2007—2017年中国甲型H3N2流感病毒HA基因特征分析

摘要：目的：回顾性分析2007—2017年我国人感染季节性甲型H3N2流感病毒血凝素（hemagglutinin, HA）的分子特征，为我国甲型H3N2流感病毒的防控和疫苗的研发提供科学依据。 方法：从全球共享禽流感数据库（the global initiative on sharing avian influenza data, GISAID）中下载中国2007—2017年人感染季节性甲型流感病毒H3N2亚型毒株HA基因序列，利用MEGA7.0生物学信息软件分析其HA的分子特征。 结果：2007—2017年，中国甲型流感病毒H3N2亚型共1 991例，总体上病毒株数呈逐渐递增趋势。HA序列分析表明，甲型H3N2流感病毒的亚型存在多样性且多种亚型共存，3C.2a.1系的病毒株自2010年起逐年增多，2016年起成为最主要的流行优势株。1系、2系、3A系、3B系、3C.1系、3C.2系、3C.2a系、3C.2a.1系、3C.3系、3C.3a系和3C.3b系的同源性分别为94.0%～100.0%、96.7%～100.0%、94.3%～100.0%、94.9%～100.0%、94.6%～100.0%、95.4%～100.0%、95.1%～100.0%、93.3%～100.0%、97.5%～100.0%、95.3%～100.0%和94.6%～100.0%。HA蛋白关键位点N121K、G/R142K出现变异，268株发生N121K突变且主要来源于2017年的毒株，358株发生G/R142K突变且主要来源于2016年和2017年的毒株。 结论：甲型H3N2流感病毒的亚型存在多样性，多种亚型共存且不同年份间的优势流行株存在差异，这些将有助于疫苗的研发和疾病的防控。

Genetic characteristics analysis of HA gene of influenza A (H3N2) virus in China during 2007 to 2017

Abstract: Objective: To analyze retrospectively the molecular characteristic of hemagglutinin (HA) gene from human infection with seasonal influenza A (H3N2) virus during 2007 to 2017 and provide scientific basis for prevention, control and vaccine development of influenza A (H3N2) virus in our country. Methods: The sequences of HA gene of influenza A (H3N2) virus strains isolated from China during 2007 to 2017 were obtained from the GISAID database. The molecular characteristics of HA gene were analyzed by bioinformatic software MEGA7.0. Results: From 2007 to 2017, a total of 1 991 strains of influenza A (H3N2) virus in China were enrolled, on the whole, the number of H3N2 strains was gradually increased. The HA sequence showed that the clades of influenza A (H3N2) virus were diverse and coexistent in one year. The virus strains belonging to 3C.2a.1 clade had been gradually increased since 2010, and were the most important predominant strains since 2016. The homologies of clade 1, clade 2, clade 3A, 3B, 3C.1, 3C.2, 3C.2a, 3C.2a.1, 3C.3, 3C.3a and 3C.3b were 94.0% to 100.0%, 96.7% to 100.0%, 94.3% to 100.0%, 94.9% to 100.0%, 94.6% to 100.0%, 95.4% to 100.0%, 95.1% to 100.0%, 93.3% to 100.0%, 97.5% to 100.0%, 95.3% to 100.0% and 94.6% to 100.0%, respectively. The mutations in key site of HA protein occurred, such as N121K and G/R142K. The 268 strains with N121K mutation mainly occurred in 2017, and 358 strains with G/R142K mutation primarily occurred during 2016 to 2017. Conclusion: The clades of influenza A (H3N2) virus should be diverse and coexistent in one year, and the predominant strains were different during different years, which will be helpful for the development of vaccines as well as the prevention and control of disease.