Patent Grant
11529414
The instant application contains a Sequence Listing which has been submitted electronically in ASCII format and is hereby incorporated by reference in its entirety. Said ASCII copy, created on Jun. 29, 2020, is named 096630-0190_SL.txt and is 51,501 bytes in size.
The present disclosure relates generally to the field of infectious disease therapy, and, in particular, nucleic acid vaccines for treating or preventing viral, bacterial, or other microbial infections. The disclosure provides compositions and methods for effectively delivering to cells of the mononuclear phagocyte system (e.g., antigen presenting cells) and other immune cells a nucleic acid encoding an immunogenic peptide. The disclosure further provides methods of treating or preventing a viral, bacterial, or other microbial disease or infection by administering to a patient a vaccine comprising a nucleic acid that encodes an immunogenic peptide, such that the immunogenic peptide is expressed in vivo, thereby activating the patient's immune system to attack the virus or bacteria that expresses the immunogenic peptide.
The following discussion is merely provided to aid the reader in understanding the disclosure and is not admitted to describe or constitute prior art thereto.
Infectious diseases caused by viruses, bacteria, and other microbes are a global public health threat. Globalization and increased international travel and commerce have created an environment that allows global disease to spread quickly throughout the world.
Coronavirus disease 2019 (COVID-19; also referred to as novel coronavirus pneumonia or 2019-nCoV acute respiratory disease) is exemplary of the kind of public health threat that can rapidly emerge without warning. COVID-19 is an infectious disease caused by the virus severe respiratory syndrome coronavirus 2 (SARS-CoV-2) (also referred to as novel coronavirus 2019, or 2019-nCoV). The disease was first identified in December 2019 and spread globally, causing a pandemic. Symptoms of COVID-19 include fever, cough, shortness of breath, fatigue, headache, loss of smell, nasal congestion, sore throat, coughing up sputum, pain in muscles or joints, chills, nausea, vomiting, and diarrhea. In severe cases, symptoms can include difficulty waking, confusion, blueish face or lips, coughing up blood, decreased white blood cell count, and kidney failure. Complications can include pneumonia, viral sepsis, acute respiratory distress syndrome, and kidney failure.
COVID-19 is especially threatening to public health because the virus is highly contagious, and studies currently indicate that it can be spread by asymptomatic carriers or by those who are pre-symptomatic. Likewise, the early stage of the disease is slow-progressing enough that carriers may not realize they are infected, leading them to expose numerous others to the virus. The combination of COVID-19's ease of transmission, its high rate of hospitalization, and its death rate make the virus a substantial public health risk, especially for countries without a healthcare system equipped to provide supportive care to pandemic-level numbers of patients. There is not yet a vaccine or specific antiviral treatment for COVID-19 and accordingly, there is a pressing need for treatments or cures.
SARS-CoV-2 is not the only coronavirus that causes disease. It is a β-coronavirus, a genus of coronaviruses that includes other human pathogens, including SARS-CoV (the causative agent of SARS), MERS-CoV (the causative agent of MERS), and HCoV-OC43 (a causative agent of the common cold). The infectivity of these viruses, and the severity of the diseases they cause, varies widely. β-coronavirus can also manifest as zoonotic infections, spread to and from humans and animals. Additionally, non-human species such as camels, bats, tigers, non-human primates, and rabbits can be susceptible to β-coronavirus. Accordingly, there is a pressing need for treatments or cures to multiple coronaviruses.
However, this need is not limited solely to coronaviruses. The next public health threat may emerge from a different type of virus or a bacteria or another type of microbe. Thus, there is a need for a vaccine platform technology that can quickly and adroitly address any infectious disease by training the immune system to recognize a given pathogen.
The immune system is made up of a variety of types of cells that are able to detect the presence of pathogens or pathologic cells in the body and remove them from the body. Sometimes this occurs when a foreign agent is enveloped by immune system cells and destroyed or carried out of the body. If living host cells have been invaded by a bacterial cell or virus, the immune system cells may target and destroy that infected cell or they may target the invading pathogen directly.
For example, monocytic cells are a type of antigen presenting cell that normally patrol the body in search of foreign, non-self-antigens, such as bacteria. Monocytic cells phagocytize bacteria, which are then digested to smaller antigenic portions in the lysosome. The resultant bacterial antigens are cycled back to the cell surface of these cells for presentation to the humoral and cellular arms of the immune system. This antigen presenting function is instrumental in the development of a host immune response to a given foreign, non-self-antigen, as the monocytes load the antigen on MEW class I and II molecules and prime CD8+ and CD4+ T cells, which then mount a specific immune response against the antigen.
Despite this understanding of the antigen presenting process, historically, it has been difficult to develop vaccines that effectively and consistently produce a sustained immunogenic response in a host to a particular antigen. Moreover, scale up and production for widespread use is exceedingly difficult. Most modern vaccines utilize whole virus or bacteria that have been killed or enfeebled prior to administration, or they utilize an isolated peptide or glycopeptide that has shown immunogenicity. Both of these types of vaccines are difficult to produce in mass, requiring large-scale bioreactors, extensive growth and production time, and often delicate and cost-intensive isolation/purification processes.
In contrast to whole pathogens (e.g., virus or bacteria) or peptides/glycopeptides, nucleic acid sequences (e.g., plasmids or expression vectors) are comparatively simple to produce in mass. Nucleic acid sequences can be quickly and reproducibly duplicated far more rapidly than peptides or pathogens, but historically, nucleic acid-based vaccines have achieved little clinical success, mostly due to the difficulty of effectively delivering nucleic acids in vivo. Indeed, with previous nucleic acid vaccines, less than 1% of the cells at an injection site of a nucleic acid vaccine actually take up the vaccine nucleic acid and far less express the encoded protein. For an effective immune response to be achieved, a nucleic acid must be delivered to a specific class of cells—antigen presenting cells (APCs)—and directly injected nucleic acid vaccines rarely reach this target.
Thus, there is a need in the art for a platform for nucleic acid vaccines. The present disclosure fulfills that need by providing multiple vaccine platforms that efficiently and effectively deliver nucleic acids to antigen presenting cells, which can then express an immunogenic peptide(s) encoded by the nucleic acid, thereby inducing a robust immune response to the immunogenic peptide.
Described herein are nucleic acid vaccines and methods of using the same for treating or preventing infections (i.e., diseases caused by viruses, bacteria, or other microbes).
In one aspect, the disclosure provides a vaccine comprising: (i) a base particle, (ii) a lysosome-evading component attached to the base particle, and (iii) a nucleic acid sequence encoding an immunogenic peptide.
In some embodiments, the base particle is a yeast cell wall particle (YCWP). In some embodiments, the base particle may be a bead (e.g., a ferro-magnetic bead).
In some embodiments, the lysosome-evading component is a non-infectious virus, such as a non-infectious adenovirus. In some embodiments, the non-infectious virus is also non-replicative. In some embodiments, the non-infectious virus is an enfeebled virus. In some embodiments, the lysosome-evading component is a quadrivalent influenza vaccine.
In some embodiments, the lysosome-evading component is a protein (e.g., a lytic protein). In some embodiments, the protein is a hexon protein, a penton protein, melittin, or LL37.
In some embodiments, the nucleic acid encoding the immunogenic peptide is comprised within an expression vector or plasmid.
In some embodiments, the immunogenic peptide is derived from a virus, bacteria, or other microbe. In some embodiments, the virus is a coronavirus, such as SARS-CoV-2.
In some embodiments, the immunogenic peptide is a viral spike protein or an immunogenic fragment thereof. In some embodiments, the immunogenic peptide comprises SEQ ID NO: 1 (i.e., the spike protein of SARS-CoV-2) or an immunogenic fragment thereof.
In some embodiments, the base particle is modified or coated with polyethyleneimine (PEI). For example, in some embodiments, the base particle may be a PEI-modified YCWP. In some embodiments, the base particle may be a PEI-modified bead.
In some embodiments, the lysosome-evading component is attached to the base particle by an antibody. For example, in some embodiments, the lysosome-evading component may be an adenovirus, which is attached to the based particle via an anti-hexon protein antibody.
In some embodiments, the base particle is modified or coated with succinimidyl 3-(2-pyridyldithio)propionate (SPDP). For example, in some embodiments, the base particle may be a SPDP-modified YCWP. In some embodiments, the base particle may be a SPDP-modified bead. In some embodiments, melittin or LL37 may be crosslinked to the base particle (e.g., a YCWP) by the SPDP.
In some embodiments, the vaccine particle is a size that allows it to be preferentially phagocytized by a monocytic cell, such as an antigen presenting cell.
In another aspect, the present disclosure provides a vaccine comprising: (i) yeast cell wall particle (YCWP) that is surface modified with polyethyleneimine (PEI), (ii) an adenovirus attached to the YCWP, and (iii) a nucleic acid sequence encoding a viral spike protein. In some embodiments, the adenovirus is attached to the YCWP indirectly via an anti-hexon protein antibody. In some embodiments, the adenovirus is non-infectious and non-replicative. In some embodiments, the viral spike protein is a SARS-CoV-2 spike protein. In some embodiments, the viral spike protein comprises SEQ ID NO: 1.
In another aspect, the present disclosure provides a vaccine comprising: (i) a non-infectious and non-replicative virus comprising polylysine cross-linked to one or more surface-exposed glutamine residues, and (ii) a nucleic acid sequence encoding an immunogenic peptide. In some embodiments, the virus is an adenovirus. In some embodiments, the one or more surface-exposed glutamine residues are located in the knob domain of an adenovirus fiber protein. In some embodiments, the nucleic acid encoding the immunogenic peptide is comprised within an expression vector or plasmid. In some embodiments, the immunogenic peptide is derived from a virus, bacteria, or other microbe. In some embodiments, the virus is a coronavirus, such as SARS-CoV-2. In some embodiments, the immunogenic peptide is a viral spike protein or an immunogenic fragment thereof. In some embodiments, the immunogenic peptide comprises SEQ ID NO: 1 or an immunogenic fragment thereof.
In another aspect, the present disclosure provides methods of treating or preventing an infectious disease in a patient comprising administering to a patient that may be exposed to an infectious disease a vaccine of any one of the foregoing aspects or embodiments.
In another aspect, the present disclosure provides methods of stimulating the immune system in a patient comprising administering to a patient a vaccine of any one of the foregoing aspects or embodiments.
In some embodiments of the disclosed methods, the vaccine is administered intradermally.
In some embodiments of the disclosed methods, the vaccine is phagocytosed by a monocytic cell and the monocytic cell subsequently expresses the immunogenic peptide and presents the immunogenic peptide on its surface.
In some embodiments of the disclosed methods, the infectious disease is caused by a virus or bacteria. In some embodiments, the infectious disease is coronavirus disease 2019 (COVID-19).
In another aspect, the present disclosure provides a vaccine according to any of the foregoing aspects or embodiments for use in preventing an infectious disease in a subject comprising administering the vaccine to the subject.
In another aspect, the present disclosure provides a vaccine according to any of the foregoing aspects or embodiments for use in stimulating the immune system of a subject in need thereof.
In another aspect, the present disclosure provides uses of the vaccine of any of the foregoing aspects or embodiments to prevent an infectious disease in a subject.
In another aspect, the present disclosure provides uses of the vaccine of any of the foregoing aspects or embodiments for stimulating the immune system of a subject in need thereof.
In another aspect, the present disclosure provides methods of preventing coronavirus disease 2019 (COVID-19) in a subject comprising, administering to a subject a vaccine comprising: (i) yeast cell wall particle (YCWP) that is surface modified with polyethyleneimine (PEI), (ii) an adenovirus attached to the YCWP, and (iii) a nucleic acid sequence encoding a viral spike protein from SARS-CoV-2 or an immunogenic fragment thereof. In some embodiments, the adenovirus is attached to the YCWP indirectly via an anti-hexon protein antibody. In some embodiments of the methods of preventing COVID-19, the adenovirus is non-infectious and non-replicative. In some embodiments, the viral spike protein comprises SEQ ID NO: 1. In some embodiments, the vaccine is administered intradermally. In some embodiments, the vaccine is phagocytosed by a monocytic cell and the monocytic cell subsequently expresses the immunogenic peptide and presents the immunogenic peptide on its surface. In some embodiments, the subject produces antibodies that specifically bind to the spike protein from SARS-CoV-2 as a result of administration of the vaccine.
The foregoing general description and following detailed description are exemplary and explanatory and not limiting of the disclosure.
In general, the present disclosure provides novel, nucleic acid vaccines for treating and preventing infections that may be caused by viruses, bacteria, or any number of other infections microbes (e.g., yeast). The disclosed vaccines provide a preventative, vaccine-like function when taken up by an antigen presenting cells (APC) and similar cells of the mononuclear phagocyte system (e.g., monocytes, macrophages, dendritic cells, or immature dendritic cells). In the field of vaccination, cells of the mononuclear phagocyte system are considered “professional” antigen presenting cells and thus, are the ideal target for vaccine delivery. It is well known that presentation of an antigen within an APC is vastly more effective in generating a strong cellular immune response than expression of the same antigen within any other cell type. Accordingly, loading the disclosed vaccine platforms with one or more nucleic acid that encodes an immunogenic peptide will result in the presentation of the immunogenic peptide on an antigen presenting cell via class I MHC and class II MHC molecules, thus eliciting a robust immune response to the immunogenic peptide and to the virus, bacteria, or other microbe from which the immunogenic peptide was derived.
Throughout this disclosure, various publications, patents and published patent specifications are referenced by an identifying citation. The disclosures of these publications, patents and published patent specifications are hereby incorporated by reference into the present disclosure to more fully describe the state of the art to which this disclosure pertains.
Definitions
Technical and scientific terms used herein have the meanings commonly understood by one of ordinary skill in the art, unless otherwise defined. Any suitable materials and/or methodologies known to those of ordinary skill in the art can be utilized in carrying out the methods described herein.
As used herein, the term “about” will be understood by persons of ordinary skill in the art and will vary to some extent depending upon the context in which it is used. If there are uses of the term which are not clear to persons of ordinary skill in the art given the context in which it is used, “about” will mean up to plus or minus 10% of the particular term as well as the specified term. For example, “about 10” should be understood as meaning “10” as well as “9 to 11.”
As used herein, the term “comprising” is intended to mean that the compositions and methods include the recited elements, but not excluding others. “Consisting essentially of” when used to define compositions and methods, shall mean excluding other elements of any essential significance to the composition or method. “Consisting of” shall mean excluding more than trace elements of other ingredients for claimed compositions and substantial method steps. Embodiments defined by each of these transition terms are within the scope of this disclosure. Accordingly, it is intended that the methods and compositions can include additional steps and components (comprising) or alternatively including steps and compositions of no significance (consisting essentially of) or alternatively, intending only the stated method steps or compositions (consisting of).
As used herein, the phrases “therapeutically effective amount” means that a dose of the disclosed particles provides the specific pharmacological effect for which the drug is administered in a subject in need of such treatment, i.e. to prevent, reduce, ameliorate, or eliminate an infection caused by a virus, bacteria, or other microbe by activating the immune system. It is emphasized that a therapeutically effective amount of a particle will not always be effective in treating or preventing the infection of every individual subject, even though such dosage is deemed to be a therapeutically effective amount by those of skill in the art. Those skilled in the art can adjust what is deemed to be a therapeutically effective amount in accordance with standard practices as needed to treat or prevent a specific subject and/or specific type of infection. The therapeutically effective amount may vary based on the route of administration, site of administration, dosage form, the age and weight of the subject, and/or the subject's condition, and/or type of infection that is being treated or prevented.
The terms “treatment” or “treating” as used herein with reference to an infection caused by a virus, bacteria, or other microbe refer to reducing, ameliorating or eliminating the number of virus, bacteria, or other microbe in the subject being treated (e.g., decreasing viral titer or bacterial load) or otherwise improving the subject's prognosis or quality of life.
The terms “prevent” or “preventing” as used herein refer to stopping an infection caused by a virus, bacteria, or other microbe before the infection develops, progresses, or causes illness in a subject or inhibiting the recurrence of an infection caused by a virus, bacteria, or other microbe.
The terms “individual,” “subject,” and “patient” are used interchangeably herein, and refer to any individual mammalian subject, e.g., bovine, canine, feline, equine, or human.
The compositions and methods of the disclosure may suitably be practiced in the absence of any element or elements, limitation or limitations, not specifically disclosed herein. Thus, for example, the terms “comprising”, “including,” containing”, etc. shall be read expansively and without limitation. Additionally, the terms and expressions employed herein have been used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the disclosure claimed.
Nucleic Acid Vaccine Platforms
The present disclosure provides two novel platforms for nucleic acid vaccines. The first described vaccine platform is particle-based, and the nucleic acid vaccine comprises (i) a base particle (e.g., a yeast cell wall particle or YCWP), (ii) a lysosome-evading component (e.g., a non-infectious virus) attached to the base particle, and (iii) a nucleic acid sequence encoding an immunogenic peptide. The second described vaccine platform is virus-based, and the nucleic acid vaccine comprises a polylysine-modified adenovirus onto which a nucleic acid sequence encoding an immunogenic peptide is attached.
Both nucleic acid vaccine platforms can be used to prepare vaccines against any number of viral, bacterial, or other microbial pathogens by substituting the nucleic acid while leaving the core (i.e., particle or polylysine-modified virus) the same. This is advantageous from both clinical and practical perspectives, as nucleic acids can be rapidly and reliably produced in large quantities, and would allow preparation of a vaccine to begin immediately upon sequencing of the pathogen genome.
As disclosed in further detail herein, both nucleic acid vaccine platforms can be used for treating or preventing infectious diseases caused by viruses (e.g., SARS-CovV-2), bacteria, or other microbes.
For the purposes of the present disclosure, both vaccine platforms share a common component of a nucleic acid that encodes an immunogenic peptide. A nucleic acid sequence encoding an immunogenic may be comprised within an expression vector (e.g., a plasmid), which is capable of expressing the immunogenic peptide in a target cell (e.g., a monocytic cell or antigen presenting cell). More specifically, the expression vector may be used to express one or more immunogenic peptides, which can then be presented on the surface of the target cell via class I MHC and/or class II MHC molecules, thus eliciting an immune response to the immunogenic peptide. An expression vector comprising the nucleic acid encoding an immunogenic peptide may further comprise regulatory sequences, including for example, a promoter, operably linked to the coding sequence, an enhancer, and/or a ribosomal entry site. The expression vector may optionally further comprise a selectable marker sequence, for instance for propagation in in vitro bacterial or cell culture systems. In some embodiments, the selectable marker may be a fluorescent peptide, such as green fluorescent protein (GFP) or red fluorescent protein (RFP).
Preferred expression vectors may comprise one or more of an origin of replication, a suitable promoter and/or enhancer, and also any necessary ribosome binding sites, polyadenylation sites, splice donor and acceptor sites, transcriptional termination sequences, and 5′ flanking non-transcribed sequences. DNA sequences derived from the SV40 or cytomegalovirus (CMV) viral genome, for example, SV40 origin, early promoter, enhancer, splice, and polyadenylation sites may be used to provide the required non-transcribed genetic elements. An exemplary expression vectors are shown in
Specific initiation signals may also be required for efficient translation and expression of the immunogenic peptide. These signals can include the ATG initiation codon and adjacent sequences. In some embodiments, an expression vector may comprise its own initiation codon and adjacent sequences may be inserted into the appropriate expression vector, and no additional translation control signals may be needed. However, in some embodiments, only a portion of an open reading frame (ORF) may be used, and exogenous translational control signals, including, for example, the ATG initiation codon, can be provided. Furthermore, the initiation codon may be in phase with the reading frame of the desired coding sequence (i.e., the nucleic acid sequence encoding the immunogenic peptide) to ensure translation of the entire target sequence.
Exogenous translational control signals and initiation codons can be of a variety of origins, both natural and synthetic. The efficiency of expression may be enhanced by the inclusion of appropriate transcription enhancer elements, transcription terminators, etc. (see Bittner et al., Methods in Enzymol. 153:516-544 (1987)). Some appropriate expression vectors are described by Sambrook, et al., in Molecular Cloning: A Laboratory Manual, Second Edition, Cold Spring Harbor, N.Y. (1989), the disclosure of which is hereby incorporated by reference. If desired, to enhance expression and facilitate proper protein folding, the codon context and codon pairing of the sequence may be optimized, as explained by Hatfield et al., U.S. Pat. No. 5,082,767.
Promoters include, but are not limited to, EF-1a promoter, CMV immediate early, HSV thymidine kinase, early and late SV40, LTRs from retrovirus, and mouse metallothionein-I. Exemplary vectors include pWLneo, pSV2cat, pOG44, pXT1, pSG (Stratagene) pSVK3, pBPV, pMSG, and pSVL (Pharmacia). Selectable markers include CAT (chloramphenicol transferase). Preferred vectors also include cytoplasmic vectors, like the T7 vector system. See Wagner et al., U.S. Pat. No. 5,591,601 (Jan. 7, 1997).
The immunogenic peptide(s) encoded by the nucleic acid of the disclosed vaccine platforms is not particularly limited so long as it elicits an immune response to the pathogenic organism (e.g., virus, bacteria, or other microbe) from which it was derived. For example, the immunogenic peptide may be a full length viral, bacterial, or other microbial protein, or it may comprise only a portion of a viral, bacterial, or other microbial protein. In general, the immunogenic peptide will be a protein or immunogenic fragment thereof that is exposed on the surface of the target virus, bacteria, or microbe, such as a viral coat protein, a bacterial membrane protein, or a bacterial cell wall protein. In some embodiments, the vaccine encodes a full length viral, bacterial, or other microbial surface protein. In some embodiments, the vaccine encodes about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% of a viral, bacterial, or other microbial surface protein, so long as the fragment is able to elicit an immune response (i.e., it is an immunogenic fragment).
When the target pathogen of the vaccine is a virus, the immunogenic peptide may be all or a portion of the spike protein (also known as “S protein” or “glycoprotein S”), which is generally responsible for viral entry into a host cell. The spike protein is ideal to serve as an immunogenic peptide because antibodies that develop against this peptide are likely to be neutralizing. The spike protein comprises two functional subunits responsible for binding to the host cell receptor (S1 subunit) and fusion of the viral and cellular membranes (S2 subunit). A vaccine of the present disclosure may encode the entire spike protein, only the S1 subunit, only the S2 subunit, or any immunogenic portion thereof. In some embodiments, the vaccine encodes a full length spike protein. In some embodiments, the vaccine encodes about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% of a viral spike protein, so long as the fragment is able to elicit an immune response (i.e., it is an immunogenic fragment). Other viral proteins that may serve as the immunogenic peptide when the target pathogen is a virus include, but are not limited to, a viral E protein, M protein, or N protein, or any other viral capsid or coat protein. In some embodiments, the vaccine encodes a full length E protein, M protein, N protein, or other viral capsid or coat protein. In some embodiments, the vaccine encodes about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% of an E protein, M protein, N protein, or other viral capsid or coat protein, so long as the fragment is able to elicit an immune response (i.e., it is an immunogenic fragment). In some embodiments, the immunogenic peptide may be derived from a coronavirus, hepatitis A, hepatitis B, hepatitis C, human immunodeficiency virus (HIV), an influenza virus, or a norovirus.
When the target pathogen of the vaccine is a bacteria, the immunogenic peptide may be all or a portion of an outer membrane protein (OMP), such as OmpA or any other exposed surface protein that is immunogenic. For instance, the immunogenic peptide may be a peptide derived from Acinetobacter baumannii, Bacteroides fragilis, Burkholderia cepacia, Clostridium difficile, Clostridium sordellii, Enterobacteriaceae sp., Enterococcus faecalis, Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus (including methicillin-resistant strains or MRSA, and vancomycin-resistant or VRSA), Morganella morganii, Mycobacterium abscessus, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Mycobacterium tuberculosis, or Enterococci sp.
In some embodiments, monocytic cells may to exposed to, and therefore phagocytose, a nucleic acid vaccine as disclosed herein, which comprise more than one expression vector, and the expression vectors may encode the same or different immunogenic peptides. For example, in some embodiments, a vaccine may comprise expression one expression vector that encodes an S1 subunit of a viral spike protein and a second expression vector that encodes an S2 subunit of a viral spike protein. As a further example, in some embodiments, a vaccine may comprise expression one expression vector that encodes a viral spike protein and a second expression vector that encodes a viral E protein, M protein, or N protein. Additionally or alternatively, in some embodiments a given monocytic cell may be exposed to, and therefore phagocytose, more than one of the disclosed nucleic acid vaccines, each of which comprises a different expression vector encoding a different immunogenic peptide. For example, a monocytic cell may phagocytose two different vaccines, one of which comprises an expression vector that encodes a viral spike protein and another of which comprises an expression vector that encodes a viral E protein, M protein, or N protein. Accordingly, in some embodiments, the present disclosure provides monocytic cells (such as antigen presenting cells) that express 1, 2, 3, 4, or 5 or more different immunogenic peptides, as disclosed herein.
Particle-Based Nucleic Acid Vaccine Platform
The present disclosure provides a particle-based nucleic acid vaccine platform for directed entry of a nucleic acid encoding an immunogenic peptide into a monocyte cell (e.g., an antigen presenting cell). A particle-based vaccine according to the present disclosure is generally composed of (i) a base particle (e.g., a yeast cell wall particle or YCWP) that can be phagocytosed by a monocytic cell, (ii) a lysosome-evading component (e.g., a non-infectious virus) attached to the base particle, and (iii) a nucleic acid sequence encoding an immunogenic peptide, which may also be attached to the based particle. The disclosed particle-based vaccines are highly specific for phagocytic cells like monocyte cells, including dendritic cells and macrophages. This pronounced selectivity for monocyte cells renders the particle-based vaccines extremely useful for presenting antigens to elicit an immune response.
The disclosed particle-based platform has demonstrated an ability to deliver its antigenic “payload” directly and specifically into APCs with remarkable efficiencies of greater than 90%. Moreover, because the disclosed platform takes advantage of the avid phagocytosis of particles, such as yeast cell wall particles (YCWPs), of a specific size range with pathogen associated molecular profiles like yeast beta glucan by monocyte cells, the pathway of entry into APCs is through the APC's phagosome. As a result of this mode of entry any molecular “payload” of the YCWPs is exposed to the highly lytic environment within the phagosome's early decedent, the phagolysosome. While exposure of protein antigens to this environment can result in nucleic acid digestion, a DNA vaccine in which a single cleavage site within a coding sequence would render that sequence useless must have a mechanism of escaping the phagosome. This phagolysosome lytic degradation of vaccine DNA sequences established a significant challenge for developing a nucleic acid vaccine. However, recognition of the ability of adenoviruses to escape phagolysosome degradation of viral DNA upon entry into virally infected cells provided a means of overcoming this challenge. As will be described in more detail below, the attachment of a lysosome-evading component (e.g., an enfeebled adenovirus particle) to a base particle, such as a YCWP, allows passage of that “decorated” particle, which can also carry a nucleic acid encoding an immunogenic peptide, through the phagosome or phagolysosome without damage to the nucleic acid.
A. Base Particle
The disclosed particle-based nucleic acid vaccines take advantage of the phagocytic activity of monocyte cells by “looking” like a bacterium. Thus, a preferred size for the base particle is one that approximates the size of the bacterial antigens that monocyte cells typically ingest. Generally, the vector particle will be about 0.5 to about 2.5 microns, or about 0.5 to about 1 micron. Thus, the vector particle may be about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, about 1.0, about 1.1, about 1.2, about 1.3, about 1.4, about 1.5, about 1.6, about 1.7, about 1.8, about 1.9, about 2.0, about 2.1, about 2.2, about 2.3, about 2.4, or about 2.5 microns.
In preferred embodiments, the base particle may be a yeast cell wall particle (YCWP), such as yeast glucan particles. In some embodiments, the base particle may be a bead.
i. Yeast Cell Wall Particle (YCWP)
A YCWP can be prepared from yeast cell wall such that the particle is porous to the delivery of various macromolecules. In one embodiment, the YCWP can be prepared from Saccharomyces cerevisiae. In another embodiment, the YCWP can a zymosan particle. In another embodiment, the YCWP approximates the size of microbial structures that cells of the mononuclear phagocyte system and other phagocytic cells typically ingests (e.g., bacteria). In specific embodiments, the YCWP can be about 1-5 μm.
In some embodiments, the YCWP may be prepared by (a) suspending yeast to produce a suspension, (b) incubating the suspension, (c) centrifuging the suspension and removing the supernatant and (d) recovering the resulting YCWP. In some embodiments, steps (a)-(d) are repeated at least 1, 2, 3 or 4 times.
In some embodiments, the YCWP may be prepared by (a) suspending yeast in a solution to produce a first suspension, (b) incubating the first suspension, (c) centrifuging the first suspension and removing the supernatant, (d) suspending the resulting pellet to produce a second suspension, (e) incubating the second suspension, (f) centrifuging the second suspension and removing the supernatant and (g) washing the resulting pellet to recover the YCWP. In some embodiments, the YCWP is sterilized.
In some embodiments, the yeast is suspended in NaOH, including 1M NaOH. In some embodiments, the first suspension is incubated at about 80° C. for about 1 hour or for 1 hour. In some embodiments, the centrifuging is performed at about 2000 times gravity for about 10 minutes, or at 2000 times gravity for 10 minutes. In some embodiments, the pellet is suspended in water, including water at about pH 4.5 or at pH 4.5. In some embodiments, the second suspension is incubated at about 55° C. for about 1 hour or at 55° C. for 1 hour. In some embodiments, the pellet is washed in water at least 1, 2, 3 or 4 times. In some embodiments, the pellet is washed once.
