Genetic and antigenic analysis of the hemagglutinin of recent swine influenza virus isolates utilizing a unique software program comparing amino acid substitutions in immunogenic sites

摘要

Antigenic drift and antigenic shift within swine influenza isolates has potential public health ramifications especially since the introduction of H3N2 virus into the US swine population in 1998 and the introduction of human-like H1N1 and H1N2 in 1999and 2000. Triple re-assortment viruses containing gene segments from human, avian and swine are frequently isolated from pigs. The recent human pandemic outbreak of H1N1 containing gene segments of human, US and Eurasian swine, and avian species underlines the necessity for swine influenza disease surveillance, vaccine escape mutant prediction, and rational vaccine virus selection. Traditionally, disease surveillance programs and vaccine candidate selection techniques have relied on partial hemagglutinin (HA) gene sequencing to subtype and genetically characterize influenza isolates. Antigenic properties of new isolates are inferred based on HA protein genetic sequence homology.