Genetics, Development and Cell Biology
Influenza A virus (IAV) is a significant threat to profitability in the swine industry. Although vaccines can prevent the damage and spread of the pathogen, changes in the antigenic properties of the virus due to evolution may cause the virus to escape the immune response. Identifying key amino acids on the hemagglutinin (HA) protein that significantly contribute to antigenicity is important for understanding how IAV adapts in response to immune pressures so more effective vaccines can be developed. In this study we took antigenic distance data obtained by hemagglutination inhibition assays from 30 H1 subtype influenza virus strains and combined it with amino acid sequence data from the HA of the same isolates. We plotted these two variables against each other to obtain linear relationships between antigenic and genetic similarity of the viruses. We then compared amino acid differences between outlier comparisons using a threshold of two antigenic distance units above the linear fit and determined the most represented positions among all outliers. We found six amino acid positions on the HA had changes that were associated with over 50% of the outlier comparisons. These results significantly contribute to the framework of H1 IAV characterization for disease prevention efforts.