Patent Grant
9463237
The present invention relates to recombinant viral vectors and methods of using the recombinant viral vectors to induce an immune response to influenza A viruses. The invention provides recombinant viral vectors based, for example, on the non-replicating modified vaccinia virus Ankara. When administered according to methods of the invention, the recombinant viral vectors are designed to be cross-protective and induce heterosubtypic immunity to influenza A viruses.
Human influenza or “the flu” is a respiratory disease that is caused by influenza A and B viruses. Epidemics of influenza cause significant illness and death worldwide each year, and vaccination is the most straightforward strategy to prevent infection and disease. Traditional influenza vaccines expose the recipient to influenza virus proteins causing the recipient to mount an immune response to the proteins. Proteins (or polypeptides) used in vaccines are commonly called “antigens.” The commonly used seasonal influenza vaccines are based on the major antigen of the viruses, the hemagglutinin (HA). There are numerous influenza A subtypes having different HA antigens. Influenza A subtypes are divided and classified based on the HA and neuraminidase (NA) proteins that are expressed by the viruses. The influenza A subtype nomenclature is based on the HA subtype (of the sixteen different HA genes known in the art) and the NA subtype (of the nine different NA genes known in the art). Exemplary subtypes, include, but are not limited to, H5N1, H1N1 and H3N2. There are also variants of the influenza A subtypes which are referred to as “strains.” For example, the virus A/VietNam/1203/2004 is an influenza A virus, subtype H5N1, with a strain name A/VietNam/1203/2004.
Protection from the seasonal vaccines based on the HA is strain-specific and new strains emerge constantly, so the classical influenza vaccines have to be re-formulated each year in an attempt to match the currently circulating strains. See, Lambert and Fauci 2010. It is therefore highly desirable for next generation vaccines to be cross-protective and induce heterosubtypic immunity, i.e., vaccines against one subtype that protect or partially protect against challenge infection with influenza A of different subtypes.
The current ‘universal vaccines’ (i.e., vaccines designed to elicit heterosubtypic immunity) that are under development are mainly based on the more conserved internal influenza virus genes including the influenza matrix proteins (M1 and M2) (Schotsaert et al. 2009), the nucleoprotein (NP) and conserved parts of the HA (Bommakanti et al. 2010; Steel et al. 2010). The polymerase proteins PA, PB1 and PB2 also induce substantial T cell responses and may be also relevant targets (Assarsson et al. 2008; Greenbaum et al. 2009; Lee et al. 2008).
Next generation influenza vaccines currently under development include recombinant proteins, synthetic peptides, virus-like particles (VLPs), DNA-based vaccines and viral vector vaccines (Lambert and Fauci, supra). The advantage of using live viral vectors is their known property to induce high levels of cellular immunity, in particular CD8 T cells. Among the most promising viral vectors are vaccinia virus-based live vaccines (Rimmelzwaan and Sutter 2009) and adenovirus-based vectors (Hoelscher et al. 2006; Hoelscher et al. 2007; Price et al. 2010; Zhou et al. 2010). Single-dose mucosal immunization using an adenovirus construct expressing NP and M2, for instance, provided protection from virulent H5N1, H3N2 and H1N1 viruses (Price et al, supra). In a further study (Price et al. 2009), DNA vaccination with nucleoprotein (NP) and matrix 2 (M2) plasmids followed by boosting with antigen-matched recombinant adenovirus (rAd) provided robust protection against virulent H1N1 and H5N1 challenges in mice and ferrets.
Recombinant vaccines based on modified vaccinia virus Ankara (MVA) have been used in many non-clinical and clinical studies. MVA has proven to be exceptionally safe. No significant side effects have been obtained when MVA was administered to more than 120,000 human patients in the context of the smallpox eradication. Due to a block in virion morphogenesis the highly attenuated vaccinia virus strain fails to productively replicate in human and most other mammalian cells. Nevertheless, the ability to express viral and foreign genes in the early and late stage is retained. These characteristics make MVA a promising live vaccine vector that induces humoral and cellular immune responses and that exhibits a high safety profile.
U.S. Pat. Nos. 6,998,252; 7,015,024; 7,045,136 and 7,045,313 relate to recombinant poxviruses, such as vaccinia.
MVA-based vaccines have been used in clinical studies, for instance, against HIV, tuberculosis, malaria and cancer. In all of these studies, at least two doses were used. The human dose of an MVA-based vaccine was 5×107 to 5×108 PFU as applied in clinical trials (Brookes et al. 2008; Cebere et al. 2006; Tykodi and Thompson 2008;).
MVA has been used recently as a vector in pandemic H5N1 (Kreijtz et al. 2008; Kreijtz et al. PLoS One 2009; Kreijtz et al. Vaccine 2009; Kreijtz et al. J. Infect. Dis. 2009; Kreijtz et al. 2007; Mayrhofer et al., 2009; Poon et al. 2009) and H1N1 (Hessel et al. 2010; Kreijtz et al., J. Infect. Dis. 2009) influenza research. An MVA-based vaccine expressing NP and M1 is currently being tested in an ongoing clinical trial (Berthoud et al. 2011).
Thus, there remains a need in the art for a more broadly protective influenza vaccine.
The present invention provides recombinant viruses (also referred to as recombinant viral vectors herein) useful for generating a heterosubtypic immune response to influenza A viruses. The recombinant viruses are recombinant vaccinia viruses, such as recombinant MVA or other non-replicating or replicating vaccinia virus known in the art. Non-replicating vaccinia viruses include, but are not limited to, defective vaccinia Lister (dVV), MVA-575 (ECACC V00120707), MVA-BN (ECACC V00083008), MVA-F6 and MVA-M4 (Antoine et al. 1998). In some embodiments, the recombinant viruses encode a fusion protein (hlHA/M2e) comprising an influenza A hemagglutinin deletion mutant “headless HA” (hlHA) with at least one influenza A M2 external domain (M2e) insert; an hlHA/M2e fusion protein and an influenza A nucleoprotein (NP); or an hlHA and NP. The recombinant viruses of the invention may further encode an influenza A matrix protein 1 (M1) and/or an influenza A polymerase PB1. When administered according to methods of the invention, the recombinant viruses are cross-protective and induce heterosubtypic humoral and cellular immune responses (including CD8 and CD4 T cell responses). The recombinant viruses are therefore contemplated to be useful as universal influenza A vaccines in humans.
In some embodiments, the hlHA amino acid sequence encoded by an open reading frame in recombinant viruses of the invention may be, for example, the hlHA amino acid sequence set out in SEQ ID NO: 15 (based on A/VietNam/1203/2004 H5N1 HA NCBI Genbank AAW80717 which is SEQ ID NO: 3). The hlHA of SEQ ID NO: 15 comprises a signal sequence, the HA1 residues 17-58 of SEQ ID NO: 3, a linker peptide of four glycines, the HA1 residues 290-343 of SEQ ID NO: 3 and the HA2 stalk region residues 344-568 of SEQ ID NO: 3.
