title: Novel approach to the development of effective H5N1 influenza A virus vaccines: use of M2 cytoplasmic tail mutants.
abstract: Outbreaks of highly pathogenic H5N1 influenza viruses in avian species began in Asia and have since spread to other continents. Concern regarding the pandemic potential of these viruses in humans is clearly warranted, and there is an urgent need to develop effective vaccines against them. Previously, we and others demonstrated that deletions of the M2 cytoplasmic tail caused a growth defect in A/WSN/33 (H1N1) influenza A virus in vitro (K. Iwatsuki-Horimoto, T. Horimoto, T. Noda, M. Kiso, J. Maeda, S. Watanabe, Y. Muramoto, K. Fujii, and Y. Kawaoka, J. Virol. 80:5233-5240, 2006; M. F. McCown and A. Pekosz, J. Virol. 79:3595-3605, 2005; M. F. McCown and A. Pekosz, J. Virol. 80:8178-8189, 2006). We therefore tested the feasibility of using M2 tail mutants as live attenuated vaccines against H5N1 virus. First we generated a series of highly pathogenic H5N1 (A/Vietnam/1203/04 [VN1203]) M2 cytoplasmic tail deletion mutants and examined their growth properties in vitro and in vivo. We found that one mutant, which contains an 11-amino-acid deletion from the C terminus (M2del11 virus), grew as well as the wild-type virus but replicated in mice less efficiently. We then generated a recombinant VN1203M2del11 virus whose hemagglutinin (HA) gene was modified by replacing sequences at the cleavage site with those of an avirulent type of HA (M2del11-HAavir virus). This M2del11-HAavir virus protected mice against challenge with lethal doses of homologous (VN1203; clade 1) and antigenically distinct heterologous (A/Indonesia/7/2005; clade 2) H5N1 viruses. Our results suggest that M2 cytoplasmic tail mutants have potential as live attenuated vaccines against H5N1 influenza viruses.
authors.affiliation: Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53706, USA.
authors.forename: Tokiko
authors.initials: T
authors.lastname: Watanabe
authors.forename: Shinji
authors.initials: S
authors.lastname: Watanabe
authors.forename: Jin Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Masato
authors.initials: M
authors.lastname: Hatta
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kawaoka
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis; D001483:Base Sequence; D002460:Cell Line; D003593:Cytoplasm / Q000276:immunology*; D017931:DNA Primers; D004285:Dogs; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics / Q000276:immunology* / Q000502:physiology; D007252:Influenza Vaccines / Q000276:immunology*; D009154:Mutation; D014779:Virus Replication
chemical_list: D000914:Antibodies, Viral; D017931:DNA Primers; D007252:Influenza Vaccines