold, or at least 2.5-fold greater than the titre of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding non-modified retroviral/lentiviral (e.g. SIV) RNA sequence.
The production of high-titre retroviral/lentiviral (e.g. SIV) vectors may impart other desirable properties on the resulting vector products. For example, without being bound by theory, it is believed that production at high titres without the need for intense concentration by methods such as TFF results in a higher quality vector product than corresponding retroviral/lentiviral (e.g. SIV) vectors with unmodified retroviral/lentiviral (e.g. SIV) RNA sequences because the vectors are exposed to less shear forces which can damage the viral particles and their RNA cargo.
Preferably, the retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence vector of the invention exhibits maintained/increased transgene expression compared with the titre of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. The retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence vector of the invention exhibits maintained/increased transgene expression and maintained/increased vector integration compared with the titre of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. The retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence vector of the invention exhibits maintained/increased transgene expression and maintained/increased vector yield/titre compared with the titre of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. More preferably, the retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence vector of the invention exhibits maintained/increased transgene expression, maintained/increased vector integration and maintained/increased vector yield/titre compared with the titre of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence.
The invention also provides host cells comprising a retroviral/lentiviral (e.g. SIV) vector of the invention. Typically a host cell is a mammalian cell, particularly a human cell or cell line. Non-limiting examples of host cells include HEK293 cells (such as HEK293F or HEK293T cells) and 293T/17 cells. Commercial cell lines suitable for the production of virus are also readily available (as described herein).
Methods for the production of retroviral/lentiviral (e.g. SIV) vectors of the invention as also described herein.
The present inventors have previously demonstrated that the use of codon-optimised gal-pol genes from SIV does not negatively impact the manufactured titre of a SIV vector pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus, and can even result in an increased titre of the vector. This is described in PCT/GB2022/050524, which is herein incorporated by reference in its entirety.
The present inventors have now shown that retroviral/lentiviral (e.g. SIV) vectors can be produced with modified retroviral/lentiviral (e.g. SIV) RNA sequences which avoid potential safety risks as described herein, whilst: (i) maintaining or even increasing transgene expression; (ii) maintaining or even increasing retroviral/lentiviral (e.g. SIV) RNA sequence integration into a host cell genome; and/or (iii) maintaining or even increasing retroviral/lentiviral (e.g. SIV) vector yield. Furthermore, the vector genome plasmids which are used in the manufacture of the retroviral/lentiviral (e.g. SIV) vectors of the invention can be combined with the use of codon-optimised gag-pol genes as described herein, again whilst maintaining, or even increasing the vector titre.
Accordingly, the present invention provides a method of producing a retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence as described herein, where said retroviral/lentiviral (e.g. SIV) is pseudotyped with hemagglutinin-neuraminidase (HN) and fusion (F) proteins from a respiratory paramyxovirus, and which comprises a promoter and a transgene. Preferably said retroviral/lentiviral (e.g. SIV) vector is a lentiviral vector, with Simian immunodeficiency virus (SIV) vectors being particularly preferred.
The method of the invention may be a scalable GMP-compatible method.
The method of the invention typically allows the generation of retroviral/lentiviral (e.g. SIV) vectors comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence with high levels of transgene expression. Typically a method of the invention produces retroviral/lentiviral (e.g. SIV) vector with a modified retroviral/lentiviral (e.g. SIV) RNA sequence as described herein that are at least equivalent in terms of transgene expression compared with retroviral/lentiviral (e.g. SIV) vector which comprises the unmodified retroviral/lentiviral (e.g. SIV) RNA sequence from which the modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived (i.e. the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence) when produced by the same method.
As used herein, the term “equivalent transgene expression” may be defined such that the modified retroviral/lentiviral (e.g. SIV) RNA sequence does not significantly decrease transgene expression of the retroviral/lentiviral (e.g. SIV) vector compared with the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. By way of non-limiting example, transgene expression by a retroviral/lentiviral (e.g. SIV) vector comprising the modified retroviral/lentiviral (e.g. SIV) RNA sequence into the host/target cell genome is no more than 2-fold lower, no more than 1.5-fold lower, no more than 1.0-fold lower, no more than 0.5-fold lower, no more than 0.25-fold lower, or less than transgene expression by the retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. The term “equivalent transgene expression” may be defined such that transgene expression by a retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence into the host/target cell genome is statistically unchanged (e.g. p<0.05, p<0.01) compared with transgene expression by the retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence produced by the same method.
Preferably, transgene expression by a retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence vector into the host/target cell genome is increased compared with transgene expression by the retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence produced by the same method. Transgene expression by a retroviral/lentiviral (e.g. SIV) vector comprising the modified retroviral/lentiviral (e.g. SIV) RNA sequence into the host/target cell genome may be at least 1.5-fold, at least 2-fold, or at least 2.5-fold greater than transgene expression by the retroviral/lentiviral (e.g. SIV) vector comprising the corresponding non-modified retroviral/lentiviral (e.g. SIV) RNA sequence produced by the same method.
The method of the invention typically allows the generation of retroviral/lentiviral (e.g. SIV) vectors comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence with high levels of vector integration into the host/target cell genome. Typically a method of the invention produces retroviral/lentiviral (e.g. SIV) vector with a modified retroviral/lentiviral (e.g. SIV) RNA sequence as described herein that are at least equivalent in terms of integration into the host/target cell genome compared with retroviral/lentiviral (e.g. SIV) vector which comprises the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence produced by the same method.
As used herein, the term “equivalent integration” may be defined such that the modified retroviral/lentiviral (e.g. SIV) RNA sequence does not significantly decrease the integration of retroviral/lentiviral (e.g. SIV) vector into the host/target cell genome compared with the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. By way of non-limiting example, integration of retroviral/lentiviral (e.g. SIV) vector comprising the modified retroviral/lentiviral (e.g. SIV) RNA sequence into the host/target cell genome is no more than 2-fold lower, no more than 1.5-fold lower, no more than 1.0-fold lower, no more than 0.5-fold lower, no more than 0.25-fold lower, or less than the integration into the host/target cell genome of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. The term “equivalent integration” may be defined such that integration of retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence into the host/target cell genome is statistically unchanged (e.g. p<0.05, p<0.01) compared with integration of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence produced by the same method.
Preferably, the integration of retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence vector into the host/target cell genome is increased compared with the integration of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence produced by the same method. The integration of retroviral/lentiviral (e.g. SIV) vector comprising the modified retroviral/lentiviral (e.g. SIV) RNA sequence into the host/target cell genome may be at least 1.5-fold, at least 2-fold, or at least 2.5-fold greater than the integration of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding non-modified retroviral/lentiviral (e.g. SIV) RNA sequence produced by the same method.