In some embodiments, the hlHA/M2e fusion protein amino acid sequence encoded by an open reading frame in recombinant viruses of the invention may be, for example, the hlHA/M2e fusion protein amino acid sequence set out in SEQ ID NO: 2. The fusion protein of SEQ ID NO: 2 comprises a signal sequence, the HA1 residues 17-58 of SEQ ID NO: 3, a linker peptide of three glycines (SEQ ID NO: 4), the M2e of H5N1 (SEQ ID NO: 5 based on A/VietNam/1203/2004 H5N1 NCBI Genbank ABP35634), a six-amino acid linker GSAGSA (SEQ ID NO: 9), the M2e of H1N1 (equivalent to H2N2 and H3N2) (SEQ ID NO: 6 based on A/New York/3315/2009 H1N1 NCBI Genbank ACZ05592), a six-amino acid linker GSAGSA (SEQ ID NO: 9), the M2e of H9N2 (SEQ ID NO: 7 based on A/chicken/Korea/SH0913/2009 H9N2 NCBI Genbank ADQ43641), a six-amino acid linker GSAGSA (SEQ ID NO: 9), the M2e of H7N2 (SEQ ID NO: 8 based on A/New York/107/2003 H7N2 NCBI Genbank ACC55276), a linker peptide of three glycines (SEQ ID NO: 4), the HA1 residues 290-343 of SEQ ID NO: 3 and the HA2 region residues 344-568 of SEQ ID NO: 3.
In some embodiments, the hlHA/M2e fusion protein may comprise one, two, three or four of the M2e polypeptides of SEQ ID NOs: 5, 6, 7 and 8. The hlHA/M2e fusion protein may comprise an influenza A M2e polypeptide other than an M2e polypeptide of SEQ ID NOs: 5, 6, 7, and 8.
In some embodiments, the NP amino acid sequence encoded by an open reading frame in recombinant viruses of the invention may be, for example, the NP amino acid sequence set out in SEQ ID NO: 13 (based on A/VietNam/1203/2004 H5N1 NP NCBI Genbank AAW80720). In some embodiments, the M1 amino acid sequence encoded by an open reading frame in recombinant viruses of the invention may be, for example, the M1 amino acid sequence set out in SEQ ID NO: 11 (based on A/VietNam/1203/2004 H5N1 M1 Genbank AAW80726). In some embodiments, the PB1 amino acid sequence encoded by an open reading frame in recombinant viruses of the invention may be, for example, the PB1 amino acid sequence set out in SEQ ID NO: 17 (based on A/VietNam/1203/2004 H5N1 PB1 Genbank AAW80711).
The invention contemplates that polypeptides encoded by an open reading frame in a recombinant virus may vary in sequence from SEQ ID NO: 2, 5, 6, 7, 8, 11, 13, 15 and/or 17 if the polypeptides retain the ability to induce a protective immune response when the recombinant virus is administered to an individual. In these embodiments, the polypeptide may be about 80%, about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 95%, about 97%, about 98% or about 99% identical to SEQ ID NO: 2, 5, 6, 7, 8, 11, 13, 15 and/or 17.
In other embodiments, hlHA/M2e fusion proteins, hlHA polypeptides and NP polypeptides encoded by recombinant viruses of the invention may be based on the same or different influenza A subtypes including, but not limited to, any combination of H1 to H16 and N1 to N9 (including H1N1, H2N1, H3N1, H4N1, H5N1, H6N1, H7N1, H8N1, H9N1, H10N1, H11N1, H12N1, H13N1, H14N1, H15N1, H16N1; H1N2, H2N2, H3N2, H4N2, H5N2, H6N2, H7N2, H8N2, H9N2, H10N2, H11N2, H12N2, H13N2, H14N2, H15N2, H16N2; H1N3, H2N3, H3N3, H4N3, H5N3, H6N3, H7N3, H8N3, H9N3, H10N3, H11N3, H12N3, H13N3, H14N3, H15N3, H16N3; H1N4, H2N4, H3N4, H4N4, H5N4, H6N4, H7N4, H8N4, H9N4, H10N4, H11N4, H12N4, H13N4, H14N4, H15N4, H16N4; H1N5, H2N5, H3N5, H4N5, H5N5, H6N5, H7N5, H8N5, H9N5, H10N5, H11N5, H12N5, H13N5, H14N5, H15N5, H16N5; H1N6, H2N6, H3N6, H4N6, H5N6, H6N6, H7N6, H8N6, H9N6, H10N6, H11N6, H12N6, H13N6, H14N6, H15N6, H16N6; H1N7, H2N7, H3N7, H4N7, H5N7, H6N7, H7N7, H8N7, H9N7, H10N7, H11N7, H12N7, H13N7, H14N7, H15N7, H16N7; H1N8, H2N8, H3N8, H4N8, H5N8, H6N8, H7N8, H8N8, H9N8, H10N8, H11N8, H12N8, H13N8, H14N8, H15N8, H16N8; H1N9, H2N9, H3N9, H4N9, H5N9, H6N9, H7N9, H8N9, H9N9, H10N9, H11N9, H12N9, H13N9, H14N9, H15N9, and H16N9). In some embodiments the influenza A subtype is a pandemic influenza A. Exemplary pandemic influenza subtypes include, but are not limited to, H1N1, H2N2, H3N2 and H5N1.
A list of identified Influenza A strains, including influenza A H1N1 strains, is available from the World Health Organization (WHO) and United States Centers for Disease Control (CDC) databases of Influenza A subtypes. The National Center for Biotechnology Information (NCBI) database maintained by the United States National Library of Medicine also maintains an updated database describing the length and sequence of HA, M2, NP, M1 and PB1 genes of viruses of influenza A species. Strains listed by these organizations and strains described in other commercial and academic databases, or in literature publications and known in the art, are contemplated for use in the invention. It is also contemplated that additional influenza A strains hereafter identified and isolated are also useful in the invention as sources of influenza A protein sequences. Accordingly, any strain specifically exemplified in the specification and those known or after discovered in the art are amenable to the recombinant vaccinia virus, pharmaceutical compositions, and methods of the invention. Exemplary strains include, but are not limited to, the strains in Table 1 below. The table also lists exemplary genes and associated database accession numbers of those strains.
In recombinant viruses of the invention, open reading frames encoding hlHA/M2e, hlHA, NP, M1 and/or PB1 may be codon-optimized for expression in human cells. In these embodiments, one or more (or all) of the naturally occurring codons in an open reading frame have been replaced in the codon-optimized open reading frame with codons frequently used in genes in human cells (sometimes referred to as preferred codons). Codons may be optimized to avoid repeat sequences to stabilize an open reading frame in the rMVA and/or to avoid unwanted transcription stop signals. Codon-optimization, in general, has been used in the field of recombinant gene expression to enhance expression of polypeptides in cells.
