Expression,Identification And Immunological Study Of H5N1 And H7N9 Influenza Virus Hemagglutinin(HA) Protein

The subtype of H5N1 and H7N9 avian influenza virus have been able to across-species transmit to humans through continuous variation, but there still has a potential threat to people lives. In order to study the main characteristics of AIV HA antigen, this study used baculovirus expression system and detected the immunological of HA protein. Firstly, H5N1 and H7N9 avain influenza virus HA gene was amplified and cloned into pFastBacI. By homologous recombination, a shuttle plasmid containing the target gene was constructed. Recombinant baculovirus was obtained by transfecting insect cell sf9 with shuttle plasmid. The HA protein was indentified by SDS-PAGE, Western-blot and indirect immunofluorescence. To evaluate immunological of HA, mice immunized twice with the purified HA protein at 0 and 14 d. Two weeks after immunization, mice immuned by H5N1 HA were challenged with H5N1 virus, Mice were observed daily to monitor body weight changes and mortality; Results : In reducing SDS-PAGE, the purified protein exhibited protein band was with a molecular mass of 65 KDa and 67 KDa;Western-blot assay showed that the purified protein had recognition specificity to rabbit IgG antiserum and chick IgG;IFA determined the expression levels of HA using chicken antisera raised against WIV and mouse IgG. Specific fluorescence was observed in HA-infectedinsect cells but not in uninfected mock cells. Our results suggest that the HA group generated protective immune responses against A/meerkat/Shanghai/SH-1/2012(clade 2.3.2.1) lethal challenges.This study successfully expressed the HA of H5N1 and H7N9 avian influenza virus, and laid the foundation for further understanding of H5N1 and H7N9 avian influenza virus, also for the study of subunit vaccines provide technical support.