The method of the invention typically allows the generation of high titre purified retroviral/lentiviral (e.g. SIV) vectors comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence. Typically a method of the invention produces a titre of retroviral/lentiviral (e.g. SIV) vector with a modified retroviral/lentiviral (e.g. SIV) RNA sequence as described herein that is at least equivalent to the titre of a retroviral/lentiviral (e.g. SIV) vector which comprises the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence when produced by a corresponding method.
As used herein, the term “equivalent titre” may be defined such that the modified retroviral/lentiviral (e.g. SIV) RNA sequence does not significantly decrease the titre of retroviral/lentiviral (e.g. SIV) vector compared with the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. By way of non-limiting example, a titre of retroviral/lentiviral (e.g. SIV) vector comprising the modified retroviral/lentiviral (e.g. SIV) RNA sequence that is no more than 2-fold lower, no more than 1.5-fold lower, no more than 1.0-fold lower, no more than 0.5-fold lower, no more than 0.25-fold lower, or less than the titre of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence. The term “equivalent titre” may be defined such that titre of retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence is statistically unchanged (e.g. p<0.05, p<0.01) compared with the titre of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence produced by the same method.
Preferably, the titre of retroviral/lentiviral (e.g. SIV) vector comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence vector is increased compared with the titre of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence produced by the same method. The titre of retroviral/lentiviral (e.g. SIV) vector comprising the modified retroviral/lentiviral (e.g. SIV) RNA sequence may be at least 1.5-fold, at least 2-fold, or at least 2.5-fold greater than the titre of retroviral/lentiviral (e.g. SIV) vector comprising the corresponding non-modified retroviral/lentiviral (e.g. SIV) RNA sequence produced by the same method.
The production of retroviral/lentiviral (e.g. SIV) vectors typically employs one or more plasmids which provide the elements needed for the production of the vector: the genome for the retroviral/lentiviral vector, the Gag-Pol, Rev, F and HN. Multiple elements can be provided on a single plasmid. Preferably each element is provided on a separate plasmid, such that there five plasmids, one for each of the vector genome, the Gag-Pol, Rev, F and HN, respectively.
Alternatively, a single plasmid may provide the Gag-Pol and Rev elements, and may be referred to as a packaging plasmid (pDNA2). The remaining elements (genome, F and HN) may be provided by separate plasmids (pDNA1, pDNA3a, pDNA3b respectively), such that four plasmids are used for the production of a retroviral/lentiviral (e.g. SIV) vector according to the invention. In the four plasmid methods, pDNA1, pDNA3a and pDNA3b may be as described herein in the context of the five-plasmid method.
In the preferred five plasmid method of the invention, the vector genome plasmid encodes all the genetic material that is packaged into final retroviral/lentiviral vector, including the transgene. The vector genome plasmid may be designated herein as “pDNA1”, and typically comprises the transgene and the transgene promoter. As described herein, only a portion of the genetic material found in the vector genome plasmid ends up in the virus, and the precise limits and boundaries of this portion cannot be readily deduced based on the primary sequence of the pDNA1. The present invention elucidates for the first time the nucleic acid sequence of a modified RNA sequence of a SIV vector which addresses numerous potential safety risks, whilst providing maintained or even increased (i) transgene expression, (ii) SIV RNA sequence integration, and/or (iii) vector yield.
The other four plasmids are manufacturing plasmids encoding the Gag-Pol, Rev, F and HN proteins. These plasmids may be designated “pDNA2a”, “pDNA2b”, “pDNA3a” and “pDNA3b” respectively.
Typically, the lentivirus is SIV, such as SIV1, preferably SIV-AGM. The F and HN proteins are derived from a respiratory paramyxovirus, preferably a Sendai virus.
In a specific embodiment relating to CFTR, the five plasmids are characterised by
When a method of the invention is used to produce A1AT, the five plasmids may be characterised by
When a method of the invention is used to produce FVIII, the five plasmids may be characterised by one of
The plasmid as defined in
In the five-plasmid method of the invention all five plasmids contribute to the formation of the final retroviral/lentiviral (e.g. SIV) vector, although only the vector genome plasmid provides nucleic acid sequence comprised in the retroviral/lentiviral (e.g. SIV) RNA sequence. During manufacture of the retroviral/lentiviral (e.g. SIV) vector, the vector genome plasmid (pDNA1) provides the enhancer/promoter, Psi, RRE, cPPT, mWPRE, SIN LTR, SV40 polyA (see
For other retroviral/lentiviral (e.g. SIV) vectors of the invention, corresponding elements from the other vector genome plasmids (pDNA1) are required for manufacture (but not found in the final vector), or are present in the final retroviral/lentiviral (e.g. SIV) vector.
The F and HN proteins from pDNA3a and pDNA3b (preferably Sendai F and HN proteins) are important for infection of target cells with the final retroviral/lentiviral (e.g. SIV) vector, i.e. for entry of a patient's epithelial cells (typically lung or nasal cells as described herein). The products of the pDNA2a and pDNA2b plasmids are important for virus transduction, i.e. for inserting the retroviral/lentiviral (e.g. SIV) DNA into the host's genome. The promoter, regulatory elements (such as WPRE) and transgene are important for transgene expression within the target cell(s).
A method of the invention may comprise or consist of the following steps: (a) growing cells in suspension; (b) transfecting the cells with one or more plasmids; (c) adding a nuclease; (d) harvesting the lentivirus (e.g. SIV); (e) adding trypsin; and (f) purification of the lentivirus (e.g. SIV).
This method may use the four- or five-plasmid system described herein. Thus, for the preferred five-plasmid method, the one or more plasmids may comprise or consist of: a vector genome plasmid pDNA1; a gagpol plasmid (e.g. codon-optimised gagpol plasmid), pDNA2a; a Rev plasmid, pDNA2b; a fusion (F) protein plasmid, pDNA3a; and a hemagglutinin-neuraminidase (HN) plasmid, pDNA3b. The pDNA1 may be pGM830. The pDNA2a may be pGM297 or pGM691, preferably pGM691. The pDNA2b may be pGM299. The pDNA3a may be pGM301. The pDNA3b may be pGM303. Any combination of pDNA1, pDNA2a, pDNA2b, pDNA3a and pDNA3b may be used. Preferably, the pDNA1 is pGM830; the pDNA2a is pGM691; the pDNA2b is pGM299; the pDNA3a is pGM301; and the pDNA3b is pGM303.
