U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version



Virology 446 (2013) 225–229; http://dx.doi.org/10.1016/j.virol.2013.08.004


Two distinct antigenic clusters were previously identified among the H3N2 swine influenza A viruses (IAVs) and were designated H3N2SIV-alpha and H3N2SIV-beta (Feng et al., 2013. Journal of Virology 87(13), 7655–7667). A consistent mutation was observed at the position 189 of hemagglutinin (R189K) between H3N2SIV-alpha and H3N2SIV-beta fair isolates. To evaluate the contribution of R189K mutation to the antigenic drift from H3N2SIV-alpha to H3N2SIV-beta, four reassortant viruses with189R or189K were generated. The antigenic cartography demonstrated that the R189K mutation in the hemagglutinin of H3N2IAV contributed to the antigenicdrift, separating these viruses into H3N2SIV-alpha to H3N2SIV- beta. This R189K mutation was also found to contribute to the cross-reaction with several ferret sera raised against historical human IAVs with hemagglutinin carrying 189K. This study suggests that the R189K mutation plays a vital role in the antigenicity of swine and human H3N2IAVs and identification of this antigenic determinant will help us rapidly identify antigenic variants in influenza surveillance.