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目的对2007～2009年度南宁市流行性感冒病毒NA序列分析,阐明NA基因变异和进化特征。方法提取2007～2009年30株(每年10株)H3N2亚型病毒RNA,采用RT-PCR扩增病毒NA基因后进行序列测定,利用VectorNTI9.0对测序结果分析处理,并与WHO推荐疫苗株进行比对,用Mage 4.1构建系统进化树。结果南宁市2007～2009年H3N2亚型流感病毒被分为3个分枝,其中疫苗株A/Wisconsin/67/2005独立形成一个分支(类群Ⅰ),A/Brisbane/59/2007与2007年毒株(除339外)形成类群Ⅱ,2008和2009年毒株聚集成类群Ⅲ。NA基因在质尾区域、极性跨膜区、柄部区域有个别毒株个别位点发生了替换。抗原区域328～336替换频率较高,2008年毒株抗原位点更活跃。A/nanning/242/2007在酶活性位点发生了D151E替换,可能导致NA对扎纳米韦和奥斯他韦的轻微耐药性;A/nanning/242/2007、A/nan ning/561/2008分别在非活性位点N234D,在G286D的替换则可能影响NA介导的病毒粒子的释放从而影响NA蛋白的活性。结论南宁市2007~2009年毒株NA均发生了较大变异,当年疫苗株均滞后南宁流行株。
Objective To analyze the NA sequence of influenza virus in Nanning from 2007 to 2009, and elucidate the NA gene variation and evolutionary characteristics. Methods Thirty strains of H3N2 subtype virus (10 strains per year) were extracted from 2007-2009. The NA gene of the virus was amplified by RT-PCR and then sequenced. The results of sequencing were analyzed by VectorNTI9.0, Alignment, build phylogenetic tree with Mage 4.1. Results The H3N2 subtype influenza viruses in Nanning City were divided into three branches from 2007 to 2009, of which vaccine strain A / