CHIMERIC RSV, IMMUNOGENIC COMPOSITIONS, AND METHODS OF USE

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Number 62/247,962 filed October 29, 2015 and U.S. Provisional Application Number 62/334,547 filed May 11, 2016. The entirety of each of these applications is hereby incorporated by reference for all purposes.

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED AS A TEXT FILE

VIA THE OFFICE ELECTRONIC FILING SYSTEM (EFS-WEB) The Sequence Listing associated with this application is provided in text format in lieu of a paper copy, and is hereby incorporated by reference into the specification. The name of the text file containing the Sequence Listing is 15198PCT_ST25.txt. The text file is 49 KB, was created on October 26, 2016, and is being submitted electronically via EFS-Web. BACKGROUND

Human respiratory syncytial virus (RSV) causes respiratory tract infections. It is the major cause of hospital visits during infancy and childhood. Palivizumab is a humanized monoclonal antibody (IgG) that binds the RSV fusion protein (RSV F) that is FDA approved for prevention of serious lower respiratory tract disease caused by RSV in certain high-risk infants. Palivizumab, as chimeric antibody administered in monthly doses, has limited efficacy and sometimes causes allergic reactions. Thus, there is a need to identify improved treatment and prevention methods for RSV.

Vaccines are typically killed (inactivated) or weakened (attenuated) versions of a live viral strain. Kim et al. report that administration of a formalin-inactivated RSV vaccine was not sufficiently effective. Am J Epidemiol 89, 422-434 (1969). Attenuated RSV vaccine candidates face significant safety hurdles, and the development of pediatric RSV live-attenuated vaccine (LAV) strains that are sufficiently attenuated and immunogenic have been elusive. See Collins et al. Progress in understanding and controlling respiratory syncytial virus: still crazy after all these years. Virus Res 162, 80-99 (2011).

Karron et al. report RSV where most of the open reading frame (ORF) of the RNA synthesis factor M2-2 was deleted yields an attenuated RSV vaccine with improved antibody responses in children. Sci Transl Med 7, 312ral75 (2015). Meng, et al. report attenuation and immunogenicity of respiratory syncytial virus by targeted codon deoptimization of virulence genes. MBio 5, e01704-01714 (2014). See also U.S. Published Application number 2016/0030549. Hotard et al. report residues in the human RSV fusion protein that modulate fusion activity and pathogenesis, 2015, J Virol 89:512-522. Rostad et al. report a recombinant respiratory syncytial virus vaccine candidate attenuated by a low-fusion F protein is immunogenic and protective against challenge in cotton rats. J Virol, 2016, 90(16):7508-7518.

References cited herein are not an admission of prior art. SUMMARY

This disclosure relates to chimeric respiratory syncytial virus (RSV), live attenuated vaccine and immunogenic compositions, and methods of use. In certain embodiments, the chimeric RSV has a mutated gene pattern encoding an RSV F protein having M at position 79, R at position 191, K at position 357, and/or Y at position 371. In certain embodiments, the RSV F protein has V at position 557 or the F protein is mutated such that position 557 is V.

In certain embodiments, M at position 79, R at position 191, K at position 357, and Y at position 371 are not in an RSV F protein wherein the naturally occurring RSV F protein has that particular pattern of amino acids, i.e., the mutant RSV F protein comprises at least one amino acid substitution such that the mutated RSF F protein has at least one modification at position 79, 191, 357 or 371 when compared to the naturally occurring sequence to provide an RSV F protein pattern of amino acids having M at position 79, R at position 191, K at position 357, and Y at position 371.

In certain embodiment the RSV F protein that is mutated is derived from an RSV F protein other than the F protein found in RSV line 19 such as an RSV strain of subgroup B, e.g., a "Buenos Aires" (BAF) strain. In certain embodiments, the RSV F protein does not contain SEQ ID NO: 3 or 4 or does not have substantial identity to SEQ ID NO: 3 or 4. In certain embodiments, the mutated RSV F has more than 85% or 90% identity to SEQ ID NO: 1 but less than 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 4. In certain embodiments, the mutated RSV F has more than 85% identity to SEQ ID NO: 1 but less than 99% identity to SEQ ID NO: 4.

In certain embodiments, the RSV F protein that is mutated has (SEQ ID NO: 1)

MELLIHRSSAIFLTLAINALYLTSSQNITEEFYQSTCSAVSRGYLSALRTGWYTSVI TIELS NIKETKCNGTDTKVKLMKQELDKYKNAVTELQLLMQNTPAAN RARREAPQYMNYTI NTTK LNVSISKKRKRRFLGFLLGVGSAIASGIAVSKVLHLEGEVNf IKNALLST KAVV SLSNGVSVLTSRVLDLKNYINNQLLPIVNQQSCRJSNIETVIEFQQKNSRLLEITREFSV NA GVTTPLSTYMLTNSELLSLINDMPITNDQKKLMSSNVQIVRQQSYSIMSIIKEEVLAYVV Q LPIYGVIDTPCWKLHTSPLCTTNIKEGSNICLTRTDRGWYCDNAGSVSFFPQADKCKVQS RVFCDTMYSLTLPSEVSLCNTDIFNSKYDCKIMTSKTDISSSVITSLGAIVSCYGKTKCT AS K RGIIKTFSNGCDYVS KGVDTVSVGNTLYYVNKLEGK LYVKGEPIINYYDPLV FPSDEFDASISQVNEKINQSLAFIRRSDELLHNVNTGKSTTNIMITAIIIVIIVVLLSLI AIGLL LYCKAKNTPVTLSKDQLSGINNIAFS, or variants thereof.

In certain embodiments, this disclosure contemplates a chimeric RSV F protein lacking the transmembrane domain, or having amino acids 1-524, e.g., (SEQ ID NO: 13) MELLIHRSSAIFLTLAINALYLTSSQNITEEFYQSTCSAVSRGYLSALRTGWYTSVITIE LS NIKETKCNGTDTKVKLMKQELDKYKNAVTELQLLMQNTPAANNRARREAPQYMNYTI NTTKNLNVSISKKRKRRFLGFLLGVGSAIASGIAVSKVLHLEGEVNf IKNALLSTNKAVV SLSNGVSVLTSRVLDLKNYINNQLLPIVNQQSCRISNIETVIEFQQKNSRLLEITREFSV NA GVTTPLSTYMLTNSELLSLINDMPITNDQKKLMSSNVQIVRQQSYSIMSIIKEEVLAYVV Q LPIYGVIDTPCWKLHTSPLCTTNIKEGSNICLTRTDRGWYCDNAGSVSFFPQADKCKVQS NRVFCDTMYSLTLPSEVSLCNTDIFNSKYDCKIMTSKTDISSSVITSLGAIVSCYGKTKC T ASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKLEGKNLYVKGEPIINYYDPLV FPSDEFDASISQVNEKINQSLAFIRRSDELLHNVNTGKSTTN.

In certain embodiments, the variant has greater than 95%, 98%, or 99% sequence identity or similarity to SEQ ID NO: 1. In certain embodiments, the variants are one, two, three, or more amino acid substitutions, deletions, or insertions provided that there are not any substitutions of M at position 79, R at position 191, K at position 357, or Y at position 371. In certain embodiments, substitutions are conserved substitutions.

In certain embodiment, an RSV F variant has a V at position 11, has F at position 20, has an A at position 23, has F at position 45, has a T or V at position 102, has a V at position 103, has a V at position 119, has an A at position 121, has an R at position 123, has an S at position 104, has a T at position 129, has an A at position 173, has an R a position 242, has an N at position 276, has an A as position 518, has a V at position 529, has a T at position 554, or combinations thereof. In certain embodiments, the variants of RSV F protein sequences disclosed herein have one, two, three, or more amino acid substitutions, deletions, or insertions provided that there are not any substitutions of M at position 79, R at position 191, K at position 357, or Y at position 371. In certain embodiments, substitutions are conserved substitutions.

In certain embodiments, the variants are one or two more amino acid substitutions, deletions, or insertions, provided the substitutions are not any substitutions of M at position 79, R at position 191, K at position 357, Y at position 371, and V at position 557. In certain embodiments, substitutions are conserved substitutions.

In certain embodiments, the variants are one, two, or three amino acid substitutions, deletions, or insertions provided the substitutions are not any substitutions of M at position 79, R at position 191, K at position 357, or Y at position 371. In certain embodiments, substitutions are conserved substitutions.

In certain embodiments, the variants are one, two, or three amino acid substitutions, deletions, or insertions, provided the substitutions are not any substitutions of M at position 79, R at position 191, K at position 357, Y at position 371, and V at position 557. In certain embodiments, substitutions are conserved substitutions.

In certain embodiments, the variants do not contain more than 4, 5, 6, 7, 8, 9, 10 or 20 amino acid substitutions, deletions, or insertions, provided the substitutions are not any substitutions of M at position 79, R at position 191, K at position 357, and Y at position 371. In certain embodiments, substitutions are conserved substitutions.

In certain embodiments, the variants do not contain more than 4, 5, 6, 7, 8, 9, 10 or 20 amino acid substitutions, deletions, or insertions, provided the substitutions are not any substitutions of M at position 79, R at position 191, K at position 357, Y at position 371, and V at position 557. In certain embodiments, substitutions are conserved substitutions.

In certain embodiments, the chimeric RSV has genes encoding RSV NS1, NS2, and G proteins are codon-deoptimized such that the rate of expression of NS1, NS2, and G is reduced by more than half in Vero cells compared to the wild type A2 virus.

In certain embodiments, the rate of expression of G in mammalian cells is reduce by more than one third (1/3), one fourth, (1/4), one fifth (1/5), or one tenth (1/10) in Vero cells compared to the wild type A2 virus. In certain embodiments, the rate of expression of NS1 is reduce by more than one third (1/3), one fourth, (1/4), one fifth (1/5), or one tenth (1/10) in Vero cells compared to the wild type line A2 virus.

In certain embodiments, the rate of expression of NS2 is reduce by more than one third (1/3), one fourth, (1/4), one fifth (1/5), or one tenth (1/10) in Vero cells compared to the wild type line A2 virus.

In certain embodiments, the gene encoding the SH protein is deleted or altered such that a truncated protein or no protein is expressed. In certain embodiments, the gene encoding the M2- 2 is deleted or altered such that a truncated protein or no protein is expressed.

In certain embodiments, the gene encoding F protein is mutated such that position 557 is not V or that I is in position 557.

In certain embodiments, the disclosure contemplates fusion proteins comprising RSV F proteins disclosed herein, e.g., SEQ ID NO: 1, 13, and variants.

In certain embodiments, this disclosure relates to vaccine and immunogenic compositions comprising chimeric RSV disclosed herein. In certain embodiments, the compositions further comprise an adjuvant and/or other pharmaceutically acceptable carrier. In certain embodiments, the adjuvant is an aluminum gel, aluminum salt, or monophosphoryl lipid A.

In certain embodiments, the adjuvant is an oil-in-water emulsion. In certain embodiments, the oil-in-water emulsion further comprises a-tocopherol, squalene, and/or a surfactant.

In certain embodiments, the disclosure relates to methods for vaccinating or immunizing a subject against respiratory syncytial virus, the method comprising administering to the subject an effective amount of a chimeric RSV disclosed herein or immunogenic composition comprising the same. In certain embodiments, the effective amount produces a protective immune response in the subject.

In certain embodiments, the subject is a pregnant mother, a child under 2, 3, or 4 years old.

In certain embodiments, subject has a reduced immune system, is over 60 or 65 years old or is regularly administered a chemotherapy or immune suppressive medication.

In certain embodiments, the disclosure relates to nucleic acids encoding an RSV F proteins disclosed herein. In certain embodiments, the nucleic acid comprises SEQ ID NO: 14

ATGGAGTTGCTGATCCATAGATCAAGTGCAATCTTCCTAACTCTTGCTATTAA TGCATTGTACCTCACCTCAAGTCAGAACATAACTGAGGAGTTTTACCAATCGACATG TAGTGCAGTTAGCAGAGGTTACTTGAGTGCTTTAAGAACAGGTTGGTATACCAGTGT CAT AACAATAGAATTAAGTAATATAAAAGAAACCAAATGCAATGGAACTGAC ACTA AAGTAAAACTTATAAAACAAGAATTAGATAAGTATAAGAATGCAGTAACAGAATTA CAGTTACTTATGCAAAACACACCAGCTGCCAACAACCGGGCCAGAAGAGAAGCACC ACAGTATATGAACTACACAATCAATACCACTAAAAACCTAAATGTATCAATAAGCA AGAAGAGGAAACGAAGATTTCTGGGCTTCTTGTTAGGTGTAGGATCTGCAATAGCA AGTGGTAT AGCTGT ATCC AAAGTTCTAC ACCTTGAAGGAGAAGTGAAC AAGATC AA AAATGCTTTGCTGTCTACAAACAAAGCTGTAGTCAGTCTATCAAATGGGGTCAGTGT TTTAACCAGCAAAGTGTTAGATCTCAAGAATTATATAAACAACCAATTATTACCTAT AGTAAATCAACAGAGTTGTCGCATTTCCAACATTGAAACAGTTATAGAATTCCAGCA GAAGAACAGCAGATTGTTGGAAATCACCAGAGAATTTAGTGTCAATGCAGGTGTAA CGAC ACCTTTAAGC ACTTAC ATGTTAACAAAC AGTGAGTTACTATC ATTAATCAATG ATATGCCTATAACAAATGATCAGAAAAAATTAATGTCAAGCAATGTTCAGATAGTA AGGCAACAAAGTTATTCTATCATGTCTATAATAAAGGAAGAAGTCCTTGCATATGTT GTACAGCTACCTATCTATGGTGTAATTGATACACCTTGCTGGAAATTACACACATCA CCTCTGTGCACCACCAACATCAAAGAAGGATCAAATATTTGTTTAACAAGGACTGAT AGAGGATGGTACTGTGATAATGCAGGATCAGTATCCTTCTTTCCACAGGCTGACACT TGTAAAGTACAGTCCAATCGAGTATTTTGTGACACTATGAACAGTTTGACATTACCA AGTGAAGTCAGCCTTTGTAACACTGACATATTCAATTCCAAGTATGACTGCAAAATT ATGACATCAAAAACAGACATAAGCAGCTCAGTAATTACTTCTCTAGGAGCTATAGTG TCATGCTATGGTAAAACTAAATGCACTGCATCCAACAAAAATCGTGGAATTATAAA GACATTTTCTAATGGTTGTGATTATGTGTCAAACAAAGGAGTAGATACTGTATCAGT GGGCAACACTTTATACTATGTCAACAAGCTGGAAGGCAAAAACCTTTATGTAAAAG GGGAACCTATAATAAATTACTATGACCCTCTAGTGTTTCCTTCTGATGAGTTTGATGC ATCAATATCTCAAGTCAATGAAAAAATTAATCAAAGTTTAGCTTTTATTCGTAGATC CGATGAATTATTACATAATGTAAATACTGGAAAATCTACTACAAATATTATGATAAC TGC AATT ATT AT AGT AATC ATTGT AGT ATTGTT ATC ATT AAT AGCT ATTGGTTT ACTG TTGTATTGCAAAGCCAAAAACACACCAGTTACACTAAGCAAAGACCAACTAAGTGG AATCAATAATATTGCATTCAGCAAATAG,

or a variants with greater than 50, 60, 70, 80, 90, 95, 98, or 99% sequence identity.

In certain embodiments, the disclosure relates to vectors comprising a nucleic acid encoding an RSV F proteins disclosed herein. In certain embodiments, the vector is selected from a plasmid or a bacterial artificial chromosome.

