Characterization of the E. coli-expressed HA1 protein of H5 subtype influenzavirus.

To produce the recombinant hemagglutinin(HA1)protein of H5 subtype avian influenza virus(AIV),the recombinant plasmid pETHA1-H5 was constructed by the RT-PCR-amplified HA1 gene and then cloned into a pET-28a expression vector.The results showed that the insoluble HA1 protein was expressed in the Escherichia coli BL21(DE3)strain transformed with the plasmid pETHA1-H5,and can be recognized with chicken,duck and goose AIV antisera(H5 subtype).The monoclonal antibodies to the prokaryotically expressed HA1 protein reacted with the influenza virus antigen(H5 subtype).The data confirmed that the E.coli-expressed HA1 protein remains the antigenic characteristics of H5 subtype avian influenza virus.In detecting the antibody to H5 subtype AIV,the HA1-based ELISA shares a higher identity to hemagglutination inhibition.The result illuminated that the recombinant HA1 protein has a potential as an ELISA antigen for monitoring antibody to H5 subtype avian influenza virus.