In some embodiments, the YCWP is sterilized using isopropanol and/or acetone following washing of the pellet. In specific embodiments, other known alcohols are appropriate. In some embodiments, the YCWP is allowed to fully dry after sterilization. In some embodiments, the YCWP is resuspended after being allowed to dry. In some embodiments, the YCWP is freeze dried and store at 4° C.
A general flow diagram for preparing YCWPs is provided in
In order to functionalize a YCWP for attachment of a lysosome-evading component (e.g., an adenovirus) and a nucleic acid encoding an immunogenic peptide, the YCWP can be surface modified with polyethyleneimine (PEI). PEI provides a highly positively charged external surface, onto which a negatively charged nucleic acid (e.g., a nucleic acid encoding an immunogenic peptide) may bind. A general flow diagram showing how a YCWP can be surface modified with PEI is provided in
Thus, in some embodiments, the particle-based nucleic acid vaccine may comprise a YCWP surface modified with polyethyleneimine (PEI), which is then bound with Adenovirus 5 Flu vaccine viruses and 2019-nCov_pcDNA3.1(+)-p2A-eGFP DNA plasmids encoding the surface glycoprotein (S protein) of COVID-19 (C19FP).
ii. Bead Particle
In those embodiments when a bead is used as the base particle, several factors must be weighed to determine the ideal bead for a given need. For instance, from the perspective of uptake, the smaller end of the ranges is preferred, because it more closely approximate the size of a bacterium. On the other hand, for manufacturing purposes, slightly larger particles may be preferred, because they may be less likely to stick together.
Furthermore, the bead particle is not limited by shape or material. The bead particle can be of any shape, size, or material that allows the bead vector to be phagocytized by monocytic cells.
In some embodiments, the base particle be selected from any known ferro-magnetic center covered by a polymer coat, such as PEI. For example, beads that can be used as a base particle include, but are not limited to, microbeads, microspheres, and silicate beads. Such beads may be preferred in certain applications because magnetic separation can be employed to separate free from bead-bound components during processing. However, bead particles for use in the disclosed delivery vectors are not limited to a specific type of material and may be made of synthetic materials like polystyrene or other plastics, as well as biological materials.
B. Lysosome-Evading Component
In addition to the base particle, a delivery vector of the present disclosure may also comprise a lysosome-evading component, for example, an adenovirus or retrovirus attached or conjugated to the base particle. The role of the lysosome-evading component with respect to the vaccine is to assist the vector in escaping the harsh environment of the lysosome following phagocytosis by a monocyte cell and to deliver the nucleic acid or expression vector that encodes an immunogenic peptide for expression and presentation on the surface of the target monocytic cell.
When a monocytic cell ingests a large antigen, a phagocytic vesicle (phagasome) is formed which engulfs the antigen. Next, a specialized lysosome contained in the monocyte cell fuses with the newly formed phagosome. Upon fusion, the phagocytized antigen is exposed to several highly reactive molecules as well as a concentrated mixture of lysosomal hydrolases. These highly reactive molecules and lysosomal hydrolases digest the contents of the phagosome. By attaching a lysosome-evading component to the particle, the nucleic acid that is attached to the base particle can escape digestion by the materials in the lysosome and enters the cytoplasm of the monocyte intact. Prior systems have failed to recognize the importance of this feature and, thus, obtained much lower levels of expression than the expression systems of the present disclosure. See Falo et al., WO 97/11605 (1997).
Thus, in some embodiments a particle-based vaccine of the present disclosure may comprise one or more lysosome-evading components attached to the surface of a base particle (e.g., a YCWP or bead particle). The lysosome-evading component may be an RNA virus, like a retrovirus, or a DNA virus, like an adenovirus. In some embodiments, the virus may be recombinant and/or non-replicative and/or non-infective, such as an enfeebled virus like an influenza vaccine (e.g., a SEQIRUS® quadrivalent flu vaccine). One of skill in the art will know of commonly used methods to make a virus non-replicative and/or non-infective. Preferred viruses include, but are not limited to, adenovirus (e.g., adenovirus 5 or Ad5), lentivirus (e.g., HIV-derived viruses), and adeno associate virus (“AAV”; e.g., AAV5, AAV9, etc.).
Because viral infection is not essential for expression of the nucleic acid or expression vector encoding an immunogenic peptide within the monocyte cell, the virus can also be replication/infection deficient. For example, one method for producing a replication/infection deficient adenovirus can be achieved by altering the virus fiber protein. Thus, in some embodiments, a virus in which the fiber protein is engineered by specific mutations to allow the fiber protein to bind to an antibody but not to its cognate cellular receptor can be used in the particles of the present disclosure. Another method for producing a replication/infection deficient virus is by intentionally causing denaturation of the viral component responsible for infectivity. In the case of adenovirus, for example, the fiber protein could be disrupted during the preparation of the virus. For HIV, this could include the envelope (env) protein. Thus, in some embodiments, a method for creating an infection deficient virus for attachment to the disclosed bead particles comprises removing the outer membranes of the virus so that only the virus core remains.
In some embodiments, transient expression may be preferred and cytoplasmic viruses, like Sindbis virus, for example, can therefore be employed.
In some embodiments, where no lysosome-evading component is naturally present on the virus, one may be added. For example, in the case of Sindbis or other such viruses, the virus can be engineered to express all or part of the adenovirus penton protein for the purpose of evading the lysosome.
In some embodiments, the lysosome-evading component can include proteins, carbohydrates, lipids, fatty acids, biomimetic polymers, microorganisms and combinations thereof. It is noted that the term “protein” encompasses a polymeric molecule comprising any number of amino acids. Therefore, a person of ordinary skill in the art would know that “protein” encompasses a peptide, which is understood generally to be a “short” protein. In some embodiments, lysosome-evading components include, but are not limited to, specific viral proteins, for example, an adenovirus hexon protein or penton protein. Adenovirus hexon proteins are a type of major coat protein in adenoviruses, and the adenovirus penton protein is a complex formed by the peripentonal hexons and penton base, which enables a virus to evade/disrupt the lysosome/phagosome. Thus, either the intact adenovirus or the isolated hexon or penton protein, or a portion thereof (see, e.g., Bal et al., Eur J Biochem 267:6074-81 (2000)), can be utilized as the lysosome-evading component. In some embodiments, fusogenic peptides derived from N-terminal sequences of the influenza virus hemagglutinin subunit HA-2 may also be used as the lysosome-evading component (Wagner, et al., Proc. Natl. Acad. Sci. USA, 89:7934-7938, 1992).
For example, in some embodiments, proteins that can serve as a lysosome-evading component include, but are not limited to, melitin and LL37. Melittin is the principal active component of apitoxin (bee venom) and is a powerful stimulator of phospholipase A2. Melittin is a peptide consisting of 26 amino acids, the sequence and structure of which are shown in
Melittin and/or LL37 can be loaded onto a base particle, such as a YCWP, by known methods, including but not limited to incubating the YCWPs in solution with melittin and/or LL37 and then freeze-drying the composition. In some embodiments, a lysosomal-evading protein (e.g., melittin or LL37) may be attached to the base particle (e.g., YCWP) via any of the following bonds, which are preferred for their ability to be cleaved or are otherwise labile in the phagosome: disulfide, poly-imine (particularly a poly-imine-coated particle and a lytic peptide comprising an aldehyde or polyaldehyde), β-thiopropionate, cis-aconityl, hydrosome, diorthoester, orthoester, vinylether, or phosphoramidate. The foregoing chemical bond are desirable because while the lysosomal-evading protein (e.g., melittin or LL37) is bound to the base particle (e.g., YCWP), it is inactive, but upon cleavage of the chemical bond within the phagosome the lysosomal-evading protein is released and can form pores in the phagosome to allow the particle and nucleic acid to escape. In some embodiments, the lysosomal-evading protein (e.g., melittin or LL37) may be indirectly connected to the base particle (e.g., YCWP) indirectly via a sulfosuccinimidyl 6-[3′(2-pyridyldithio)-propionamido (SPDP) alone or in combination with PEI. SPDP are a unique group of amine- and sulfhydryl-reactive heterobifunctional crosslinkers that can be used to form amine-to-amine or amine-to-sulfhydryl crosslinks among molecules, and the SPDP reagents produce disulfide-containing linkages that can be cleaved later by, for example, reducing agents. Accordingly, SPDP can react with the sulfhydrl group of a cysteine, such as the N-terminal cysteine in the commercially available Cys-LC-LL37 (available from AnaSpec, Inc.; catalog number AS-63692) or the terminal amine group of melittin.
The disclosed delivery particles may comprise about 5.0×105 to about 3.0×106 molecules of melittin and/or LL37 per particle. Thus, the disclosed delivery particles may comprise about 5.0×105, about 5.5×105, about 6.0×105, about 6.5×105, about 7.0×105, about 7.5×105, about 8.0×105, about 8.5×105, about 9.0×105, 9.1×105, about 9.2×105, about 9.3×105, about 9.4×105, about 9.5×105, about 9.6×105, 9.7×105, about 9.8×105, about 9.9×105, about 1.0×106, about 1.1×106, about 1.2×106, about 1.3×106, about 1.4×106, about 1.5×106, about 1.6×106, about 1.7×106, about 1.8×106, about 1.9×106, about 2.0×106, about 2.1×106, about 2.2×106, about 2.3×106, about 2.4×106, about 2.5×106, or about 3.0×106 molecules of melittin and/or LL37 per particle. The amount of melittin and/or LL37 per particle may be at least any of these amounts or more.
Lysosome evading compounds similar to melittin, which are also within the scope of the disclosure, include bombolitin from bumblebee venom (17 amino acid amphiphilic alpha-helix), mastoparan from wasp venom (14 amino acid amphiphilic alpha-helix) and crabrolin from hornet venom (13 amino acid amphiphilic alpha-helix) Argiolas A. and Pisano J. J., 1985, J. Biol. Chem. 260, 1437-1444). Additionally, the lysosome evading component my comprise a cytolytic derivative or analog of melittin, so long as the derivative or analog is able to lyse the lysosome to safely deliver the nucleic acid of interest into the cytoplasm of the target cell. For example, Werkmeister et al. (1993), Biochim. Biophys. Acta 1157: 50-54, discloses the effect of sequence and structural variations on the cytolytic activity of melittin, and is hereby incorporated by reference in its entirety. Thus, other lysosome evading components include melittin analogs and derivatives that contain at least one γ-linked glutamate residue linked via a peptide bond to the epsilon amino group of a lysine (hereinafter “γ-glutamate-masked melittin analog”).
Other lysosome evading components include, but are not limited to, biomimetic polymers such as Poly (2-propyl acrylic acid) (PPAAc), which has been shown to enhance cell transfection efficiency due to enhancement of the endosomal release of a conjugate containing a plasmid of interest (see Lackey et al., Abstracts of Scientific Presentations: The Third Annual Meeting of the American Society of Gene Therapy, Abstract No. 33, May 31, 2000-Jun. 4, 2000, Denver, Colo.) Examples of other lysosome evading components envisioned by the present invention are discussed by Stayton, et al. J. Control Release, 1; 65(1-2):203-20, 2000.
A single base particle may have numerous lysosome-evading components (e.g., viruses, such as an adenovirus, or proteins, such as a penton protein, melittin, or LL37) attached or conjugated to its surface.
Viruses or proteins that are utilized as the lysosome-evading component can be attached to the base particles directly, using conventional methods, or indirectly. See Hammond et al., Virology 254:37-49 (1999). For example, YCWPs can be oxidized with sodium periodate to generate aldehydes, which can be further reacted with adipic acid dihydrazide to form ADH-particles. These ADH-particles can be derivatized with SPDP (succinimidyl 3-(2-pyridyldithio)propionate) crosslinker and reacted with SPDS derivatized streptavidin to form YCWP conjugated with streptavidin, i.e., streptavidin-modified YCWPs. Streptavidin-modified YCWPs can be directly used for conjugation of biotinylated viral particles (e.g., biotinylated adenovirus), biotinylated antibodies (e.g., an anti-hexon protein antibody, such as the adenovirus 5 hexon-specific antibody from Invitrogen: PA1-28357), or they can be further modified with Biotin-polyethyleneimine (PEI). Avidin-modified YCWPs can be saturated with PEI-g-PEG-Biotin to form PEI modified particles, PEI-particles. Adenovirus (and other anionic viruses) can be carried by PEI-particles through charge interactions between the PEI and the anionic charge of the virus coat. Alternatively, if a biotinylated antibody (e.g., an anti-hexon protein antibody) is attached to the streptavidin-modified YCWPs, subsequently contacting/incubating the particles with particles with a virus or protein to which the antibodies can bind will indirectly attach the virus or protein to the particle. Accordingly, in some embodiments, the lysosome-evading component may be a virus, such as an adenovirus 5, that is bound to the base particle (e.g., YCWP) via a biotinylated antibody that binds to adenovirus 5 hexon protein. In some embodiments, the lysosome-evading component may be a hexon protein, melittin, LL37, or the like that is bound to the base particle (e.g., YCWP) via a biotinylated antibody that binds to any one of the recited lysosome-evading proteins.
Thus, in some embodiments, the nucleic acid may escape lysosomal digestion as a result of the particle comprising a lysosome-evading component that is conjugated to the base particle via a biotin-streptavidin linkage. The base particle may be modified to attach a linker comprising streptavidin and the lysosome-evading component may be biotinylated (e.g., a biotinylated virus) or indirectly bound to the particle by an intermediate connection that is biotinylated (e.g., a biotinylated anti-hexon protein antibody).
Indeed, antibody attachment is an efficient way to attach a desired virus to the base particle. One example of antibody attachment encompassed may comprise a single antibody that is chemically affixed to the bead vector particle. The antibody is specific to the component to be attached to the base particle (e.g., a virus or lysosome-evading protein).
In some embodiments, two or more antibodies can be used. In this case, one antibody, which is attached to the base particle, may be specific for a second antibody. The second antibody may be specific to the virus to be attached to the base particle. Thus, the virus-specific antibody binds the virus, and that antibody, in turn, is bound by the antibody attached to the base particle. For instance, a goat- or rabbit-anti-mouse antibody may be bound to the bead and a mouse monoclonal antibody can be used to bind the specific virus. Or, in another alternative format, the two or more antibodies my each be specific for a different viruses or proteins to be attached to the particle, such that the particle is decorated with two or more distinct lysosome-evading components.
In another example of antibody attachment, protein A, or any similar molecule with an affinity for antibodies, may be employed. In this example, the base particle may be coated with protein A, which binds to an antibody, and, in turn is bound to the virus being attached to the base particle.
In some embodiments, attaching viruses to a base particle can also be accomplished by engineering the virus to express certain proteins on its surface. For instance, the HIV env protein might be replaced with the adenovirus penton protein, or a portion thereof. The recombinant virus then could be attached via an anti-penton antibody, with attachment to the base particle mediated, for example, by another antibody or protein A. In some embodiments, a penton protein may also serve as a lysosome evading component.
Virus-Based Nucleic Acid Vaccine Platform
The present disclosure provides a virus-based nucleic acid vaccine platform for directed entry of a nucleic acid encoding an immunogenic peptide into a monocyte cell (e.g., an antigen presenting cell). A virus-based vaccine according to the present disclosure is generally composed of an enfeebled or non-infective virus, such as an adenovirus, that has been surface modified with polylysine such that a nucleic acid encoding an immunogenic protein can bind to the positively charged polylysine via electrostatic interaction with the negatively charge nucleic acid.
Without being bound by theory, it is believed that, as a result of the addition of bundles of nucleic acid to the surface of the poly-lysine modified virus, the disclosed virus-based vaccines may be of a size that encourages phagocytosis by monocytic cells much in the same way that the particle-based vaccines described above.
For the purposes of the virus-based vaccine platform, adenovirus (e.g., adenovirus 4 or adenovirus 5) are a preferred base or core onto which the nucleic acid encoding an immunogenic peptide can be added. Adenoviruses (Ads) are nonenveloped virions 70-90 nm in diameter with a capsid consisting of three main exposed structural proteins, the hexon, fiber, and penton base. Hexon accounts for the majority of the structural components of the capsid, which consists of 240 trimeric hexon capsomeres and 12 pentameric penton bases. The trimeric fiber protein protrudes from the penton base at each of the 12 vertices of the capsid and is a knobbed rod-like structure. A distinct difference in the surface of adenovirus capsids compared to that of most other icosahedral viruses is the presence of the long, thin fiber protein, the primary role of which is to tether the viral capsid to a target cell surface via its interaction with a cellular receptor.
The fiber proteins of all human adenovirus serotypes share a common architecture: an N-terminal tail, a central shaft made of repeating sequences, and a C-terminal globular knob domain. The first ˜45 residues of the fiber are highly conserved among different serotypes and are responsible for binding to the penton base. As shown in
The glutamine residues of the adenovirus fiber knob domain can be functionalized by contacting an isolated adenovirus with transglutaminase. Transglutaminases are enzymes that catalyze the formation of an isopeptide bond between γ-carboxamide groups (—(C═O)NH2) of glutamine residue side chains and the ε-amino groups (—NH3) of lysine residue side chains with subsequent release of ammonia (NH3). Lysine and glutamine residues must be bound to a peptide or a protein so that this cross-linking (between separate molecules) or intramolecular (within the same molecule) reaction can happen. Bonds formed by transglutaminase exhibit high resistance to proteolytic degradation (proteolysis). The reaction is:
Transglutaminases can also join a primary amine (RNH2) to the side chain carboxyamide group of a protein/peptide bound glutamine residue thus forming an isopeptide bond:
These enzymes can also deamidate glutamine residues to glutamic acid residues in the presence of water:
Thus, incubating adenovirus in the presence of polylysine and transglutaminase results in the polylysine being cross-linked and attached to the exposed glutamine residues of the knob domain of the fiber protein. Upon formation of the polylysine-decorated virus, further incubation with nucleic acid molecules (e.g., DNA), such as an expression vector encoding an immunogenic peptide, results in the binding of the nucleic acids to the polylysine-decorated virus via electrostatic interaction. The resulting virus can function as a vaccine much in the same way as the particle-based platform described above.
While not being bound by theory, it is believed that the decorated virus is phagocytosed by monocytic cells and escapes lysosomal digestion in the same way that an undecorated virus would do so. Once in the cytoplasm of the target monocytic cell, the nucleic acid attached to the surface of the virus via the polylysine can be expressed, such that the immunogenic peptide encoded therein is produced within and subsequently presented on the cell.
While adenovirus may be preferred for this platform, other non-replicative and/or non-infective viruses may additionally be suitable, so long as the virus can be decorated with polylysine. Accordingly, suitable viruses may include, but are not limited to, adenovirus (e.g., adenovirus 5, adenovirus 4), lentivirus (e.g., HIV-derived viruses), and adeno associate virus (e.g., AAV5, AAV9, etc.).
Pharmaceutical Compositions
Pharmaceutical compositions suitable for use in the methods described herein can include the disclosed delivery vectors and a pharmaceutically acceptable carrier or diluent.
In some embodiments, the disclosed delivery vectors may be formulated for parenteral administration by, for example, intradermal, intravenous, intramuscular or subcutaneous injection. Formulations for injection may be presented in unit dosage form, e.g., in ampules or in multi-dose containers, optionally with an added preservative. The compositions may take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilizing and/or dispersing agents. The delivery vector may also be formulated using a pharmaceutically acceptable excipient. Such excipients are well known in the art, but typically will be a physiologically tolerable aqueous solution. Physiologically tolerable solutions are those which are essentially non-toxic. Preferred excipients will either be inert or enhancing. Intradermal injection is a preferred route of administration.
In some embodiments, the disclosed vaccines may be formulated to be administered concurrently with another therapeutic agent. In some embodiments, the vaccines may be formulated to be administered in sequence with another therapeutic agent. For example, the vaccine may be administered either before or after the subject has received a regimen of an anti-viral or antibacterial therapy.
