【作者】 梁丽君； 黄平； 侯年妹； 张欣； 倪汉忠；

【Author】 LIANG Lijun,HUANG Ping,HOU Nianmei,ZHANG Xin,NI Hanzhong,ZHANG Yonghui,KE Changwen.Key Laboratory for Emergency Pathogen Detection,Center for Disease Control and Prevention of Guangdong Province,Guangzhou 510300,P R China

【机构】 广东省疾病预防控制中心广东省应急病原学检测重点实验室； 中山大学公共卫生学院；

【摘要】 目的:揭示广东地区2007～2010年甲型H3N2毒株神经氨酸酶(NA)基因特征、变异及对奥司他韦和扎那米韦的药物敏感性。方法:采用时区抽样方法抽取毒株,检测广东2007～2010年甲型H3N2毒株NA基因核苷酸序列,同时检索全球NA基因序列作为参照,采用Mega5.05和BioEdit7.0.1软件对NA基因核苷酸序列进行比对和分析;分析毒株变异进化速度;采用NA酶活性阻断试验检测病毒的奥司他韦和扎那米韦药物敏感性。结果:广东2007～2010年H3N2毒株NA基因同义进化(Ks)和错义进化(Ka)速度分别为4.74×10-6～5.16×10-6核苷酸/日和2.94×10-6～3.16×10-6核苷酸/日,Ks值约为Ka值的1.5倍,揭示NA基因受自然选择压力较大。疫苗株Perth-10-2009与2010年和2011年广东毒株NA基因分同源性别为97.7%～98.2%、97.6%～97.7%。广东毒株NA基因有6个抗原表位变异,尤其是367位和369位氨基酸的变异频率较高。毒株Guangdong-548-2008发生耐药相关位点D151V,出现对奥司他韦敏感性降低;其余分离毒株均对奥司他韦和扎那米韦敏感;各年份毒株药物敏感性差异没有统计学意义。结论:广东2007～2010年甲型H3N2毒株NA基因的6个抗原表位有变异,抗原变异的积累可能出现流感暴发;D151V变异可能降低H3N2病毒对奥司他韦敏感性,但广东大多数H3N2毒株对奥司他韦和扎那米韦仍敏感。更多还原

【Abstract】 Objective:To reveal molecular characterization,phylogenetic analysis and sensitivity to oseltamivir and zanamivir of neuraminidase (NA) genes of human H3N2 influenza A viruses in Guangdong,China from 2007 to 2010.Methods:By Time-region sampling of strains,the NA genes of H3N2 strains isolated from Guangdong were sequenced while others searched from Internet as references.Evolution and variation of NA genes were conducted by Mega 5.05 and BioEdit7.0.1and the evolutionary rates were analyzed by epidemiological data.Antiviral susceptibility was detected by neuraminidase inhibition assay.Results:Phylogenetic tree was established by alignment of 17 Guangdong strains and 26 global reference strains.Ks rates and Ka rates of NA genes were 4.74×10-6～5.16×10-6 and 2.94×10-6～3.16×10-6 Nt/Day during 2007～ 2010,respectively.Ks about Ka 1.5 times,which means that strains was under natural selection pressure.Compared with NA of vaccine strain Perth-10-2009,the genetic homologies of Guangdong strains in 2009 reached to 97.7%～98.2% and those of Guangdong strains in 2010 reached to 97.6%～97.7%.There were six epitope variations of amino acid sites in NA genes of 2007～2010 strains in Guangdong,where the amino acid sites 367 and 369 were with high frequency of amino acid variation.Thus there was antigenic difference between the currently used vaccine strains and circulating H3N2 strains.Strains Guangdong-548-2008 appeared D151V in enzyme active site meanwhile the ability of this strain to combine to oseltamivir is weaker.Conclusions:Mutations of NA epitopes of Influenza A H3N2 strains in Guangdong were in vary degrees and the accumulation of antigenic variation may cause antigenic drift or an outbreak of influenza.The D151V mutation may lead to lower antiviral susceptibility to oseltamivir.Majority of Guangdong strain are sensitive to oseltamivir and zanamivir.更多还原