Patent Application
20090137005
The present invention relates to improved cytokine expression in mammalian cells by optimizing all steps of gene expression of the cytokine.
Interleukin-12 (IL-12) is a proinflammatory cytokine that induces the production of interferon-gamma (IFN-γ), promotes the differentiation of T helper-1 (Th1) cells and connects innate and adaptive immune response pathways (Trinchieri, Nat Rev Immunol (2003) 3:133). IL-12 is produced by dendritic cells (DC) and phagocytes (e.g., macrophages, neutrophils, immature dendritic cells) in response to pathogens during infection (Id.). Structurally, IL-12 is a heterodimeric protein comprised of two polypeptide chains, a p35 chain and a p40 chain (Airoldi, et al., Haematologica (2002) 87:434-42). IL-12 is structurally related to at least two other heterodimeric proinflammatory cytokines, interleukin-23 (IL-23) and interleukin-27 (IL-27) (Hunter, Nat Rev Immunol (2005) 5:521; and Vandenbroeck, et al., J Pharm Pharmacol (2004) 56:145).
Cytokines, including IL-12, play a critical role as molecular adjuvants for vaccines to induce improved immune responses. IL-12 has been shown to increase the magnitude of vaccine-induced immune responses (see, for example, Tomioka, Curr Pharm Des (2004) 10:3297; El-Aneed, Eur J Pharmacol (2004) 498:1; Stevceva, Curr Pharm Des (2005) 11:801; and Toka, et al, Immunol Rev (2004)199:100). To provide IL-12 as molecular adjuvant, it is important to develop efficient expression vectors and efficiently expressing coding nucleic acid sequences for this cytokine. The present invention addresses this need.
The present invention provides nucleic acid sequences, expression vectors and mammalian cells for the high-level expression of interleukin-12. The invention further provides methods for the high-level expression of interleukin-12 in mammalian cells.
Accordingly, in a first aspect, the invention provides a nucleic acid sequence pair encoding an interleukin-12 (IL-12) protein heterodimer comprised of an IL-12p35 and an IL-12p40, the IL-12p35 and the IL-12p40 each having at least 95%, 96%, 97%, 98%, 99% sequence identity to a native mammalian IL-12 protein heterodimer, wherein the nucleic acid sequence encoding the IL-12p35 differs from a nucleic acid sequence encoding the native IL-12p35 by at least 50% of the 136 changed codons identified in
In some embodiments, the nucleic acid sequence encoding the IL-12p35 differs from a nucleic acid sequence encoding the native IL-12p35 by at least about 55% (e.g. 75 codons), 60% (e.g., 82 codons), 65% (e.g., 89 codons), 70% e.g., (95 codons), 75% (e.g., 102 codons), 80% (e.g., 109 codons), 85% (e.g., 116 codons), 90% (e.g., 122 codons), 95% (e.g., 129 codons) of the 136 changed codons identified in
In some embodiments, the nucleic acid sequence encoding the IL-12p35 differs from a nucleic acid sequence encoding the native IL-12p35 at codon numbers 2, 3, 6, 7, 8, 9, 11, 12, 15, 16, 19, 20, 21, 22, 23, 25, 26, 28, 29, 30, 32, 33, 36, 38, 41, 42, 46, 47, 48, 49, 52, 55, 56, 57, 58, 59, 60, 61, 63, 65, 66, 67, 69, 70, 71, 72, 73, 75, 76, 77, 78, 81, 84, 85, 86, 87, 88, 89, 90, 91, 93, 95, 97, 98, 99, 100, 102, 103, 105, 106, 107, 109, 112, 113, 114, 116, 117, 118, 121, 124, 125, 126, 127, 128, 129, 131, 140, 142, 143, 145, 148, 149, 151, 154, 155, 156, 157, 161, 162, 163, 164, 166, 169, 170, 171, 174, 176, 178, 179, 180, 181, 182, 183, 184, 185, 187, 188, 189, 190, 191, 192, 197, 198, 199, 200, 203, 204, 206, 208, 209, 210, 211, 214, 215, 217 and 219, wherein the codon numbers are as identified in
The codons can differ in any way such that an identical or similar amino acid is encoded. In some embodiments, the codons are changed to increase GC content. In some embodiments, the improved IL-12p35 and IL-12p40 nucleic acid sequences each comprise at least about 55%, 60%, 65%, 70% or 75% or more GC content (e.g., deoxyguanosine and deoxycytidine deoxyribonucleoside residues or guanosine and cytidine ribonucleoside residues) over the length of the sequence.
