Expression of Hemagglutinin Gene of Avian influenza virus Subtype H5 in Escherichia coli and the Preliminary Analysis of Bioactivity

The hemagglutinin(HA)HAI gene of Avian intluenza virus(AIV)subtype H5 was amplified by RT-PCR according to the sequence published on GenBank.It was cloned into the expression vector PET-28a.The protein encoded by this gene was expressed in Escherichia coli strain BL21(DE3)and identified by SDS-PAGE and Western-blot.The results indicated that this protein could be specifically recognized by H5 subtype AIV antiserum.The cross-reactivity test results showed that this protein could only react with H5 subtype AIV antiserum but not with any other antiserum against NDV,IBV,etc.The results from detection of 236 serum samples by ELISA using the purified protein were 100% in agreement with that of HI test.All these results demonstrate that this expressed protein is of good antigenicity and can hold great promise for development of diagnostic kits for avian influenza.