海南省2019—2020年H3N2亚型流感病毒血凝素基因特性

Genetic characteristics of hemagglutinin genes of Influenza A viruses(H3N2)in Hainan,2019-2020

目的了解海南省2019—2020年H3N2亚型流感病毒血凝素基因遗传进化规律与氨基酸变异情况。方法选取2019—2020监测年度海南省5家流感监测网络实验室分离的16株H3N2亚型流感毒株进行一代全基因组测序,利用MEGA 10.1.8构建血凝素基因系统进化树,并分析氨基酸位点替换情况,应用DNA Star 7.0.1软件进行血凝素基因同源性分析。结果系统进化树显示,相比于疫苗株A/Kansas/14/2017(2019—2020),16株H3N2亚型流感病毒分离株血凝素基因在进化树上与疫苗株A/Singapore/INFIMH-16-0019/2016(2018—2019)亲缘关系更近,属于3C.2a1分支,核苷酸与氨基酸同源性范围分别为98.5%~98.9%、97.9%~98.4%。16株分离株在抗原性位点发生8处氨基酸位点替换,涉及5个抗原决定簇;15株分离株在糖基化位点发生2处缺失。结论2019—2020年监测年度海南省H3N2亚型流感病毒与2018—2019年疫苗株亲缘关系较近,血凝素蛋白抗原性位点在5个决定簇均有变异,易造成较大流行,WHO推荐的2019—2020年疫苗株保护效果可能不理想。应密切关注H3N2亚型流感病毒的流行与基因变异情况,为流感病毒疫苗株推荐及防控提供科学依据。

Objective To investigate the genetic evolution characteristics and the amino acid substitutions of Influenza A viruses(H3N2)based on the hemagglutinin genes in Hainan during 2019-2020.Methods 16 strains of H3N2 viruses isolated by Hainan province influenza surveillance network laboratory were collected and the whole genomes were sequenced.The phylogenetic tree were constructed by MEGA 10.1.8 and amino acid variants were analyzed.The DNA Star 7.0.1 software were applied to analyze the neuraminidase gene similarities.Results The phylogenetic tree showed that all the analyzed H3N2 strains were belong to the 3c.2a1 clade.The genetic relationship was closer to the WHO recommended vaccine strain A/Singapore/INFIMH-16-0019/2016(2018-2019)than the A/Kansas/14/2017(2019-2020)strain.Compared with the 2018-2019 vaccine strain.The nucleotide and amino acid similarities were 98.5%-98.9%,97.9%-98.4%respectively.A total of 8 sites of amino acid substitutions covering all the five antigenic determinant clusters were detected in 16 strains and two glycosylation sites were lost in the analyzed 15 strains.Conclusion The genetic relationship of H3N2 Influenza viruses prevailed in Hainan during 2019-2020 was close to the 2018-2019 vaccine strain.The antigenic determinants referred to five clusters get changed which might lead to an influenza pandemic.We should pay more attention to the H3N2 subtype Influenza viruses epidemic situation and genetic variation,providing scientific evidence for the influenza virus prevention and vaccine strains recommendation.