| Abstract: | The hemagglutinin (HA) of avian influenza virus (AIV) plays a key role in determining the pathogenicity, cell receptor-binding property and host range of the virus. A goose origin AIV A/Goose/Guangdong/1/96(H5N1) (GD/96) was confirmed as a highly pathogenic AIV (HPAIV) by the tests of intravenous pathogenic index (IVPI) and the assay of plaque formation. The sequence results of the HA gene cDNA of the isolate reveal that there is an insertion of 6 basic amino acids ( R-R-R-K-K-R-) in the cleavage site between the HA1 and HA2, which is the characterization of the H5 subtype HPAIV. When compared with the lethal A/Hongkong/156/97 (H5N1) (HK/97), there is a homology of 98% at the nucleotide level and 98. 2% at the amino acid level. Furthermore, no difference of nucleotides related to all of the 6 potential glycosylation sites, the 2 receptor-binding sites and the basic amino acid insert within the HA existed between GD/96 and HK/97. These results imply that the GD/96 and HK/97 have a closely related common ancestor and share the same biological properties decided by the HA. |