Methods of Treatment and Prevention
Provided herein are methods of treating and/or preventing infections and diseases caused by viruses, bacteria, and other pathogenic microbes by administering the disclosed vaccines. More specifically, the disclosure provides for methods of stimulating the immune system to mount an anti-viral or antibacterial response by expressing within a monocytic cell (e.g., an antigen presenting cell) an immunogenic peptide derived from a pathogen (e.g., virus, bacteria, etc.) for which protection from infection is sought. The mechanism of immune stimulation may be multi-faceted and may vary depending on the components of the immunogenic peptide being expressed and the type of monocytic cell expressing the immunogenic peptide.
In some embodiments, the disclosed vaccine may provide to a monocytic cell, such as a macrophage or dendritic cell, a nucleic acid sequence and/or expression vector that encodes at least one immunogenic peptide. In some embodiments, the disclosed vaccines may provide to a monoctyic cell 1, 2, 3, 4, or 5 or more nucleic acid sequences and/or expression vectors that encode 1, 2, 3, 4, or 5 or more different immunogenic peptides. When such an immunogenic peptide is presented on the surface of a monocytic cell, such as an antigen presenting cell, the immune system is stimulated to produce antibodies that bind to the immunogenic peptide and to mount a systemic defense against the pathogen from which the peptide was derived.
For example, in some embodiments, the nucleic acid or expression vector encoding an immunogenic peptide may encode a viral spike protein (also known as “S protein” or “glycoprotein S”), which is generally responsible for viral entry into a host cell. The spike protein is ideal to serve as an immunogenic peptide because antibodies that develop against this peptide are likely to be neutralizing. The spike protein comprises two functional subunits responsible for binding to the host cell receptor (S1 subunit) and fusion of the viral and cellular membranes (S2 subunit). A vaccine of the present disclosure may encode the entire spike protein, only the S1 subunit, only the S2 subunit, or any immunogenic portion thereof. In some embodiments, the vaccine encodes a full length spike protein. In some embodiments, the vaccine encodes only an immunogenic fragment of a viral spike protein. Other viral proteins that may serve as the immunogenic peptide when the target pathogen is a virus include, but are not limited to, a viral E protein, M protein, or N protein, or any other viral capsid or coat protein. In some embodiments, the vaccine encodes a full length E protein, M protein, N protein, or other viral capsid or coat protein, while in some embodiments, the vaccine my encode only an immunogenic fragment of one of these proteins.
Furthermore, when the disclosed vaccine comprises a YCWP as the base particle, the vector can possess even further anti-tumor activity by loading the YCWP with a biological material, such as a tumor lysate. Inclusion of a biological material like a tumor lysate within the YCWP provides a vaccine-like function when the delivery vectors are taken up by an antigen presenting cell (APC) like cells of the mononuclear phagocyte system, including monocytes, macrophages, dendritic cells or immature dendritic cells. In the field of vaccination, cells of the mononuclear phagocyte system are considered “professional” antigen presenting cells and thus, are the ideal target for vaccine delivery. It is well known that presentation of an antigen within an APC is vastly more effective in generating a strong cellular immune response than expression of this same antigen within any other cell type. Accordingly, loading the YWCP with an antigenic biological material like a tumor lysate will result in the presentation of a tumor antigen on an antigen presenting cell via class I MHC and class II MHC molecules, thus dramatically enhancing the immune response elicited by the disclosed delivery vectors.
The disclosed vaccines are highly selective for monocyte cells. It is, therefore, useful for any application involving selectively introducing an expression into a monocyte cell. In some embodiments, the disclosed vectors are administered to treat or prevent an infectious disease, and, in particular, viral or bacterial diseases. In view of the foregoing explanation of the putative mechanism of action, it is believed that the disclosed vaccines may be used to treat or prevent almost any type of infectious disease, which may include, but is not limited to, coronavirus infections (discussed in more detail below), influenza, retroviral infections (e.g., HIV/AIDS), hepatitis A, hepatitis B, hepatitis C, norovirus infections, or infections caused by Acinetobacter baumannii, Bacteroides fragilis, Burkholderia cepacia, Clostridium difficile, Clostridium sordellii, Enterobacteriaceae sp., Enterococcus faecalis, Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus (including methicillin-resistant strains or MRSA, and vancomycin-resistant or VRSA), Morganella morganii, Mycobacterium abscessus, Psuedomonas aeruginosa, Stenotrophomonas maltophilia, Mycobacterium tuberculosis, or Enterococci sp. Typical methods of treatment or prevention of a disease or infection (e.g., the foregoing diseases and infections) comprise contacting a monocytic cell with a disclosed vaccine, such that it is phagocytosed by the monocytic cell and the immunogenic is subsequently expressed and presented on the surface of the cell.
As noted above, the vaccines may be injected intradermally, subcutaneously, or systemically (i.e., into the peritoneal of the subject). In some embodiments, the delivery vectors may be administered intradermally proximate a lymph node (e.g., under the arm).
In some embodiments a monocyte cell may be contacted with the disclosed vaccine either in vivo or in vitro. Hence, both in vivo and ex vivo methods of treatment are contemplated herein. In some embodiments, a patient's monocytic cells can be isolated and contacted with the disclosed vaccines in vitro before the cells are returned to the patient. While such embodiments are contemplated in the present disclosure, the disclosed vaccines provide a substantial improvement because they may be used in both in vivo and ex vivo methods. Moreover, altering the route of administration can alter the monocytic cells targeted. For example, in the case of intravenous injection, macrophages may be targeted, and in the case of intradermal and subcutaneous injection.
Dosage regimens can be adjusted to provide the optimum desired response (e.g., production of antibodies against a given pathogen). For example, in some embodiments, a single bolus of vaccine may be administered, while in some embodiments, several divided doses may be administered over time as boosters, or the dose may be proportionally reduced or increased as indicated by the situation. For example, in some embodiments the disclosed vaccines may be administered once or twice weekly by subcutaneous or intradermal injection. In some embodiments, the disclosed delivery vectors may be administered once or twice monthly by subcutaneous or intradermal injection. In some embodiments, the disclosed delivery vectors may be administered once every week, once every other week, once every three weeks, once every four weeks, once every other month, once every three months, once every four months, once every five months, once every six months, once every seven weeks, once every eight weeks, once every three months, once every four months, once every five months, once every six months, or once a year. In some embodiments, a subject may be administered an initial bolus dose and then receive one or more booster doses with a predefined span of time in between each dose (e.g., 1, 2, 3, or 4 week, or 1, 2, 3, 4, 5, 6, 9, or 12 months). In some embodiments, a subject may receive only a single dose (e.g., about 108 particles). In some embodiments, a subject may receive an initial dose followed by one or more subsequent doses of an equal or lesser concentration at a set time after this initial dose, such as 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, 8 weeks, 9 weeks, 10 weeks, 11 weeks, 12 weeks, 13 weeks, 14 weeks, 15 weeks, 16 weeks, 17 weeks, 18 weeks, 19 weeks, or 20 or more weeks.
Doses may likewise by adjusted to provide the optimum desired response. For example, in some embodiments, a dose of the disclosed vaccines may comprise 1.0×108 to 1.0×1012 particles. For example, a single dose may comprise 1.0×108, 1.5×108, 2.0×108, 2.5×108, 3.0×108, 3.5×108, 4.0×108, 4.5×108, 5.0×108, 5.5×108, 6.0×108, 6.5×108, 7.0×108, 7.5×108, 8.0×108, 8.5×108, 9.0×108, 9.5×108, 1.0×109, 1.5×109, 2.0×109, 2.5×109, 3.0×109, 3.5×109, 4.0×109, 4.5×109, 5.0×109, 5.5×109, 6.0×109, 6.5×109, 7.0×109, 7.5×109, 8.0×109, 8.5×109, 9.0×109, 9.5×109, 1.0×1010, 1.5×1010, 2.0×1010, 2.5×1010, 3.0×1010, 3.5×1010, 4.0×1010, 4.5×1010, 5.0×1010, 5.5×1010, 6.0×1010, 6.5×1010, 7.0×1010, 7.5×1010, 8.0×1010, 8.5×1010, 9.0×1010, 9.5×1010, 1.0×1011, 1.5×1011, 2.0×1011, 2.5×1011, 3.0×1011, 3.5×1011, 4.0×1011, 4.5×1011, 5.0×1011, 5.5×1011, 6.0×1011, 6.5×1011, 7.0×1011, 7.5×1011, 8.0×1011, 8.5×1011, 9.0×1011, 9.5×1011, or 1.0×1012 particles. In some embodiments, the dose may be about 9.5×108, about 9.75×108, about 9.85×108, about 9.95×108, about 1.0×109, about 1.1×109, about 1.15×109, about 1.2×109, about 1.25×109, about 1.3×109, about 1.35×109, about 1.4×109, about 1.45×109, or about 1.5×109 particles.
Furthermore, while the subject of the methods is generally a human patient, the age of the patient is not limited. The disclosed methods are useful for preventing infectious diseases in patients with various levels of risk exposure and prognostic outcomes, across all age groups and cohorts. Thus, in some embodiments, the subject may be a pediatric subject, while in other embodiments, the subject may be an adult subject, while in other embodiments, the subject may be 60, 65, 70, 75, or 80 years of age or older.
In sum, the disclosed methods provide a broad spectrum approach to preventing and treating infectious diseases, such as viral, bacterial, and other microbial diseases, using a platform that relies on expression of an immunogenic peptide by antigen presenting cells. The disclosed nucleic acid vaccine platforms provide a simple and flexible approach that can be readily adapted to elicit an immune response to any type of pathogen.
The following examples are given to illustrate the present disclosure. It should be understood that the invention is not to be limited to the specific conditions or details described in these examples.
Coronaviruses and Coronavirus Infections
The vaccines and pharmaceutical compositions described herein may be administered to a subject to treat or prevent a disease in a subject in need thereof, in particular when the disease is a viral infection, such as a coronavirus infection (e.g., COVID-19). Further disclosed herein are uses of any of the vaccines or pharmaceutical compositions disclosed herein in the manufacture of a medicament for treating or preventing a viral infection, such as a coronavirus infection (e.g., COVID-19).
