Diversifying selective pressure on influenza B virus hemagglutinin.

摘要: Influenza B virus hemagglutinin (HA) is a major surface glycoprotein with frequent amino acid substitutions. However, the roles of antibody selection in substitutions HA were still poorly understood. In order to gain insights into this important issue, an analysis was conducted on total 271 HA1 sequences influenza strains isolated during 1940–2007. analysis, phylogenetic by maximum likelihood (PAML) package used detect existence positive and identify positively selected sites HA1. Strikingly, all located four epitopes (120-loop, 150-loop, 160-loop, 190-helix) identified previous studies, thus supporting predominant role evolution. Of particular significance involvement 120-loop selection, which may become increasingly future field isolates. Despite absence different subtypes, continued evolve new sublineages, within targeted selectively selection. Thus, any newly emerging need be placed context their evolutionary history understand predict epidemic potential. J. Med. Virol. 81:114–124, 2009. © 2008 Wiley-Liss, Inc.