Molecular characteristics of the hemagglutinin gene of influenza B viruses isolated in Nanjing,2011

[Objective] To characterize the molecular characteristics of hemagglutinin(HA) of influenza B viruses isolated in Nanjing in 2011.[Methods] We chose 7 strains representative influenza B virus in different epidemic time in 2011.In order to monitor evolution;of the virus,then we carried out HA sequencing,and analyzing the genetic characteristics of HA with the bioinformatics method.[Results] Of the 7 randomly selected Inf-B strains,4 strains were Victoria lineage strains,and 3 strains belong to Yamagata lineage.Comparison of nucleotide and amino acid sequences of HA gene with the correspondent vaccine strains,we find changes at antigenic sites 146 and 197 of Victoria lineage strains,and 116 and 198 of Yamagata lineage strains as well.197/198 receptor-binding sites belong to Victoria/Yamagata lineage strains correspondently.As the result,197/196 sites in Victoria/Yamagata isolates virus added an potential glycosylatio site.[Conclusion] Both B/Victoria and B/Yamagata lineage viruses co-circulated in Nanjing,the further researches of the changes at 197/198 sites of HA1 gene of Victoria/Yamagata isolates virus are valuable worthy.