In some embodiments of the disclosed method and uses, the disease being treated is a viral disease. In some embodiments, the viral disease is caused by an RNA virus. In some embodiments, the RNA virus is a single-stranded RNA virus (ssRNA virus). In some embodiments, the ssRNA virus is a positive-sense single-stranded RNA virus ((+)ssRNA virus). In some embodiments, the (+)ssRNA virus is a coronavirus.
Coronaviruses are a family of viruses (i.e., the coronaviridae family) that cause respiratory infections in mammals and that comprise a genome that is roughly 30 kilobases in length. The coronaviridae family is divided into four genera and the genome encodes 28 proteins across multiple open reading frames, including 16 non-structural proteins.
The coronaviridae family includes both α-coronaviruses or β-coronaviruses, which both mainly infect bats, but can also infect other mammals like humans, camels, and rabbits. β-coronaviruses have, to date, been of greater clinical importance, having caused epidemics including severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and COVID-19. The disclosed vaccines and pharmaceutical compositions may be used to treat or prevent diseases caused by β-coronaviruses and α-coronaviruses. Thus, in some embodiments of the disclosed methods and uses the coronavirus is a β-coronavirus, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (also known by the provisional name 2019 novel coronavirus, or 2019-nCoV), human coronavirus OC43 (hCoV-OC43), Middle East respiratory syndrome-related coronavirus (MERS-CoV, also known by the provisional name 2012 novel coronavirus, or 2012-nCoV), and severe acute respiratory syndrome-related coronavirus (SARS-CoV, also known as SARS-CoV-1). In some embodiments of the disclosed methods and uses the coronavirus is a α-coronavirus.
Several disease-causing coronaviruses share a high degree of homology across their genomes. Accordingly, the disclosed vaccines and pharmaceutical compositions may provide a broad spectrum treatment or preventative effect for multiple different types of coronavirus, such as MERS-CoV, SARS-CoV-1, and SARS-CoV-2.
In some embodiments of the disclosed methods and uses, the immunogenic peptide encoded by the nucleic acid vaccine may be all or a portion of a structural protein from a coronavirus, such as SARS-CoV-2. In some embodiments, the immunogenic peptide is selected from genome of SARS-CoV-2, which corresponds to the nucleotide sequence of GenBank Accession No. NC_045512.2, and which is incorporated by reference in its entirety. The SARS-COV-2 genome is also shown in Table 1 below.
In some embodiments, the immunogenic peptide may be all or a portion of the spike protein (also known as “S protein” or “glycoprotein S”), which is responsible for viral entry into a host cell. The spike protein is ideal to serve as an immunogenic peptide because antibodies that develop against this peptide are likely to be neutralizing. The spike protein comprises two functional subunits responsible for binding to the host cell receptor (S1 subunit) and fusion of the viral and cellular membranes (S2 subunit). The SARS-COV-2 spike protein (NCBI Reference Sequence: YP_009724390.1) comprises 1273 amino acids shown below.
A vaccine of the present disclosure may encode the entire spike protein (SEQ ID NO: 1), only the S1 subunit, only the S2 subunit, or any immunogenic portion thereof. In some embodiments, the vaccine encodes SEQ ID NO: 1. In some embodiments, the vaccine encodes about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% of SEQ ID NO: 1, so long as the fragment is able to elicit an immune response (i.e., it is an immunogenic fragment).
The vaccines of the present disclosure may be used to treat or prevent an infectious disease in a subject in need thereof. In some embodiments, a method of treating or preventing a disease in a subject in need thereof comprises administering to the subject any of the nucleic acid vaccines disclosed herein. In some embodiments, a method of treating or preventing a disease in a subject in need thereof comprises administering to the subject any of the pharmaceutical compositions disclosed herein.
In some embodiments of the disclosed methods and uses, the disease is a respiratory disease. In some embodiments, the respiratory disease is a viral infection. In some embodiments, the respiratory disease is viral pneumonia. In some embodiments, the respiratory disease is an acute respiratory infection. In some embodiments, the respiratory disease is coronavirus disease 2019 (COVID-19). In some embodiments, the respiratory disease can include one or more symptoms selected from coughing, sore throat, runny nose, sneezing, headache, fever, shortness of breath, myalgia, abdominal pain, fatigue, difficulty breathing, persistent chest pain or pressure, difficulty waking, loss of smell and taste, muscle or joint pain, chills, nausea or vomiting, nasal congestion, diarrhea, hemoptysis, conjunctival congestion, sputum production, chest tightness, and palpitations. In some embodiments, the respiratory disease can include complications selected from sinusitis, otitis media, pneumonia, acute respiratory distress syndrome, disseminated intravascular coagulation, pericarditis, and kidney failure.
In some embodiments, the subject is a mammal. In some embodiments, the subject is a human. In some embodiments, the subject is a non-human primate. In some embodiments, the subject is a cat, dog, cow, pig, horse, sheep, goat, or rodent. In some embodiments in which the subject is a human, the subject may be at least 40 years old, at least 45 years old, at least 50 years old, at least 55 years old, at least 60 years old, at least 65 years old, at least 70 years old, at least 75 years old, or at least 80 years old or older. In some embodiments, the human subject is a pediatric subject (i.e., less than 18 years old).
The vaccines of the present disclosure may be given in any forms suitable for administration, which generally comprises an injection. Preferably, the disclosed vaccines are administered intradermally, intramuscularly, or subcutaneously. In some embodiments, the vaccines are administered via intradermal injection.
In some embodiments, the present disclosure provides methods of treating or preventing a coronavirus infection, comprising administering to a subject in need thereof a therapeutically effective amount of one or more of the nucleic acid vaccines or a pharmaceutical composition as disclosed herein. In some embodiments, the coronavirus infection is selected from the group consisting of Middle East Respiratory Syndrome (MERS), Severe Acute Respiratory Syndrome (SARS), and COVID-19. In some embodiments, the subject has been treated with one or more additional coronavirus treatment agents. In some embodiments, the subject is concurrently treated with one or more additional coronavirus treatment agents.
Actual dosage levels of the nucleic acid vaccines in the pharmaceutical compositions of this disclosure may be varied so as to obtain an amount of the active ingredient which is effective to achieve the desired therapeutic response for a particular patient, composition, and mode of administration, without being toxic to the patient.
The selected dosage level will depend upon a variety of factors including the activity of the particular vaccine, the route of administration, the time of administration, the duration of the treatment, the age, sex, weight, condition, general health and prior medical history of the patient being treated, and like factors well known in the medical arts.
A physician or veterinarian having ordinary skill in the art can readily determine and prescribe the effective amount of the pharmaceutical composition required. For example, the physician or veterinarian could start doses of the vaccines of the disclosure employed in the pharmaceutical composition at levels lower than that required in order to achieve the desired therapeutic effect and gradually increase the dosage until the desired effect is achieved.
In various embodiments of the disclosed particles could be used to treat or prevent any infectious disease caused by a virus, bacteria, or other pathogenic microbe. Indeed, the flexibility of the disclosed nucleic acid vaccine platform sets the disclosed particles apart from previous nucleic acid-based vaccines. The present example relates specifically to the preparation of a COVID-19 vaccine, but those of skill in the art will understand that the following manufacturing techniques could be applied to any other virus, bacteria, or pathogenic microbe for which a vaccine is desired.
With all inputs readily available, a COVID-19 YCWP vaccine takes only hours to manufacture and can be manufactured on a large scale with ease. The manufacturing of the vaccine can be divided into three phases: (1) making of the YCWPs (see
Manufacturing YCWP
Yeast cell wall particles (YCWP) were made from Fleishmans Baker's yeast through a series of steps.
The contents of the yeast were dissolved in 1M NaOH, the resulting undissolved yeast cell walls were recovered and washed extensively in water, isopropanol, acetone, and finally freeze dried in 1×PBS.
YCWP were prepared by suspending Saccharomyces cerevisiae (100 g of Fleishmans Baker's yeast, AB Mauri Food Inc., Chesterfield, Mo.) in 1 L of 1 M NaOH and heating to 90° C. for one hour. The insoluble material containing the yeast cell walls was collected by centrifugation at 2000×g for 10 minutes. This insoluble material was then suspended in 1 L of water, brought to pH 4-5 with HCl, then incubated at 75° C. for one hour. The insoluble residue was again collected by centrifugation and washed once with 1 L of water, four times with 200 mL of isopropanol, and twice with 200 mL of acetone. The resulting slurry was dried at room temperature in a sterile hood to produce 12.4 g of a fine, slightly off-white powder.
The powder composed of dry YCWP was carefully weighed and suspended in sterile distilled water at a concentration of 10 mg/ml, and 1 ml aliquots were placed in sterile Eppendorf tubes, frozen at −60° C., and freeze-dried at 0.012 mBar. Because the boiling point of isopropanol and acetone is considerably below that of water, any possible contamination by these solvents was removed under these high vacuum conditions and physically assured by the loss of water.
Furthermore, each batch of YCWP is tested to assure their non-viability by seeding an aliquot onto agar plates containing CMC Yeast growth media (Invitrogen, Inc.) and the batch is only be released for use in vaccine manufacture if no yeast colonies appear after one full week of incubation.
The prepared YCWP will be placed in CMC yeast growth media (Invitrogen, Inc.) and monitored for growth over 7 days. All prior testing has never shown any viable and proliferating yeast after the extensive YCWP production procedures outlined above. Un-manipulated Saccharomyces cerevisiae is used as a parallel positive control.
Treating YCWPs with PEI
YCWPs were oxidized with sodium periodate. Next, the YCWPs were reacted with streptavidin by reductive amination in the presences of sodium cyanoborohydride to equal 1 mg streptavidin/10 mg YCWP.
50 μg of 25 kd PEI-g-PEG-Biotin was used to coat 10 mg of streptavidin modified particles with PEI.
Loading the Surface of the YCWPs with COVID-19 Plasmid and Flu Virus
10 mg of PEI coated YCWPs were mixed with 20 μg of the plasmid pRFP-C-RS shRNA in PBS for 30 minutes at 15° C. to 25° C. Next recombinant GFP adenoviral particles were added in PBS and incubated at 15° C. to 25° C. for 30 minutes. Single use aliquots were then set aside.