Any appropriate ratio of vector genome plasmid:gagpol plasmid:Rev plasmid:F plasmid:HN plasmid may be used to further optimise (increase) the retroviral/lentiviral (e.g. SIV) titre produced. By way of non-limiting example, the ratio of vector genome plasmid:gagpol plasmid:Rev plasmid:F plasmid:HN plasmid may by in the range of 10-40:-4-20:3-12:3-12:3-12, typically 15-20:7-11:4-8:4-8:4-8, such as about 18-22:7-11:4-8:4-8:4-8, 19-21:8-10:5-7:5-7:5-7. Preferably the ratio of vector genome plasmid:gagpol plasmid:Rev plasmid:F plasmid:HN plasmid is about 20:9:6:6:6.
Steps (a)-(f) of the method are typically carried out sequentially, starting at step (a) and continuing through to step (f). The method may include one or more additional step, such as additional purification steps, buffer exchange, concentration of the retroviral/lentiviral (e.g. SIV) vector after purification, and/or formulation of the retroviral/lentiviral (e.g. SIV) vector after purification (or concentration). Each of the steps may comprise one or more sub-steps. For example, harvesting may involve one or more steps or sub-steps, and/or purification may involve one or more steps or sub-steps.
Any appropriate cell type may be transfected with the one or more plasmids (e.g. the five-plasmids described herein) to produce a retroviral/lentiviral (e.g. SIV) vector of the invention. Typically mammalian cells, particularly human cell lines are used. Non-limiting examples of cells suitable for use in the methods of the invention are HEK293 cells (such as HEK293F or HEK293T cells) and 293T/17 cells. Commercial cell lines suitable for the production of virus are also readily available (e.g. Gibco Viral Production Cells—Catalogue Number A35347 from ThermoFisher Scientific).
The cells may be grown in animal-component free media, including serum-free media. The cells may be grown in a media which contains human components. The cells may be grown in a defined media comprising or consisting of synthetically produced components.
Any appropriate transfection means may be used according to the invention. Selection of appropriate transfection means is within the routine practice of one of ordinary skill in the art. By way of non-limiting example, transfection may be carried out by the use of PEIPro™, Lipofectamine2000™ or Lipofectamine3000™.
Any appropriate nuclease may be used according to the invention. Selection of appropriate nuclease is within the routine practice of one of ordinary skill in the art. Typically the nuclease is an endonuclease. By way of non-limiting example, the nuclease may be Benzonase® or Denarase®. The addition of the nuclease may be at the pre-harvest stage or at the post-harvest stage, or between harvesting steps.
The gag-pol genes used in the production of a retroviral/lentiviral (e.g. SIV) vectors of the invention may be codon-optimised. Thus, the gag-pol genes within the pDNA2a plasmid may be codon-optimised. By way of non-limiting example, codon-optimised gag-pol genes may comprise or consist of the nucleic acid sequence of SEQ ID NO: 17, or a variant thereof (as defined herein). In particular, the codon-optimised gag-pol genes of the invention may comprise or consist of a nucleic acid sequence having at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or more sequence identity to SEQ ID NO: 17, preferably at least 95%, identity to SEQ ID NO: 17. The codon-optimised gag-pol genes may consist of the nucleic acid sequence of SEQ ID NO: 17. The preferred pDNA2a, pGM691, comprises the codon-optimised gag-pol genes of SEQ ID NO: 17.
The gag-pol genes (e.g. SIV gag-pol genes), including codon-optimised gag-pol genes are typically operably linked to a promoter to facilitate expression of the gag-pol proteins. Any suitable promoter may be used, including those described herein in the context of promoters for the transgene. Preferably, the promoter is a CAG promoter, as used on the exemplified pGM691 plasmid. An exemplary CAG promoter is set out in SEQ ID NO: 45. The codon-optimised gag-pol genes of SEQ ID NO: 17 comprise a translational slip, and so do not form a single conventional open reading frame.
Codon-optimised gag-pol genes (or nucleic acids comprising or consisting thereof) and plasmids comprising said genes or nucleic acids are advantageous in the production of retroviral/lentiviral (e.g. SIV) vectors using methods of the invention, as they allow for the production of high titre F/HN retroviral/lentiviral (e.g. SIV) vectors. Typically said codon-optimised gag-pol genes (or nucleic acids comprising or consisting thereof) and plasmids comprising said genes or nucleic acids can be used to produces a titre of retroviral/lentiviral (e.g. SIV) vector that is at least equivalent to the titre of retroviral/lentiviral (e.g. SIV) vector produced by a corresponding method which does not use codon-optimised gag-pol genes, as described herein. Thus, the use of codon-optimised gag-pol genes can be combined with a modified retroviral/lentiviral (e.g. SIV) RNA sequence to further maintain/increase vector titre.
Codon-optimised gag-pol genes are further disclosed in PCT/GB2022/050524, which is herein incorporated by reference in its entirety.
The invention also provides a retroviral/lentiviral (e.g. SIV) vector obtainable by a method of the invention.
Typically, the retroviral/lentiviral (e.g. SIV) vector obtainable by a method of the invention is produced at a high-titre, as described herein. Titre may be measured in terms of transducing units, as defined here. As described herein, the methods of the invention typically produce retroviral/lentiviral (e.g. SIV) vectors comprising a modified retroviral/lentiviral (e.g. SIV) RNA sequence at equivalent or higher titres than retroviral/lentiviral (e.g. SIV) vectors comprising the corresponding unmodified retroviral/lentiviral (e.g. SIV) RNA sequence, and/methods which do not use codon-optimised gag-pol genes.
Accordingly, the retroviral/lentiviral (e.g. SIV) vectors of the invention, including those obtainable by a method of the invention may optionally be at a titre of at least about 2.5×106 TU/mL, at least about 3.0×106 TU/mL, at least about 3.1×106 TU/mL, at least about 3.2×106 TU/mL, at least about 3.3×106 TU/mL, at least about 3.4×106 TU/mL, at least about 3.5×106 TU/mL, at least about 3.6×106 TU/mL, at least about 3.7×106 TU/mL, at least about 3.8×106 TU/mL, at least about 3.9×106 TU/mL, at least about 4.0×106 TU/mL or more. Preferably the retroviral/lentiviral (e.g. SIV) vector is produced at a titre of at least about 3.0×106 TU/mL, or at least about 3.5×106 TU/mL.
The production of high-titre retroviral/lentiviral (e.g. SIV) vectors may impart other desirable properties on the resulting vector products. For example, without being bound by theory, it is believed that production at high titres without the need for intense concentration by methods such as TFF results in a higher quality vector product than retroviral/lentiviral (e.g. SIV) vectors produced by corresponding methods without the use of codon-optimised gag-pol genes (and optionally a modified vector genome plasmid), because the vectors are exposed to less shear forces which can damage the viral particles and their RNA cargo.