In certain embodiments, chimeric RSV comprises SEQ ID NO: 15

ACGCGAAAAAATGCGTACAACAAACTTGCATAAACCAAAAAAATGGGGCAA ATAAGAATTTGATAAGTACCACTTAAATTTAACTCCCTTGCTTAGCGATGGTGAGCG AGCTGATT AAGGAGAAC ATGC AC ATGAAGCTGT AC ATGGAGGGC ACCGTGAAC AAC CACCACTTCAAGTGCACATCCGAGGGCGAAGGCAAGCCCTACGAGGGCACCCAGAC CATGAGAATCAAGGCGGTCGAGGGCGGCCCTCTCCCCTTCGCCTTCGACATCCTGGC TACCAGCTTCATGTACGGCAGCAAAACCTTCATCAACCACACCCAGGGCATCCCCGA CTTCTTTAAGCAGTCCTTCCCCGAGGGCTTCACATGGGAGAGAGTCACCACATACGA AGACGGGGGCGTGCTGACCGCTACCCAGGACACCAGCCTCCAGGACGGCTGCCTC A TCTACAACGTCAAGATCAGAGGGGTGAACTTCCCATCCAACGGCCCTGTGATGCAG AAGAAAACACTCGGCTGGGAGGCCTCCACCGAGACCCTGTACCCCGCTGACGGCGG CCTGGAAGGCAGAGCCGACATGGCCCTGAAGCTCGTGGGCGGGGGCCACCTGATCT GCAACTTGAAGACCACATACAGATCCAAGAAACCCGCTAAGAACCTCAAGATGCCC GGCGTCTACTATGTGGACAGAAGACTGGAAAGAATCAAGGAGGCCGACAAAGAGA CCTACGTCGAGCAGCACGAGGTGGCTGTGGCCAGATACTGCGACCTCCCTAGCAAA CTGGGGCACAGATGAGTATTCAATTATAGTTATTAAAAACTTAACAGAAGACAAAA ATGGGGCAAATAAGAATTTGATAAGTACCACTTAAATTTAACTCCCTTGCTTAGCGA TGGGTTCGAATTCGCTATCGATGATAAAAGTACGTCTACAAAATCTATTTGATAATG ATGAAGTAGCGCTACTAAAAATAACGTGTTATACGGATAAACTAATACATCTAACG AATGCGCTAGCGAAAGCGGTAATACATACGATAAAACTAAATGGTATAGTATTTGT ACATGTAATAACGTCGTCGGATATATGTCCGAATAATAATATAGTAGTAAAATCGAA TTTTACGACGATGCCGGTACTACAAAATGGTGGTTATATATGGGAAATGATGGAACT AACGCATTGTTCGCAACCGAATGGTCTACTAGATGATAATTGTGAAATAAAATTTTC GAAAAAACTATCGGATTCGACGATGACGAATT AT ATGAATC AACT ATCGGAACTAC TAGGTTTTGATCTAAATCCGTAAATTATAATTAATATCAACTAGCAAATCAATGTCA CTAACACCATTAGTTAATATAAAACTTAACAGAAGACAAAAATGGGGCAAATAAAT CAATTCAGCCAACCCAACCATGGATACGACGCATAATGATAATACGCCGCAACGTC TAATGATAACGGATATGCGTCCGCTATCGCTAGAAACGATAATAACGTCGCTAACGC GTGATATAATAACGCATAAATTTATATATCTAATAAATCATGAATGTATAGTACGTA AACTAGATGAACGTCAAGCGACGTTTACGTTTCTAGTAAATTATGAAATGAAACTAC TACATAAAGTAGGTTCGACGAAATATAAAAAATATACGGAATATAATACGAAATAT GGTACGTTTCCGATGCCGATATTTATAAATCATGATGGTTTTCTAGAATGTATAGGT ATAAAACCGACGAAACATACGCCGATAATATATAAATATGATCTAAATCCGTAAAT TTCAACACAATATTCACACAATCTAAAACAACAACTCTATGCATAACTATACTCCAT AGTCC AGATGGAGCCTGAAAATTAT AGT AATTT AAAATT AAGGAGAGAT ATAAGAT AGAAGATGGGGCAAATACAAAGATGGCTCTTAGCAAAGTCAAGTTGAATGATACAC TCAACAAAGATCAACTTCTGTCATCCAGCAAATACACCATCCAACGGAGCACAGGA GATAGTATTGATACTCCTAATTATGATGTGCAGAAACACATCAATAAGTTATGTGGC ATGTTATTAATCACAGAAGATGCTAATCATAAATTCACTGGGTTAATAGGTATGTTA TATGCGATGTCTAGGTTAGGAAGAGAAGACACCATAAAAATACTC AGAGATGCGGG ATATCATGTAAAAGCAAATGGAGTAGATGTAACAACACATCGTCAAGACATTAATG GAAAAGAAATGAAATTTGAAGTGTTAACATTGGCAAGCTTAACAACTGAAATTCAA ATCAACATTGAGATAGAATCTAGAAAATCCTACAAAAAAATGCTAAAAGAAATGGG AGAGGTAGCTCCAGAATACAGGCATGACTCTCCTGATTGTGGGATGATAATATTATG TATAGCAGCATTAGTAATAACTAAATTAGCAGCAGGGGACAGATCTGGTCTTACAG CCGTGATTAGGAGAGCTAATAATGTCCTAAAAAATGAAATGAAACGTTACAAAGGC TTACTACCCAAGGACATAGCCAACAGCTTCTATGAAGTGTTTGAAAAACATCCCCAC TTTATAGATGTTTTTGTTCATTTTGGTATAGCACAATCTTCTACCAGAGGTGGCAGTA GAGTTGAAGGGATTTTTGCAGGATTGTTTATGAATGCCTATGGTGCAGGGCAAGTGA TGTTACGGTGGGGAGTCTTAGCAAAATCAGTTAAAAATATTATGTTAGGACATGCTA GTGTGCAAGCAGAAATGGAACAAGTTGTTGAGGTTTATGAATATGCCCAAAAATTG GGTGGTGAAGCAGGATTCTACCATATATTGAACAACCCAAAAGCATCATTATTATCT TTGACTCAATTTCCTCACTTCTCCAGTGTAGTATTAGGCAATGCTGCTGGCCTAGGCA TAATGGGAGAGTACAGAGGTACACCGAGGAATCAAGATCTATATGATGCAGCAAAG GC AT ATGCTGAAC AACTC AAAGAAAATGGTGTGATT AACT AC AGTGT ACT AGACTTG ACAGCAGAAGAACTAGAGGCTATCAAACATCAGCTTAATCCAAAAGATAATGATGT AGAGCTTTGAGTTAATAAAAAATGGGGCAAATAAATCATCATGGAAAAGTTTGCTC CTGAATTCCATGGAGAAGATGCAAACAACAGGGCTACTAAATTCCTAGAATCAATA AAGGGCAAATTCACATCACCCAAAGATCCCAAGAAAAAAGATAGTATCATATCTGT CAACTCAATAGATATAGAAGTAACCAAAGAAAGCCCTATAACATCAAATTCAACTA TTATCAACCCAACAAATGAGACAGATGATACTGCAGGGAACAAGCCCAATTATCAA AGAAAACCTCTAGTAAGTTTCAAAGAAGACCCTACACCAAGTGATAATCCCTTTTCT AAACTATACAAAGAAACCATAGAAACATTTGATAACAATGAAGAAGAATCCAGCTA TTCATACGAAGAAATAAATGATCAGACAAACGATAATATAACAGCAAGATTAGATA GGATTGATGAAAAATTAAGTGAAATACTAGGAATGCTTCACACATTAGTAGTGGCA AGTGC AGGACCT AC ATCTGCTCGGGATGGTAT AAGAGATGCC ATGATTGGTTTAAGA GAAGAAATGATAGAAAAAATCAGAACTGAAGCATTAATGACCAATGACAGATTAGA AGCTATGGCAAGACTCAGGAATGAGGAAAGTGAAAAGATGGCAAAAGACACATCA GATGAAGTGTCTCTCAATCCAACATCAGAGAAATTGAACAACCTATTGGAAGGGAA TGATAGTGACAATGATCTATCACTTGAAGATTTCTGATTAGTTACCACTCTTCACATC AAC AC AC AATACCAAC AGAAGACC AACAAACTAACC AACCCAATCATCCAACCAAA CATCCATCCGCCAATCAGCCAAACAGCCAACAAAACAACCAGCCAATCCAAAACTA ACCACCCGGAAAAAATCTATAATATAGTTACAAAAAAAGGAAAGGGTGGGGCAAAT ATGGAAACATACGTGAACAAGCTTCACGAAGGCTCCACATACACAGCTGCTGTTCA ATACAATGTCTTAGAAAAAGACGATGACCCTGCATCACTTACAATATGGGTGCCCAT GTTCCAATCATCTATGCCAGCAGATTTACTTATAAAAGAACTAGCTAATGTCAACAT ACTAGTGAAACAAATATCCACACCCAAGGGACCTTCACTAAGAGTCATGATAAACT CAAGAAGTGCAGTGCTAGCACAAATGCCCAGCAAATTTACCATATGCGCTAATGTGT CCTTGGATGAAAGAAGCAAACTAGCATATGATGTAACCACACCCTGTGAAATCAAG GCATGTAGTCTAACATGCCTAAAATCAAAAAATATGTTGACTACAGTTAAAGATCTC ACTATGAAGACACTCAACCCTACACATGATATTATTGCTTTATGTGAATTTGAAAAC ATAGTAACATCAAAAAAAGTCATAATACCAACATACCTAAGATCCATCAGTGTCAG AAATAAAGATCTGAACACACTTGAAAATATAACAACCACTGAATTCAAAAATGCTA TCACAAATGCAAAAATCATCCCTTACTCAGGATTACTATTAGTCATCACAGTGACTG ACAACAAAGGAGCATTCAAATACATAAAGCCACAAAGTCAATTCATAGTAGATCTT GGAGCTT ACCTAGAAAAAGAAAGT AT AT ATTATGTTACC AC AAATTGGAAGC AC AC AGCTACACGATTTGCAATCAAACCCATGGAAGATTAACCTTTTTCCTCTACATCAGT GTGTTAATTCATACAAACTTTCTACCTACATTCTTCACTTCACCATCACAATCACAAA CACTCTGTGGTTCAACCAATCAAACAAAACTTATCTGAAGTCCCAGATCATCCCAAG TCATTGTTTATCAGATCTAGTACTCAAATAAGTTAATAAAAAATATACACATGGACG TCCATGGGGCAAATGCAAACATGTCCAAAAACAAGGACCAACGCACCGCTAAGACA TTAGAAAGGACCTGGGACACTCTCAATCATTTATTATTCATATCATCGTGCTTATATA AGTTAAATCTTAAATCTGTAGCACAAATCACATTATCCATTCTGGCAATGATAATCT CAACTTCACTTATAATTGCAGCCATCATATTCATAGCCTCGGCAAACCACAAAGTCA CACCAACAACTGCAATCATACAAGATGCAACAAGCCAGATCAAGAACACAACCCCA ACATACCTCACCCAGAATCCTCAGCTTGGAATCAGTCCCTCTAATCCGTCTGAAATT AC ATC AC AAATC ACC ACC ATACTAGCTTC AAC AAC ACC AGGAGTC AAGTC AACCCT GCAATCCACAACAGTCAAGACCAAAAACACAACAACAACTCAAACACAACCCAGC AAGCCCACCACAAAACAACGCCAAAACAAACCACCAAGCAAACCCAATAATGATTT TCACTTTGAAGTGTTCAACTTTGTACCCTGCAGCATATGCAGCAACAATCCAACCTG CTGGGCTATCTGCAAAAGAATACCAAACAAAAAACCAGGAAAGAAAACCACTACC AAGCCCACAAAAAAACCAACCCTC AAGACAACCAAAAAAGATCCCAAACCTCAAA CCACTAAATCAAAGGAAGTACCCACCACCAAGCCCACAGAAGAGCCAACCATCAAC ACCACCAAAACAAACATCATAACTACACTACTCACCTCCAACACCACAGGAAATCC AGAACTCACAAGTCAAATGGAAACCTTCCACTCAACTTCCTCCGAAGGCAATCCAA GCCCTTCTCAAGTCTCTACAACATCCGAGTACCCATCACAACCTTCATCTCCACCCA ACACACCACGCCAGTAGTTACTTAAAAACATATTATCACAAAAGGCCTTGACCAAC CGCGGAGAATCAAAATAAACTCTGGGGCAAATAACAATGGAGTTGCTGATCCATAG ATCAAGTGCAATCTTCCTAACTCTTGCTATTAATGCATTGTACCTCACCTCAAGTCAG AACATAACTGAGGAGTTTTACCAATCGACATGTAGTGCAGTTAGCAGAGGTTACTTG AGTGCTTTAAGAACAGGTTGGTATACCAGTGTCATAACAATAGAATTAAGTAATATA AAAGAAACCAAATGCAATGGAACTGACACTAAAGTAAAACTTATAAAACAAGAATT AGATAAGTATAAGAATGCAGTAACAGAATTACAGTTACTTATGCAAAACACACCAG CTGCCAACAACCGGGCCAGAAGAGAAGCACCACAGTATATGAACTACACAATCAAT ACCACTAAAAACCTAAATGTATCAATAAGCAAGAAGAGGAAACGAAGATTTCTGGG CTTCTTGTTAGGTGTAGGATCTGCAATAGCAAGTGGTATAGCTGTATCCAAAGTTCT AC ACCTTGAAGGAGAAGTGAAC AAGATC AAAAATGCTTTGCTGTCT AC AAAC AAAG CTGTAGTCAGTCTATCAAATGGGGTCAGTGTTTTAACCAGCAAAGTGTTAGATCTCA AGAATTATATAAACAACCAATTATTACCTATAGTAAATCAACAGAGTTGTCGCATTT CCAACATTGAAACAGTTATAGAATTCCAGCAGAAGAACAGCAGATTGTTGGAAATC ACCAGAGAATTTAGTGTCAATGCAGGTGTAACGACACCTTTAAGCACTTACATGTTA ACAAACAGTGAGTTACTATCATTAATCAATGATATGCCTATAACAAATGATCAGAAA AAATTAATGTCAAGCAATGTTCAGATAGTAAGGCAACAAAGTTATTCTATCATGTCT ATAATAAAGGAAGAAGTCCTTGCATATGTTGTACAGCTACCTATCTATGGTGTAATT GATACACCTTGCTGGAAATTACACACATCACCTCTGTGCACCACCAACATCAAAGAA GGATCAAATATTTGTTTAACAAGGACTGATAGAGGATGGTACTGTGATAATGCAGG ATCAGTATCCTTCTTTCCACAGGCTGACACTTGTAAAGTACAGTCCAATCGAGTATTT TGTGAC ACTATGAAC AGTTTGAC ATTACC AAGTGAAGTC AGCCTTTGT AAC ACTGAC ATATTCAATTCCAAGTATGACTGCAAAATTATGACATCAAAAACAGACATAAGCAG CTCAGTAATTACTTCTCTAGGAGCTATAGTGTCATGCTATGGTAAAACTAAATGCAC TGCATCCAACAAAAATCGTGGAATTATAAAGACATTTTCTAATGGTTGTGATTATGT GTCAAACAAAGGAGTAGATACTGTATCAGTGGGCAACACTTTATACTATGTCAACA AGCTGGAAGGC AAAAACCTTTATGTAAAAGGGGAACCTATAATAAATTACTATGAC CCTCTAGTGTTTCCTTCTGATGAGTTTGATGCATCAATATCTCAAGTCAATGAAAAA ATTAATCAAAGTTTAGCTTTTATTCGTAGATCCGATGAATTATTACATAATGTAAATA CTGGAAAATCTACTACAAATATTATGATAACTGCAATTATTATAGTAATCATTGTAG TATTGTTATCATTAATAGCTATTGGTTTACTGTTGTATTGCAAAGCCAAAAACACACC AGTTACACTAAGCAAAGACCAACTAAGTGGAATCAATAATATTGCATTCAGCAAAT AGATAAAAATAGCACCTAATCATGTTCTTACAATGGTTTACTATCTGCTCATAGACA ACCCATCTATCATTGGATTTTCTTAAAATCTGAACTTCATCGAAACTCTTATCTATAA ACCATCTCACTTACACTATTTAAGTAGATTCCTAGTTTATAGTTATATAAAACACAAT TGAATGCCAGTCGACCTTACCATCTGTAAAAATGAAAACTGGGGCAAATATGTCAC GAAGGAATCCTTGCAAATTTGAAATTCGAGGTCATTGCTTAAATGGTAAGAGGTGTC ATTTTAGTCATAATTATTTTGAATGGCCACCCCATGCACTGCTTGTAAGACAAAACTT TATGTTAAACAGAATACTTAAGTCTATGGATAAAAGTATAGATACCTTATCAGAAAT AAGTGGAGCTGCAGAGTTGGACAGAACAGAAGAGTATGCTCTTGGTGTAGTTGGAG TGCTAGAGAGTTATATAGGATCAATAAACAATATAACTAAACAATCAGCATGTGTTG CC ATGAGC AAACTCCTC ACTGAACTC AAT AGTGATGATATC AAAAAGCTGAGGGAC AATGAAGAGCTAAATTCACCCAAGATAAGAGTGTACAATACTGTCATATCATATATT GAAAGCAACAGGAAAAACAATAAACAAACTATCCATCTGTTAAAAAGATTGCCAGC AGACGTATTGAAGAAAACCATCAAAAACACATTGGATATCCATAAGAGCATAACCA TCAACAACCCAAAAGAATCAACTGTTAGTGATACAAATGACCATGCCAAAAATAAT GATACTACCTGACAAATATCCTTGTAGTATAACTTCCATACTAATAACAAGTAGATG TAGAGTTACTATGTATAATCAAAAGAACACACTATATTTCAATCAAAACAACCCAAA TAACCATATGTACTCACCGAATCAAACATTCAATGAAATCCATTGGACCTCTCAAGA ATTGATTGACACAATTCAAAATTTTCTACAACATCTAGGTATTATTGAGGATATATA TACAATATATATATTAGTGTCATAACACTCAATTCTAACACTCACCACATCGTTACAT TATTAATTCAAACAATTCAAGTTGTGGGACAAAATGGATCCCATTATTAATGGAAAT TCTGCTAATGTTT ATCTAACCGAT AGTT ATTT AAAAGGTGTTATCTCTTTCTC AGAGT GTAATGCTTTAGGAAGTTACATATTCAATGGTCCTTATCTCAAAAATGATTATACCA ACTTAATTAGTAGACAAAATCCATTAATAGAACACATGAATCTAAAGAAACTAAAT ATAACACAGTCCTTAATATCTAAGTATCATAAAGGTGAAATAAAATTAGAAGAACC TACTTATTTTCAGTCATTACTTATGACATACAAGAGTATGACCTCGTCAGAACAGAT TGCTACCACTAATTTACTTAAAAAGATAATAAGAAGAGCTATAGAAATAAGTGATG TCAAAGTCTATGCTATATTGAATAAACTAGGGCTTAAAGAAAAGGACAAGATTAAA TCCAACAATGGACAAGATGAAGACAACTCAGTTATTACGACCATAATCAAAGATGA TATACTTTCAGCTGTTAAAGATAATCAATCTCATCTTAAAGCAGACAAAAATCACTC TACAAAACAAAAAGACACAATCAAAACAACACTCTTGAAGAAATTGATGTGTTCAA TGCAACATCCTCCATCATGGTTAATACATTGGTTTAACTTATACACAAAATTAAACA ACATATTAACACAGTATCGATCAAATGAGGTAAAAAACCATGGGTTTACATTGATA GATAATCAAACTCTTAGTGGATTTCAATTTATTTTGAACCAATATGGTTGTATAGTTT ATCATAAGGAACTCAAAAGAATTACTGTGACAACCTATAATCAATTCTTGACATGGA AAGATATTAGCCTTAGTAGATTAAATGTTTGTTTAATTACATGGATTAGTAACTGCTT GAACACATTAAATAAAAGCTTAGGCTTAAGATGCGGATTCAATAATGTTATCTTGAC ACAACTATTCCTTTATGGAGATTGTATACTAAAGCTATTTCACAATGAGGGGTTCTA CATAATAAAAGAGGTAGAGGGATTTATTATGTCTCTAATTTTAAATATAACAGAAGA AGATCAATTCAGAAAACGATTTTATAATAGTATGCTCAACAACATCACAGATGCTGC TAATAAAGCTCAGAAAAATCTGCTATCAAGAGTATGTCATACATTATTAGATAAGAC AGTGTCCGAT AATAT AAT AAATGGC AGATGGATAATTCTATT AAGT AAGTTCCTT AA ATTAATTAAGCTTGCAGGTGACAATAACCTTAACAATCTGAGTGAACTATATTTTTT GTTCAGAATATTTGGACACCCAATGGTAGATGAAAGACAAGCCATGGATGCTGTTA AAATTAATTGCAATGAGACCAAATTTTACTTGTTAAGCAGTCTGAGTATGTTAAGAG GTGCCTTTATATATAGAATTATAAAAGGGTTTGTAAATAATTACAACAGATGGCCTA CTTTAAGAAATGCTATTGTTTTACCCTTAAGATGGTTAACTTACTATAAACTAAACAC TTATCCTTCTTTGTTGGAACTTACAGAAAGAGATTTGATTGTGTTATCAGGACTACGT TTCTATCGTGAGTTTCGGTTGCCTAAAAAAGTGGATCTTGAAATGATTATAAATGAT AAAGCTATATCACCTCCTAAAAATTTGATATGGACTAGTTTCCCTAGAAATTACATG CCATCACACATACAAAACTATATAGAACATGAAAAATTAAAATTTTCCGAGAGTGA TAAATCAAGAAGAGTATTAGAGTATTATTTAAGAGATAACAAATTCAATGAATGTG ATTT AT AC AACTGTGTAGTTAATC AAAGTTATCTC AAC AACCCTAATC ATGTGGTAT CATTGACAGGCAAAGAAAGAGAACTCAGTGTAGGTAGAATGTTTGCAATGCAACCG GGAATGTTCAGACAGGTTCAAATATTGGCAGAGAAAATGATAGCTGAAAACATTTT ACAATTCTTTCCTGAAAGTCTTACAAGATATGGTGATCTAGAACTACAAAAAATATT AGAATTGAAAGCAGGAATAAGTAACAAATCAAATCGCTACAATGATAATTACAACA ATTACATTAGTAAGTGCTCTATC ATC ACAGATCTC AGCAAATTC AATC AAGCATTTC GATATGAAACGTCATGTATTTGTAGTGATGTGCTGGATGAACTGCATGGTGTACAAT CTCTATTTTCCTGGTTACATTTAACTATTCCTCATGTCACAATAATATGCACATATAG GCATGCACCCCCCTATATAGGAGATCATATTGTAGATCTTAACAATGTAGATGAACA AAGTGGATTATATAGATATCACATGGGTGGCATCGAAGGGTGGTGTCAAAAACTGT GGACCATAGAAGCTATATCACTATTGGATCTAATATCTCTCAAAGGGAAATTCTCAA TTACTGCTTTAATTAATGGTGAC AATC AATC AATAGATATAAGCAAACC AATC AGAC TCATGGAAGGTCAAACTCATGCTCAAGCAGATTATTTGCTAGCATTAAATAGCCTTA A ATT AC TGT AT A A AGAGT ATGC AGGC AT AGGC C AC A A ATT AAA AGG A AC TGAGAC T TATATATCACGAGATATGCAATTTATGAGTAAAACAATTCAACATAACGGTGTATAT TACCCAGCTAGTATAAAGAAAGTCCTAAGAGTGGGACCGTGGATAAACACTATACT TGATGATTTCAAAGTGAGTCTAGAATCTATAGGTAGTTTGACACAAGAATTAGAATA TAGAGGTGAAAGTCTATTATGCAGTTTAATATTTAGAAATGTATGGTTATATAATCA GATTGCTCTACAATTAAAAAATC ATGC ATT ATGTAACAATAAACTATATTTGGACAT ATTAAAGGTTCTGAAACACTTAAAAACCTTTTTTAATCTTGATAATATTGATACAGC ATTAACATTGTATATGAATTTACCCATGTTATTTGGTGGTGGTGATCCCAACTTGTTA TATCGAAGTTTCTATAGAAGAACTCCTGACTTCCTCACAGAGGCTATAGTTCACTCT GTGTTCATACTTAGTTATTATACAAACCATGACTTAAAAGATAAACTTCAAGATCTG TCAGATGATAGATTGAATAAGTTCTTAACATGCATAATCACGTTTGACAAAAACCCT AATGCTGAATTCGTAACATTGATGAGAGATCCTCAAGCTTTAGGGTCTGAGAGACAA GCTAAAATTACTAGCGAAATCAATAGACTGGCAGTTACAGAGGTTTTGAGTACAGCT CCAAACAAAATATTCTCCAAAAGTGCACAACATTATACTACTACAGAGATAGATCTA AATGATATTATGCAAAATATAGAACCTACATATCCTCATGGGCTAAGAGTTGTTTAT GAAAGTTTACCCTTTTATAAAGCAGAGAAAATAGTAAATCTTATATCAGGTACAAAA TCTATAACTAACATACTGGAAAAAACTTCTGCCATAGACTTAACAGATATTGATAGA GCCACTGAGATGATGAGGAAAAACATAACTTTGCTTATAAGGATACTTCCATTGGAT TGTAAC AGAGAT AAAAGAGAGATATTGAGTATGGAAAACCT AAGT ATT ACTGAATT AAGCAAATATGTTAGGGAAAGATCTTGGTCTTTATCCAATATAGTTGGTGTTACATC ACCCAGTATCATGTATACAATGGACATCAAATATACTACAAGCACTATATCTAGTGG CATAATTATAGAGAAATATAATGTTAACAGTTTAACACGTGGTGAGAGAGGACCCA CTAAACCATGGGTTGGTTCATCTACACAAGAGAAAAAAACAATGCCAGTTTATAAT AGAC AAGTCTTAACC AAAAAACAGAGAGATCAAATAGATCTATTAGCAAAATTGGA TTGGGTGTATGCATCTATAGATAACAAGGATGAATTCATGGAAGAACTCAGCATAG GAACCCTTGGGTTAACATATGAAAAGGCCAAGAAATTATTTCCACAATATTTAAGTG TCAATTATTTGCATCGCCTTACAGTCAGTAGTAGACCATGTGAATTCCCTGCATCAAT ACCAGCTTATAGAACAACAAATTATCACTTTGACACTAGCCCTATTAATCGCATATT AACAGAAAAGTATGGTGATGAAGATATTGACATAGTATTCCAAAACTGTATAAGCT TTGGCCTTAGTTTAATGTCAGTAGTAGAACAATTTACTAATGTATGTCCTAACAGAA TTATTCTCATACCTAAGCTTAATGAGATACATTTGATGAAACCTCCCATATTCACAG GTGATGTTGATATTCACAAGTTAAAACAAGTGATACAAAAACAGCATATGTTTTTAC CAGACAAAATAAGTTTGACTCAATATGTGGAATTATTCTTAAGTAATAAAACACTCA AATCTGGATCTCATGTTAATTCTAATTTAATATTGGCACATAAAATATCTGACTATTT TCATAATACTTACATTTTAAGTACTAATTTAGCTGGACATTGGATTCTGATTATACAA CTTATGAAAGATTCTAAAGGTATTTTTGAAAAAGATTGGGGAGAGGGATATATAACT GATCATATGTTTATTAATTTGAAAGTTTTCTTCAATGCTTATAAGACCTATCTCTTGT GTTTTCATAAAGGTTATGGCAAAGCAAAGCTGGAGTGTGATATGAACACTTCAGATC TTCT ATGTGT ATTGGAATT AAT AGAC AGTAGTT ATTGGAAGTCT ATGTCTAAGGT ATT TTTAGAACAAAAAGTTATCAAATACATTCTTAGCCAAGATGCAAGTTTACATAGAGT AAAAGGATGTCATAGCTTCAAATTATGGTTTCTTAAACGTCTTAATGTAGCAGAATT CACAGTTTGCCCTTGGGTTGTTAACATAGATTATCATCCAACACATATGAAAGCAAT ATTAACTTATATAGATCTTGTTAGAATGGGATTGATAAATATAGATAGAATACACAT TAAAAATAAACACAAATTCAATGATGAATTTTATACTTCTAATCTCTTCTACATTAAT TATAACTTCTCAGATAATACTCATCTATTAACTAAACATATAAGGATTGCTAATTCTG AATTAGAAAATAATTACAACAAATTATATCATCCTACACCAGAAACCCTAGAGAAT ATACTAGCCAATCCGATTAAAAGTAATGACAAAAAGACACTGAATGACTATTGTAT AGGTAAAAATGTTGACTCAATAATGTTACCATTGTTATCTAATAAGAAGCTTATTAA ATCGTCTGCAATGATTAGAACCAATTACAGCAAACAAGATTTGTATAATTTATTCCC T ATGGTTGTGATTGAT AGAATT ATAGATC ATTC AGGC AATAC AGCC AAATCC AACC A ACTTTACACTACTACTTCCCACCAAATATCTTTAGTGCACAATAGCACATCACTTTAC TGCATGCTTCCTTGGCATCATATTAATAGATTCAATTTTGTATTTAGTTCTACAGGTT GTAAAATTAGTATAGAGTATATTTTAAAAGATCTTAAAATTAAAGATCCCAATTGTA TAGCATTCATAGGTGAAGGAGCAGGGAATTTATTATTGCGTACAGTAGTGGAACTTC ATCCTGAC AT AAGAT ATATTT AC AGAAGTCTGAAAGATTGC AATGATC AT AGTTT AC CTATTGAGTTTTTAAGGCTGTACAATGGACATATCAACATTGATTATGGTGAAAATT TGACCATTCCTGCTACAGATGCAACCAACAACATTCATTGGTCTTATTTACATATAA AGTTTGCTGAACCTATCAGTCTTTTTGTCTGTGATGCCGAATTGTCTGTAACAGTCAA CTGGAGTAAAATTATAATAGAATGGAGCAAGCATGTAAGAAAGTGCAAGTACTGTT CCTCAGTTAATAAATGTATGTTAATAGTAAAATATCATGCTCAAGATGATATTGATT TCAAATTAGACAATATAACTATATTAAAAACTTATGTATGCTTAGGCAGTAAGTTAA AGGGATCGGAGGTTTACTTAGTCCTTACAATAGGTCCTGCGAATATATTCCCAGTAT TTAATGTAGTACAAAATGCTAAATTGATACTATCAAGAACCAAAAATTTCATCATGC CTAAGAAAGCTGATAAAGAGTCTATTGATGCAAATATTAAAAGTTTGATACCCTTTC TTTGTTACCCTATAACAAAAAAAGGAATTAATACTGCATTGTCAAAACTAAAGAGTG TTGTTAGTGGAGATATACTATCATATTCTATAGCTGGACGTAATGAAGTTTTCAGCA ATAAACTTATAAATCATAAGCATATGAACATCTTAAAATGGTTCAATCATGTTTTAA ATTTCAGATCAACAGAACTAAACTATAACCATTTATATATGGTAGAATCTACATATC CTTACCTAAGTGAATTGTTAAACAGCTTGACAACCAATGAACTTAAAAAACTGATTA AAATC AC AGGTAGTCTGTT AT AC AACTTTC ATAATGAAT AATGAAT AAAGATCTT AT AATAAAAATTCCCATAGCTATACACTAACACTGTATTCAATTATAGTTATTAAAAAT TAAAAATCGTACGATTTTTTAAATAACTTTTAGTGAACTAATCCTAAAGTTATCATTT TAATCTTGGAGGAATAAATTTAAACCCTAATCTAATTGGTTTATATGTGTATTAACTA AATTACGAGATATTAGTTTTTGACACTTTTTTTCTCGT

or variants having greater than 50, 60, 70, 80, 90, 95, 98, or 99% sequence identity.

In certain embodiments, the chimeric RSV includes those which are infectious to a human subject and those which are not infectious to a human subject.

In certain embodiments, the disclosure relates to a particle, RSV particle, or virus like particle comprising a mutated RSV F protein disclosed herein. In certain embodiments, the particle comprises a live and infectious attenuated RSV genome or antigenome. In certain embodiments, the particle comprises and inactivated RSV genome or antigenome, e.g., without nucleic acids or with nucleic acids that are not capable of expressing one, two, three or more or any of the RSV proteins. In certain embodiments, the particles are killed using a method such as heat or formaldehyde. In certain embodiments, the particles are reconstituted by expression of viral structural proteins and the mutated RSV F proteins disclosed herein.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 illustrates an RSV sequence comparison of an F protein having a 1557 V mutation (Query) (SEQ ID NO: 3) and the typical wild type RSV strain line 19 sequence (Sbjct) (SEQ ID NO: 4).

Figure 2 illustrates the RSV vaccine candidate OE4. RSV with codon-deoptimized NS1 and NS2 (dNSl/dNS2) is genetically stable and attenuates RSV while retaining immunogenicity like wild type virus A2. OE4 also has codon-deoptimization of the G protein, deletion of the SH protein, and expresses RSV line 19 F protein.

Figure 3 shows westerns of Vero cell lysates indicating reduced protein expression for the codon-deoptimized RSV G, NS1, NS2 genes when the RSVs infect Vero cells.

Figure 4 shows data indicating chimeric, RSV, expressing, Line 19 F (A2 Linel9F) exhibits a pre-fusion F bias compared to RSV F of strain A2.

Figure 5 A illustrates the sequence of an F protein with substitution of M at position 79, R at position 191, K at position 357, and Y at position 371 designated as DB 1 QUAD (Query) (SEQ ID NO: 1) when compared to a consensus sequence (Sbjct) (SEQ ID NO: 2) for a low-fusion RSV subgroup B strain of the Buenos Aires clade (BAF). Figure 5B illustrates a comparison of the amino acid sequences of the DB1 QUAD F protein (Query) (SEQ ID NO: 1) and the typical wild type RSV strain line 19 sequence (Sbjct) (SEQ ID NO: 4). There is an identity of 519/573 (91%) and similarity of 548/573 (95%).

Figure 6A shows data on the thermostability of certain RSV constructs after 7 days including DB 1 which contains the consensus F protein of SEQ ID NO: 2.

Figure 6B shows data on thermostability of certain RSV constructs after 7 days including a DB1 construct containing F protein amino acids that correspond to certain positions found in the F protein of line 19. The DB1 QUAD refers to the F protein having SEQ ID NO: 1 including an amino acid pattern of M at position 79, R at position 191, K at position 357, and Y at position 371, and V at position 557.

Figure 6C shows data indicating the ratio of pre-fusion F to total F (pre-fusion and post- fusion F) of certain vaccine candidates.

Figure 7A shows data on the attenuation of vaccine constructs in BALB/c mice indicating that DB1 QUAD was more attenuated when compared to the A2-Linel9F.

Figure 7B shows data on the immunogenicity of vaccine constructs in BALB/c mice against different RSV strains indicating DB 1 QUAD increased immunogenicity against RSV B.

DETAILED DESCRIPTION

Before the present disclosure is described in greater detail, it is to be understood that this disclosure is not limited to particular embodiments described, and as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present disclosure will be limited only by the appended claims.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present disclosure, the preferred methods and materials are now described.

All publications and patents cited in this specification are herein incorporated by reference as if each individual publication or patent were specifically and individually indicated to be incorporated by reference and are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the present disclosure is not entitled to antedate such publication by virtue of prior disclosure. Further, the dates of publication provided could be different from the actual publication dates that may need to be independently confirmed.

As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present disclosure. Any recited method can be carried out in the order of events recited or in any other order that is logically possible.

Embodiments of the present disclosure will employ, unless otherwise indicated, techniques of immunology, medicine, organic chemistry, biochemistry, molecular biology, pharmacology, physiology, and the like, which are within the skill of the art. Such techniques are explained fully in the literature.

It must be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. In this specification and in the claims that follow, reference will be made to a number of terms that shall be defined to have the following meanings unless a contrary intention is apparent.

Prior to describing the various embodiments, the following definitions are provided and should be used unless otherwise indicated.

The terms "protein" and "polypeptide" refer to compounds comprising amino acids joined via peptide bonds and are used interchangeably.

The term "portion" when used in reference to a protein (as in "a portion of a given protein") refers to fragments of that protein. The fragments may range in size from four amino acid residues to the entire amino sequence minus one amino acid.

The terms "chimeric respiratory syncytial virus" or "chimeric RSV" refer to a nucleic acid that contains sufficient RSV genes to allow the genome or antigenome to replicate in host cells (e.g. Vero cells) and the sequence nucleic acid is altered to include at least one nucleic acid segment that is not structurally the same a natural RSV strain, i.e., as the RSV strain occurs naturally over the whole RSV genome. A chimeric respiratory syncytial virus includes an RSV gene wherein the codons are altered to be different from those naturally occurring even though the RSV produces a polypeptide with an identical amino acid sequence to those naturally expressed. Different strains of RSV will have different nucleotide sequences and express proteins with different amino acid sequences that have similar functions. Thus, a chimeric RSV includes an RSV gene wherein one or more genes from one strain are replaced from genes in alternative or second strain such that the nucleic acid sequence of the entire RSV genome is not identical to an RSV found in nature. In certain embodiments, the chimeric RSV includes those strains where nucleic acids are deleted after a codon for starting translation in order to truncate the proteins expression, provided such truncation pattern for the genome is not found in naturally occurring RSV. In certain embodiments, the chimeric RSV includes those which are infectious and can replicate in a human subject.

The term "fusion" when used in reference to a polypeptide refers to the expression product of two or more coding sequences obtained from different sources such that they do not exist together in a natural environment, that have been cloned together and that, after translation, act as a single polypeptide sequence. Fusion polypeptides are also referred to as "hybrid" polypeptides. The coding sequences include those obtained from the same or from different species of organisms.

However, this type of fusion protein is not the same as the RSV fusion protein in the disclosed vaccines. The RSV fusion protein (F) is a major surface glycoprotein that causes the virion membrane to fuse to the target cell membrane. The fusion protein exists in a metastable pre- fusion conformation that subsequently undergoes major refolding into a stable post-fusion form that approximates virion and target cell membranes and enables fusion. The F protein is highly conserved among RSV strains and is a potent RSV immunogen. After natural infection in humans, the majority of anti-RSV neutralizing antibodies are directed against the F protein, specifically against the pre-fusion conformation of F.

The term "homolog" or "homologous" when used in reference to a polypeptide refers to a high degree of sequence identity between two polypeptides, or to a high degree of similarity between the three-dimensional structure or to a high degree of similarity between the active site and the mechanism of action. In a preferred embodiment, a homolog has a greater than 60% sequence identity, and more preferably greater than 75% sequence identity, and still more preferably greater than 90% sequence identity, with a reference sequence. As applied to polypeptides, the term "substantial identity" means that two peptide sequences, when optimally aligned, such as by the programs GAP or BESTFIT using default gap weights, share at least 80 percent sequence identity, preferably at least 90 percent sequence identity, more preferably at least 95 percent sequence identity or more (e.g., 99 percent sequence identity). Preferably, residue positions which are not identical differ by conservative amino acid substitutions.

The terms "variant" and "mutant" when used in reference to a polypeptide refer to an amino acid sequence that differs by one or more amino acids from another, usually related polypeptide. The variant may have "conservative" changes, wherein a substituted amino acid has similar structural or chemical properties. One type of conservative amino acid substitutions refers to the interchangeability of residues having similar side chains. For example, a group of amino acids having aliphatic side chains is glycine, alanine, valine, leucine, and isoleucine; a group of amino acids having aliphatic-hydroxyl side chains is serine and threonine; a group of amino acids having amide-containing side chains is asparagine and glutamine; a group of amino acids having aromatic side chains is phenylalanine, tyrosine, and tryptophan; a group of amino acids having basic side chains is lysine, arginine, and histidine; and a group of amino acids having sulfur-containing side chains is cysteine and methionine. Preferred conservative amino acids substitution groups are: valine-leucine-isoleucine, phenylalanine-tyrosine, lysine-arginine, alanine-valine, and asparagine- glutamine. More rarely, a variant may have "non-conservative" changes (e.g., replacement of a glycine with a tryptophan). Similar minor variations may also include amino acid deletions or insertions (in other words, additions), or both. Guidance in determining which and how many amino acid residues may be substituted, inserted or deleted without abolishing biological activity may be found using computer programs well known in the art, for example, DNAStar software. Variants can be tested in functional assays. Preferred variants have less than 10%, and preferably less than 5%, and still more preferably less than 2% changes (whether substitutions, deletions, and so on).

The term "gene" refers to a nucleic acid (e.g., DNA or RNA) sequence that comprises coding sequences necessary for the production of an RNA, or a polypeptide or its precursor (e.g., proinsulin). A functional polypeptide can be encoded by a full length coding sequence or by any portion of the coding sequence as long as the desired activity or functional properties (e.g., enzymatic activity, ligand binding, signal transduction, etc.) of the polypeptide are retained. The term "portion" when used in reference to a gene refers to fragments of that gene. The fragments may range in size from a few nucleotides to the entire gene sequence minus one nucleotide. Thus, "a nucleotide comprising at least a portion of a gene" may comprise fragments of the gene or the entire gene.

The term "gene" also encompasses the coding regions of a structural gene and includes sequences located adjacent to the coding region on both the 5' and 3' ends for a distance of about 1 kb on either end such that the gene corresponds to the length of the full-length mRNA. The sequences which are located 5' of the coding region and which are present on the mRNA are referred to as 5' non-translated sequences. The sequences which are located 3' or downstream of the coding region and which are present on the mRNA are referred to as 3' non -translated sequences. The term "gene" encompasses both cDNA and genomic forms of a gene. A genomic form or clone of a gene contains the coding region interrupted with non-coding sequences termed "introns" or "intervening regions" or "intervening sequences." Introns are segments of a gene which are transcribed into nuclear RNA (mRNA); introns may contain regulatory elements such as enhancers. Introns are removed or "spliced out" from the nuclear or primary transcript; introns therefore are absent in the messenger RNA (mRNA) transcript. The mRNA functions during translation to specify the sequence or order of amino acids in a nascent polypeptide.

In addition to containing introns, genomic forms of a gene may also include sequences located on both the 5' and 3' end of the sequences which are present on the RNA transcript. These sequences are referred to as "flanking" sequences or regions (these flanking sequences are located 5' or 3' to the non-translated sequences present on the mRNA transcript). The 5' flanking region may contain regulatory sequences such as promoters and enhancers which control or influence the transcription of the gene. The 3' flanking region may contain sequences which direct the termination of transcription, posttranscriptional cleavage and polyadenylation.

The term "heterologous gene" refers to a gene encoding a factor that is not in its natural environment (i.e., has been altered by the hand of man). For example, a heterologous gene includes a gene from one species introduced into another species. A heterologous gene also includes a gene native to an organism that has been altered in some way (e.g., mutated, added in multiple copies, linked to a non-native promoter or enhancer sequence, etc.). Heterologous genes are distinguished from endogenous plant genes in that the heterologous gene sequences are typically joined to nucleotide sequences comprising regulatory elements such as promoters that are not found naturally associated with the gene for the protein encoded by the heterologous gene or with plant gene sequences in the chromosome, or are associated with portions of the chromosome not found in nature (e.g., genes expressed in loci where the gene is not normally expressed).

The term "polynucleotide" refers to a molecule comprised of two or more deoxyribonucleotides or ribonucleotides, preferably more than three, and usually more than ten. The exact size will depend on many factors, which in turn depends on the ultimate function or use of the oligonucleotide. The polynucleotide may be generated in any manner, including chemical synthesis, DNA replication, reverse transcription, or a combination thereof. The term "oligonucleotide" generally refers to a short length of single-stranded polynucleotide chain usually less than 30 nucleotides long, although it may also be used interchangeably with the term "polynucleotide."

The term "nucleic acid" refers to a polymer of nucleotides, or a polynucleotide, as described above. The term is used to designate a single molecule, or a collection of molecules. Nucleic acids may be single stranded or double stranded, and may include coding regions and regions of various control elements, as described below.

The term "a polynucleotide having a nucleotide sequence encoding a gene" or "a polynucleotide having a nucleotide sequence encoding a gene" or "a nucleic acid sequence encoding" a specified polypeptide refers to a nucleic acid sequence comprising the coding region of a gene or in other words the nucleic acid sequence which encodes a gene product. The coding region may be present in either a cDNA, genomic DNA or RNA form. When present in a DNA form, the oligonucleotide, polynucleotide, or nucleic acid may be single-stranded (i.e., the sense strand) or double-stranded. Suitable control elements such as enhancers/promoters, splice junctions, polyadenylation signals, etc. may be placed in close proximity to the coding region of the gene if needed to permit proper initiation of transcription and/or correct processing of the primary RNA transcript. Alternatively, the coding region utilized in the expression vectors of the present disclosure may contain endogenous enhancers/promoters, splice junctions, intervening sequences, polyadenylation signals, etc. or a combination of both endogenous and exogenous control elements.

The term "recombinant" when made in reference to a nucleic acid molecule refers to a nucleic acid molecule which is comprised of segments of nucleic acid joined together by means of molecular biological techniques. The term "recombinant" when made in reference to a protein or a polypeptide refers to a protein molecule which is expressed using a recombinant nucleic acid molecule.

The terms "complementary" and "complementarity" refer to polynucleotides (i.e., a sequence of nucleotides) related by the base-pairing rules. For example, for the sequence "A-G- T," is complementary to the sequence "T-C-A." Complementarity may be "partial," in which only some of the nucleic acids' bases are matched according to the base pairing rules. Or, there may be "complete" or "total" complementarity between the nucleic acids. The degree of complementarity between nucleic acid strands has significant effects on the efficiency and strength of hybridization between nucleic acid strands. This is of particular importance in amplification reactions, as well as detection methods which depend upon binding between nucleic acids.

The term "homology" when used in relation to nucleic acids refers to a degree of complementarity. There may be partial homology or complete homology (i.e., identity). "Sequence identity" refers to a measure of relatedness between two or more nucleic acids or proteins, and is given as a percentage with reference to the total comparison length. The identity calculation takes into account those nucleotide or amino acid residues that are identical and in the same relative positions in their respective larger sequences. Calculations of identity may be performed by algorithms contained within computer programs such as "GAP" (Genetics Computer Group, Madison, Wis.) and "ALIGN" (DNAStar, Madison, Wis.). A partially complementary sequence is one that at least partially inhibits (or competes with) a completely complementary sequence from hybridizing to a target nucleic acid is referred to using the functional term "substantially homologous." The inhibition of hybridization of the completely complementary sequence to the target sequence may be examined using a hybridization assay (Southern or Northern blot, solution hybridization and the like) under conditions of low stringency. A substantially homologous sequence or probe will compete for and inhibit the binding (i.e., the hybridization) of a sequence which is completely homologous to a target under conditions of low stringency. This is not to say that conditions of low stringency are such that non-specific binding is permitted; low stringency conditions require that the binding of two sequences to one another be a specific (i.e., selective) interaction. The absence of non-specific binding may be tested by the use of a second target which lacks even a partial degree of complementarity (e.g., less than about 30% identity); in the absence of non-specific binding the probe will not hybridize to the second non-complementary target. The following terms are used to describe the sequence relationships between two or more polynucleotides: "reference sequence", "sequence identity", "percentage of sequence identity", and "substantial identity". A "reference sequence" is a defined sequence used as a basis for a sequence comparison; a reference sequence may be a subset of a larger sequence, for example, as a segment of a full-length cDNA sequence given in a sequence listing or may comprise a complete gene sequence. Generally, a reference sequence is at least 20 nucleotides in length, frequently at least 25 nucleotides in length, and often at least 50 nucleotides in length. Since two polynucleotides may each (1) comprise a sequence (i.e., a portion of the complete polynucleotide sequence) that is similar between the two polynucleotides, and (2) may further comprise a sequence that is divergent between the two polynucleotides, sequence comparisons between two (or more) polynucleotides are typically performed by comparing sequences of the two polynucleotides over a "comparison window" to identify and compare local regions of sequence similarity. A "comparison window", as used herein, refers to a conceptual segment of at least 20 contiguous nucleotide positions wherein a polynucleotide sequence may be compared to a reference sequence of at least 20 contiguous nucleotides and wherein the portion of the polynucleotide sequence in the comparison window may comprise additions or deletions (i.e., gaps) of 20 percent or less as compared to the reference sequence (which does not comprise additions or deletions) for optimal alignment of the two sequences. Optimal alignment of sequences for aligning a comparison window may be conducted by the local homology algorithm of Smith and Waterman (Smith and Waterman, Adv. Appl. Math. 2: 482 (1981)) by the homology alignment algorithm of Needleman and Wunsch (Needleman and Wunsch, J. Mol. Biol. 48:443 (1970)), by the search for similarity method of Pearson and Lipman (Pearson and Lipman, Proc. Natl. Acad. Sci. (U.S.) 85:2444 (1988)), by computerized implementations of these algorithms (GAP, BESTFIT, FASTA, and TFASTA in the Wisconsin Genetics Software Package Release 7.0, Genetics Computer Group, 575 Science Dr., Madison, Wis.), or by inspection, and the best alignment (i.e., resulting in the highest percentage of homology over the comparison window) generated by the various methods is selected. The term "sequence identity" means that two polynucleotide sequences are identical (i.e., on a nucleotide- by-nucleotide basis) over the window of comparison.

