2009−2015年中国甲型H1N1流感病毒血凝素基因进化分析

Evolution of hemagglutinin gene of influenza A/H1N1(09pdm) virus in China, 2009−2015

摘要:

【目的】为了解中国地区2009?2015年甲型H1N1流感病毒流行态势，分析血凝素(Hemagglutinin，HA)基因的变异情况及其遗传进化特征。【方法】汇集国家流感中心2009?2015年流感周报的流感流行数据，分析甲型H1N1流感的流行病学特征；从全球共享禽流感数据倡议组织数据库及美国国家生物技术中心数据库下载甲型H1N1流感病毒HA基因序列，采用生物学软件进行系统进化和遗传特性的分析。【结果】2009?2015年全国共发生4次甲型H1N1流感的流行高峰。2009?2015年毒株与参考毒株A/California/07/2009(H1N1)的HA基因同源性逐年降低。遗传进化分析显示同一年份的毒株在系统进化树上基本呈现集中分布，2011年的毒株独立形成2个分支。分子特征表现为HA基因的4个抗原决定簇氨基酸位点均有变异，其中Ca区的203位、Sa区的163位和Sb区的185位氨基酸位点逐渐替换为新的氨基酸。除2010年与2012年，其他年份的毒株通过不同模型均得到正向压力选择HA氨基酸位点240。【结论】甲型H1N1流感在中国地区成为主要流行的亚型之一。HA基因与其编码的氨基酸逐年变异，未来进一步的流感监测能力还需加强。

Abstract:

[Objective] To analyze the tendency, genetic characteristics and evolution of hemagglutinin gene of the influenza A/H1N1(09pdm) virus circulating in China between 2009 and 2015. [Methods] Epidemiological data of A/H1N1(09pdm) and hemagglutinin sequences were analyzed. Epidemiological data were collected from the website of Chinese National Influenza Center and HA sequences of the influenza A/H1N1(09pdm) virus were filtered from The Global Initiative on Sharing All Influenza Data and National Center for Biotechnology Information. Phylogenetic trees and the mutations of amino acids were constructed and analyzed by biological software. [Results] A total of 4 activity influenza peaks emerged between 2009 and 2015. Compared with vaccine strain A/California/07/2009(H1N1), the HA gene sequence of 2009?2015 shared different nucleic acid sequence similarity decreased with years. The phylogenetic analysis showed that HA gene of the same year clustered nearly on the phylogenetic tree. The HA gene from 2011 divided into two clusters. The amino acid substitutions of HA protein were observed in all four epitopes. Position 203 in epitope Ca, position 163 in epitope Sa and position 185 in epitope Sb changed into new amino acid gradually. The positive pressure site was observed HA protein site 240 in each year except 2010 and 2012. [Conclusion] The influenza A/H1N1(09pdm) has become one of the main subtypes in China. The HA gene and amino acid changes gradually and this emphasize the importance of reinforcing virus surveillance.