Typically the gag-pol genes (e.g. codon-optimised gag-pol genes) used are matched to the retroviral/lentiviral vector being produced. By way of non-limiting example, when the lentiviral vector is an HIV vector, the codon-optimised gag-pol genes used are HIV gag-pol genes. By way of non-limiting example, when the lentiviral vector is an SIV vector, the codon-optimised gag-pol genes used are SIV gag-pol genes.
Preferably the codon-optimised gag-pol genes used are SIV gag-pol genes.
As described herein, the retroviral/lentiviral (e.g. SIV) vectors of the invention comprise a modified retroviral/lentiviral (e.g. SIV) RNA sequence, which is typically modified to reduce the number of retroviral/lentiviral (e.g. SIV) ORFs. Accordingly, the vector genome plasmid used in the production of a retroviral/lentiviral (e.g. SIV) vector of the invention may be modified to reduce the number of retroviral/lentiviral (e.g. SIV) ORFs. Any disclosure herein in relation to modification of the retroviral/lentiviral (e.g. SIV) RNA sequence, including modifications to reduce the number of retroviral/lentiviral (e.g. SIV) ORFs within the retroviral/lentiviral (e.g. SIV) RNA sequence, applies equally and without reservation to the vector genome plasmids (pDNA1) described herein, which may be used in the production of retroviral/lentiviral (e.g. SIV) vectors of the invention.
As used herein, the term “trypsin” refers to both trypsin and equivalents thereof. An equivalent enzyme is one with the same or essentially the same cleavage specificity as trypsin. Trypsin cleavage activity may be defined as cleavage C-terminal to arginine or lysine residues, typically exclusively C-terminal to arginine or lysine residues. The trypsin activity may preferably be provided by an animal origin free, recombinant enzyme such as TrypLE Select™. The addition of trypsin may be at the pre-harvest stage or at the post-harvest stage, or between harvesting steps.
Any appropriate purification means may be used to purify the retroviral/lentiviral (e.g. SIV) vector. Non-limiting examples of suitable purification steps include depth/end filtration, tangential flow filtration (TFF) and chromatography. The purification step typically comprises at least on chromatography step. Non-limiting examples of chromatography steps that may be used in accordance with the invention include mixed-mode size exclusion chromatography (SEC) and/or anion exchange chromatography. Elution may be carried out with or without the use of a salt gradient, preferably without.
This method may be used to produce the retroviral/lentiviral (e.g. SIV) vectors of the invention, such as those comprising a CFTR, A1AT and/or FVIII gene as described herein. Alternatively, the retroviral/lentiviral (e.g. SIV) vector of the invention comprises any of the above-mentioned genes, or the genes encoding the above-mentioned proteins.
The method, may use any combination of one or more of the specific plasmid constructs provided by
The invention also provides a method of increasing retroviral/lentiviral (e.g. SIV) vector titre comprising the use of a modified retroviral/lentiviral (e.g. SIV) RNA sequence as described herein, or a vector genome plasmid from which such a modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived. This method may be combined with the use of codon-optimised gag-pol genes (or nucleic acids comprising or consisting thereof), a plasmid comprising said genes or nucleic acids as described herein to further increase retroviral/lentiviral (e.g. SIV) vector titre. Said method of increasing retroviral/lentiviral (e.g. SIV) vector titre according to the invention may increase titre by at least 1.5-fold, at least 2-fold, or at least 2.5-fold or more compared with a corresponding method which uses the corresponding non-modified retroviral/lentiviral (e.g. SIV) RNA sequence or a vector genome plasmid from which the corresponding non-modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived, and optionally also uses non-codon-optimised versions of the gag-pol genes (or nucleic acids comprising or consisting thereof), or plasmids or host cells comprising said non-codon optimised gag-pol genes or nucleic acids. Alternatively, a method of increasing retroviral/lentiviral (e.g. SIV) titre according to the invention may increase titre by at least about 25%, at least about 50%, at least about 100%, at least about 150%, at least about 200% or more compared with a corresponding method which uses the corresponding non-modified retroviral/lentiviral (e.g. SIV) RNA sequence or a vector genome plasmid from which the corresponding non-modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived, and optionally also uses non-codon-optimised versions of the gag-pol genes (or nucleic acids comprising or consisting thereof), or plasmids comprising said non-codon optimised genes or nucleic acids. Preferably, a method of increasing retroviral/lentiviral (e.g. SIV) vector titre according to the invention may increase titre by (a) by at least 1.5-fold or at least 2-fold; and/or (b) by at least about 25%, more preferably at least about 50%, even more preferably at least about 100%. Typically the corresponding method is identical to the method of the invention except for the use of the corresponding non-modified retroviral/lentiviral (e.g. SIV) RNA sequence or a vector genome plasmid from which the corresponding non-modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived, and optionally the codon-optimised gag-pol genes (or nucleic acids comprising or consisting thereof), a plasmid comprising said genes or nucleic acids. All the disclosure herein in relation to method of producing a retroviral/lentiviral (e.g. SIV) vector applies equally and without reservation to the methods of increasing retroviral/lentiviral (e.g. SIV) titre of the invention.
The invention also provides the use of a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention (or vector genome plasmid from which said modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived) to increase the titre of a retroviral/lentiviral (e.g. SIV) vector. This use may be combined with the use of codon-optimised gag-pol genes (or nucleic acids comprising or consisting thereof), a plasmid comprising said genes or nucleic acids as described herein to further increase retroviral/lentiviral (e.g. SIV) vector titre. Said use may increase retroviral/lentiviral (e.g. SIV) vector titre by at least 1.5-fold, at least 2-fold, or at least 2.5-fold or more compared with the use of a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention (or vector genome plasmid from which said modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived), and optionally a corresponding non-codon-optimised version of the gag-pol genes (or nucleic acids comprising or consisting thereof), or plasmids comprising said non-codon optimised genes or nucleic acids. Alternatively, said use may increase retroviral/lentiviral (e.g. SIV) titre by at least about 25%, at least about 50%, at least about 100%, at least about 150%, at least about 200% or more compared with the use of a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention (or vector genome plasmid from which said modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived), and optionally a corresponding non-codon-optimised version of the gag-pol genes (or nucleic acids comprising or consisting thereof), or plasmids comprising said non-codon optimised genes or nucleic acids. Preferably, said use increases retroviral/lentiviral (e.g. SIV) titre by (a) by at least 1.5-fold or at least 2-fold; and/or (b) at least about 25%, more preferably at least about 50%, even more preferably at least about 100%. Typically the corresponding use is identical to the method of the invention except for the use of the modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention (or vector genome plasmid from which said modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived), and optionally the codon-optimised gag-pol genes (or nucleic acids comprising or consisting thereof), a plasmid comprising said genes or nucleic acids. All the disclosure herein in relation to method of producing a retroviral/lentiviral (e.g. SIV) vector applies equally and without reservation to the use of a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention (or vector genome plasmid from which said modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived) and optionally codon-optimised gag-pol genes (or nucleic acids comprising or consisting thereof), a plasmid comprising said genes or nucleic acids to increase the titre of a retroviral/lentiviral (e.g. SIV) vector according to the invention.
