| Avian influenza (AI) is a fowl disease, which is caused by type A influenzavirus. The fatal disease, named "highly pathogenic avian influenza", is caused bysubtypes H5 and H7 of influenza A virus. In recently years, new changes appear thatavian influenza virus (AIV) could cause waterfowl death and especially, highlypathogenic avian influenza viruses could infect humans directly, resulting illness anddeath. The variability of hemagglutinin (HA) gene is the biggest in AIV genes, andthe antigenicity and pathogenicity of AIV depend on the variability of HA gene inmost degree. Hemaglutinin plays an important role in the process of cohesion andtransmembrane of AIV that makes the host produces the neutralizing antibody,neutralizing the infection of virus. Humoral immunity against HA is the maindeterminant for protecting the host against disease. Based on the above, H5 avianinfluenza virus from different sources were selected to study the antigenic variationand molecular genetic relation of HA gene. The experiment is divided into two parts.The first part: Study on antigenic variation of influenza A virus subtype H5hemagglutininSPF chicken embryo was inoculated with various concentration of AIV (H5 subtype)to obtain the allantoic fluid, and then the antigen of LS02 and DJ02 stains wereprepared to immune SPF chicken, getting the single serum, respectively. Byhemagglutination inhibition (HI) tests, HA gene of all AIV antigenic variation inSerology was compared. The result showed that there were some antigenicdifference in isolates, the range of HI titer discrepancy is from 1 to 4, the differenceof isolates from chicken is smaller, but the difference of isolates between from gooseand from other strains is bigger.The second part: Study on genetic variation of influenza A virus subtype H5hemagglutininSPF chicken embryo was inoculated with various concentration of AIV (H5 subtype)to obtain the allantoic fluid. The genomic RNA of the eight AIV isolate were... |
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