In some embodiments, the nucleic acid sequence encoding the IL-12p35 differs from a nucleic acid sequence encoding the native IL-12p35 as identified in
In a further aspect, the invention further includes expression vectors and mammalian cells comprising the nucleic acid sequences of the invention, including the embodiments described above.
In some embodiments, the nucleic acid sequence pair further includes pharmaceutical excipients for use as a vaccine adjuvant.
In another aspect, the invention provides methods for expressing IL-12 in a mammalian cell, the method comprising introducing a recombinant vector into a mammalian cell to express a nucleic acid sequence pair encoding an IL-12 protein heterodimer comprised of an IL-12p35 and an IL-12p40, the IL-12p35 and the IL-12p40 each having at least 95%, 96%, 97%, 98%, 99% sequence identity to a native mammalian IL-12 protein heterodimer, wherein the nucleic acid sequence encoding the IL-12p35 differs from a nucleic acid sequence encoding the native IL-12p35 by at least 50% of the codons identified in
The terms “IL-12 protein heterodimer” or “IL-12 heterodimer” or “IL-12p70” refer to an IL-12 cytokine protein composed of its two monomeric polypeptide subunits, an IL-12p35 chain and an IL-12p40 chain. See, for example, Airoldi, et al., Haematologica (2002) 87:434-42.
The term “native mammalian IL-12” refers to any naturally occurring interleukin-12 nucleic acid and amino acid sequences of the IL-12 monomeric sequences, IL-12p35 and IL-12p40 from a mammalian species. Those of skill in the art will appreciate that interleukin-12 sequences are publicly available in gene databases, for example, GenBank through the National Center for Biotechnological Information on the worldwideweb at ncbi.nlm.nih.gov/entrez/query.fcgi?db=Nucleotide and ncbi.nlm.nih.gov/entrez/query.fcgi?db=Protein. Exemplified native mammalian IL-12 nucleic acid or amino acid sequences can be from, for example, human, primate, canine, feline, porcine, equine, bovine, ovine, rodentia, murine, rat, hamster, guinea pig, etc. Accession numbers for exemplified native mammalian IL-12 nucleic acid sequences include NM—002187 (human p40, SEQ ID NO:4), NM—000882 (human p35, SEQ ID NO:1), AY234218 (baboon p40), AY234219 (baboon p35); U19841 (rhesus monkey p40, SEQ ID NO:10), U19842 (rhesus monkey p35, SEQ ID NO:7); NM—022611 (rat p40), NM—053390 (rat p35), and NM—008352 (mouse p40), NM—008351 (mouse p35). Accession numbers for exemplified native mammalian IL-12 amino acid sequences include NP—002178 (human p40, SEQ ID NO:5), NP—000873 (human p35), AAK84425 or AAD56385 (human p35, SEQ ID NO:2); AAA86707 (rhesus monkey p35; SEQ ID NO:8); P48095 (rhesus monkey p40, SEQ ID NO:11); NP—072133 (rat p40), AAD51364 (rat p35), and NP—032378 (mouse p35), NP—032377 (mouse p40).
The term “interleukin-12” or “IL-12” refers to a polypeptide that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to a native mammalian IL-12 amino acid sequence, or a nucleotide encoding such a polypeptide, is biologically active, meaning the mutated protein (“mutein”) has functionality similar (75% or greater) to that of a native IL-12 protein in at least one functional assay. Exemplified functional assays of an IL-12 polypeptide include inducing the production of interferon-gamma (IFN-γ), for example, by T cells or natural killer (NK) cells, and promoting the differentiation of T helper-1 (Th1) cells. A T helper cell differentiated into a Th1 cell can be identified by secretion of IFN-γ. IFN-γ secreted by IL-12 stimulated T cells or NK cells can be conveniently detected, for example, in serum or cell culture supernatant using ELISA. ELISA methods and techniques are well known in the art, and kits for detecting IFN-γ are commercially available (e.g., R&D Systems, Minneapolis, Minn.; Peprotech, Rocky Hill, N.J.; and Biosource Intl., Camarillo, Calif.) See also, Coligan, et al., Current Methods in Immunology, 1991-2006, John Wiley & Sons; Harlow and Lane, Using Antibodies: A Laboratory Manual, 1998, Cold Spring Harbor Laboratory Press; and The ELISA Guidebook, Crowther, ed., 2000, Humana Press.