In certain embodiments, term "percentage of sequence identity" is calculated by comparing two optimally aligned sequences over the window of comparison, determining the number of positions at which the identical nucleic acid base (e.g., A, T, C, G, U, or I) occurs in both sequences to yield the number of matched positions, dividing the number of matched positions by the total number of positions in the window of comparison (i.e., the window size), and multiplying the result by 100 to yield the percentage of sequence identity.

In certain embodiments, sequence "identity" refers to the number of exactly matching amino acids (expressed as a percentage) in a sequence alignment between two sequences of the alignment calculated using the number of identical positions divided by the greater of the shortest sequence or the number of equivalent positions excluding overhangs wherein internal gaps are counted as an equivalent position. For example, the polypeptides GGGGGG and GGGGT have a sequence identity of 4 out of 5 or 80%. For example, the polypeptides GGGPPP and GGGAPPP have a sequence identity of 6 out of 7 or 85%. In certain embodiments, any recitation of sequence identity expressed herein may be substituted for sequence similarity. Percent "similarity" is used to quantify the similarity between two sequences of the alignment. This method is identical to determining the identity except that certain amino acids do not have to be identical to have a match. Amino acids are classified as matches if they are among a group with similar properties according to the following amino acid groups: Aromatic - F Y W; hydrophobic-A V I L; Charged positive: R K H; Charged negative - D E; Polar - S T N Q.

The terms "substantial identity" as used herein denotes a characteristic of a polynucleotide sequence, wherein the polynucleotide comprises a sequence that has at least 85 percent sequence identity, preferably at least 90 to 95 percent sequence identity, more usually at least 99 percent sequence identity as compared to a reference sequence over a comparison window of at least 20 nucleotide positions, frequently over a window of at least 25-50 nucleotides, wherein the percentage of sequence identity is calculated by comparing the reference sequence to the polynucleotide sequence which may include deletions or additions which total 20 percent or less of the reference sequence over the window of comparison. The reference sequence may be a subset of a larger sequence, for example, as a segment of the full-length sequences of the compositions claimed in the present disclosure.

When used in reference to a double-stranded nucleic acid sequence such as a cDNA or genomic clone, the term "substantially homologous" refers to any probe that can hybridize to either or both strands of the double-stranded nucleic acid sequence under conditions of low to high stringency as described above. When used in reference to a single-stranded nucleic acid sequence, the term "substantially homologous" refers to any probe that can hybridize (i.e., it is the complement of) the single- stranded nucleic acid sequence under conditions of low to high stringency as described above.

The terms "in operable combination", "in operable order" and "operably linked" refer to the linkage of nucleic acid sequences in such a manner that a nucleic acid molecule capable of directing the transcription of a given gene and/or the synthesis of a desired protein molecule is produced. The term also refers to the linkage of amino acid sequences in such a manner so that a functional protein is produced.

The term "regulatory element" refers to a genetic element which controls some aspect of the expression of nucleic acid sequences. For example, a promoter is a regulatory element which facilitates the initiation of transcription of an operably linked coding region. Other regulatory elements are splicing signals, polyadenylation signals, termination signals, etc.

Transcriptional control signals in eukaryotes comprise "promoter" and "enhancer" elements. Promoters and enhancers consist of short arrays of DNA sequences that interact specifically with cellular proteins involved in transcription (Maniatis, et al., Science 236: 1237, 1987). Promoter and enhancer elements have been isolated from a variety of eukaryotic sources including genes in yeast, insect, mammalian and plant cells. Promoter and enhancer elements have also been isolated from viruses and are found in prokaryotes. The selection of a particular promoter and enhancer depends on the cell type used to express the protein of interest. Some eukaryotic promoters and enhancers have a broad host range while others are functional in a limited subset of cell types (for review, see Voss, et al., Trends Biochem. Sci., 11 :287, 1986; and Maniatis, et al., supra 1987).

The terms "promoter element," "promoter," or "promoter sequence" as used herein, refer to a DNA sequence that is located at the 5' end (i.e. precedes) the protein coding region of a DNA polymer. The location of most promoters known in nature precedes the transcribed region. The promoter functions as a switch, activating the expression of a gene. If the gene is activated, it is said to be transcribed, or participating in transcription. Transcription involves the synthesis of mRNA from the gene. The promoter, therefore, serves as a transcriptional regulatory element and also provides a site for initiation of transcription of the gene into mRNA.

Promoters may be tissue specific or cell specific. The term "tissue specific" as it applies to a promoter refers to a promoter that is capable of directing selective expression of a nucleotide sequence of interest to a specific type of tissue (e.g., seeds) in the relative absence of expression of the same nucleotide sequence of interest in a different type of tissue (e.g., leaves). Tissue specificity of a promoter may be evaluated by, for example, operably linking a reporter gene to the promoter sequence to generate a reporter construct, introducing the reporter construct into the genome of a plant such that the reporter construct is integrated into every tissue of the resulting transgenic plant, and detecting the expression of the reporter gene (e.g., detecting mRNA, protein, or the activity of a protein encoded by the reporter gene) in different tissues of the transgenic plant. The detection of a greater level of expression of the reporter gene in one or more tissues relative to the level of expression of the reporter gene in other tissues shows that the promoter is specific for the tissues in which greater levels of expression are detected. The term "cell type specific" as applied to a promoter refers to a promoter which is capable of directing selective expression of a nucleotide sequence of interest in a specific type of cell in the relative absence of expression of the same nucleotide sequence of interest in a different type of cell within the same tissue. The term "cell type specific" when applied to a promoter also means a promoter capable of promoting selective expression of a nucleotide sequence of interest in a region within a single tissue. Cell type specificity of a promoter may be assessed using methods well known in the art, e.g., immunohistochemical staining. Briefly, tissue sections are embedded in paraffin, and paraffin sections are reacted with a primary antibody which is specific for the polypeptide product encoded by the nucleotide sequence of interest whose expression is controlled by the promoter. A labeled (e.g., peroxidase conjugated) secondary antibody which is specific for the primary antibody is allowed to bind to the sectioned tissue and specific binding detected (e.g., with avidin/biotin) by microscopy.

Promoters may be constitutive or regulatable. The term "constitutive" when made in reference to a promoter means that the promoter is capable of directing transcription of an operably linked nucleic acid sequence in the absence of a stimulus (e.g., heat shock, chemicals, light, etc.). Typically, constitutive promoters are capable of directing expression of a transgene in substantially any cell and any tissue.

In contrast, a "regulatable" or "inducible" promoter is one which is capable of directing a level of transcription of an operably linked nucleic acid sequence in the presence of a stimulus (e.g., heat shock, chemicals, light, etc.) which is different from the level of transcription of the operably linked nucleic acid sequence in the absence of the stimulus. The enhancer and/or promoter may be "endogenous" or "exogenous" or "heterologous." An "endogenous" enhancer or promoter is one that is naturally linked with a given gene in the genome. An "exogenous" or "heterologous" enhancer or promoter is one that is placed in juxtaposition to a gene by means of genetic manipulation (i.e., molecular biological techniques) such that transcription of the gene is directed by the linked enhancer or promoter. For example, an endogenous promoter in operable combination with a first gene can be isolated, removed, and placed in operable combination with a second gene, thereby making it a "heterologous promoter" in operable combination with the second gene. A variety of such combinations are contemplated (e.g., the first and second genes can be from the same species, or from different species).

Efficient expression of recombinant DNA sequences in eukaryotic cells typically requires expression of signals directing the efficient termination and polyadenylation of the resulting transcript. Transcription termination signals are generally found downstream of the polyadenylation signal and are a few hundred nucleotides in length. The term "poly(A) site" or "poly(A) sequence" as used herein denotes a DNA sequence which directs both the termination and polyadenylation of the nascent RNA transcript. Efficient polyadenylation of the recombinant transcript is desirable, as transcripts lacking a poly(A) tail are unstable and are rapidly degraded. The poly(A) signal utilized in an expression vector may be "heterologous" or "endogenous." An endogenous poly(A) signal is found naturally at the 3' end of the coding region of a given gene in the genome. A heterologous poly(A) signal is one which has been isolated from one gene and positioned 3' to another gene. A commonly used heterologous poly(A) signal is the SV40 poly(A) signal. The SV40 poly(A) signal is contained on a 237 bp BamHI/BclI restriction fragment and directs both termination and polyadenylation.

The term "vector" refers to nucleic acid molecules that transfer DNA segment(s) from one cell to another. The term "vehicle" is sometimes used interchangeably with "vector."

The terms "expression vector" or "expression cassette" refer to a recombinant nucleic acid containing a desired coding sequence and appropriate nucleic acid sequences used for the expression of the operably linked coding sequence in a particular host organism. Nucleic acid sequences used for expression in prokaryotes typically include a promoter, an operator (optional), and a ribosome binding site, often along with other sequences. Eukaryotic cells are known to utilize promoters, enhancers, and termination and polyadenylation signals. The term "host cell" refers to any cell capable of replicating and/or transcribing and/or translating a heterologous gene. Thus, a "host cell" refers to any eukaryotic or prokaryotic cell (e.g., bacterial cells such as E. coli, yeast cells, mammalian cells, avian cells, amphibian cells, plant cells, fish cells, and insect cells), whether located in vitro or in vivo. For example, host cells may be located in a transgenic animal.

A "selectable marker" is a nucleic acid introduced into a recombinant vector that encodes a polypeptide that confers a trait suitable for artificial selection or identification (report gene), e.g., beta-lactamase confers antibiotic resistance, which allows an organism expressing beta-lactamase to survive in the presence antibiotic in a growth medium. Another example is thymidine kinase, which makes the host sensitive to ganciclovir selection. It may be a screenable marker that allows one to distinguish between wanted and unwanted cells based on the presence or absence of an expected color. For example, the lac-z-gene produces a beta-galactosidase enzyme which confers a blue color in the presence of X-gal (5-bromo-4-chloro-3-indolyl-P-D-galactoside). If recombinant insertion inactivates the lac-z-gene, then the resulting colonies are colorless. There may be one or more selectable markers, e.g., an enzyme that can complement to the inability of an expression organism to synthesize a particular compound required for its growth (auxotrophic) and one able to convert a compound to another that is toxic for growth. URA3, an orotidine-5' phosphate decarboxylase, is necessary for uracil biosynthesis and can complement ura3 mutants that are auxotrophic for uracil. URA3 also converts 5-fluoroorotic acid into the toxic compound 5-fluorouracil. Additional contemplated selectable markers include any genes that impart antibacterial resistance or express a fluorescent protein. Examples include, but are not limited to, the following genes: ampr, camr, tetr, blasticidinr, neor, hygr, abxr, neomycin phosphotransferase type II gene (nptll), p-glucuronidase (gus), green fluorescent protein (gfp), egfp, yfp, mCherry, p- galactosidase (lacZ), lacZa, lacZAM15, chloramphenicol acetyltransferase (cat), alkaline phosphatase (phoA), bacterial luciferase (luxAB), bialaphos resistance gene (bar), phosphomannose isomerase (pmi), xylose isomerase (xylA), arabitol dehydrogenase (atlD), UDP- glucose:galactose-l -phosphate uridyltransferasel (galT), feedback-insensitive a subunit of anthranilate synthase (OASA1D), 2-deoxy glucose (2-DOGR), benzyladenine-N-3-glucuronide, E. coli threonine deaminase, glutamate 1-semialdehyde aminotransferase (GSA-AT), D-amino acidoxidase (DAAO), salt-tolerance gene (rstB), ferredoxin-like protein (pflp), trehalose-6-P synthase gene (AtTPSl), lysine racemase (lyr), dihydrodipicolinate synthase (dapA), tryptophan synthase beta 1 (AtTSB l), dehalogenase (dhlA), mannose-6-phosphate reductase gene (M6PR), hygromycin phosphotransferase (HPT), and D-serine ammonialyase (dsdA).

A "label" refers to a detectable compound or composition that is conjugated directly or indirectly to another molecule, such as an antibody or a protein, to facilitate detection of that molecule. Specific, non-limiting examples of labels include fluorescent tags, enzymatic linkages, and radioactive isotopes. In one example, a "label receptor" refers to incorporation of a heterologous polypeptide in the receptor. A label includes the incorporation of a radiolabeled amino acid or the covalent attachment of biotinyl moieties to a polypeptide that can be detected by marked avidin (for example, streptavidin containing a fluorescent marker or enzymatic activity that can be detected by optical or colorimetric methods). Various methods of labeling polypeptides and glycoproteins are known in the art and may be used. Examples of labels for polypeptides include, but are not limited to, the following: radioisotopes or radionucleotides (such as ³⁵ S or ¹³¹ I) fluorescent labels (such as fluorescein isothiocyanate (FITC), rhodamine, lanthanide phosphors), enzymatic labels (such as horseradish peroxidase, beta-galactosidase, luciferase, alkaline phosphatase), chemiluminescent markers, biotinyl groups, predetermined polypeptide epitopes recognized by a secondary reporter (such as a leucine zipper pair sequences, binding sites for secondary antibodies, metal binding domains, epitope tags), or magnetic agents, such as gadolinium chelates. In some embodiments, labels are attached by spacer arms of various lengths to reduce potential steric hindrance.

In certain embodiments, the disclosure relates to recombinant polypeptides comprising sequences disclosed herein or variants or fusions thereof wherein the amino terminal end or the carbon terminal end of the amino acid sequence are optionally attached to a heterologous amino acid sequence, label, or reporter molecule.

In certain embodiments, the disclosure relates to the recombinant vectors comprising a nucleic acid encoding a polypeptide disclosed herein or fusion protein thereof.

In certain embodiments, the recombinant vector optionally comprises a mammalian, human, insect, viral, bacterial, bacterial plasmid, yeast associated origin of replication or gene such as a gene or retroviral gene or lentiviral LTR, TAR, RRE, PE, SLIP, CRS, and INS nucleotide segment or gene selected from tat, rev, nef, vif, vpr, vpu, and vpx or structural genes selected from gag, pol, and env. In certain embodiments, the recombinant vector optionally comprises a gene vector element (nucleic acid) such as a selectable marker region, lac operon, a CMV promoter, a hybrid chicken B-actin/CMV enhancer (CAG) promoter, tac promoter, T7 RNA polymerase promoter, SP6 RNA polymerase promoter, SV40 promoter, internal ribosome entry site (IRES) sequence, cis-acting woodchuck post regulatory regulatory element (WPRE), scaffold-attachment region (SAR), inverted terminal repeats (ITR), FLAG tag coding region, c-myc tag coding region, metal affinity tag coding region, streptavidin binding peptide tag coding region, polyHis tag coding region, HA tag coding region, MBP tag coding region, GST tag coding region, polyadenylation coding region, SV40 polyadenylation signal, SV40 origin of replication, Col El origin of replication, fl origin, pBR322 origin, or pUC origin, TEV protease recognition site, loxP site, Cre recombinase coding region, or a multiple cloning site such as having 5, 6, or 7 or more restriction sites within a continuous segment of less than 50 or 60 nucleotides or having 3 or 4 or more restriction sites with a continuous segment of less than 20 or 30 nucleotides.

The term "reporter gene" refers to a gene encoding a protein that may be assayed. Examples of reporter genes include, but are not limited to, modified katushka, mkate and mkate2 (See, e.g., Merzlyak et al., Nat. Methods, 2007, 4, 555-557 and Shcherbo et al., Biochem. J., 2008, 418, 567- 574), luciferase (See, e.g., deWet et al., Mol. Cell. Biol. 7:725 (1987) and U.S. PatNos., 6,074,859; 5,976,796; 5,674,713; and 5,618,682; all of which are incorporated herein by reference), green fluorescent protein (e.g., GenBank Accession Number U43284; a number of GFP variants are commercially available from ClonTech Laboratories, Palo Alto, Calif), chloramphenicol acetyltransferase, beta-galactosidase, alkaline phosphatase, and horse radish peroxidase.

The term "wild-type" when made in reference to a gene refers to a gene which has the characteristics of a gene isolated from a naturally occurring source. The term "wild-type" when made in reference to a gene product refers to a gene product which has the characteristics of a gene product isolated from a naturally occurring source. The term "naturally-occurring" as used herein as applied to an object refers to the fact that an object can be found in nature. For example, a polypeptide or polynucleotide sequence that is present in an organism (including viruses) that can be isolated from a source in nature and which has not been intentionally modified by man in the laboratory is naturally-occurring. A wild-type gene is that which is most frequently observed in a population and is thus arbitrarily designated the "normal" or "wild-type" form of the gene. In contrast, the term "modified" or "mutant" when made in reference to a gene or to a gene product refers, respectively, to a gene or to a gene product which displays modifications in sequence and/or functional properties (i.e., altered characteristics) when compared to the wild-type gene or gene product. It is noted that naturally-occurring mutants can be isolated; these are identified by the fact that they have altered characteristics when compared to the wild-type gene or gene product.

The term "antisense" or "antigenome" refers to a nucleotide sequence whose sequence of nucleotide residues is in reverse 5' to 3' orientation in relation to the sequence of nucleotide residues in a sense strand. A "sense strand" of a DNA duplex refers to a strand in a DNA duplex which is transcribed by a cell in its natural state into a "sense mRNA." Thus an "antisense" sequence is a sequence having the same sequence as the non-coding strand in a DNA duplex.

The term "isolated" refers to a biological material, such as a virus, a nucleic acid or a protein, which is substantially free from components that normally accompany or interact with it in its naturally occurring environment. The isolated material optionally comprises material not found with the material in its natural environment, e.g., a cell. For example, if the material is in its natural environment, such as a cell, the material has been placed at a location in the cell (e.g., genome or genetic element) not native to a material found in that environment. For example, a naturally occurring nucleic acid (e.g., a coding sequence, a promoter, an enhancer, etc.) becomes isolated if it is introduced by non-naturally occurring means to a locus of the genome (e.g., a vector, such as a plasmid or virus vector, or amplicon) not native to that nucleic acid. Such nucleic acids are also referred to as "heterologous" nucleic acids. An isolated virus, for example, is in an environment (e.g., a cell culture system, or purified from cell culture) other than the native environment of wild-type virus (e.g., the nasopharynx of an infected individual).

An "immunologically effective amount" of RSV is an amount sufficient to enhance an individual's (e.g., a human's) own immune response against a subsequent exposure to RSV. Levels of induced immunity can be monitored, e.g., by measuring amounts of neutralizing secretory and/or serum antibodies, e.g., by plaque neutralization, complement fixation, enzyme-linked immunosorbent, or microneutralization assay.

A "protective immune response" against RSV refers to an immune response exhibited by an individual (e.g., a human) that is protective against serious lower respiratory tract disease (e.g., pneumonia and/or bronchiolitis) when the individual is subsequently exposed to and/or infected with wild-type RSV. Chimeric respiratory syncytial virus (RSV)

Naturally occurring RSV particles typically contain a viral genome within a helical nucleocapsid which is surrounded by matrix proteins and an envelope containing glycoproteins. The genome of human wild-type RSVs encode the proteins, NS1, NS2, N, P, M, SH, G, F, M2-1, M2-2, and L. G, F, and SH are glycoproteins. RSV polymerase activity consists of the large protein (L) and phosphoprotein (P). The viral M2-1 protein is used during transcription and is likely to be a component of the transcriptase complex. The viral N protein is used to encapsidate the nascent RNA during replication.

The genome is transcribed and replicated in the cytoplasm of a host cell. Host-cell transcription typically results in synthesis of ten methylated and polyadenylated mRNAs. The antigenome is positive-sense RNA complement of the genome produced during replication, which in turn acts as a template for genome synthesis. The viral genes are flanked by conserved gene- start (GS) and gene-end (GE) sequences. At the 3' and 5' ends of the genome are leader and trailer nucleotides. The wild type leader sequence contains a promoter at the 3' end. When the viral polymerase reaches a GE signal, the polymerase polyadenylates and releases the mRNA and reinitiates RNA synthesis at the next GS signal. The L-P complex is believed to be responsible for recognition of the promoter, RNA synthesis, capping and methylation of the 5' termini of the mRNAs and polyadenylation of their 3' ends. It is believed that the polymerase sometimes dissociates from the gene at the junctions. Because the polymerase initiates transcription at the 3' end of the genome, this results in a gradient of expression, with the genes at the 3' end of the genome being transcribed more frequently than those at the 5' end.

To replicate the genome, the polymerase does not respond to the cis-acting GE and GS signals and generates positive-sense RNA complement of the genome, the antigenome. At the 3' end of the antigenome is the complement of the trailer, which contains a promoter. The polymerase uses this promoter to generate genome-sense RNA. Unlike mRNA, which is released as naked RNA, the antigenome and genome RNAs are encapsidated with virus nucleoprotein (N) as they are synthesized.

After translation of viral mRNAs, a full-length (+) antigenomic RNA is produced as a template for replication of the (-) RNA genome. Infectious recombinant RSV (rRSV) particles may be recovered from transfected plasmids. Co-expression of RSV N, P, L, and M2-1 proteins as well as the full-length antigenomic RNA is sufficient for RSV replication. See Collins et al., Proc Natl Acad Sci U S A., 1995, 92(25): 11563-11567 and U.S. Patent No. 6,790,449.

In certain embodiments, the disclosure relates to certain desirable sequence of RSV F polypeptides and recombinant nucleic acids encoding the same. In certain embodiments, the disclosure contemplates recombinant vectors comprising nucleic acids encoding these polypeptides and cells comprising said vectors. In certain embodiments, the vector comprises a selectable marker or reporter gene.

Common vectors for storing RSV include plasmids and bacterial artificial chromosomes (BAC). Typically, a bacterial artificial chromosome comprises one or more genes selected from the group consisting of oriS, repE, parA, and parB genes of Factor F in operable combination with a selectable marker, e.g., a gene that provides resistance to an antibiotic. The nucleic acid sequence may be the genomic or antigenomic sequence of the virus which is optionally mutated, e.g., RSV strain which is optionally mutated.

Cultivating RSV in E. coli bacteria may be accomplished by utilizing a bacterial artificial chromosome (BAC). A BAC vector for storing and genetically engineering RSV is reported in Stobart et al., Methods Mol Biol., 2016, 1442: 141-53 and U.S. Patent Application Publication number 2012/0264217. The disclosed BAC contains the complete antigenomic sequence of respiratory syncytial virus (RSV) strain A2 except the F gene, which is the antigenomic sequence of RSV strain line 19. Along with helper plasmids, it can be used in the reverse genetics system for the recovery of infectious virus. The antigenome sequence on the plasmid can be mutated prior to virus recovery to generate viruses with desired mutations.

In certain embodiments, the disclosure relates to methods of generating respiratory syncytial virus (RSV) particles comprising inserting a vector with a BAC gene and a RSV antigenome into an isolated eukaryotic cell and inserting one or more vectors selected from the group consisting of: a vector encoding an N protein of RSV, a vector encoding a P protein of RSV, a vector encoding an L protein of RSV, and a vector encoding an M2-1 protein of RSV into the cell under conditions such that RSV virion is formed. Inserting a vector into a cell may occur by physically injecting, electroporating, or mixing the cell and the vector under conditions such that the vector enters the cell.

Chimeric RSV is contemplated to include certain mutations, deletions, or variant combinations, such as cold-passaged (cp) non-temperature sensitive (ts) derivatives of RSV, cpRSV, such as rA2cp248/404/1030ASH. rA2cp248/404ASH contains 4 independent attenuating genetic elements: cp which is based on 5 missense mutations in the N and L proteins and the F glycoprotein that together confer the non-ts attenuation phenotype of cpRSV; ts248, a missense mutation in the L protein; ts404, a nucleotide substitution in the gene-start transcription signal of the M2 gene; and ASH, complete deletion of the SH gene. rA2cp248/404/1030ASH contains 5 independent attenuating genetic elements: those present in rA2cp248/404ASH and tsl030, another missense mutation in the L protein. See Karron et al., J Infect Dis., 2005, 191(7): 1093-1104, hereby incorporated by reference. Within certain embodiments, it is contemplated that the RSV anitgenome may contain deletion or mutations in nonessential genes (e.g., the SH, NS1, NS2, and M2-2 genes) or combinations thereof.

Due to the redundancy of the genetic code, individual amino acids are encoded by multiple sequences of codons, sometimes referred to as synonymous codons. In different species, synonymous codons are used more or less frequently, sometimes referred to as codon bias. Genetic engineering of under-represented synonymous codons into the coding sequence of a gene has been shown to result in decreased rates of protein translation without a change in the amino acid sequence of the protein. Mueller et al. report virus attenuation by changes in codon bias. See, Science, 2008, 320: 1784. See also WO/2008121992, WO/2006042156, Burns et al., J Virology, 2006, 80(7):3259 and Mueller et al., J Virology, 2006, 80(19):9687.

Usage of codon deoptimization in RSV is reported in Meng, et al., MBio 5, e01704-01714 (2014) and U.S. Patent Application Publication number 2016/0030549. In certain embodiments, this disclosure relates to isolated nucleic acids, recombinant respiratory syncytial virus (RSV) with codon deoptimization, vaccines produced therefrom, and vaccination methods related thereto. In certain embodiments, the codon deoptimization is in the nonstructural genes NS1 and NS2 and optionally in a gene G and optionally in a gene L. In further embodiments, the gene SH is deleted. In further embodiments, the gene F is mutated, e.g., RSV F protein having an amino acid pattern of M at position 79, R at position 191, K at position 357, and Y at position 371, and a V at position 557.

In certain embodiments, the disclosure relates to isolated nucleic acids encoding deoptimized genes NS 1 and/or NS2 and optionally the gene G and optionally the gene L of a wild- type human RSV or variant wherein the nucleotides are substituted such that a codon to produce Gly is GGT, a codon to produce Asp is GAT, a codon to produce Glu is GAA, a codon to produce His is CAT, a codon to produce He is ATA, a codon to produce Lys is AAA, a codon to produce Leu is CTA, a codon to produce Asn is AAT, a codon to produce Gin is CAA, a codon to produce Val is GTA, or a codon to produce Tyr is TAT, or combinations thereof. In certain embodiments, a gene in the isolated nucleic acid further comprises a combination of at least two, three, four, five, six, seven, eight nine, ten, or all of the individual codons. In certain embodiment, a gene in the isolated nucleic acid comprises at least 20, 30, 40, or 50 or more of the codons.

In certain embodiments, this disclosure relates to isolated nucleic acid as disclosed herein wherein the nucleotides are substituted such that a codon to produce Ala is GCG, a codon to produce Cys is TGT, a codon to produce Phe is TTT, a codon to produce Pro is CCG, a codon to produce Arg is CGT, a codon to produce Ser is TCG, or a codon to produce Thr is ACG, or combinations thereof. In certain embodiments, a gene containing the nucleic acid comprises a combination of at least two, three, four, five, six, seven, eight nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, or all of the individual codons. In certain embodiments, a gene in the isolated nucleic acid further comprises at least 20, 30, 40, or 50 or more of the codons.

Glenn et al. report a randomized, blinded, controlled, dose-ranging study of a respiratory syncytial virus recombinant fusion (F) nanoparticle vaccine in healthy women of childbearing age. J Infect Dis. 2016, 213(3):411-22. In certain embodiments, this disclosure relates to virus particles and virus-like particles (VLPs) that contain a mutated F protein reported herein. Virus particles are commonly used as an inactivated vaccine (or killed vaccine). RSV can be grown in culture and then killed using a method such as heat or formaldehyde. Live attenuated vaccines are typically weakened such that rate of replication and/or infection is slower.

In certain embodiments, the disclosure contemplates a chimeric RSV particle as a whole virus vaccine, e.g., the entire virus particle exposed to heat, chemicals, or radiation such that the genome of the RSV is non-replicative or non-infectious. In certain embodiments, the disclosure contemplates a chimeric RSV particle in a split virus vaccine produced by using a detergent to disrupt the virus and by purifying out the mutated F proteins disclosed herein as antigens to stimulate the immune system to mount a response to the virus.

VLPs closely resemble mature virions, but they do not contain viral genomic material (i.e., viral genomic RNA). Therefore, VLPs are non-replicative in nature. In addition, VLPs can express proteins on the surface of the VLP. Moreover, since VLPs resemble intact virions and are multivalent particulate structures, VLPs can be effective in inducing neutralizing antibodies to the surface protein. VLPs can be administered repeatedly.

In certain embodiments, the disclosure contemplates VLP comprising a mutated F protein disclosed herein on the surface and an influenza virus matrix (Ml) protein core. Quan et al. report methods of producing virus-like particles (VLPs) made-up of an influenza virus matrix (Ml) protein core and RSV-F on the surface J Infect Dis. 2011, 204(7): 987-995. One can generate recombinant baculoviruses (rBVs) expressing RSV F and influenza Ml and transfect them into insect cells for production. Methods of use

In certain embodiments, the disclosure relates to immunogenic compositions comprising an immunologically effective amount of a chimeric respiratory syncytial virus (RSV), RSV polypeptide, RSV particle, RSV virus-like particle, and/or nucleic acid disclosed herein. In certain embodiments, the disclosure relates to methods for stimulating the immune system of an individual to produce a protective immune response against RSV. In certain embodiments, an immunologically effective amount of a chimeric RSV, polypeptide, and/or nucleic acid disclosed herein is administered to the individual in a physiologically acceptable carrier.

In certain embodiments, the disclosure relates to medicaments and vaccine products comprising nucleic acids disclosed herein for uses disclosed herein.

In certain embodiments, the disclosure relates to the use of nucleic acids or vectors disclosed herein for the manufacture of a medicament for uses disclosed herein.

The disclosure also provides the ability to analyze other types of attenuating mutations and to incorporate them into chimeric RSV for vaccine or other uses. For example, a tissue culture- adapted nonpathogenic strain of pneumonia virus of mice (the murine counterpart of RSV) lacks a cytoplasmic tail of the G protein (Randhawa et al., Virology 207: 240-245 (1995)). By analogy, the cytoplasmic and transmembrane domains of each of the RSV glycoproteins, F, G and SH, can be deleted or modified to achieve attenuation.

Other mutations for use in infectious RSV of the present disclosure include mutations in cis-acting signals identified during mutational analysis of RSV minigenomes. For example, insertional and deletional analysis of the leader and trailer and flanking sequences identified viral promoters and transcription signals and provided a series of mutations associated with varying degrees of reduction of RNA replication or transcription. Saturation mutagenesis (whereby each position in turn is modified to each of the nucleotide alternatives) of these cis-acting signals also has identified many mutations which reduced (or in one case increased) RNA replication or transcription. Any of these mutations can be inserted into the complete antigenome or genome as described herein. Other mutations involve replacement of the 3' end of genome with its counterpart from antigenome, which is associated with changes in RNA replication and transcription. In addition, the intergenic regions (Collins et al., Proc. Natl. Acad. Sci. USA 83 :4594-4598 (1986), incorporated herein by reference) can be shortened or lengthened or changed in sequence content, and the naturally-occurring gene overlap (Collins et al., Proc. Natl. Acad. Sci. USA 84:5134-5138 (1987), incorporated herein by reference) can be removed or changed to a different intergenic region by the methods described herein.

For vaccine use, virus produced according to the present disclosure can be used directly in vaccine formulations, or lyophilized, as desired, using lyophilization protocols well known to the artisan. Lyophilized virus will typically be maintained at about 4 degrees C. When ready for use the lyophilized virus is reconstituted in a stabilizing solution, e.g., saline or comprising SPG, Mg, and HEPES, with or without adjuvant, as further described below.

Typically, the RSV vaccines of the disclosure contain as an active ingredient an immunogenetically effective amount of RSV produced as described herein. The modified virus may be introduced into a subject with a physiologically acceptable carrier and/or adjuvant. Useful carriers are well known in the art, and include, e.g., water, buffered water, 0.4% saline, 0.3% glycine, hyaluronic acid and the like. The resulting aqueous solutions may be packaged for use as is, or lyophilized, the lyophilized preparation being combined with a sterile solution prior to administration, as mentioned above. The compositions may contain pharmaceutically acceptable auxiliary substances as required to approximate physiological conditions, such as pH adjusting and buffering agents, tonicity adjusting agents, wetting agents and the like, for example, sodium acetate, sodium lactate, sodium chloride, potassium chloride, calcium chloride, sorbitan monolaurate, triethanolamine oleate, and the like. Acceptable adjuvants include incomplete Freund's adjuvant, aluminum phosphate, aluminum hydroxide, or alum, which are materials well known in the art.