The use of codon-optimised gag-pol genes in combination with a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention, or vector genome plasmid from which said modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived, may provide a further advantage, in terms of safety and/or vector titre. Thus, the increased vector yields as described herein may be achieved using a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention (or vector genome plasmid from which said modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived) in combination with codon-optimised gag-pol genes. Any and all disclosure herein in relation to increased vector titre in the context of methods using a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention (or vector genome plasmid from which said modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived) applies equally and without reservation to methods using a modified retroviral/lentiviral (e.g. SIV) RNA sequence of the invention (or vector genome plasmid from which said modified retroviral/lentiviral (e.g. SIV) RNA sequence is derived) in combination with codon-optimised gag-pol genes, and to vectors produced by such methods.
The retroviral/lentiviral (e.g. SIV) vectors of the present invention enable higher and sustained gene expression through efficient gene transfer whilst also reducing the risk of side-effects due to the expression of retroviral ORFs, such as upstream ORFs. The F/HN-pseudotyped retroviral/lentiviral (e.g. SIV) vectors of the invention are capable of: (i) airway transduction without disruption of epithelial integrity; (ii) persistent gene expression; (iii) lack of chronic toxicity; and (iv) efficient repeat administration. Long term/persistent stable gene expression, preferably at a therapeutically-effective level, may be achieved using repeat doses of a vector of the present invention. Alternatively, a single dose may be used to achieve the desired long-term expression.
Thus, advantageously, the retroviral/lentiviral (e.g. SIV) vectors of the present invention can be used in gene therapy. By way of example, the efficient airway cell uptake properties of the retroviral/lentiviral (e.g. SIV) vectors of the invention make them highly suitable for treating respiratory tract diseases. The retroviral/lentiviral (e.g. SIV) vectors of the invention can also be used in methods of gene therapy to promote secretion of therapeutic proteins. By way of further example, the invention provides secretion of therapeutic proteins into the lumen of the respiratory tract or the circulatory system. Thus, administration of a retroviral/lentiviral (e.g. SIV) vector of the invention and its uptake by airway cells may enable the use of the lungs (or nose or airways) as a “factory” to produce a therapeutic protein that is then secreted and enters the general circulation at therapeutic levels, where it can travel to cells/tissues of interest to elicit a therapeutic effect. In contrast to intracellular or membrane proteins, the production of such secreted proteins does not rely on specific disease target cells being transduced, which is a significant advantage and achieves high levels of protein expression. Thus, other diseases which are not respiratory tract diseases, such as cardiovascular diseases and blood disorders, particularly blood clotting deficiencies, can also be treated by the retroviral/lentiviral (e.g. SIV) vectors of the present invention.
Retroviral/lentiviral (e.g. SIV) vectors of the invention can effectively treat a disease by providing a transgene for the correction of the disease. For example, inserting a functional copy of the CFTR gene to ameliorate or prevent lung disease in CF patients, independent of the underlying mutation. Accordingly, retroviral/lentiviral (e.g. SIV) vectors of the invention may be used to treat cystic fibrosis (CF), typically by gene therapy with a CFTR transgene as described herein.
As another example, retroviral/lentiviral (e.g. SIV) vectors of the invention may be used to treat Alpha-1 Antitrypsin (A1AT) deficiency, typically by gene therapy with a A1AT transgene as described herein. A1AT is a secreted anti-protease that is produced mainly in the liver and then trafficked to the lung, with smaller amounts also being produced in the lung itself. The main function of A1AT is to bind and neutralise/inhibit neutrophil elastase. Gene therapy with A1AT according to the present invention is relevant to A1AT deficient patient, as well as in other lung diseases such as CF or chronic obstructive pulmonary disease (COPD), and offers the opportunity to overcome some of the problems encountered by conventional enzyme replacement therapy (in which A1AT isolated from human blood and administered intravenously every week), providing stable, long-lasting expression in the target tissue (lung/nasal epithelium), ease of administration and unlimited availability.
Transduction with a retroviral/lentiviral (e.g. SIV) vector of the invention may lead to secretion of the recombinant protein into the lumen of the lung as well as into the circulation. One benefit of this is that the therapeutic protein reaches the interstitium. A1AT gene therapy may therefore also be beneficial in other disease indications, non-limiting examples of which include type 1 and type 2 diabetes, acute myocardial infarction, ischemic heart disease, rheumatoid arthritis, inflammatory bowel disease, transplant rejection, graft versus host (GvH) disease, multiple sclerosis, liver disease, cirrhosis, vasculitides and infections, such as bacterial and/or viral infections.
A1AT has numerous other anti-inflammatory and tissue-protective effects, for example in pre-clinical models of diabetes, graft versus host disease and inflammatory bowel disease. The production of A1AT in the lung and/or nose following transduction according to the present invention may, therefore, be more widely applicable, including to these indications.
Other examples of diseases that may be treated with gene therapy of a secreted protein according to the present invention include cardiovascular diseases and blood disorders, particularly blood clotting deficiencies such as haemophilia (A, B or C), von Willebrand disease and Factor VII deficiency.
Other examples of diseases or disorders to be treated include Primary Ciliary Dyskinesia (PCD), acute lung injury, Surfactant Protein B (SFTB) deficiency, Pulmonary Alveolar Proteinosis (PAP), Chronic Obstructive Pulmonary Disease (COPD) and/or inflammatory, infectious, immune or metabolic conditions, such as lysosomal storage diseases.
Accordingly, the invention provides a method of treating a disease, the method comprising administering a retroviral/lentiviral (e.g. SIV) vector of the invention to a subject. Typically the retroviral/lentiviral (e.g. SIV) vector is produced using a method of the present invention. Any disease described herein may be treated according to the invention. In particular, the invention provides a method of treating a lung disease using a retroviral/lentiviral (e.g. SIV) vector of the invention. The disease to be treated may be a chronic disease. Preferably, a method of treating CF is provided.
The invention also provides a retroviral/lentiviral (e.g. SIV) vector as described herein for use in a method of treating a disease. Typically the retroviral/lentiviral (e.g. SIV) vector is produced using a method of the present disclosure. Any disease described herein may be treated according to the invention. In particular, the invention provides a retroviral/lentiviral (e.g. SIV) vector of the invention for use in a method of treating a lung disease. The disease to be treated may be a chronic disease. Preferably, a retroviral/lentiviral (e.g. SIV) vector for use in treating CF is provided.
