Comparison of influenza virus replication fidelity in vitro using selection pressure with monoclonal antibodies

The replication fidelity of reassortant A/Fujian/411/02(H3N2)-like influenza viruses was assessed by in vitro detection of escape mutants developing under selective pressure from monoclonal antibodies. The results showed A/Wyoming/3/03(H3N2) possessed lower fidelity relative to the A/California/7/04(H3N2) and A/Wisconsin/57/05(H3N2) viruses through the emergence of mutant viruses carrying H156Q hemagglutinin mutation which allows antibody escape. Using the neutralization assay to compare the fidelity of reassortant pandemic A/California/7/09(H1N1) viruses, the pandemic virus was shown to possess relative higher fidelity compared to A/Wyoming/3/03. This higher fidelity may contribute to the lack of major antigenic changes in the pandemic virus since the emergence in 2009.