Upon immunization with a RSV composition as described herein, via aerosol, droplet, oral, topical or other route, the immune system of the subject responds to the vaccine by producing antibodies specific for RSV virus proteins, e.g., F glycoproteins. As a result of the vaccination the subject becomes at least partially or completely immune to RSV infection, or resistant to developing moderate or severe RSV infection, particularly of the lower respiratory tract.

The subject to which the vaccines are administered can be any mammal which is susceptible to infection by RSV or a closely related virus and which subject is capable of generating a protective immune response to the antigens of the vaccinating strain. Thus, suitable subjects include humans, non-human primates, bovine, equine, swine, ovine, caprine, lagamorph, rodents, etc. Accordingly, the disclosure provides methods for creating vaccines for a variety of human and veterinary uses.

The vaccine compositions containing the RSV of the disclosure are administered to a subject susceptible to or otherwise at risk of RSV infection to enhance the subject's own immune response capabilities. Such an amount is defined to be an "immunogenically effective dose." In this use, the precise amounts again depend on the subject's state of health and weight, the mode of administration, the nature of the formulation. The vaccine formulations should provide a quantity of modified RSV of the disclosure sufficient to effectively protect the subject patient against serious or life-threatening RSV infection.

The RSV produced in accordance with the present disclosure can be combined with viruses of the other subgroup or strains to achieve protection against multiple RSV subgroups or strains, or protective epitopes of these strains can be engineered into one virus as described herein. Typically, the different viruses will be in admixture and administered simultaneously, but may also be administered separately. For example, as the F glycoproteins of the two RSV subgroups differ by only about 11% in amino acid sequence, this similarity is the basis for a cross-protective immune response as observed in animals immunized with RSV or F antigen and challenged with a heterologous strain. Thus, immunization with one strain may protect against different strains of the same or different subgroup.

In some instances, it may be desirable to combine the RSV vaccines of the disclosure with vaccines which induce protective responses to other agents, particularly other childhood viruses. For example, the RSV vaccine of the present disclosure can be administered simultaneously with parainfluenza virus vaccine, such as described in Clements et al., J. Clin. Microbiol. 29: 1175-1182 (1991), incorporated herein by reference. In another aspect of the disclosure the RSV can be employed as a vector for protective antigens of other respiratory tract pathogens, such as parainfluenza, by incorporating the sequences encoding those protective antigens into the RSV genome or antigenome which is used to produce infectious RSV as described herein.

Single or multiple administrations of the vaccine compositions of the disclosure can be carried out. In neonates and infants, multiple, sequential administrations may be required to elicit sufficient levels of immunity. Administration may begin within the first month of life, or before, about two months of age, typically not later than six months of age, and at intervals throughout childhood, such as at two months, six months, one year and two years, as necessary to maintain sufficient levels of protection against native (wild-type) RSV infection. Similarly, adults who are particularly susceptible to repeated or serious RSV infection, such as, for example, health care workers, day care workers, family members of young children, the elderly (over 55, 60, or 65 years), or individuals with compromised cardiopulmonary function may require multiple immunizations to establish and/or maintain protective immune responses. Levels of induced immunity can be monitored by measuring amounts of neutralizing secretory and serum antibodies, and dosages adjusted or vaccinations repeated as necessary to maintain desired levels of protection. Further, different vaccine viruses may be advantageous for different recipient groups. For example, an engineered RSV strain expressing an additional protein rich in T cell epitopes may be particularly advantageous for adults rather than for infants.

In yet another aspect of the disclosure, RSV is employed as a vector for transient gene therapy of the respiratory tract. According to this embodiment, the recombinant RSV genome or antigenome incorporates a sequence which is capable of encoding a gene product of interest. The gene product of interest is under control of the same or a different promoter from that which controls RSV expression. The infectious RSV produced by coexpressing the recombinant RSV genome or antigenome with the N, P, L and M2 -1 proteins and containing a sequence encoding the gene product of interest is administered to a patient. Administration is typically by aerosol, nebulizer, or other topical application to the respiratory tract of the patient being treated. Recombinant RSV is administered in an amount sufficient to result in the expression of therapeutic or prophylactic levels of the desired gene product. Examples of representative gene products which are administered in this method include those which encode, for example, those particularly suitable for transient expression, e.g., interleukin-2, interleukin-4, gamma-interferon, GM-CSF, G-CSF, erythropoietin, and other cytokines, glucocerebrosidase, phenylalanine hydroxylase, cystic fibrosis transmembrane conductance regulator (CFTR), hypoxanthine-guanine phosphoribosyl transferase, cytotoxins, tumor suppressor genes, antisense RNAs, and vaccine antigens.

In certain embodiments, the disclosure relates to immunogenic compositions (e.g., vaccines) comprising an immunologically effective amount of a recombinant RSV of the invention (e.g., an attenuated live recombinant RSV or inactivated, non-replicating RSV), an immunologically effective amount of a polypeptide disclosed herein, and/or an immunologically effective amount of a nucleic acid disclosed herein.

In certain embodiments, the disclosure relates to methods for stimulating the immune system of an individual to produce a protective immune response against RSV. In the methods, an immunologically effective amount of a recombinant RSV disclosed herein, an immunologically effective amount of a polypeptide disclosed herein, and/or an immunologically effective amount of a nucleic acid disclosed herein is administered to the individual in a physiologically acceptable carrier.

Typically, the carrier or excipient is a pharmaceutically acceptable carrier or excipient, such as sterile water, aqueous saline solution, aqueous buffered saline solutions, aqueous dextrose solutions, aqueous glycerol solutions, ethanol, or combinations thereof. The preparation of such solutions ensuring sterility, pH, isotonicity, and stability is effected according to protocols established in the art. Generally, a carrier or excipient is selected to minimize allergic and other undesirable effects, and to suit the particular route of administration, e.g., subcutaneous, intramuscular, intranasal, oral, topical, etc. The resulting aqueous solutions can e.g., be packaged for use as is or lyophilized, the lyophilized preparation being combined with a sterile solution prior to administration

In certain embodiments, the RSV (or RSV components) is administered in a quantity sufficient to stimulate an immune response specific for one or more strains of RSV (e.g., an immunologically effective amount of RSV or an RSV component is administered). Preferably, administration of RSV elicits a protective immune response. Dosages and methods for eliciting a protective anti-viral immune response, adaptable to producing a protective immune response against RSV, are known to those of skill in the art. See, e.g., U.S. Pat. No. 5,922,326; Wright et al. (1982) Infect. Immun. 37:397-400; Kim et al. (1973) Pediatrics 52:56-63; and Wright et al. (1976) J. Pediatr. 88:931-936. For example, virus can be provided in the range of about 10 ³ -10 ⁶ pfu (plaque forming units) per dose administered (e.g., 10 ⁴ -10 ⁵ pfu per dose administered). Typically, the dose will be adjusted based on, e.g., age, physical condition, body weight, sex, diet, mode and time of administration, and other clinical factors. The vaccine formulation can be systemically administered, e.g., by subcutaneous or intramuscular injection using a needle and syringe or a needleless injection device. Preferably, the vaccine formulation is administered intranasally, e.g., by drops, aerosol (e.g., large particle aerosol (greater than about 10 microns)), or spray into the upper respiratory tract. While any of the above routes of delivery results in a protective systemic immune response, intranasal administration confers the added benefit of eliciting mucosal immunity at the site of entry of the virus. For intranasal administration, attenuated live virus vaccines are often preferred, e.g., an attenuated, cold adapted and/or temperature sensitive recombinant RSV, e.g., a chimeric recombinant RSV. As an alternative or in addition to attenuated live virus vaccines, killed virus vaccines, nucleic acid vaccines, and/or polypeptide subunit vaccines, for example, can be used, as suggested by Walsh et al. (1987) J. Infect. Dis. 155: 1198-1204 and Murphy et al. (1990) Vaccine 8:497-502.

In certain embodiments, the attenuated recombinant RSV is as used in a vaccine and is sufficiently attenuated such that symptoms of infection, or at least symptoms of serious infection, will not occur in most individuals immunized (or otherwise infected) with the attenuated RSV - in embodiments in which viral components (e.g., the nucleic acids or polypeptides herein) are used as vaccine or immunogenic components. However, virulence is typically sufficiently abrogated such that mild or severe lower respiratory tract infections do not typically occur in the vaccinated or incidental subject.

While stimulation of a protective immune response with a single dose is preferred, additional dosages can be administered, by the same or different route, to achieve the desired prophylactic effect. In neonates and infants, for example, multiple administrations may be required to elicit sufficient levels of immunity. Administration can continue at intervals throughout childhood, as necessary to maintain sufficient levels of protection against wild-type RSV infection. Similarly, adults who are particularly susceptible to repeated or serious RSV infection, such as, for example, health care workers, day care workers, family members of young children, the elderly, and individuals with compromised cardiopulmonary function may require multiple immunizations to establish and/or maintain protective immune responses. Levels of induced immunity can be monitored, for example, by measuring amounts of virus-neutralizing secretory and serum antibodies, and dosages adjusted or vaccinations repeated as necessary to elicit and maintain desired levels of protection.

Alternatively, an immune response can be stimulated by ex vivo or in vivo targeting of dendritic cells with virus. For example, proliferating dendritic cells are exposed to viruses in a sufficient amount and for a sufficient period of time to permit capture of the RSV antigens by the dendritic cells. The cells are then transferred into a subj ect to be vaccinated by standard intravenous transplantation methods.

Optionally, the formulation for administration of the RSV also contains one or more adjuvants for enhancing the immune response to the RSV antigens. Contemplated adjuvants include aluminum salts such as Alhydrogel® and Adjuphos®. Contemplated adjuvants include oil-in-water emulsions, where the oil acts as the solute in the water phase and forms isolated droplets, stabilized by emulsifying agents. In certain embodiments, emulsions contain a squalene or a-tocopherol (vitamin E) with additional emulsifying agents such as sorbitan trioleate and polysorbate-80 (PS80) as surfactants. In certain embodiments, emulsions contain a glucopyranosyl lipid A (GLA). GLA can be formulated with chimeric RSV, particles or RSV F protein either alone or in a squalene-based oil-in-water stable emulsion (SE). Iyer et al report oil-in-water adjuvants of different particle size using Respiratory Syncytial Virus Fusion protein (RSV-F). Hum Vaccin Immunother, 2015, 11(7): 1853-1864

Suitable adjuvants include, for example: complete Freund's adjuvant, incomplete Freund's adjuvant, saponin, mineral gels such as aluminum hydroxide, surface active substances such as lysolecithin, pluronic polyols, polyanions, peptides, oil or hydrocarbon emulsions, bacille Calmette-Guerin (BCG), Corynebacterium parvum, and the synthetic adjuvant QS-21.

If desired, prophylactic vaccine administration of RSV can be performed in conjunction with administration of one or more immunostimulatory molecules. Immunostimulatory molecules include various cytokines, lymphokines and chemokines with immunostimulatory, immunopotentiating, and pro-inflammatory activities, such as interleukins (e.g., IL-1, IL-2, IL-3, IL-4, IL-12, IL-13); growth factors (e.g., granulocyte-macrophage (GM)-colony stimulating factor (CSF)); and other immunostimulatory molecules, such as macrophage inflammatory factor, Flt3 ligand, B7.1; B7.2, etc. The immunostimulatory molecules can be administered in the same formulation as the RSV, or can be administered separately. Either the protein or an expression vector encoding the protein can be administered to produce an immunostimulatory effect. Although vaccination of an individual with an attenuated RSV of a particular strain of a particular subgroup can induce cross-protection against RSV of different strains and/or subgroups, cross-protection can be enhanced, if desired, by vaccinating the individual with attenuated RSV from at least two strains, e.g., each of which represents a different subgroup. Similarly, the attenuated RSV vaccines can optionally be combined with vaccines that induce protective immune responses against other infectious agents.

Assembly and rescue of chimeric RSV viruses

The following recombinant viruses: A2, A2-linel9F, A2-linel9F(M79I), A2- linel9F(R191K), A2-linel9F(K357T), A2-linel9F(Y371N), A2-linel9F(I557V), A2- linel9F(K357T/Y371N), and A2-mKate2-2-20F/G, can be prepared as described in:

Hotard et al. Identification of residues in the human respiratory syncytial virus fusion protein that modulate fusion activity and pathogenesis. J Virol 89, 512-522 (2015).

Meng et al. Respiratory Syncytial Virus Attachment Glycoprotein Contribution to Infection Depends on the Specific Fusion Protein. Journal of virology 90, 245-253 (2015)

Hotard et al. A stabilized respiratory syncytial virus reverse genetics system amenable to recombination-mediated mutagenesis. Virology 434, 129-136 (2012).

The bacterial artificial chromosome (BAC) construct for OE4 was generated through modification of the published BAC containing A2-mKate2-linel9F(I557V). The gene for monomelic Katushka 2 (mKate2, K), a far-red fluorescent reporter, is in the first gene position of the RSV antigenomic cDNA. Inclusion of mKate2 in this position did not attenuate RSV in vitro or in mice. Deletion of SH (ASH) was performed by recombination-mediated mutagenesis (recombineering). The following oligonucleotides (Integrated DNA Technologies / IDT) were used to PCR-amplify the galK cassette such that the amplicon termini are homologous to the target site to replace SH with galK: dSH50f (SEQ ID NO: 5) 5' - AGATCTAGTACTCAAATAAGTTAATAAAAAATATACACATGGACGTCCATCCTGTTG ACAATTAATCATCGGCA - 3'), where the underlined portions represent the 50 nt immediately upstream of the SH gene start in the BAC, and dSH50r (SEQ ID NO: 6) 5' - GTCTTAGCGGTGCGTTGGTCCTTGTTTTTGGACATGTTTGCATTTGCCCCTCAGCACT GTCCTGCTCCTT - 3'), where the underlined portion represents the complement of 50 nt beginning with the G gene start in the BAC. The non-underlined portions of the primers are specific to the galK cassette, as described37. Recombination in E coli resulted in replacing SH, from the beginning of the gene start to the end of the SH-G intergenic region, with the galK cassette. The following complementary oligonucleotides were annealed and used for removing the galK cassette in the second step of recombineering: dSHlOOf (SEQ ID NO: 7) 5' - AGATCTAGTACTCAAATAAGTTAATAAAAAATATACACATGGACGTCCATGGGGCA AATGCAAACATGTCCAAAAACAAGGACCAACGCACCGCTAAGAC - 3') and dSHlOOr (SEQ ID NO: 8) 5'

GTCTTAGCGGTGCGTTGGTCCTTGTTTTTGGACATGTTTGCATTTGCCCCATGGACGT CCATGTGTATATTTTTTATTAACTTATTTGAGTACTAGATCT - 3'). Precise deletion of SH was confirmed by sequencing, yielding A2-K-ASH-linel9F(I557V) BAC.

The human codon-deoptimized NS1 and NS2 coding region (dNSh) was digested from the BAC used for recovery of A2-dNSh and ligated into the A2-K-ASH-linel9F(I557V) BAC yielding an A2-K-dNSh-ASH-linel9F(I557V). This construct was used for recovery of OE4 + wild-type A2 G (termed OE4 + wtG). Codon-deoptimization of G was performed through substitution in silico of all codons least frequently used based on human codon usage bias into the RSV G sequence of A2. A point mutation (M48I) was introduced to ablate the secreted form of G. The coding region of codon-deoptimized G (dG) was synthesized by GenScript and cloned by restriction digestion and ligation into the A2-K-dNSh-ASH-linel9F(I557V) BAC yielding A2-K- dNSh-ASH-dG-linel9F(I557V) yielding the recovery BAC for OE4.