Purification of Flu Vaccine Virus Particles
Flu vaccine was as a source of adenovirus particles. Flu vaccine virus particles were purified with a PUREVIRUS™ Adenovirus Purification Kit from Cell Biolab and concentrated with Amicon Centrifugal Filter Units with a 100 kd molecular cutoff.
Toxicology
No adverse effects of the COVID-19 YCWP-DNA vaccine are expected since trials using a similar particle technology have shown remarkable safety in prior clinical trials in melanoma patients. The reason for such a safety profile lies in the fact that these particles are specifically and selectively taken up by antigen presenting cells (APCs) and do not expose other cells nor accessory tissues to their composition, and any adjuvant effects of the beta glucan composition of the YCWPs is selectively experienced only by these APCs, which are terminally differentiated cells. This cell specific adjuvant effect is unique to the YCWP technology.
Sterility Testing
In-process sterility testing and final product sterility testing are assessed by different methods. The in-process sterility testing, can be performed in-house and assesses aerobic and anaerobic microbial contamination. The results for in-process are available after a five-day incubation period.
The final product sterility testing is performed according to the USP<71>direct inoculation sterility test method including a 14 day incubation is performed at a contract testing laboratory approved by the agency. In-process sterility testing is used to assess all steps of the manufacturing process to screen for and isolate any contamination. However, all final product sterility test results will be available before lot release and shipping.
Endotoxin Testing
Endotoxin testing is performed on the final product. It has been shown that YCWP will cause low-level positive endotoxin test results; therefore, the limits have been increased to accommodate these low level false positives.
Additionally, sterile empty YCWP are run as a negative control in all assays. Only results that are 20% above the negative control will be considered positive. The increased upper limit for the endotoxin assay readout is not meant to permit a higher endotoxin level in the final product, which is well below the 5 EU/kg body weight limit. Instead, the increased limit is to account for a known and well-established low level false positive result with this assay due to the beta glucan in the denuded yeast cell wall. Therefore, empty, un-manipulated and sterile YCWP are used as a control for the endotoxin assay to set an appropriate release limit for the final vaccine.
Recombinant adenovirus encoding the GFP gene was constructed with the VIRAPOWER™ Adenoviral Gateway™ Expression system. The GFP gene sequence was cloned into the destination vector pAd/CMV/V5-DEST under the control of a CMV promoter as shown in the vector map shown in
This genetic construction was transfected into 293A cells for recombinant adenovirus packaging. Recombinant adenoviral particles were purified with a PUREVIRUS™ Adenovirus Purification Kit from Cell Biolab and concentrated with Amicon Centrifugal Filter Units with a 100 kd molecular cutoff.
Plasmid DNA of the pRFP-C-RS shRNA plasmid (cat #TR30014) from Origen, as shown in the plasmid map in
YCWPs were modified to contain a highly positively charged external surface by reaction with polyethyleneimine (PEI). First YCWPs were surface modified with streptavidin. Briefly, YCWPs were first oxidized with sodium periodate and then the resulting surface aldehyde groups were reacted with streptavidin (Promega) by reductive amination in the presence of sodium cyanoborohydride. The resulting modified YCWPs contained about 1 mg streptavidin/10 mg YCWP (1.51×10−8 mole streptavidin/10 mg particle, about 3.64×1016 biotin binding sites). 50 μg of 25 kd PEI-g-PEG-Biotin (2 nM, about 1.2×1015 molecules; shown in Formula I below) from Nanosoft polymers was used to coat 10 mg of streptavidin modified particles with PEI, which is about 1.5×106 PEI molecules/particle.
10 mg of PEI coated particles were mixed with 20 μg of the plasmid pRFP-C-RS shRNA in PBS for 30 minutes at 15° C. to 25° C. to form the DNA/PEI complex on the surface of the particle. This gives a N/P ratio around 20. After the PEI/DNA complex was formed, 4×1011 or 8×1011 recombinant GFP adenoviral particles in PBS were added into the mixture and incubated for another 30 minutes at 15° C. to 25° C. This is equivalent to about 500 to 1000 viruses per YCWP.
For cell transfection, mouse RAW 264.7 cells and human THP-1 cells were used. The plasmid DNA/Ad5 virus/YCWPs were added to these cultures at a ratio of about 2 particles per cell. Red and green fluorescence were observed 24 hours after transfection by fluorescence microscopy. Cells fluorescing green show the presence of functioning Ad5 GFP indicating effective escape and phagosome release of the bound viruses, while red fluorescing cells show the presence and functionality of the plasmid DNA attached to the YCWPs.
The basic procedure for the formation of this particulate vector was the same as that described above for the vector described above. Ad5/RFP (Ad-RFP), the virus used in this particle vector, was from Vector biolab and is a recombinant human type 5 adenovirus expressing Red Fluorescent Protein (RFP) under the control of a CMV promoter. The plasmid, 2019-nCov_pcDNA3.1(+)-P2A-eGFP, is from Genscript. The COVID-19 surface glycoprotein is under the control of a CMV promoter with the GFP gene sequence fused in frame via P2A sequence for tracking. A map of the plasmid encoding a COVID-19 surface glycoprotein S is shown in
Mouse RAW 264.7 cells were transfected with Ad5/RFP-COVID-19-GFP plasmid/-YCWPs. The green color shows the expression of not only the green fluorescent protein but also the COVID-19 S protein, since both proteins are driven off the same promoter. The percentage of cells showing green fluorescence reflects the COVID-19 S protein transfection efficiency, as exemplified by
10 mg of streptavidin modified yeast particles were mixed with 2 μl of protein A/G biotin (1 mg/ml)(MBL: JM-6508-1), 2 μl of adenovirus type 5 Hexon antibody (4 mg/ml)(Invitrogen: PA1-28357) and 100 μg of Biotin-PEI (branched 25 KD) (Nanosoft polymers: 12674-25k-1000-10). The mixture was rotated at RT for two hours.
The mixture was washed 3× with PBS by centrifugation at 500×g for 5 minutes and resuspended in 1 ml PBS (gently sonicate if aggregates appear). About 1012 viral particles were added to the mixture and rotated for another 2 hours. The viral particles included the commercially available Seqirus quadrivalent vaccine, which was attached to the YCWP via the anti-hexon antibody. The results showed that the Seqirus quadrivalent vaccine, which is a flu vaccine made of enfeebled virus particles, was equally as effective as a research adenovirus.
At the end of incubation, 100 μl of the mixture (1 mg particles equivalent to about 20 PEI) were mixed with different amount of plasmid DNA (5, 10, 15, 20, 25 μg) and incubated for 30 minutes. 10 μl of the mixture were used for transfection of a well in a 12-well plate.
C57B mice were divided into four treatment groups:
Four mice were included within each treatment group. The mice received intradermal vaccinations of 106 vaccine particles suspended in PBS near an inguinal lymph node.
The mice were bled one week after administration, and serum was isolated. The serum was assess for the presence of anti-glycoprotein S antibodies using an enzyme-linked immunosorbent assay (ELISA). More specifically, ELISA plates were coated with recombinant surface glycoprotein (S protein) of COVID-19 at a concentration of 0.4 μg/ml in PBS at 4° C. overnight. Plates were washed and blocked with PBS containing 0.05% Tween 20, 0.5% of BSA for 1 h at 37° C. Diluted serum samples were then added and incubated at 4° C. overnight. After washing, goat anti-mouse immunoglobulins conjugated to HRP (1:1000) were added, and plates were incubated for one hour at 37° C. Finally, plates were washed and developed with 3,3′,5,5′-tetramethylbenzidine. The reaction was stopped by adding 50 μl of 2.5M H2504 and the OD450 nm was measured. Cutoff values were determined as average OD450 of sera from mice immunized without plasmid DNA at dilutions 100 to 200 plus 3 STDV. End-point titer was as the dilution at which OD450 of the serum sample falls below the cut-off.
For each treatment group receiving a vaccine, antibodies were detected in the serum up to a dilution of 1:200. Moreover, antibodies were detected in a comparable amount in both the DNA vaccines and the protein vaccine. This result was, in and of itself, remarkable, as protein vaccines generally elicit a more robust immune response than DNA vaccines. Moreover, the fragment of the glycoprotein S that was encoded by the plasmid is the portion of the protein that binds to the receptor on the cells it infects, which suggests that the antibodies elicited by the vaccine are likely to be neutralizing antibodies.
ELISPOT assays will be used for monitoring specific cellular immune responses:
Mice will be sacrificed 21 days post prime, or 14 days post boost immunization. Spleen cells will be collected, and cellular immune responses will be measured by single or Dual-color ELISPOT kits from R&D System. The following kits will be used:
Briefly, a total of 2.5×105 splenocytes per well will be plated and stimulated for 20 h with recombinant COVID-19 S protein at a concentration of 10 μg/ml. The costimulatory anti-CD28 antibody will also be added to the cells during the incubation to stimulate production of IL-2 to synchronize it with secretion of INF-α. The plates will be processed according to manufacturer's protocol. If necessary, intracellular IFN-gamma staining can be performed by flow cytometric analysis, which can be combined with CD4 and CD8 surface maker staining to further analyze the percentages of CD4 and CD8 population.
Around 5×1011 adenovirus particles (Ad5/LacZ) were linked to 100 μg of polylysine polymer by transglutaminase in 1 ml of buffer at 37° C. for 1.5 hours. After buffer exchange, about 1.5 μg of polylysine/adenovirus complex was mixed with 10 μg of plasmid DNA and incubate at room temperature for 30 minutes in rotation in a 100/100 volume. The plasmid DNA encoded both green fluorescent protein (GFP) and SARS-CoV-2 S protein (i.e., spike protein).
Following incubation of the polylysine/adenovirus complex with the DNA, 10 μl of the vaccine composed of polylysine-decorated adenovirus bound by plasmid DNA was added into a well of a 12 well plate with RAW cells.
One skilled in the art readily appreciates that the present disclosure is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. Modifications therein and other uses will occur to those skilled in the art. These modifications are encompassed within the spirit of the disclosure and are defined by the scope of the claims, which set forth non-limiting embodiments of the disclosure.
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