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 with 189R or 189K were generated. The antigenic cartography demonstrated that the R189K mutation in the hemagglutinin of H3N2 IAV contributed to the antigenic drift, 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 H3N2 IAVs and identification of this antigenic determinant will help us rapidly identify antigenic variants in influenza surveillance.
Bibliographical noteFunding Information:
We are grateful for Dr. Zhixin Feng for his assistance in ferret sera generation. This work was supported in part by the Minnesota Center of Excellence for Influenza Research and Surveillance (MCEIRS) with federal funds from the Centers of Excellence for Influenza Research and Surveillance (CEIRS) , National Institute of Allergy and Infectious Diseases , National Institutes of Health, Department of Health and Human Services , under Contract no. HHSN266200700007C . The finding and conclusions in this study are those of the authors and do not necessarily reflect the views of the funding agency.
- Antigenic cartography
- Antigenic drift
- Antigenic variant
- Influenza A virus
- Serological assay