Gene cassettes encoding hlHA/M2e, hlHA, NP, M1 and PB1 in recombinant viruses of the invention include an open reading frame under the control of (i.e., operatively linked to) a promoter that functions (i.e., directs transcription of the open reading frame) in the recombinant vaccinia viruses. In exemplary embodiments, expression from gene cassettes is under the control of the strong early/late vaccinia virus mH5 promoter (SEQ ID NO: 18) or the synthetic early/late selP promoter (SEQ ID NO: 19) (Chakrabarti et al. 1997). In the gene cassettes of the invention the open reading frame is also operatively linked to a transcription stop signal such as a vaccinia virus early transcription stop signal.
In one aspect, the invention provides recombinant vaccinia virus comprising a gene cassette encoding an influenza A hlHA/M2e fusion protein. In some embodiments, the recombinant vaccinia virus is a recombinant MVA comprising a gene cassette expressing the hlHA/M2e fusion protein set out in SEQ ID NO: 2. In some embodiments, the recombinant vaccinia virus further comprises a gene cassette expressing the M1 protein (for example, the M1 set out in SEQ ID NO: 11) and/or a gene cassette expressing the PB1 protein (for example, the PB1 protein set out in SEQ ID NO: 17).
In another aspect, the invention provides recombinant vaccinia virus comprising a first gene cassette encoding an influenza A hlHA/M2e fusion protein. and a second gene cassette encoding an influenza NP. In some embodiments, the recombinant vaccinia virus is a recombinant MVA comprising a first gene cassette expressing the hlHA/M2e fusion protein set out in SEQ ID NO: 2 and a second gene cassette expressing the NP set out in SEQ ID NO: 13. In some embodiments, the recombinant vaccinia virus further comprises a gene cassette expressing the M1 protein (for example, the M1 set out in SEQ ID NO: 11) and/or a gene cassette expressing the PB1 protein (for example, the PB1 protein set out in SEQ ID NO: 17).
In yet another aspect, the invention provides recombinant vaccinia virus comprising a first gene cassette encoding an influenza A hlHA and a second gene cassette encoding an influenza NP. In some embodiments, the recombinant vaccinia virus is a recombinant MVA comprising a first gene cassette expressing the hlHA set out in SEQ ID NO: 15 and a second gene cassette expressing the NP set out in SEQ ID NO: 13. In some embodiments, the recombinant vaccinia virus further comprises a gene cassette expressing the M1 protein (for example, the M1 set out in SEQ ID NO: 11) and/or a gene cassette expressing the PB1 protein (for example, the PB1 protein set out in SEQ ID NO: 17).
In recombinant vaccinia viruses of the invention, the gene cassettes may be inserted in non-essential regions of the vaccinia virus genome, such as the deletion I region, the deletion II region, the deletion III region, the deletion IV region, the thymidine kinase locus, the D4R/5R intergenic region, or the HA locus. In exemplified embodiments of recombinant MVA, the insertion of the hlHA/M2e and hlHA gene cassettes is in the D4R/5R intergenic region and the insertion of the NP gene cassette is in the deletion III region. The recombinant MVA is derived from an MVA free of bovine spongiform encephalopathy (BSE) such as MVA74 LVD6 obtained from the National Institutes of Health.
The recombinant viruses of the invention may be formulated as pharmaceutical compositions according to methods known in the art. In some embodiments, the recombinant viruses are formulated as described in International Publication No. WO 2010/056991.
The invention provides methods of inducing a heterosubtypic influenza A immune response in an individual comprising administering compositions of recombinant vaccinia virus of the invention to the individual. In the methods, the composition may be administered as a single dose, a double dose or multiple doses. The administration route in humans may be inhalation, intranasally, orally, and parenterally. Examples of parenteral routes of administration include intradermal, intramuscular, intravenous, intraperitoneal and subcutaneous administration. The range of the human immunization dose may be about 106 to about 109 PFU. The methods of the invention induce humoral and cellular immune responses in the individual. Moreover, in embodiments of the invention the methods induce a protective immune response in the individual. The protective immune response may be where the individual exhibits no symptoms of infection, a reduction in symptoms, a reduction in virus titer in tissues or nasal secretions, and/or complete protection against infection by influenza virus.
The invention also provides kits for administering recombinant vaccinia virus of the invention packaged in a manner which facilitates their use to practice methods of the invention. In one embodiment, such a kit includes a recombinant virus or composition described herein, packaged in a container such as a sealed bottle or vessel, with a label affixed to the container or included in the package that describes use of the compound or composition in practicing the method. Preferably, the recombinant virus or composition is packaged in a unit dosage form. The kit may further include a device suitable for administration according to a specific route of administration or for practicing a screening assay. Preferably, the kit contains a label that describes use of the recombinant vaccinia virus. In some embodiments, the kit comprises instructions for administration to a human subject.
Also provided are methods of producing a recombinant vaccinia virus expressing a gene cassette of the invention. As illustrated with MVA, the methods comprise the steps of: a) infecting primary chicken embryo cells or a suitable permanent cell line (e.g., avian) with MVA, b) transfecting the infected cells with a plasmid comprising the gene cassette and comprising DNA flanking the gene cassette that is homologous to a non-essential region of the MVA genome, c) growing the cells to allow the plasmid to recombine with the MVA genome during replication of the MVA in chicken cells thereby inserting the gene cassette into the MVA genome in the non-essential region, and d) obtaining the recombinant MVA produced. Exemplary chicken embryo cells are described in U.S. Pat. No. 5,391,491. (Slavik et al. 1983) Other avian cells (e.g., DF-1) are also contemplated. In the methods, the non-essential MVA region is the deletion I region, the deletion II region (Meyer et al. 1991), the deletion III region (Antoine et al. 1996), the deletion IV region (Meyer et al., supra; Antoine et al. 1998) the thymidine kinase locus (Mackett et al. 1982), the D4R/5R intergenic region (Holzer et al. 1998), or the HA locus (Antoine et al. supra). In one exemplified embodiment, the insertion is in the deletion III region. In another exemplified embodiment, the insertion is in the D4R/5R intergenic region. If two gene cassettes are to be inserted, the two are inserted in different non-essential regions. Gene cassettes may additionally be inserted into any other suitable genomic region or intergenomic regions.
Other vertebrate cell lines are useful for culture and growth of vaccinia virus of the invention. Exemplary vertebrate cells useful to culture vaccinia virus of the invention include, but are not limited to, MRC-5, MRC-9, CV-1 (African Green monkey), HEK (human embryonic kidney), PerC6 (human retinoblast), BHK-21 cells (baby hamster kidney), BSC (monkey kidney cell), LLC-MK2 (monkey kidney) and permanent avian cell lines such as DF-1.
Vero cells are an accepted cell line for production of viral vaccines according to the World Health Organization. In some embodiments, recombinant replicating vaccinia virus of the invention are produced in Vero cells.
Additional aspects and details of the invention will be apparent from the following examples, which are intended to be illustrative rather than limiting.
The present invention is illustrated by the following examples wherein Example 1 describes the choice and design of influenza A antigens in exemplary recombinant MVA of the invention, Example 2 details the production of single-insert recombinant MVAs, Example 3 describes animal experiments with the single-insert MVAs, Example 4 details the production of double-insert recombinant MVAs, Example 5 describes animal experiments with the double-insert MVAs, Example 6 details the production of triple-insert recombinant MVAs and Example 7 describes animal experiments with the triple-insert MVAs.
Influenza headless HA, a headless HA/M2e fusion protein, NP, M1, M2 and PB1 were the influenza A antigens chosen to be encoded by exemplary recombinant MVA of the invention.
Monoclonal antibodies against the HA stalk domain, the HA2 region, are broadly cross-reactive and neutralize several subtypes of viruses (Ekiert et al. 2009; Kashyap et al. 2008; Okuno et al. 1993; Sanchez-Fauquier et al. 1987; Sui et al. 2009; Throsby et al. 2008). The antibodies target the HA2 region of the molecule and presumably act by preventing the conformational change of HA at low pH, thus presumably blocking fusion of viral and host membranes during influenza infection. However, the production of soluble, native (neutral pH-like) HA2 immunogen has proven to be difficult, owing to the metastable nature of HA (Chen et al. 1995). To induce an immune response against the neutral pH conformation, a headless HA was chosen as an antigen. The headless HA consists of two HA1 regions that interact with an HA2 subunit, stabilizing the neutral pH conformation (Bommakanti et al., supra; Steel et al., supra).
The extracellular domain of the M2 protein (M2e, 23AS) is highly conserved across influenza A virus subtypes. In animals, M2e specific antibodies reduce the severity of infection with a wide range of influenza A virus strains (Fan et al. 2004; Neirynck et al. 1999). Many groups have reported M2e-based vaccine candidates in different forms (De Filette et al. 2008; Denis et al. 2008; Eliasson et al. 2008; Fan et al., supra; Neirynck et al., supra). Recently, Zhao et al. reported that a tetra-branched multiple antigenic peptide vaccine based on H5N1 M2e induced strong immune responses and cross protection against different H5N1 clades and even heterosubtypic protection from 2009 H1N1 (Zhao et al. 2010b; Zhao et al. 2010a).
Vaccination using vectors expressing the conserved influenza NP, or a combination of NP and matrix protein has been studied in animal models and various degrees of protection against both homologous and heterologous viruses have been demonstrated (Price et al., supra; Ulmer et al. 1993). NP elicit a robust CD8+ T cell response in mice and in humans (McMichael et al., 1986; Yewdell et al., 1985) that, as epidemiological studies suggest, may contribute to resistance against severe disease following influenza A virus infection (Epstein 2006).
The headless HA included in rMVA of the invention is a new headless HA (hlHA) based on the VN/1203 influenza strain. The hlHA contains a polybasic cleavage site which is cleaved during expression from the rMVA exposing the fusion peptide for the immune system. The amino acid sequence of the hlHA is set out in
The amino acid sequence of the headless HA/M2e fusion protein included in rMVA of the invention is set out in
The following single-insert, recombinant MVA (rMVA) are utilized in the experiments described herein.
For construction of single-insert rMVA vectors expressing hlHA, the hlHA/M2e fusion protein or PB1, the hlHA, hlHA/M2e and PB 1 genes were chemically synthesized (Geneart, Inc., Regensburg, Germany). The synthetic genes are driven by the strong vaccinia early/late promoter mH5 (Wyatt et al. 1996) and terminated with a vaccinia virus specific stop signal downstream of the coding region that is absent internally. The gene cassettes were cloned in the plasmid pDM-D4R (Ricci et al., 2011) resulting in plasmids pDM-hlHA, pDM-hlHA/M2e and pDM-PB1-VN, respectively. The introduction of the foreign genes into the D4R/D5R intergenic region of MVA was done as described elsewhere (Ricci et al. 2011) resulting in viruses MVA-hlHA, MVA-hlHA/M2e, MVA-PB1-VN.
For the construction of the rMVA expressing M1, the M1 sequence (accession number AY818144) was placed downstream of the strong vaccinia early/late promoter selP (Chakrabarti et al. 1997) and cloned in pDM-D4R, resulting in pDM-M1-VN. The expression cassette of pDD4-M2-VN—including the M2 sequence (accession number EF541453) under the control of the mH5 promoter—was cloned in pDM-D4R resulting in pDM-M2-VN. The plasmids were then used for recombination with MVA according to Holzer et al, supra resulting in the viruses MVA-M1-VN and MVA-M2-VN, respectively as shown in
For the construction of single-insert MVAs expressing the NP protein, the NP expression cassette of pDD4-mH5-mNP-VN (Mayrhofer et al., supra) was cloned in plasmid pd3-lacZ-gpt, resulting in pd3-lacZ-mH5-NP-VN. Plasmid pd3-lacZ-gpt contains a lacZ/gpt selection marker cassette and a multiple cloning site (MCS) for insertion of genes of interest. The sequences are framed by genomic MVA sequences of the del III region. The marker cassette is destabilized by a tandem repeat of MVA del III flank, thus the final recombinant is free of any auxiliary sequences. The insertion plasmid directs the gene cassettes into the MVA deletion III (del III) region. After infection of primary chicken embryo cells with MOI 1, cells were transfected with pd3-lacZ-mH5-NP-VN according to the calcium phosphate technique (Graham and van der Eb 1973), resulting MVA-NP-VN shown in
The single-insert MVA vectors expressing the NP, PB1, M1, M2, hlHA, and hlHA/M2e were characterized by PCR and Western blot as described in Hessel et al, supra. Recombinant viruses were grown in CEC or DF-1 cells and purified by centrifugation through a sucrose cushion. Primary CEC were produced in-house and cultivated in Med199 (Gibco®) supplemented with 5% fetal calf serum (FCS). The DF-1 (CRL-12203) cell line was obtained from the ATCC (American Type Culture Collection) and cultivated in DMEM (Biochrom, Inc.) supplemented with 5% FCS.
The correct expression of the influenza proteins by the rMVAs was confirmed by Western blotting. For this purpose CEC or the permanent chicken cell line DF-1 were infected with a MOI of 0.1 and cell lysates were prepared 48-72 hrs post infections. The recombinant MVAs that express the hlHA (MVA-hlHA and MVA-hlHA/M2e) were analyzed in a Western blot using an anti-influenza A/Vietnam/1194/04 (H5N1) polyclonal serum (NIBSC 04/214) for detection. Donkey-anti-sheep alkaline phosphatase-conjugated IgG (Sigma Inc.) was used as a secondary antibody. The recombinant MVAs that express the M2 and M2e (MVA-M2-VN and MVA-hlHA/M2e) were analyzed in Western Blots using an anti-avian influenza M2 antibody binding a peptide present at the amino terminus of the H5N1 M2 (ProSci, Cat#4333). Goat-anti-rabbit alkaline phosphatase-conjugated IgG (Sigma Inc.) antibody was used as a secondary antibody. As shown in
The expression of the M1, NP and PB1 protein is detected with polyclonal guinea-pig anti-influenza H5N1 serum produced in house, a polyclonal goat antibody detecting the PB1 of Influenza A virus (Santa Cruz, Cat#: vC-19), and a monoclonal mouse-anti-NP-antibody (BioXcell, Cat# BE0159), respectively. The MVA-M1-VN and MVA-NP-VN induce expression of the M1 protein (around 27 kDa) and the NP protein (around 60 kDa) (not shown).
Protection Experiment
A standard protection experiment consists of two arms (primed with about 1×103-1×105 TCID50 H1N1v CA/07 and unprimed) of nine groups of mice each (respectively vaccinated i.m. with 1×106 pfu of the nine vaccines and controls shown in Table 2), a group consisting of six animals resulting in 108 animals, defines one set. The animals of one set are challenged with one of the six challenge viruses shown in Table 3 below.
Female Balb/c mice are 8-10 weeks old at the pre-treatment time point and 14-16 weeks old at the time point of immunization with the vaccines and controls shown in Table 2. Mice were immunized intramuscularly twice (days 42 and 63) with 106 pfu of the vaccines or wild type MVA, 3.75 μg whole virus preparation H9N2 A/HongKong/G9/1997 or with buffer (PBS). At day 84, mice were challenged intranasally with 103 TCID50 H5N1 A/Vietnam/1203/2004 (H5N1, CDC #2004706280), with 2.5×104 TCID50 mouse adapted H9N2 A/HongKong/G9/1997 or with 1.66×104TCID50H7N1 A/FPV/Rostock/34. The challenge doses correspond to approx. 30 LD50 for the H5N1 challenge and 32 LD50 for the H9N2 challenge per animal. Sera are collected at days 41, 62 and 85 and analyzed for HA-specific IgG concentration by HI titer or microneutralization assay.
The primary outcome of the animal experiments is protection as measured by lethal endpoint, weight loss, or lung titer. Further the ELISA titers of pooled pre-challenge sera measured against inactivated whole virus H5N1 strain A/Vietnam/1203/2004 are determined.
T Cell Experiments
Frequencies of influenza-specific CD4 and CD8 T cells are determined in immunized mice by flow cytometry. In a standard experiment, groups of 5 female BALB/c mice are immunized twice with the vaccines or controls listed in Table 2. Splenocytes are re-stimulated in-vitro using inactivated whole virus antigens of different influenza strains for CD4 T-cells and, when available, peptides representing the CD8 T-cell epitopes of the vaccine insert constructs and IFN-γ production are measured. All experiments are performed twice, using a total of 140 animals.
Other Experiments
An evaluation of the cell-mediated immunity after a single immunization, demonstration of functional activity of cytotoxic T-cells in a VITAL assay and assessment of recruitment of influenza-specific T-cells into the lungs of challenged animals are also carried out. The induction/expansion of vaccine-specific T-cells is also monitored in the primed mouse model by immunizing mice which resolved a influenza virus infection once with these vaccines.
The following double-insert, rMVA and controls are utilized in the experiments described herein.
For the construction of the double insert rMVA vector co-expressing either the hlHA or hlHA/M2e gene cassette in combination with the NP protein gene cassette, the single insert MVA recombinants of Example 2 containing the hlHA or hlHA/M2e gene cassette are used. CEC cells were infected with MVA-hlHA or MVA-hlHA/Me2 and afterwards transfected with pd3-lacZ-mH5-NP-VN (see Example 2). Homologous recombination and propagation of the recombinant MVA vectors are performed as described in Example 2. The resulting double insert MVA vectors, named MVA-hlHA-NP or MVA-hlHA/M2e-NP, contain the hlHA or hlHA/M2e expression cassette in the D4R/D5R locus and the NP expression cassette in the del III locus. See
The recombinant MVAs were characterized by Western Blot as described in Example 2.
Protection Experiment
A standard experiment included eight groups of mice (vaccinated with the six vaccines and controls shown in Table 5) each group consisting of six animals. The protection experiments were carried out as described in Example 3. After challenge mice were monitored over a time period of 14 days and weight loss or symptoms including ruffled fur (score of 1), curved posture (score of 2), apathy (score of 3), and death (score of 4) were recorded. For ethical reasons, mice were euthanized after weight loss of >25%. Protection results are compiled in Table 5 and displayed in
(1)VN1203, challenge strain A/Vietnam/1203/2004;
(2)HK/G9, challenge strain A/HongKong/G9/1997;
(3)n/nt, survival per group,
(4)Homologous control vaccine;
(5)wild-type MVA (NIH74 LVD clone 6).
As positive control mice were vaccinated with homologous control constructs. In case of H5N1 challenge mice were vaccinated with MVA-HA-VN (Hessel et al., 2011) and in case of H9N2 challenge mice were vaccinated with an inactivated whole virus preparation of the H9N2 A/HongKong/G9/1997 influenza virus. Both controls induced full protection (Table 5;
Surprisingly, however, vaccination with the double construct expressing the fusion protein hlHA/M2e and the NP protein resulted in nearly full protection (
T Cell Experiments
Frequencies of influenza-specific CD4 and CD8 T cells are determined in immunized mice by flow cytometry. In a standard protocol experiment, groups of 5 female BALB/c mice are immunized twice with the vaccines or controls listed in Table 4. Splenocytes are re-stimulated in-vitro using inactivated whole virus antigens of different influenza strains for CD4 T-cells and, when available, peptides representing the CD8 T-cell epitopes of the vaccine insert constructs and IFN-γ production are measured. All experiments are performed twice.
Other Experiments
An evaluation of the cell mediated immunity after a single immunization, demonstration of functional activity of cytotoxic T-cells in a VITAL assay and assessment of recruitment of influenza-specific T-cells into the lungs of challenged animals are also carried out. The induction/expansion of vaccine-specific T-cells is also monitored in the primed mouse model by immunizing mice which resolved a influenza virus infection once with these vaccines.
Influenza virus-like particles (VLPs) induce humoral and cellular responses and can protect against lethal challenges (Bright et al. 2007; Pushko et al. 2005; Song et al. 2010). VLPs chosen for experiments herein comprise either hlHA or hlHA/M2e in combination with NP and M1. The VLPs are generated from triple-insert MVA vectors.
For the construction of the triple-insert MVA vectors co-expressing either hlHA or hlHA/M2e in combination with the M1 (SEQ ID NO: 11) and the NP protein (SEQ ID NO: 13), the M1 gene (SEQ ID NO: 10) of pDD4-M1-VN is cloned downstream of the synthetic early/late promotor selP (Chakrabarti et al. 1997). The resulting gene cassette is cloned downstream of the hlHA or hlHA/M2e gene cassette in pDM-hlHA or pDM-hlHA/M2e. The resulting plasmids harboring a double gene cassette (pDM-hlHA-M1 and pDM-hlHA/M2e-M1) are used for recombination into defective MVA as described above. Afterwards, a recombination with an NP gene cassette (SEQ ID NO: 12)-containing plasmid (pD3-lacZ-gpt-NP-VN) is done resulting in a triple-insert MVA virus. This triple-insert MVA is plaque purified under transient marker selection.
The triple-insert MVA vectors, named MVA-hlHA-M1-NP or MVA-hlHA/M2e-M1-NP contain the hlHA or hlHA/M2e expression cassette and M1 expression cassette in tandem order in the D4R/D5R locus and the NP expression cassette in the del III locus (
Detection of VLPs is as follows. HeLa or 293 cells are seeded into T175 cm2 flasks and grown in DMEM+10% FCS+Pen/Strep. To generate VLPs, cells are infected with 1 MOI of single-insert MVA or triple-insert MVA recombinants, respectively. Empty MVA vectors or single-insert MVA recombinants without M1 are used as controls. At 1 h post infection (p.i.), the medium is replaced by DMEM+Pen/Strep and culture medium is harvested 48 h p.i. and cellular debris is pelleted by centrifugation at 2.000×g for 10 min. The procedure for analyzing VLPs by sucrose gradient density flotation and sucrose cushion has been described previously (Chen et al. 2007; Chen et al. 2005; Gomez-Puertes et al. 2000). The samples are then analyzed by immunoblotting. Additionally, electron microscopy (EM) analysis with medium of infected cells is performed.
A standard experiment includes 6 groups of primed and unprimed mice (vaccinated with the 6 vaccines and controls shown in Table 5), each group consisting of 6 animals, resulting in 36 animals (1 set). The animals are challenged with one of the 6 challenge viruses shown in Table 3. In sum, there are 6 sets of 72 animals each requiring 432 mice to assess cross-protection in the primed and naive models.
The present invention is illustrated by the foregoing examples and variations thereof will be apparent to those skilled in the art. Therefore, no limitations other than those set out in the following claims should be placed on the invention.
All documents cited in this application are hereby incorporated by reference in their entirety for their disclosure described.
Kreijtz, J. H., Y. Suezer, G. de Mutsert, J. M. van den Brand, G. van Amerongen, B. S. Schnierle, T. Kuiken, R. A. Fouchier, J. Lower, A. D. Osterhaus, G. Sutter, and G. F. Rimmelzwaan. 2009. Recombinant modified vaccinia virus Ankara expressing the hemagglutinin gene confers protection against homologous and heterologous H5N1 influenza virus infections in macaques. J Infect Dis 199:405-13.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US2012/023085 | 1/30/2012 | WO | 00 | 11/5/2013 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2012/106231 | 8/9/2012 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 6998252 | Moss et al. | Feb 2006 | B1 |
| 7015024 | Moss et al. | Mar 2006 | B1 |
| 7045136 | Moss et al. | May 2006 | B1 |
| 7045313 | Moss et al. | May 2006 | B1 |
| Number | Date | Country |
|---|---|---|
| WO-2008118487 | Oct 2008 | WO |
| WO-2010056991 | May 2010 | WO |
| WO 2010117786 | Oct 2010 | WO |
| WO-2010117786 | Oct 2010 | WO |
| Entry |
|---|
| Bender et al (Journal of Virology 70:6418-6425, 1996). |
| Steel et al (mBio1(1):e300018-10, pp. 1-9; 2010). |
| Sun et al (PNAS 108:4164-4169, 2011). |
| Andrew et al., Cell-mediated immune responses to influenza virus antigens expressed by vaccinia virus recombinants, Microbial Pathogenesis, 1:443-52 (1986). |
| Andrew et al., The roles of influenza virus haemagglutinin and nucleoprotein in protection: analysis using vaccinia virus recombinants, Scand J. Immunol., 25:21-8 (1987). |
| Antoine et al., Characterization of the vaccinia MVA hemagglutinin gene locus and its evaluation as an insertion site for foreign genes, Gene, 177(1-2):43-6 (1996). |
| Antoine et al., The complete genomic sequence of the modified vaccinia Ankara strain: comparison with other orthopoxviruses, Virology, 244(2):365-96 (1998). |
| Assarsson et al., Immunomic analysis of the repertoire of T-cell specificities for influenza A virus in humans, J. Virol., 82(24):12241-51 (2008). |
| Berthoud et al., Potent CD8+ T-cell immunogenicity in humans of a novel heterosubtypic influenza A vaccine, MVA-NP+M1, Clin. Infect. Dis., 52(1):1-7 (2011). |
| Bommakanti et al., Design of an HA2-based Escherichia coli expressed influenza immunogen that protects mice from pathogenic challenge, Proc. Natl. Acad. Sci. USA, 107(31):13701-6 (2010). |
| Bright et al., Influenza virus-like particles elicit broader immune responses than whole virion inactivated influenza virus or recombinant hemagglutinin, Vaccine, 24(19):3871-8 (2007). |
| Brookes et al., Safety and immunogenicity of the candidate tuberculosis vaccine MVA85A in West Africa, PLoS One, 3(8):e2921 (2008). |
| Carroll et al., Poxviruses as expression vectors, Curr. Opin. Biotechnol., 8(5):573-7 (1997). |
| Cebere et al., Phase I clinical trial safety of DNA- and modified virus Ankara-vectored human immunodeficiency virus type 1 (HIV-1) vaccines administered alone and in a prime-boost regime to healthy HIV-1-uninfected volunteers, Vaccine, 24(4):417-25 (2006). |
| Chakrabarti et al., Compact, synthetic, vaccinia virus early/late promoter for protein expression, Biotechniques, 23(6):1094-7 (1997). |
