title: Peptide mimics of a conserved H5N1 avian influenza virus neutralization site.
abstract: A panel of 52 murine monoclonal antibodies was found to recognize antigenic determinants that had been conserved among all major genetic subgroups of the H5N1 avian influenza virus prevalent since 1997. We screened a phage display library for peptides recognized by one such antibody (8H5). We analysed the specificity of 8H5 for reactive peptides presented as fusion proteins of HBc (hepatitis B core protein) and HEV (hepatitis E virus) structural protein, p239. This was then related to the specificity of the native HA (haemagglutinin) molecule by virtue of the capacity of fusion proteins to compete for 8H5 binding with different strains of H5N1 virus and the reactivity of antisera generated against fusion proteins to bind native HA molecules, and to inhibit haemagglutination and arrest infection by the virus. Nine reactive peptides of different amino acid sequences were identified, six of which were also reactive with the antibody in association with HBc and four were in association with p239. Binding occurred with the dimeric form of the four p239-fusion proteins and one of the HBc-fusion proteins, but not with the monomeric form. The HBc-fusion proteins blocked 8H5 binding with four strains of H5N1 influenza virus. Mouse antisera generated against fusion proteins bound to HA molecules, but did not inhibit haemagglutination or arrest H5N1 infection. Our findings indicate that 8H5 recognizes discontinuous sites presented by secondary and possibly higher structural orders of the peptides in spatially favourable positions for binding with the antibody, and that the peptides partially mimic the native 8H5 epitopes on the H5N1 virus.
authors.affiliation: The Key Laboratory of Education Minister for Cell Biology and Tumor Cell Engineering of Xiamen University, School of Life Sciences, Xiamen University, Xiamen 361005, China. wxluo@xmu.edu.cn
authors.forename: Wenxin
authors.initials: W
authors.lastname: Luo
authors.forename: Yingwei
authors.initials: Y
authors.lastname: Chen
authors.forename: Mingqiao
authors.initials: M
authors.lastname: Wang
authors.forename: Yixin
authors.initials: Y
authors.lastname: Chen
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Zheng
authors.forename: Huijuan
authors.initials: H
authors.lastname: Song
authors.forename: Honglin
authors.initials: H
authors.lastname: Chen
authors.forename: Yi
authors.initials: Y
authors.lastname: Guan
authors.forename: Mun Hon
authors.initials: MH
authors.lastname: Ng
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.forename: Ningshao
authors.initials: N
authors.lastname: Xia
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015153:Blotting, Western; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006384:Hemagglutination; D006512:Hepatitis B Core Antigens / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D006518:Hepatitis Viruses / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D007106:Immune Sera / Q000276:immunology; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D019151:Peptide Library; D010455:Peptides / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D018411:Spodoptera; D014764:Viral Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D006512:Hepatitis B Core Antigens; D007106:Immune Sera; D019151:Peptide Library; D010455:Peptides; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins