title: A critical HA1 neutralizing domain of H5N1 influenza in an optimal conformation induces strong cross-protection.
abstract: The highly pathogenic avian influenza (HPAI) H5N1 viruses, especially the laboratory-generated H5N1 mutants, have demonstrated the potential to cross the species barrier and infect mammals and humans. Consequently, the design of an effective and safe anti-H5N1 vaccine is essential. We previously demonstrated that the full-length hemagglutinin 1 (HA1) could induce significant neutralizing antibody response and protection. Here, we intended to identify the critical neutralizing domain (CND) in an optimal conformation that can elicit strong cross-neutralizing antibodies and protection against divergent H5N1 strains. We thus constructed six recombinant proteins covering different regions of HA1 of A/Anhui/1/2005(H5N1), each of which was fused with foldon (Fd) and Fc of human IgG. We found that the critical fragment fused with Fd/Fc (HA-13-263-Fdc, H5 numbering) that could elicit the strongest neutralizing antibody response is located in the N-terminal region of HA1 (residues 13-263), which covers the receptor-binding domain (RBD, residues 112-263). We then constructed three additional recombinants fused with Fd plus His tag (HA-13-263-Fd-His), Fc only (HA-13-263-Fc), and His tag only (HA-13-263-His), respectively. We found that the HA-13-263-Fdc, which formed an oligomeric conformation, induced the strongest neutralizing antibody response and cross-protection against challenges of two tested H5N1 virus strains covering clade 1: A/VietNam/1194/2004 (VN/1194) or clade 2.3.4: A/Shenzhen/406H/06 (SZ/406H), while HA-13-263-Fc dimer and HA-13-263-Fd-His trimer elicited higher neutralizing antibody response and protection than HA-13-263-His monomer. These results suggest that the oligomeric form of the CND containing the RBD can be further developed as an effective and safe vaccine for cross-protection against divergent strains of H5N1 viruses.
authors: Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America.
authors: Lanying
authors: L
authors: Du
authors: Guangyu
authors: G
authors: Zhao
authors: Shihui
authors: S
authors: Sun
authors: Xiujuan
authors: X
authors: Zhang
authors: Xiaojun
authors: X
authors: Zhou
authors: Yan
authors: Y
authors: Guo
authors: Ye
authors: Y
authors: Li
authors: Yusen
authors: Y
authors: Zhou
authors: Shibo
authors: S
authors: Jiang
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000096:biosynthesis* / Q000627:therapeutic use; D000914:Antibodies, Viral / Q000096:biosynthesis* / Q000627:therapeutic use; D000956:Antigens, Viral / Q000276:immunology; D003429:Cross Reactions; D005260:Female; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000737:chemistry* / Q000276:immunology*; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000737:chemistry / Q000276:immunology* / Q000472:pathogenicity; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009500:Neutralization Tests / Q000379:methods*; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D000956:Antigens, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines; D011993:Recombinant Fusion Proteins; D014614:Vaccines, Synthetic; C109963:hemagglutinin, avian influenza A virus