| Chang et al., A single dose of DNA vaccine based on conserved H5N1 subtype proteins provides protection against lethal H5N1 challenge in mice pre-exposed to H1N1 influenza virus, Virol. J., 7:197 (2010). |
| Chen et al., A soluble domain of the membrane-anchoring chain of influenza virus hemagglutinin (HA2) folds in Escherichia coli into the low-pH-induced conformation, Proc. Natl. Acad. Sci. USA, 92(26):12205-9 (1995). |
| Chen et al., Influenza virus hemagglutinin (H3 subtype) requires palmitoylation of its cytoplasmic tail for assembly: M1 proteins of two subtypes differ in their ability to support assembly, J. Virol., 79(21):13673-84 (2005). |
| Chen et al., Influenza virus hemagglutinin and neuraminidase, but not the matrix protein, are required for assembly and budding of plasmid-derived virus-like particles, J. Virol., 81(13):7111-23 (2007). |
| De Filette et al., An influenza A vaccine based on tetrameric ectodomain of matrix protein 2, J. Biol. Chem., 283(17):11382-7 (2008). |
| Denis et al., Development of a universal influenza A vaccine based on the M2e peptide fused to the papaya mosaic virus (PapMV) vaccine platform, Vaccine, 26(27-28):3395-403 (2008). |
| Du et al., Research and development of universal influenza vaccines, Microbes and Infection, 12:280-6 (2010). |
| Ekiert et al., Antibody recognition of a highly conserved influenza virus epitope, Science, 324(5924):246-51 (2009). |
| Eliasson et al., CTA1-M2e-DD: a novel mucosal adjuvant targeted influenza vaccine, Vaccine, 26(9):1243-52 (2008). |
| Epstein, Prior H1N1 influenza infection and susceptibility of Cleveland Family Study participants during the H2N2 pandemic of 1957: an experiment of nature, J. Infect. Dis., 193(1):49-53 (2006). |
| Fan et al., Preclinical study of influenza virus a M2 peptide conjugate vaccines in mice, ferrets, and rhesus monkeys, Vaccine, 22(23-24):2993-3003 (2004). |
| Fiers et al., M2e-based universal influenza A vaccine, Vaccine, 27(45):6280-3 (2009). |
| Gomez-Puertas et al., Influenza virus matrix protein is the major driving force in virus budding, J. Virol., 74(24):11538-47 (2000). |
| Gomez-Puertas et al., Efficient formation of influenza virus-like particles: dependence on the expression levels of viral proteins, J. Gen. Virol., 80:1635-45 (1999). |
| Graham et al., A new technique for the assay of infectivity of human adenovirus 5 DNA, Virology, 52(2):456-67 (1973). |
| Greenbaum et al., Pre-existing immunity against swine-origin H1N1 influenza viruses in the general human population, Proc. Natl. Acad. Sci. USA, 106(48):20365-70 (2009). |
| Hessel et al., A pandemic influenza H1N1 live vaccine based on modified vaccinia Ankara is highly immunogenic and protects mice in active and passive immunizations, PLoS One, 5(8):e12217 (2010). |
| Hessel et al., Vectors based on modified vaccinia Ankara expressing influenza H5N1 hemagglutinin induce substantial cross-clade protective immunity, PLoS One, 6(1):e16247 (2011). |
| Hoelscher et al., Development of adenoviral-vector-based pandemic influenza vaccine against antigenically distinct human H5N1 strains in mice, Lancet, 367(9509):475-81 (2006). |
| Hoelscher et al., New pre-pandemic influenza vaccines: an egg- and adjuvant-independent human adenoviral vector strategy induces long-lasting protective immune responses in mice, Clin. Pharmacol. Ther., 82(6):665-71 (2007). |
| Holzer et al., Dominant host range selection of vaccinia recombinants by rescue of an essential gene, Virology, 249(1):160-6 (1998). |
| International Preliminary Report on Patentability, corresponding international application No. PCT/US2012/023085, Aug. 6, 2013. |
| International Search Report and Written Opinion, corresponding international application No. PCT/US2012/023085, Aug. 8, 2012. |
| Joseph et al., Evaluation of replication and pathogenicity of avian influenza A H7 subtype viruses in a mouse model, J. Virol., 81(19):10558-66 (2007). |
| Kang et al., Novel vaccines against influenza viruses, Virus Res., 162(1-2):31-8 (2011). |
| Kashyap et al., Combinatorial antibody libraries from survivors of the Turkish H5N1 avian influenza outbreak reveal virus neutralization strategies, Proc. Natl. Acad. Sci. USA, 105(16):5986-91 (2008). |
| Katz et al., Molecular correlates of influenza A H5N1 virus pathogenesis in mice, J. Virol., 74(22):10807-10 (2000). |
| Kistner et al., Cell culture (vero) derived whole virus (H5N1) vaccine based on wild-type strain induces cross-protective immune responses, Vaccine 25(32):6028-36 (2007). |
| Kreijtz et al., Cross-recognition of avian H5N1 influenza virus by human cytotoxic T-lymphocyte populations directed to human influenza A virus, J. Virol., 82(11):5161-6 (2008). |
| Kreijtz et al., Evaluation of a modified vaccinia virus Ankara (MVA)-based candidate pandemic influenza A/H1N1 vaccine in the ferret model, J. Gen. Virol., 91:2745-52 (2010). |
| Kreijtz et al., MVA-based H5N1 vaccine affords cross-clade protection in mice against influenza A/H5N1 viruses at low doses and after single immunization, PLoS One, 4(11):e7790 (2009). |
| Kreijtz et al., Preclinical evaluation of a modified vaccinia virus Ankara (MVA)-based vaccine against influenza A/H5N1 viruses, Vaccine, 27(45):6296-9 (2009). |
| Kreijtz et al., Recombinant modified vaccinia virus Ankara expressing the hemagglutinin gene confers protection against homologous and heterologous H5N1 influenza virus infections in macaques, J. Infect. Dis., 199(3):405-13 (2009). |
| Kreijtz et al., Recombinant modified vaccinia virus Ankara-based vaccine induces protective immunity in mice against infection with influenza virus H5N1, J. Infect. Dis., 195(11):1598-606 (2007). |
| Lamb et al., The proton selective ion channels of influenza A and B viruses, pp. 65-92, IN: Kawaoka (ed.), Influenza Virology: Current Topics, Caister Academic Press (2006). |
| Lambert et al., Influenza vaccines for the future, N. Engl. J. Med., 363(21):2036-44 (2010). |
| Latham et al., Formation of wild-type and chimeric influenza virus-like particles following simultaneous expression of only four structural proteins, J. Virol., 75(13):6154-65 (2001). |