The invention also provides the use of a retroviral/lentiviral (e.g. SIV) vector as described herein in the manufacture of a medicament for use in a method of treating a disease. Typically the retroviral/lentiviral (e.g. SIV) vector is produced using a method of the present disclosure. Any disease described herein may be treated according to the invention. In particular, the invention provides the use of a retroviral/lentiviral (e.g. SIV) vector of the invention for the manufacture of a medicament for use in a method of treating a lung disease. The disease to be treated may be a chronic disease. Preferably, the use of a retroviral/lentiviral (e.g. SIV) vector in the manufacture of a medicament for use in a method of treating CF is provided.
The retroviral/lentiviral (e.g. SIV) vectors of the invention may be administered in any dosage appropriate for achieving the desired therapeutic effect. Appropriate dosages may be determined by a clinician or other medical practitioner using standard techniques and within the normal course of their work. Non-limiting examples of suitable dosages include 1×108 transduction units (TU), 1×109 TU, 1×1010 TU, 1×1011 TU or more.
The invention also provides compositions comprising the retroviral/lentiviral (e.g. SIV) vectors described above, and a pharmaceutically-acceptable carrier. Non-limiting examples of pharmaceutically acceptable carriers include water, saline, and phosphate-buffered saline. In some embodiments, however, the composition is in lyophilized form, in which case it may include a stabilizer, such as bovine serum albumin (BSA). In some embodiments, it may be desirable to formulate the composition with a preservative, such as thiomersal or sodium azide, to facilitate long-term storage.
The retroviral/lentiviral (e.g. SIV) vectors of the invention may be administered by any appropriate route. It may be desired to direct the compositions of the present invention (as described above) to the respiratory system of a subject. Efficient transmission of a therapeutic/prophylactic composition or medicament to the site of infection in the respiratory tract may be achieved by oral or intra-nasal administration, for example, as aerosols (e.g. nasal sprays), or by catheters. Typically the retroviral/lentiviral (e.g. SIV) vectors of the invention are stable in clinically relevant nebulisers, inhalers (including metered dose inhalers), catheters and aerosols, etc. Typically, therefore, the retroviral/lentiviral (e.g. SIV) vectors of the invention are formulated for administration to the lungs by any appropriate means, e.g. they may be formulated for intratracheal administration, intranasal administration, aerosol delivery, or direct injection or delivery to the lungs (e.g. delivered by catheter). Other modes of delivery, e.g. intravenous delivery, are also encompassed by the invention.
In some embodiments the nose is a preferred production site for a therapeutic protein using a retroviral/lentiviral (e.g. SIV) vector of the invention for at least one of the following reasons: (i) extracellular barriers such as inflammatory cells and sputum are less pronounced in the nose; (ii) ease of vector administration; (iii) smaller quantities of vector required; and (iv) ethical considerations. Thus, transduction of nasal epithelial cells with a retroviral/lentiviral (e.g. SIV) vector of the invention may result in efficient (high-level) and long-lasting expression of the therapeutic transgene of interest. Accordingly, nasal administration of a retroviral/lentiviral (e.g. SIV) vector of the invention may be preferred.
Formulations for intra-nasal administration may be in the form of nasal droplets or a nasal spray. An intra-nasal formulation may comprise droplets having approximate diameters in the range of 100-5000 μm, such as 500-4000 μm, 1000-3000 μm or 100-1000 μm. Alternatively, in terms of volume, the droplets may be in the range of about 0.001-100 μl, such as 0.1-50 μl or 1.0-25 μl, or such as 0.001-1 μl.
The aerosol formulation may take the form of a powder, suspension or solution. The size of aerosol particles is relevant to the delivery capability of an aerosol. Smaller particles may travel further down the respiratory airway towards the alveoli than would larger particles. In one embodiment, the aerosol particles have a diameter distribution to facilitate delivery along the entire length of the bronchi, bronchioles, and alveoli. Alternatively, the particle size distribution may be selected to target a particular section of the respiratory airway, for example the alveoli. In the case of aerosol delivery of the medicament, the particles may have diameters in the approximate range of 0.1-50 μm, preferably 1-25 μm, more preferably 1-5 μm.
Aerosol particles may be for delivery using a nebulizer (e.g. via the mouth) or nasal spray. An aerosol formulation may optionally contain a propellant and/or surfactant.
The formulation of pharmaceutical aerosols is routine to those skilled in the art, see for example, Sciarra, J. in Remington's Pharmaceutical Sciences (supra). The agents may be formulated as solution aerosols, dispersion or suspension aerosols of dry powders, emulsions or semisolid preparations. The aerosol may be delivered using any propellant system known to those skilled in the art. The aerosols may be applied to the upper respiratory tract, for example by nasal inhalation, or to the lower respiratory tract or to both. The part of the lung that the medicament is delivered to may be determined by the disorder. Compositions comprising a vector of the invention, in particular where intranasal delivery is to be used, may comprise a humectant. This may help reduce or prevent drying of the mucus membrane and to prevent irritation of the membranes. Suitable humectants include, for instance, sorbitol, mineral oil, vegetable oil and glycerol; soothing agents; membrane conditioners; sweeteners; and combinations thereof. The compositions may comprise a surfactant. Suitable surfactants include non-ionic, anionic and cationic surfactants. Examples of surfactants that may be used include, for example, polyoxyethylene derivatives of fatty acid partial esters of sorbitol anhydrides, such as for example, Tween 80, Polyoxyl 40 Stearate, Polyoxy ethylene 50 Stearate, fusieates, bile salts and Octoxynol.
In some cases after an initial administration a subsequent administration of a retroviral/lentiviral (e.g. SIV) vector may be performed. The administration may, for instance, be at least a week, two weeks, a month, two months, six months, a year or more after the initial administration. In some instances, retroviral/lentiviral (e.g. SIV) vector of the invention may be administered at least once a week, once a fortnight, once a month, every two months, every six months, annually or at longer intervals. Preferably, administration is every six months, more preferably annually. The retroviral/lentiviral (e.g. SIV) vectors may, for instance, be administered at intervals dictated by when the effects of the previous administration are decreasing.
Any two or more retroviral/lentiviral (e.g. SIV) vectors of the invention may be administered separately, sequentially or simultaneously. Thus two retroviral/lentiviral (e.g. SIV) vectors or more retroviral/lentiviral (e.g. SIV) vectors, where at least one retroviral/lentiviral (e.g. SIV) vectors is a retroviral/lentiviral (e.g. SIV) vector of the invention, may be administered separately, simultaneously or sequentially and in particular two or more retroviral/lentiviral (e.g. SIV) vectors of the invention may be administered in such a manner. The two may be administered in the same or different compositions. In a preferred instance, the two retroviral/lentiviral (e.g. SIV) vectors may be delivered in the same composition.
Any of a variety of sequence alignment methods can be used to determine percent identity, including, without limitation, global methods, local methods and hybrid methods, such as, e.g., segment approach methods. Protocols to determine percent identity are routine procedures within the scope of one skilled in the art. Global methods align sequences from the beginning to the end of the molecule and determine the best alignment by adding up scores of individual residue pairs and by imposing gap penalties. Non-limiting methods include, e.g., CLUSTAL W, see, e.g., Julie D. Thompson et al., CLUSTAL W: Improving the Sensitivity of Progressive Multiple Sequence Alignment Through Sequence Weighting, Position—Specific Gap Penalties and Weight Matrix Choice, 22(22) Nucleic Acids Research 4673-4680 (1994); and iterative refinement, see, e.g., Osamu Gotoh, Significant Improvement in Accuracy of Multiple Protein. Sequence Alignments by Iterative Refinement as Assessed by Reference to Structural Alignments, 264(4) J. Mol. Biol. 823-838 (1996). Local methods align sequences by identifying one or more conserved motifs shared by all of the input sequences. Non-limiting methods include, e.g., Match-box, see, e.g., Eric Depiereux and Ernest Feytmans, Match-Box: A Fundamentally New Algorithm for the Simultaneous Alignment of Several Protein Sequences, 8(5) CABIOS 501-509 (1992); Gibbs sampling, see, e.g., C. E. Lawrence et al., Detecting Subtle Sequence Signals: A Gibbs Sampling Strategy for Multiple Alignment, 262(5131) Science 208-214 (1993); Align-M, see, e.g., Ivo Van Walle et al., Align-M—A New Algorithm for Multiple Alignment of Highly Divergent Sequences, 20(9) Bioinformatics:1428-1435 (2004).
Thus, percent sequence identity is determined by conventional methods. See, for example, Altschul et al., Bull. Math. Bio. 48: 603-16, 1986 and Henikoff and Henikoff, Proc. Natl. Acad. Sci. USA 89:10915-19, 1992. Briefly, two amino acid sequences are aligned to optimize the alignment scores using a gap opening penalty of 10, a gap extension penalty of 1, and the “blosum 62” scoring matrix of Henikoff and Henikoff (ibid.) as shown below (amino acids are indicated by the standard one-letter codes).
The “percent sequence identity” between two or more nucleic acid or amino acid sequences is a function of the number of identical positions shared by the sequences. Thus, % identity may be calculated as the number of identical nucleotides/amino acids divided by the total number of nucleotides/amino acids, multiplied by 100. Calculations of % sequence identity may also take into account the number of gaps, and the length of each gap that needs to be introduced to optimize alignment of two or more sequences. Sequence comparisons and the determination of percent identity between two or more sequences can be carried out using specific mathematical algorithms, such as BLAST, which will be familiar to a skilled person.
The percent identity is then calculated as:
Substantially homologous polypeptides are characterized as having one or more amino acid substitutions, deletions or additions. These changes are preferably of a minor nature, that is conservative amino acid substitutions (as described herein) and other substitutions that do not significantly affect the folding or activity of the polypeptide; small deletions, typically of one to about 30 amino acids; and small amino- or carboxyl-terminal extensions, such as an amino-terminal methionine residue, a small linker peptide of up to about 20-25 residues, or an affinity tag.
In addition to the 20 standard amino acids, non-standard amino acids (such as 4-hydroxyproline, 6-N-methyl lysine, 2-aminoisobutyric acid, isovaline and α-methyl serine) may be substituted for amino acid residues of the polypeptides of the present invention. A limited number of non-conservative amino acids, amino acids that are not encoded by the genetic code, and unnatural amino acids may be substituted for polypeptide amino acid residues. The polypeptides of the present invention can also comprise non-naturally occurring amino acid residues.
Non-naturally occurring amino acids include, without limitation, trans-3-methylproline, 2,4-methano-proline, cis-4-hydroxyproline, trans-4-hydroxy-proline, N-methylglycine, allo-threonine, methyl-threonine, hydroxy-ethylcysteine, hydroxyethylhomo-cysteine, nitro-glutamine, homoglutamine, pipecolic acid, tert-leucine, norvaline, 2-azaphenylalanine, 3-azaphenyl-alanine, 4-azaphenyl-alanine, and 4-fluorophenylalanine. Several methods are known in the art for incorporating non-naturally occurring amino acid residues into proteins. For example, an in vitro system can be employed wherein nonsense mutations are suppressed using chemically aminoacylated suppressor tRNAs. Methods for synthesizing amino acids and aminoacylating tRNA are known in the art. Transcription and translation of plasmids containing nonsense mutations is carried out in a cell free system comprising an E. coli S30 extract and commercially available enzymes and other reagents. Proteins are purified by chromatography. See, for example, Robertson et al., J. Am. Chem. Soc. 113:2722, 1991; Ellman et al., Methods Enzymol. 202:301, 1991; Chung et al., Science 259:806-9, 1993; and Chung et al., Proc. Natl. Acad. Sci. USA 90:10145-9, 1993). In a second method, translation is carried out in Xenopus oocytes by microinjection of mutated mRNA and chemically aminoacylated suppressor tRNAs (Turcatti et al., J. Biol. Chem. 271:19991-8, 1996). Within a third method, E. coli cells are cultured in the absence of a natural amino acid that is to be replaced (e.g., phenylalanine) and in the presence of the desired non-naturally occurring amino acid(s) (e.g., 2-azaphenylalanine, 3-azaphenylalanine, 4-azaphenylalanine, or 4-fluorophenylalanine). The non-naturally occurring amino acid is incorporated into the polypeptide in place of its natural counterpart. See, Koide et al., Biochem. 33:7470-6, 1994. Naturally occurring amino acid residues can be converted to non-naturally occurring species by in vitro chemical modification. Chemical modification can be combined with site-directed mutagenesis to further expand the range of substitutions (Wynn and Richards, Protein Sci. 2:395-403, 1993).
A limited number of non-conservative amino acids, amino acids that are not encoded by the genetic code, non-naturally occurring amino acids, and unnatural amino acids may be substituted for amino acid residues of polypeptides of the present invention.
