Prediction of the antigenic changes of the pandemic (H1N1) 2009 influenza virus hemagglutinin

摘要

A pandemic influenza virus (2009 H1N1) was recently introduced into the human population. The hemagglutinin (HA) gene of 2009 H1N1 is derived from 'classical swine H1N1' virus, which likely shares a common progenitor strain with the human H1N1 virus that caused the pandemic in 1918.Since antigenic changes of influenza virus HA occur more slowly in swine than in humans, we hypothesized that 2009 H1N1 might still retain an antigenic structure similar to that of 1918 H1N1 or the early isolates of its descendants.In this study, we compared HA antigenic structures of 2009 H1N1 and human H1N1 viruses by a molecular modeling approach to demonstrate the existence of shared epi-topes for neutralizing antibodies. We found that HAs of 2009 H1N1 and the 1918 H1N1 virus shared a significant number of amino acid residues in known antigenic regions. From this observation, we hypothesize that the 2009 H1N1 HA antigenic sites will be targeted by antibody-mediated selection pressure in humans in the near future. We further discuss possible directions of antigenic changes in the evolutionary process of 2009 H1N1.