The term “nucleic acid” refers to deoxyribonucleotides or ribonucleotides and polymers thereof in either single- or double-stranded form. The term encompasses nucleic acids containing known nucleotide analogs or modified backbone residues or linkages, which are synthetic, naturally occurring, and non-naturally occurring, which have similar binding properties as the reference nucleic acid, and which are metabolized in a manner similar to the reference nucleotides. Examples of such analogs include, without limitation, phosphorothioates, phosphoramidates, methyl phosphonates, chiral-methyl phosphonates, 2-O-methyl ribonucleotides, peptide-nucleic acids (PNAs).
Unless otherwise indicated, a particular nucleic acid sequence also implicitly encompasses conservatively modified variants thereof (e.g., degenerate codon substitutions) and complementary sequences, as well as the sequence explicitly indicated. Degenerate codon substitutions can be achieved by generating sequences in which the third position of one or more selected (or all) codons is substituted with mixed-base and/or deoxyinosine residues (Batzer et al., Nucleic Acid Res. 19:5081 (1991); Ohtsuka et al., J. Biol. Chem. 260:2605-2608 (1985); Rossolini et al., Mol. Cell. Probes 8:91-98 (1994)). The term nucleic acid is used interchangeably with gene, cDNA, mRNA, oligonucleotide, and polynucleotide.
Degenerate codon substitutions for naturally occurring amino acids are in Table 1.
The terms “identical” or percent “identity,” in the context of two or more nucleic acids or polypeptide sequences, refer to two or more sequences or subsequences that are the same or have a specified percentage of amino acid residues or nucleotides that are the same (i.e., about 70% identity, preferably 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or higher identity over a specified region (e.g., any one of SEQ ID NOs:1-23), when compared and aligned for maximum correspondence over a comparison window or designated region) as measured using a BLAST or BLAST 2.0 sequence comparison algorithms with default parameters described below, or by manual alignment and visual inspection (see, e.g., NCBI web site or the like). Such sequences are then said to be “substantially identical.” This definition also refers to, or can be applied to, the compliment of a test sequence. The definition also includes sequences that have deletions and/or additions, as well as those that have substitutions. As described below, the preferred algorithms can account for gaps and the like. Preferably, identity exists over a region that is at least about 25, 50, 75, 100, 150, 200 amino acids or nucleotides in length, and oftentimes over a region that is 225, 250, 300, 350, 400, 450, 500 amino acids or nucleotides in length or over the full-length of am amino acid or nucleic acid sequences.
For sequence comparison, typically one sequence acts as a reference sequence, to which test sequences are compared (here, an entire “native mammalian” IL-12 p35 or IL-12 p40 amino acid or nucleic acid sequence). When using a sequence comparison algorithm, test and reference sequences are entered into a computer, subsequence coordinates are designated, if necessary, and sequence algorithm program parameters are designated. Preferably, default program parameters can be used, or alternative parameters can be designated. The sequence comparison algorithm then calculates the percent sequence identities for the test sequences relative to the reference sequence, based on the program parameters.
A preferred example of algorithm that is suitable for determining percent sequence identity and sequence similarity are the BLAST algorithms, which are described in Altschul et al., Nuc. Acids Res. 25:3389-3402 (1977) and Altschul et al., J. Mol. Biol. 215:403-410 (1990), respectively. BLAST software is publicly available through the National Center for Biotechnology Information on the worldwide web at ncbi.nlm.nih.gov/. Both default parameters or other non-default parameters can be used. The BLASTN program (for nucleotide sequences) uses as defaults a wordlength (W) of 11, an expectation (E) of 10, M=5, N=−4 and a comparison of both strands. For amino acid sequences, the BLASTP program uses as defaults a wordlength of 3, and expectation (E) of 10, and the BLOSUM62 scoring matrix (see Henikoff & Henikoff, Proc. Natl. Acad. Sci. USA 89:10915 (1989)) alignments (B) of 50, expectation (E) of 10, M=5, N=−4, and a comparison of both strands.