Essential amino acids in the polypeptides of the present invention can be identified according to procedures known in the art, such as site-directed mutagenesis or alanine-scanning mutagenesis (Cunningham and Wells, Science 244: 1081-5, 1989). Sites of biological interaction can also be determined by physical analysis of structure, as determined by such techniques as nuclear magnetic resonance, crystallography, electron diffraction or photoaffinity labeling, in conjunction with mutation of putative contact site amino acids. See, for example, de Vos et al., Science 255:306-12, 1992; Smith et al., J. Mol. Biol. 224:899-904, 1992; Wlodaver et al., FEBS Lett. 309:59-64, 1992. The identities of essential amino acids can also be inferred from analysis of homologies with related components (e.g. the translocation or protease components) of the polypeptides of the present invention.
Multiple amino acid substitutions can be made and tested using known methods of mutagenesis and screening, such as those disclosed by Reidhaar-Olson and Sauer (Science 241:53-7, 1988) or Bowie and Sauer (Proc. Natl. Acad. Sci. USA 86:2152-6, 1989). Briefly, these authors disclose methods for simultaneously randomizing two or more positions in a polypeptide, selecting for functional polypeptide, and then sequencing the mutagenized polypeptides to determine the spectrum of allowable substitutions at each position. Other methods that can be used include phage display (e.g., Lowman et al., Biochem. 30:10832-7, 1991; Ladner et al., U.S. Pat. No. 5,223,409; Huse, WIPO Publication WO 92/06204) and region-directed mutagenesis (Derbyshire et al., Gene 46:145, 1986; Ner et al., DNA 7:127, 1988).
Multiple amino acid substitutions can be made and tested using known methods of mutagenesis and screening, such as those disclosed by Reidhaar-Olson and Sauer (Science 241:53-7, 1988) or Bowie and Sauer (Proc. Natl. Acad. Sci. USA 86:2152-6, 1989). Briefly, these authors disclose methods for simultaneously randomizing two or more positions in a polypeptide, selecting for functional polypeptide, and then sequencing the mutagenized polypeptides to determine the spectrum of allowable substitutions at each position. Other methods that can be used include phage display (e.g., Lowman et al., Biochem. 30:10832-7, 1991; Ladner et al., U.S. Pat. No. 5,223,409; Huse, WIPO Publication WO 92/06204) and region-directed mutagenesis (Derbyshire et al., Gene 46:145, 1986; Ner et al., DNA 7:127, 1988).
The invention is now described with reference to the Examples below. These are not limiting on the scope of the invention, and a person skilled in the art would be appreciate that suitable equivalents could be used within the scope of the present invention. Thus, the Examples may be considered component parts of the invention, and the individual aspects described therein may be considered as disclosed independently, or in any combination.
The inventors reviewed sequences of the construction plasmids and identified several regions of concern within the original vector genome plasmid pGM326. In particular, the pGM326 partial Gag RRE cPPT hCEF region contains:
In particular, 14 ATG start codons were identified in the partial Gag/RRE region of the pGM326 genome plasmid that could result in ORFs of longer than 10 amino acids. These are illustrated in
As such, the inventors designed a modified version of the pGM326 plasmid with a combination of additional modifications intended to reduce the number of intact SIV ORFs (and in particular to remove these 2 large ORFs) for improved safety. The modifications are made to the 2 large ORFs upstream of the hCEF promoter and CFTR transgene (soCFTR2). The changes made were as follows:
Approach 1 made frameshift mutations to ATG codons (fsATG) 1, 2, 3 and 5 in the SIV-CFTR partial-Gag region. Approach 2 made frameshift mutations to ATG codons 1 and 3 in the SIV-CFTR partial-Gag region. Approach 3 made point mutations to ATG codons (mtATG) 1 and 3 in the SIV-CFTR partial-Gag region. Approach 4 made a mutation of the 6th codon of the SIV-CFTR partial-Gag region into a STOP codon, and a point mutation to ATG codon 3 in the partial-Gag region. Approach 5 made frameshift mutations to ATG codons 1, 2, 3 and 5 and point mutations to ATG codons 7, 12 and 13 of the SIV-CFTR partial-Gag/RRE region. Approach 6 made a mutation of the 6th codon of the SIV-CFTR partial-Gag region into a STOP codon, and point mutations to ATG codons 3, 7, 12 and 13 across the SIV-CFTR partial-Gag/RRE region. Approach 5 produced the vector genome plasmid of pGM830 as shown in
Each novel vector genome plasmid was assessed for functionality by two rounds of transient lentiviral vector (LV) production, comprising transfection of the plasmid being tested with SIV GagPol, SIV Rev, SeV Fct4 and SIVct+SeV HN plasmids into A459 cells in an Ambr®15 bioreactor system at 12 mL volume. Following LV production, vector product was activated before being filtered through a 0.45 μm filter and stored at −80° C. Post thaw, activated material was diluted 1 in 50 and transduced onto into A459 cells. The resulting LV titre was quantified using CFTR FACS.
As shown in
Comparisons of vector titre using either pGM326 and the modified vector genome plasmids in an otherwise identical production protocol demonstrated that the use of modified vector genome plasmids at least gave a comparable titre to pGM326, indicating that an improved safety profile could be achieved without adversely affecting titre.
The LV production of Example 1 was repeated using HEK239T cells.
The resulting LV titre was quantified using a 3-day integration assay. DNA from transduced cells was harvested 3-days post-transduction and non-integrated DNA removed. qPCR was then used to determine and quantify the vector was present/integrated into the host cell DNA.
As shown in
Again, comparisons of vector titre using either pGM326 and the modified vector genome plasmids in an otherwise identical production protocol demonstrated that the use of modified vector genome plasmids at least gave a comparable LV integration to pGM326, indicating that an improved safety profile could be achieved without adversely affecting LV functionality.
SIV-CFTR generated using pGM326or pGM830 were used to transduce A549 cells in the presence and absence of AZT and Raltegravir. All cells were stained for CFTR expression 3-days post-transduction, and subsequently only cells transduced in the absence of inhibitors were passaged and stained again for CFTR expression 10-Days post-transduction, in order to investigate the extent of pseudotransduction (transduction without proviral DNA integration into the host genome), which could also give rise to CFTR expression.
As shown in
Furthermore,
Thus, this comparison of CFTR transgene expression using either pGM326 and pGM830 demonstrated that the use of modified vector genome plasmids at least gave comparable transgene expression compared with LV produced using unmodified pGM326, indicating that an improved safety profile could be achieved without adversely affecting LV functionality.
LV produced according to Example 1 was assessed for F protein cleavage following the addition of a trypsin-like enzyme. Activation of F protein occurs by cleavage into 2 subunits, F1 and F2. Thus, cleavage of F protein is an accepted proxy for F protein activation and hence fusion capability.
Following incubation of the LV with the trypsin-like enzyme, Western blotting was carried out using an anti-PIV1 antibody ab20791 at a dilution of 1:5000. As shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2212472.1 | Aug 2022 | GB | national |
