Expression of recombinant HA1 protein for specific detection of influenza A/H1N1/2009 antibodies in human serum



Yan Li, National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, Manitoba, Canada R3E 3R2. Tel: +204 789 6045; fax: 204 789 2082; email:


The hemagglutinin genes (HA1 subunit) from human and animal 2009 pandemic H1N1 virus isolates were expressed with a baculovirus vector. Recombinant HA1 (rHA1) protein-based ELISA was evaluated for detection of specific influenza A(H1N1)pdm09 antibodies in serum samples from vaccinated humans. It was found that rHA1 ELISA consistently differentiated between antibodies recognizing the seasonal influenza H1N1 and pdm09 viruses, with a concordance of 94% as compared to the hemagglutination inhibition test. This study suggests the utility of rHA1 ELISA in serosurveillance.