Amino acids can be referred to herein by either their commonly known three letter symbols or by the one-letter symbols recommended by the IUPAC-IUB Biochemical Nomenclature Commission. Nucleotides, likewise, can be referred to by their commonly accepted single-letter codes.
“Conservatively modified variants” as used herein applies to amino acid sequences. One of skill will recognize that individual substitutions, deletions or additions to a nucleic acid, peptide, polypeptide, or protein sequence which alters, adds or deletes a single amino acid or a small percentage of amino acids in the encoded sequence is a “conservatively modified variant” where the alteration results in the substitution of an amino acid with a chemically similar amino acid. Conservative substitution tables providing functionally similar amino acids are well known in the art. Such conservatively modified variants are in addition to and do not exclude polymorphic variants, interspecies homologs, and alleles of the invention.
The following eight groups each contain amino acids that are conservative substitutions for one another:
The term “GC content” refers to the percentage of a nucleic acid sequence comprised of deoxyguanosine (G) and/or deoxycytidine (C) deoxyribonucleosides, or guanosine (G) and/or cytidine (C) ribonucleoside residues.
The terms “mammal” or “mammalian” refer to any animal within the taxonomic classification mammalia. A mammal can refer to a human or a non-human primate. A mammal can refer to a domestic animal, including for example, canine, feline, rodentia, including lagomorpha, murine, rattus, Cricetinae (hamsters), etc. A mammal can refer to an agricultural animal, including for example, bovine, ovine, porcine, equine, etc.
The cytokine interleukin-12 finds use as a vaccine adjuvant, particularly when co-administered with antigen as a nucleic acid that expresses IL-12. Native IL-12 sequences do not express IL-12 heterodimer optimally because of several different reasons, including signals within the RNA sequence such as potential splice sites and low stability determinants (oftentimes A/T or A/U rich) sequences embedded within the coding sequences. By minimizing potential splice sites and low stability sequences from IL-12 sequences, expression of IL-12 heterodimeric protein can be increased as much as 3-fold, 4-fold, 5-fold, 6-fold, or more in comparison to expression from native mammalian IL-12 sequences. A general method has been established for this purpose, comprising changing several codons of the encoded mRNA to alternative codons encoding the same amino acid (see, e.g., U.S. Pat. Nos. 5,965,726; 5,972,596; 6,174,666; 6,291,664; 6,414,132; and 6,794,498, the disclosures of each of which are hereby incorporated herein by reference in their entirety for all purposes). This results in the change of any negatively acting signals embedded into the RNA without altering the produced protein (see,
The improved high expressing IL-12 nucleic acid sequences of the invention are usually based on a native mammalian interleukin-12 coding sequence as a template. Nucleic acids sequences encoding native interleukin-12 can be readily found in publicly available databases including nucleotide, protein and scientific databases available on the worldwide web through the National Center for Biotechnology Information at ncbi.nlm.nih.gov. Native IL-12 nucleic acid sequences can be conveniently cloned from mammalian B-lymphoblastoid cells, macrophages or monocytes following appropriate stimulation (Brunda, J Leukoc Biol. (1994) 55:280-8). Protocols for isolation and stimulation of desired immune cell populations are well known in the art. See, for example, Current Protocols in Immunology, Coligan, et al., eds., 1991-2005, John Wiley & Sons.
The sequences are modified according to methods that simultaneously rectify several factors affecting mRNA traffic, stability and expression. Codons are altered to change the overall mRNA AT(AU)-content, to minimize or remove all potential splice sites, and to alter any other inhibitory sequences and signals affecting the stability and processing of mRNA such as runs of A or T/U nucleotides, AATAAA, ATTTA and closely related variant sequences, known to negatively affect mRNA stability. The methods applied to IL-12 coding nucleic acid sequences in the present application have been described in U.S. Pat. Nos. 6,794,498; 6,414,132; 6,291,664; 5,972,596; and 5,965,726 the disclosures of each of which are hereby incorporated herein by reference in their entirety for all purposes.
Generally, the changes to the nucleotide bases or codons of a coding IL-12 sequence do not alter the amino acid sequence of the translated monomers comprising an IL-12 heterodimer from the native IL-12 p35 and p40 subunit polypeptides (see,
Oftentimes, in carrying out the present methods for increasing the stability of an IL-12 coding sequence, a relatively more A/T-rich codon of a particular amino acid is replaced with a relatively more G/C rich codon encoding the same amino acid (see, for example,
Depending on the number of changes introduced, the improved IL-12 nucleic acid sequences of the present invention can be conveniently made as completely synthetic sequences. Techniques for constructing synthetic nucleic acid sequences encoding a protein or synthetic gene sequences are well known in the art. Synthetic gene sequences can be commercially purchased through any of a number of service companies, including DNA 2.0 (Menlo Park, Calif.), Geneart (Toronto, Ontario, Canada), CODA Genomics (Irvine, Calif.), and GenScript, Corporation (Piscataway, N.J.). Alternatively, codon changes can be introduced using techniques well known in the art. The modifications also can be carried out, for example, by site-specific in vitro mutagenesis or by PCR or by any other genetic engineering methods known in art which are suitable for specifically changing a nucleic acid sequence. In vitro mutagenesis protocols are described, for example, in In Vitro Mutagenesis Protocols, Braman, ed., 2002, Humana Press, and in Sankaranarayanan, Protocols in Mutagenesis, 2001, Elsevier Science Ltd.
High level expressing improved IL-12 sequences can be constructed by altering select codons throughout a native IL-12 nucleic acid sequence, or by altering codons at the 5′-end, the 3′-end, or within a middle subsequence. It is not necessary that every codon be altered, but that a sufficient number of codons are altered so that the expression (i.e., transcription and/or translation) of the improved IL-12 nucleic acid sequence is at least about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, or more abundant in comparison to expression from a native IL-12 nucleic acid sequence under the same conditions. Expression can be detected over time or at a designated endpoint, using techniques known to those in the art, for example, using gel electrophoresis or anti-IL-12 antibodies in solution phase or solid phase binding reactions (e.g., ELISA, immunohistochemistry). Interleukin-12 ELISA kits for detecting either the p35 or p40 subunits polypeptides, or the p70 heterodimer, are commercially available from, for example, R & D Systems (Minneapolis, Minn.), and PeproTech, Rocky Hill, N.J.
Usually at least about 50% of the changed codons identified in
The codon positions that can be changed for an improved IL-12 p35 nucleic acid sequence as identified in
The codon positions that can be changed for an improved IL-12 p40 nucleic acid sequence as identified in
The GC-content of an improved IL-12 nucleic acid sequence is usually increased in comparison to a native IL-12 nucleic acid sequence when applying the present methods. For example, the GC-content of an improved IL-12p35 nucleic acid sequence can be at least about 50%, 51%, 52%,53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65% or more. The GC-content of an improved IL-12p40 nucleic acid sequence can be at least about 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70% or more.
Once a high level expressing improved IL-12 nucleic acid sequence has been constructed, it can be cloned into a cloning vector, for example a TA-cloning® vector (Invitrogen, Carlsbad, Calif.) before subjecting to further manipulations for insertion into one or more expression vectors. Manipulations of improved IL-12 nucleic acid sequences, including recombinant modifications and purification, can be carried out using procedures well known in the art. Such procedures have been published, for example, in Sambrook and Russell, Molecular Cloning: A Laboratory Manual, 2000, Cold Spring Harbor Laboratory Press and Current Protocols in Molecular Biology, Ausubel, et al., eds., 1987-2005, John Wiley & Sons.
Both IL-12 subunit chains can be recombinantly expressed from a single plasmid or expression vector (see,
The expression vector can optionally also have a third independent expression vector for expressing a selectable marker. Selectable markers are well known in the art, and can include, for example, proteins that confer resistance to an antibiotics, fluorescent proteins, antibody epitopes, etc. Exemplified markers that confer antibiotic resistance include sequences encoding β-lactamases (against P-lactams including penicillin, ampicillin, carbenicillin), or sequences encoding resistance to tetracylines, aminoglycosides (e.g., kanamycin, neomycin), etc. Exemplified fluorescent proteins include green fluorescent protein, yellow fluorescent protein and red fluorescent protein.
The promoter(s) included in the expression cassette(s) should promote expression of one or both of the IL-12 subunit chains in a mammalian cell. The promoter or promoters can be viral, oncoviral or native mammalian, constitutive or inducible, or can preferentially regulate transcription of one or both IL-12 subunit chains in a particular tissue type or cell type (e.g., “tissue-specific”).
A “constitutive” promoter is a promoter that is active under most environmental and developmental conditions. Exemplified constitutive promoters in mammalian cells include oncoviral promoters (e.g., simian cytomegalovirus (CMV), human CMV, simian virus 40 (SV40), rous sarcoma virus (RSV)), promoters for immunoglobulin elements (e.g., IgH), promoters for “housekeeping” genes (e.g., β-actin, dihydrofolate reductase).
In another embodiment, inducible promoters may be desired. An “inducible” promoter is a promoter that is active under environmental or developmental regulation. Inducible promoters are those which are regulated by exogenously supplied compounds, including without limitation, a zinc-inducible metallothionine (MT) promoter; an isopropyl thiogalactose (IPTG)-inducible promoter, a dexamethasone (Dex)-inducible mouse mammary tumor virus (MMTV) promoter; a tetracycline-repressible system (Gossen et al, Proc. Natl. Acad. Sci. USA, 89: 5547-5551 (1992)); the tetracycline-inducible system (Gossen et al., Science, 268: 1766-1769 (1995); see also Harvey et al., Curr. Opin. Chem. Biol., 2: 512-518 (1998)); the RU486-inducible system (Wang et al., Nat. Biotech., 15: 239-243 (1997) and Wang et al., Gene Ther., 4: 432-441 (1997)); and the rapamycin-inducible system (Magari et al. J. Clin. Invest., 100: 2865-2872 (1997)). Other types of inducible promoters which can be useful in this context are those which are regulated by a specific physiological state, e.g., temperature, acute phase, or in replicating cells only.
In another embodiment, the native promoter for a mammalian IL-12 can be used. The native promoter may be preferred when it is desired that expression of improved IL-12 sequences should mimic the native expression. The native promoter can be used when expression of the improved IL-12 must be regulated temporally or developmentally, or in a tissue-specific manner, or in response to specific transcriptional stimuli. In a further embodiment, other native expression control elements, such as enhancer elements, polyadenylation sites or Kozak consensus sequences may also be used to mimic expression of native IL-12.
In another embodiment, the improved IL-12 sequences can be operably linked to a tissue-specific promoter. For instance, if expression in lymphocytes or monocytes is desired, a promoter active in lymphocytes or monocytes, respectively, should be used. Examples of promoters that are tissue-specific are known for numerous tissues, including liver (albumin, Miyatake et al. J. Virol., 71: 5124-32 (1997); hepatitis B virus core promoter, Sandig et al., Gene Ther., 3: 1002-9 (1996); alpha-fetoprotein (AFP), Arbuthnot et al. Hum. Gene Ther. 7: 1503-14 (1996)), bone (osteocalcin, Stein et al., Mol. Biol. Rep., 24: 185-96 (1997); bone sialoprotein, Chen et al., J. Bone Miner. Res., 11: 654-64 (1996)), lymphocytes (CD2, Hansal et al., J. Immunol., 161: 1063-8 (1998); immunoglobulin heavy chain; T cell receptor a chain), neuronal (neuron-specific enolase (NSE) promoter, Andersen et al. Cell. Mol. Neurobiol., 13: 503-15 (1993); neurofilament light-chain gene, Piccioli et al., Proc. Natl. Acad. Sci. USA, 88: 5611-5 (1991); the neuron-specific vgf gene, Piccioli et al., Neuron, 15: 373-84 (1995)); among others.
Dual-promoter expression vectors for the concurrent expression of two polypeptide chains in a mammalian cell are commercially available, for example, the pVITRO vector from InvivoGen (San Diego, Calif.). An exemplified dual-promoter expression vector is shown in
The expression vectors of the invention can be expressed in mammalian host cells. The host cells can be in vivo in a host or in vitro. For example, expression vectors containing high-level expressing IL-12 nucleic acid sequences can be transfected into cultured mammalian host cells in vitro, or delivered to a mammalian host cell in a mammalian host in vivo.