The BAC for rescue of BAF was generated by cloning the Buenos Aires consensus F (BAF) gene sequence into the OE4 + wtG BAC through the methods described above. BAF-357/371 was generated through introduction of the Linel9 F residues K357 and Y371 into the BAF coding sequence. The BAC for rescue of Α2-ΔΜ2-2 was generated by recombineering. As had been done for ΔΜ2-238234 nt (from the 7th codon to the stop codon) of M2-2 were deleted. The following oligonucleotides were used to PRC-amplify the galK cassette for the first step of recombineering, delM2-l-f (SEQ ID NO: 9) 5'

TTAGTGATACAAATGACCATGCCAAAAATAATGATACTACCTGACAAATACCTGTTG ACAATTAATCATCGGCA - 3') and delM2-2-r (SEQ ID NO: 10) 5' - ATTGTTTGAATTAATAATGTAACGATGTGGTGAGTGTTAGAATTGAGTGTTCAGCAC TGTCCTGCTCCTT - 3'). The following complementary oligonucleotides were annealed and used for the second recombineering step, M22_100f (SEQ ID NO: 11) 5' - TTAGTGATACAAATGACCATGCCAAAAATAATGATACTACCTGACAAATAACACTC AATTCTAACACTCACCACATCGTTACATTATTAATTCAAACAAT - 3'), and M22_100r (SEQ ID NO: 12) 5'

ATTGTTTGAATTAATAATGTAACGATGTGGTGAGTGTTAGAATTGAGTGTTATTTGTC AGGTAGTATCATTATTTTTGGCATGGTCATTTGTATCACTAA - 3'). Precise deletion of the targeted 234 nt was confirmed by sequencing.

Recombinant viruses were rescued in BSR-T7/5 cells, and virus stocks were propagated in Vero cells.

The panel of RSV strains used for quantification of RSV nAb titers in cotton rat anti-sera were generated by first having cDNAs of F and G genes of the following A and B strains synthesized (GeneArt, Invitrogen): RSVA/1998/12-21 (JX069802), Riyadh A/91/2009 (JF714706/JF714710); and RSV B strains NH1276 (JQ680988/JQ736678), 9320 (AY353550), and TX11-56 (JQ680989JQ736679). The G and F gene segments were cloned into the A2-K BAC by restriction digestion and ligation, and the reporter viruses were recovered by transfection into BSR-T7/5 cells, followed by propagation of stocks in HEp-2 cells.

Recombinant viruses were recovered by cotransfecting the RSV antigenomic BACs with four human codon-optimized helper plasmids that expressed RSV N, P, M2-1, or L protein into BSR T7/5 cells. Master and working virus stocks of vaccine strains were subsequently propagated and harvested in Vero cells.

Pre-F Antigen ELISA

Virus aliquots were thawed and diluted in MEM to yield high titer stock suspensions. 100 μΐ, of each virus stock suspension was added to triplicate series of wells in a Costar Assay Plate, High Binding (Corning). The plates were covered and incubated at room temperature overnight. The next day, the virus suspension was dumped from the plate, and the plate was washed once with 150 μΐ, per well of PBS-Tween (PBST, 0.05% Tween20 in PBS) followed by addition of 150 μΙ_, of 5% BSA (in PBS) per well for blocking. The plate was incubated at room temperature for 2 h. Pre-F-specific mAb MPE839 was generated by U-Protein Express in HEK293-X2FreeStyle cells using human codon-optimized VH and VL sequences. Motavizumab mAb which binds pre- F and post-F was provided by Nancy Ulbrandt (Medlmmune/AZ). MPE8 and motavizumab antibodies were prepared by diluting the antibodies to 1 μg/mL in PBS before further dilution of 1 : 10,000 to 1 :320,000 by serial dilutions in 1% BSA. Following blocking, the plate was washed once again with 150 μΐ _^ per well of PBST before 100 μΐ _^ of the diluted primary antibodies were applied to the wells. The plate was incubated for 2 h at room temperature before being dumped and washed three times with 150 μΐ _^ per well of PBST. After washing, 100 μΐ _^ of a 1 : 10,000 dilution of anti-human-HRP antibody in 1% BSA was applied and the plate incubated an hour at room temperature. Then the plate was dumped and washed 3 times with 150 pL of PBST before 100 μΐ _^ of a pre-mixed reactive substrate reagent mixture (R&D Systems) was applied to catalyze a colorimetric reaction. The plate was covered and incubated for approximately 10 min before the reaction was quenched by the addition of 100 μΐ _^ of 0.2N sulfuric acid. The plate was read at 450 nm on an ELIS A plate reader. The absorbance readings collected were subtracted from background and plotted to a curve. The ratio of the area under the curve for MPE8 (pre-F) to the area under the curve for motavizumab (pre-F and post-F, total F) was used to determine pre-F level normalized to total F. Growth in Vero

BEAS-2B, NHBE, and HAE cells. The media from 70% confluent Vero or BEAS-2B cells in 6-well plates was aspirated, and 0.5 mL of virus at an MOI of 0.01 was added to replicate wells for each of the time points to be acquired for each virus strain. The plates were rocked at room temperature for 1 h. Following infection, the virus was carefully aspirated and the monolayers washed twice with 1 mL of PBS before 2 mL of pre-warmed complete E-MEM (Vero) or RPMI (BEAS-2B) was added. The plates were incubated at 37°C and 5% C02 for the duration of the time courses. Time points were acquired at 1, 12, 24, 36, 48, 72, and 96 h post-infection. At each time point, the monolayers were scrapped into the supernatant, vortexed briefly, and flash frozen in liquid nitrogen before storage at -80°C. NHBE cells from two donors were differentiated at ALI and the monolayers washed with PBS before being infected apically with 100 μΐ. of virus at an MOI of 2.6. The virus was left to incubate for 2 h at 37°C before removal and 3 subsequent washes with PBS. At designated time points, 150 μΐ. of differentiated medium without inducer was incubated on the apical surface for 10 min at 37°C before harvesting and transfer into microcentrifuge tubes. The process was repeated to yield a total of 300 μΐ. of pooled apical wash, which was frozen in liquid nitrogen and stored at -80°C for later titration. Similar to the NHBE infection, HAE cells from two donors were differentiated at ALI, the apical surface washed with PBS, and infected with an initial MOI of 6.7. Following 2 hr incubation at 37°C, the virus inoculum was aspirated, the apical layer washed 3 times with PBS and the culture incubated at 37°C. For each designated time point, the apical layers were washed with 425 μΐ _^ of media for 30 min at 37°C and the supernatant stored at -80°C. FFU titration was performed for all analyses as described above on either FEp-2 or Vero cells.

Viral load, neutralization titers, and protection in mice

For determination of viral load, 7-week-old female BALB/c mice (Charles River) were infected i.n. under sedation with 100 μΐ _^ of virus in serum-free MEM. On days 2, 4, 6, and 8, the mice were euthanized and the left lung harvested for viral FFU titer assay. Titers below the limit of detection were assigned a value equal to half of the limit of detection. For determination of serum nAb titers and challenge studies, 7-week-old female BALB/c mice (Jackson) were infected i.n. with 100 μΐ. of virus in serum-free MEM. On days 35, 70, and 100, the mice were sedated and serum samples obtained via submandibular vein bleeding. Sera were stored at -80°C until quantification by a FFU microneutralization assay. Neutralization titers were determined by co- incubating heat-inactivated (56°C, 30 min) sera, which had been two-fold serially diluted with 50 - 100 FFU of virus for 1 h at 37°C. The serum-virus mixtures were then spinoculated onto F£Ep-2 monolayers in 96-well plates at 2900 x g for 30 min at 4°C before being overlaid with 0.75% methylcellulose in complete MEM. FFU per well were counted 2 days later, and EC50 titers were determined by nonlinear regression analysis. To challenge the mice after vaccination, the mice were sedated on day 102 post-inoculation and infected i.n. with 105 PFU A2-linel9F. After 4 days, the viral load was determined on the left lung by plaque assay on F£Ep-2 cells. A live-attenuated RSV vaccine with enhanced thermal stability and immunogenicity

Like other paramyxovirus fusion proteins, RSV fusion glycoprotein (RSV F) is a type I integral membrane protein that mediates fusion of the viral envelope and target cell. RSV F initially assembles in the virion membrane as a trimer in a metastable, pre-fusion conformation. Triggering results in major refolding of F into a post-fusion form, which approximates viral and target membranes and mediates fusion. Since both pre-F and post-F are present on RSV virions in prepared virus stocks, the relative amount of pre-F antigen in RSV stocks using an ELISA-based approach was evaluated. Strain A2-linel9F, which expresses the F protein of strain line 19 in the background of the prototypical A2 strain, exhibited significantly higher relative binding to a pre- F-specific mAb than strain A2. Intranasal (i.n.) inoculation of BALB/c mice with A2-linel9F resulted in higher nAb titers than A2.

There are five amino acid residues unique to line 19 F: M79, R191, K357, Y371, and 1557. Pre-F antigen ELISAs on A2-linel9F mutants containing A2 residues at each of these positions showed that residues K357 and Y371 are important for line 19 F pre-F antigen levels.

RSV is known to be a heat-labile virus, and elevated temperatures can trigger transition to the RSV post-F conformation. RSV with enhanced pre-F levels should be more resistant to temperature-inactivation. RSV A2-linel9F infectivity was more thermostable over time than A2 at 4°C and 37°C, a phenotype mediated in part by the K357 and Y371 residues of line 19 F. K357 and Y371 were introduced into the F of a genetically divergent vaccine strain DBl, which expresses a consensus F gene of the antigenic subgroup B "Buenos Aires" (BAF) clade. We previously described the generation of DB l, which also contains codon-deoptimized nonstructural protein genes and deleted SH gene, with a genotype RSV-A2-dNSl-dNS2-ASH-BAF. DBl expressed low levels of pre-F antigen and was thermally unstable; however, incorporation of the K357 and Y371 residues to generate DB 1-357/371 enhanced MPE8 binding and partially restored thermal stability. These data demonstrated that residues 357 and 371 governed not only MPE8 binding, a correlate of pre-F antigen levels, but also viral resistance to thermal inactivation in viral stocks.

An RSV LAV called OE4, was generated by incorporating line 19 F into a multi- component vaccine. The NS1 and NS2 genes, which encode two nonstructural proteins of RSV that suppress host innate immunity by targeting interferon pathways and suppressing apoptosis, were codon-deptimized. Codon-deoptimization of NS1 and NS2 genes was genetically stable and reduced NS1 and NS2 protein expression, resulting in virus attenuation with slightly enhanced immunogenicity in mice. The small hydrophobic (SH) protein gene was deleted with the goal of increasing the transcription of downstream viral genes, including F, by altering their proximity to the viral leader. The deletion of SH is also mildly attenuating in mice and chimpanzees, but conferred no apparent attenuation in a vaccine candidate in children in prior studies. The RSV attachment (G) glycoprotein gene was codon-deoptimized, and the secreted form of G was ablated by a point mutation. RSV expresses a membrane-bound form (Gm) and a secreted form (G _s ) of G, which are not required for viral replication in immortalized cell lines. RSV G is capable of eliciting protective neutralizing antibodies. However, G is less conserved than F and suppresses the innate immune response through chemokine mimicry. G _s functions as an antigen decoy and can alter dendritic cell signaling and activation through interactions with C-type lectins. The resulting genotype of the OE4 vaccine candidate was RSV-A2-dNSl- dNS2-ASH-dGm-Gsnuii-linel9F. Using Western blotting, it was determined that OE4 had decreased expression levels of NS1, NS2, and G compared to parental A2. OE4 had higher levels of F expression than A2-linel9F, likely attributable to the deletion of SH.

MPE8 and D25 binding of OE was analyzed, and vaccine thermal stability at 4°C and 37°C was measured. Similar to A2-linel9F, OE4 exhibited high relative pre-F antigen levels by antibody binding and thermal stability consistent with its expression of the line 19 F protein. Pre-F stability as measured was quantified by MPE8 binding of OE4 and A2 from virus stocks incubated at 4°C over time. Relative pre-F antigen levels declined in both viruses over a period of 8 days. Therefore, the kinetics of thermal stability of A2 and OE4 infectivity did not correlate with the decay of pre- F antigen levels. However, OE4 maintained greater than twice the levels of pre-F antigen levels at each time point compared to A2, and a minimal threshold of pre-F may be sufficient to maintain infectivity.

In order to assess the overall structure of the virions and glycoprotein incorporation into RSV A2 and OE4, thin-section transmission electron microscopy (TEM), native immuno-TEM, and cryo-electron tomography (cryo-ET) of viruses budded from BEAS-2B cells was performed. BEAS-2B are an immortalized human bronchial epithelial cell line. Virus-infected cells and released virions were analyzed following minimal sample processing to maximize preservation of the native structure of the virions. First, native immunogold labeling combined with thin-section TEM was performed using mAbs which preferentially bound pre-F (MPE8), post-F (131 -2A), total F (motavizumab), or G (131-2G). The density of gold particles per membrane length was quantified for each virus and immunolabel. OE4 virus particles exhibited a greater density of incorporated pre-F and total F than A2, potentially due to the deletion of SH. There was no significant difference in the amount of post-F detected on the surfaces of A2 and OE4 particles. G protein density on OE4 particles was significantly reduced, as was expected in the setting of codon- deoptimization of the G gene. The OE4 vaccine candidate was characterized in vitro by measuring attenuation levels in immortalized cells and in primary human airway epithelial cells. In Vero cells, which were used for virus stock generation, OE4 grew to titers slightly below the parental un-attenuated A2-line 19F . OE4 was more attenuated relative to wild-type in BEAS-2B cells. We then evaluated OE4 growth in primary human airway epithelial cells, which are an established system for approximating RSV LAV attenuation in seronegative children. We implemented two models, HBE-ALI and HAE- ALI, and found that OE4 was significantly attenuated in both models and exhibited deficiency in spreading through the cultures. The codon-deoptimization of G in OE4 contributed significantly to the level of attenuation compared to OE4 expressing wild-type G (OE4 + wtG) in NHBE-ALI, likely due to the previously described attachment role of G in primary cells. In BALB/c mice, OE4 was moderately attenuated and elicited nAb titers equivalent to A2-linel9F and higher than A2. Following i.n. inoculation, mice were challenged on day 102 with A2-linel9F, and the OE4- vaccinated mice were completely protected against the challenge.

OE4 was evaluated in cotton rats prior to clinical testing. In cotton rats, OE4 was highly attenuated in the upper and lower respiratory tracts and OE4 induced relatively high levels of serum nAb against a panel of RSV strains representing RSV diversity. OE4-vaccinated cotton rats were completely protected against RSV challenge, not only in lungs but also in the upper respiratory tract. OE4 established effective mucosal immunity despite being highly attenuated.

A primary concern highlighted, by the failure of another RSV vaccine candidate, formalin- inactivated RSV, is the potential for vaccine-enhanced priming for disease upon natural infection. Although RSV LAV candidates have not been shown to cause enhanced illness, whether the novel vaccination strategy employed by OE4 results in priming for enhanced disease upon challenge was evaluated in cotton rats. RSV challenge did not result in enhanced illness following infection with OE4 compared to mock. In contrast, formalin-inactivated RSV did result in enhanced disease associated with elevated peribronchiolar infiltration and alveolitis compared to OE4 and mock.

A chimeric respiratory syncytial virus vaccine candidate attenuated by a low-fusion F protein is immunogenic and protective against challenge in cotton rats

The Buenos Aires F protein (B AF), when expressed alone, was poorly fusogenic compared to A2F and linel9F proteins. Reverse genetics were implemented to design a LAV that combined the codon deoptimization of genes for non- structural proteins NSl and NS2 (dNS); deletion of the small hydrophobic protein (ASH) gene; and replacement of the wild-type fusion (F) protein gene with a low-fusion RSV subgroup B F consensus sequence of the Buenos Aires clade (BAF). This vaccine candidate RSV-A2-dNS-ASH-BAF named "DBl" was attenuated in two models of primary human airway epithelial cells and in the upper and lower airways of cotton rats. DBl was also highly immunogenic in cotton rats and elicited broadly neutralizing antibodies against a diverse panel of recombinant RSV strains. When vaccinated cotton rats were challenged with wild- type RSV A, DBl reduced viral titers in the upper and lower airways by 3.8 logio total PFU and 2.7 logio PFU/g tissue respectively compared to unvaccinated animals (P < 0.0001). DB l was thus attenuated, highly immunogenic, and protective against RSV challenge in cotton rats. DBl is the first RSV LAV to incorporate a low-fusion F protein as a strategy to attenuate viral replication and preserve immunogenicity.

DBl was greater than 10-fold attenuated in cotton rat upper and lower airways, yet still elicited high titers of broadly nAb to a diverse panel of RSV A and B recombinant strains. DBl also generated mucosal immunity in the form of RS V-specific IgA antibodies in cotton rat nasal wash specimens. When vaccinated animals were challenged with RSV, DBl reduced challenge strain titers by > 99% in both the nasal wash and lung lavage specimens. Thus, DB 1 was attenuated, highly immunogenic, and efficacious at protecting against RSV challenge in cotton rats.