| Lee et al., Memory T cells established by seasonal human influenza A infection cross-react with avian influenza A (H5N1) in healthy individuals, J. Clin. Invest., 118(10):3478-90 (2008). |
| Lu et al., A mouse model for the evaluation of pathogenesis and immunity to influenza A (H5N1) viruses isolated from humans, J. Virol., 73(7):5903-11 (1999). |
| Mackett et al., Vaccinia virus: a selectable eukaryotic cloning and expression vector, Proc. Natl. Acad. Sci. USA, 79(23):7415-9 (1982). |
| Mayr et al., Abstammung, eigenschaften and verwendung des attenuierten vaccinia-stammes MVA, Infection, 3:6-14 (1975)—Abstract in English only. |
| Mayrhofer et al., Nonreplicating vaccinia virus vectors expressing the H5 influenza virus hemagglutinin produced in modified Vero cells induce robust protection, J. Virol., 83(10):5192-203 (2009). |
| McMichael et al., Recognition of influenza A virus nucleoprotein by human cytotoxic T lymphocytes, J. Gen. Virol., 67(Pt. 4):719-26 (1986). |
| Mena et al., Rescue of a synthetic chloramphenicol acetyltransferase RNA into influenza viruslike particles obtained from recombinant plasmids, 70(8):5016-24 (1996). |
| Meyer et al., Mapping of deletions in the genome of the highly attenuated vaccinia virus MVA and their influence on virulence, J. Gen. Virol., 72(Pt. 5):1031-8 (1991). |
| Moss et al., Host range restricted, non-replicating vaccinia virus vectors as vaccine candidates, Adv. Exp. Med. Biol., 397:7-13 (1996). |
| Neirynck et al., A universal influenza A vaccine based on the extracellular domain of the M2 protein, Nat. Med., 5(10):1157-63 (1999). |
| Noton et al., Identification of the domains of the influenza A virus M1 matrix protein required for NP binding, oligomerization and incorporation into virions, J. Gen. Virol., 88:2280-90 (2007). |
| Okuno et al., A common neutralizing epitope conserved between the hemagglutinins of influenza A virus H1 and H2 strains, J. Virol., 67(5):2552-8 (1993). |
| Poon et al., Vaccinia virus-based multivalent H5N1 avian influenza vaccines adjuvanted with IL-15 confer sterile cross-clade protection in mice, J. Immunol., 182(5):3063-71 (2009). |
| Price et al., Single-dose mucosal immunization with a candidate universal influenza vaccine provides rapid protection from virulent H5N1, H3N2 and H1N1 viruses, PLoS One, 5(10):e13162 (2010). |
| Price et al., Vaccination focusing immunity on conserved antigens protects mice and ferrets against virulent H1N1 and H5N1 influenza A viruses, Vaccine, 27(47):6512-21 (2009). |
| Pushko et al., Influenza virus-like particles comprised of the HA, NA, and M1 proteins of H9N2 influenza virus induce protective immune responses in BALB/c mice, Vaccine, 23(50):5751-9 (2005). |
| Rao et al., Comparative efficacy of hemagglutinin, nucleoprotein, and matrix 2 protein gene-based vaccination against H5N1 influenza in mouse and ferret, PLoS One, 5(3):e9812 (2010). |
| Ricci et al., Selection of recombinant MVA by rescue of the essential D4R gene, Virol. J., 8:429 (2011). |
| Rimmelzwaan et al., Candidate influenza vaccines based on recombinant modified vaccinia virus Ankara, Expert Rev. Vaccines, 8(4):447-54 (2009). |
| Sanchez-Fauquier et al., Isolation of cross-reactive, subtype-specific monoclonal antibodies against influenza virus HA1 and HA2 hemagglutinin subunits, Arch. Virol., 94(3-4):251-65 (1987). |
| Scheiflinger et al., Transient marker stabilisation: a general procedure to construct marker-free recombinant vaccinia virus, Arch. Virol., 143(3):467-74 (1998). |
| Schotsaert et al., Universal M2 ectodomain-based influenza A vaccines: preclinical and clinical developments, Expert Rev. Vaccines, 8(4):499-508 (2009). |
| Slavik et al., Optimalized conditions of tick-borne encephalitis virus production in vitro, Acta Virol., 27(2):97-104 (1983). |
| Smith et al., Synthesis and cellular location of the ten influenza polypeptides individually expressed by recombinant vaccinia viruses, Virology, 160(2):336-45 (1987). |
| Song et al., Protective immunity against H5N1 influenza virus by a single dose vaccination with virus-like particles, Virology, 405(1):165-75 (2010). |
| Steel et al., Influenza virus vaccine based on the conserved hemagglutinin stalk domain, MBio, 1(1):e00018-10 (2010). |
| Sui et al., Structural and functional bases for broad-spectrum neutralization of avian and human influenza A viruses, Nat. Struct. Mol. Biol., 16(3):265-73 (2009). |
| Throsby et al., Heterosubtypic neutralizing monoclonal antibodies cross-protective against H5N1 and H1N1 recovered from human IgM+ memory B cells, PLoS One, 3(12):e3942 (2008). |
| Tykodi et al., Development of modified vaccinia Ankara-5T4 as specific immunotherapy for advanced human cancer, Expert Opin. Biol. Ther., 8(12):1947-53 (2008). |
| Ulmer et al., Heterologous protection against influenza by injection of DNA encoding a viral protein, Science, 259(5102):1745-9 (1993). |
| Wu et al., Heterosubtypic protection conferred by combined vaccination with M2e peptide and split influenza vaccine, Vaccine, 27(43):6095-101 (2009). |
| Wyatt et al., Development of a replication-deficient recombinant vaccinia virus vaccine effective against parainfluenza virus 3 infection in an animal model, Vaccine, 14(15):1451-8 (1996). |
| Yewdell et al., Influenza A virus nucleoprotein is a major target antigen for cross-reactive anti-influenza A virus cytotoxic T lymphocytes, Proc. Natl. Acad. Sci. USA, 82(6):1785-9 (1985). |
| Zhao et al., An H5N1 M2e-based multiple antigenic peptide vaccine confers heterosubtypic protection from lethal infection with pandemic 2009 H1N1 virus, Virol. J., 7:151 (2010). |
| Zhao et al., An M2e-based multiple antigenic peptide vaccine protects mice from lethal challenge with divergent H5N1 influenza viruses, Virol. J., 7:9 (2010). |
| Zhou et al., A universal influenza A vaccine based on adenovirus expressing matrix-2 ectodomain and nucleoprotein protects mice from lethal challenge, Mol. Ther., 18(12):2182-9 (2010). |
| Ilyushina et al., Adaptation of pandemic H1N1 influenza viruses in mice, J. Virol., 84(17):8607-16 (2010). |
| Number | Date | Country | |
|---|---|---|---|
| 20140050759 A1 | Feb 2014 | US |
| Number | Date | Country | |
|---|---|---|---|
| 61438024 | Jan 2011 | US |