Exemplary host cells that can be used to express improved IL-12 nucleic acid sequences include mammalian primary cells and established mammalian cell lines, including COS, CHO, HeLa, NIH3T3, HEK 293-T, RD and PC12 cells. Mammalian host cells for expression of IL-12 protein from high level expressing improved IL-12 nucleic acid sequences are commercially available from, for example, the American Type Tissue Collection (ATCC), Manassas, Va. Protocols for in vitro culture of mammalian cells is also well known in the art. See, for example, Handbook of Industrial Cell Culture: Mammalian, Microbial, and Plant Cells, Vinci, et al., eds., 2003, Humana Press; and Mammalian Cell Culture: Essential Techniques, Doyle and Griffiths, eds., 1997, John Wiley & Sons.
Protocols for transfecting mammalian host cells in vitro and expressing recombinant nucleic acid sequences are well known in the art. See, for example, Sambrook and Russell, and Ausubel, et al, supra; Gene Delivery to Mammalian Cells: Nonviral Gene Transfer Techniques, Methods in Molecular Biology series, Heiser, ed., 2003, Humana Press; and Makrides, Gene Transfer and Expression in Mammalian Cells, New Comprehensive Biochemistry series, 2003, Elsevier Science. Mammalian host cells modified to express the improved IL-12 nucleic acid sequences can be transiently or stably transfected with a recombinant vector. The improved IL-12 sequences can remain epigenetic or become chromosomally integrated.
The high level expression improved IL-12 nucleic acid sequences are suitable for use as an adjuvant co-delivered with a vaccine antigen. The use of IL-12 as an adjuvant in antimicrobial therapy, anticancer therapy and for stimulating mucosal immunity is known in the art. See, for example, Tomioka, Curr Pharm Des (2004) 10:3297; El-Aneed, Eur J Pharmacol (2004) 498:1; Stevceva and Ferrari, Curr Pharm Des (2005) 11:801; and Toka, et al., Immunol Rev (2004) 199:100).
In a preferred embodiment, high level expressing improved IL-12 nucleic acid sequences are co-administered with one or more vaccine antigens, with at least the improved IL-12 nucleic acid sequences delivered as naked DNA. The antigen can be delivered as one or more polypeptide antigens or a nucleic acid encoding one or more antigens. Naked DNA vaccines are generally known in the art; see, Wolff, et al., Science (1990) 247:1465; Brower, Nature Biotechnology (1998) 16:1304-130; and Wolff, et al., Adv Genet (2005) 54:3. Methods for the use of nucleic acids as DNA vaccines are well known to one of ordinary skill in the art. See, DNA Vaccines, Ertl, ed., 2003, Kluwer Academic Pub and DNA Vaccines: Methods and Protocols, Lowrie and Whalen, eds., 1999, Humana Press. The methods include placing a nucleic acid encoding one or more antigens under the control of a promoter for expression in a patient. Co-administering high level expressing improved IL-12 nucleic acid sequences further enhances the immune response against the one or more antigens. Without being bound by theory, following expression of the polypeptide encoded by the DNA vaccine, cytotoxic T-cells, helper T-cells and antibodies are induced which recognize and destroy or eliminate cells or pathogens expressing the antigen.
The invention contemplates compositions comprising improved IL-12 nucleic acid sequences in a physiologically acceptable carrier. While any suitable carrier known to those of ordinary skill in the art may be employed in the pharmaceutical compositions of this invention, the type of carrier will vary depending on the mode of administration. For parenteral administration, including subcutaneous or intramuscular injection, the carrier preferably comprises water, saline, and optionally an alcohol, a fat, a polymer, a wax, one or more stabilizing amino acids or a buffer. General formulation technologies are known to those of skill in the art (see, for example, Remington: The Science and Practice of Pharmacy (20th edition), Gennaro, ed., 2000, Lippincott Williams & Wilkins; Injectable Dispersed Systems: Formulation, Processing And Performance, Burgess, ed., 2005, CRC Press; and Pharmaceutical Formulation Development of Peptides and Proteins, Frkjr et al., eds., 2000, Taylor & Francis).
Naked DNA can be delivered in solution (e.g., a phosphate-buffered saline solution) by injection, usually by an intra-arterial, intravenous, subcutaneous or intramuscular route. In general, the dose of a naked nucleic acid composition is from about 10 μg to 10 mg for a typical 70 kilogram patient. Subcutaneous or intramuscular doses for naked nucleic acid (typically DNA encoding a fusion protein) will range from 0.1 mg to 50 mg for a 70 kg patient in generally good health.
