摘要目的 分析北京市怀柔区2013—2018年间甲型H1N1流感病毒血凝素(HA)基因的变异情况,了解其遗传进化特征.方法 选取北京市怀柔区2013—2018年间不同监测年度、明确鉴定为甲型H1N1流感病毒亚型的细胞培养阳性毒株42株,通过RT-PCR扩增、测序并获得HA基因序列.运用MEGA 6.0软件分析HA的分子特征,构建系统进化树.结果 2013—2018年间各监测年度流感病毒株与疫苗株A/California/07/2009的HA基因核苷酸的平均遗传距离分别为0.017、0.020、0.028、0.027、0.033.系统进化树结果显示,甲型H1N1流感病毒有两大分支:2013—2015年聚集至A/California/07/2009分支;2016—2018聚集至A/Michigan/45/2015(6B.1)分支.HA抗原位点发生变异的有10处,包括S220T、P154S、H155Y、E252G、S91R、K180Q、S181T、S179N、S202T、A203V.结论 北京市怀柔区2013—2018年甲型H1N1流感病毒HA基因在不断地发生变异,与2009年疫苗株的距离在逐渐增加,抗原决定簇变异频率增高、基因的多样性增加,均提示监测流感病毒分子特征的重要性.

abstractsObjective To analyze the mutations in hemagglutinin (HA) gene of influenza A(H1N1)pdm09 virus in Huairou district from 2013 to 2018, so as to understand the characteristics of genetic evolution. Methods Forty-two strains of influenza that were positive by cell culture and were identified as influenza A(H1N1)pdm09 virus in Huairou district were selected from different periods of surveillance during 2013 to 2018. HA gene sequences were obtained by RT-PCR and sequencing. MEGA6.0 software was used to analyze the molecular characteristics of HA and to construct the phylogenetic tree. Results The average genetic distances of nucleotides in HA gene between influenza A(H1N1)pdm09 virus strains isolated in each year from 2013 to 2018 and vaccine strains A/California/07/2009 were 0.017, 0.020, 0.028, 0.027 and 0.033, respectively. The phylogenetic tree show that the influenza A(H1N1) pdm09 virus strains formed two main branches. The strains isolated from 2013 to 2015 aggregated to A/California/07/2009 while the strains from 2016-2018 aggregated to A/Michigan/ 45/2015 (6B.1). There were 10 mutations in HA antigenic sites, including S220T, P154S, H155Y, E252G, S91R, K180Q, S181T, S179N, S202T and A203V. Conclusions The HA gene of influenza A(H1N1)pdm09 virus strains in Huairou District from 2013 to 2018 was constantly mutating, and the distance to the vaccine strain in 2009 was gradually increasing. Increments of both mutation frequency of antigenic sites and genetic diversity indicated the importance of surveillance for the molecular characteristics of influenza virus.