DNA vaccinations can be administered once or multiple times. In some embodiments, the improved IL-12 nucleic acid sequences are administered more than once, for example, 2, 3, 4, 5, 6, 7, 8, 10, 15, 20 or more times as needed to induce the desired response (e.g., specific antigenic response). Multiple administrations can be administered, for example, bi-weekly, weekly, bi-monthly, monthly, or more or less often, as needed, for a time period sufficient to achieve the desired response.
In some embodiments, the improved IL-12 nucleic acid compositions are administered by liposome-based methods, electroporation or biolistic particle acceleration. A delivery apparatus (e.g., a “gene gun”) for delivering DNA into cells in vivo can be used. Such an apparatus is commercially available (e.g., BioRad, Hercules, Calif., Chiron Vaccines, Emeryville, Calif.). Naked DNA can also be introduced into cells by complexing the DNA to a cation, such as polylysine, which is coupled to a ligand for a cell-surface receptor (see, for example, Wu, G. and Wu, C. H. (1988) J. Biol. Chem. 263:14621; Wilson et al. (1992) J. Biol. Chem. 267:963-967; and U.S. Pat. Nos. 5,166,320; 6,846,809; 6,733,777; 6,720,001; 6,290,987). Liposome formulations for delivery of naked DNA to mammalian host cells are commercially available from, for example, Encapsula NanoSciences, Nashville, Tenn. An electroporation apparatus for use in delivery of naked DNA to mammalian host cells is commercially available from, for example, Inovio Biomedical Corporation, San Diego, Calif.
The improved IL-12 nucleic acid vaccine compositions are administered to a mammalian host. The mammalian host usually is a human or a primate. In some embodiments, the mammalian host can be a domestic animal, for example, canine, feline, lagomorpha, rodentia, rattus, hamster, murine. In other embodiment, the mammalian host is an agricultural animal, for example, bovine, ovine, porcine, equine, etc.
The methods of the present invention provide for expressing IL-12 in a mammalian cell by introducing a recombinant vector into the cell to express the high level improved IL-12 p35 and p40 nucleic acid sequences described herein. The modified mammalian cell can be in vitro or in vivo in a mammalian host.
It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety for all purposes.
The following examples are offered to illustrate, but not to limit the claimed invention.
The strategy for introducing nucleotide changes into IL-12 sequences is to simultaneously rectify several factors affecting mRNA traffic, stability and expression. Codons are altered to change the overall mRNA AT(AU)-content or to remove any other inhibitory signals within the RNA such as all potential splice sites (computer programs predicting potential splice sites can be found for example at web sites such as fruitfly.org/seq_tools/splice.html, or sun1.softberry.com/berry.phtml) and also to alter sequences such as runs of A or T/U nucleotides, AATAAA, ATTTA and closely related variant sequences, known to negatively affect mRNA. By substituting codons with a different codon encoding the identical amino acid, the chosen codon can be more GC-rich, or can have a different sequence that is sufficient to alter the RNA structure. This approach has been described in several patents, each of which is hereby incorporated herein by reference in their entirety: U.S. Pat. Nos. 5,965,726; 5,972,596; 6,174,666; 6,291,664; 6,414,132; and 6,794,498.
Standard lab techniques are used to generate, purify and sequence plasmid DNAs. One microgram (1 μg) of the plasmids containing the indicated IL-12 coding sequence were transfected into human 293 or RD cells seeded into 60 mm plates the day before with 106 cells using calcium coprecipitation technique (293 cells) and the SuperFect Reagent protocol (Qiagen) for RD4 cells. 2-3 days later, intracellular and extracellular and total IL-12 protein was measured using commercial kits (R&D system). Due to the high homology of the human and Rhesus IL-12 proteins, their protein levels were determined by the same commercial ELISA kit. The results of different experiments are shown in
This application claims the benefit of U.S. Provisional Application No. 60/758,680, filed Jan. 13, 2006, the entire contents of which is hereby incorporated herein by reference for all purposes.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US07/00825 | 1/12/2007 | WO | 00 | 7/9/2008 |
| Number | Date | Country | |
|---|---|---|---|
| 60758680 | Jan 2006 | US |
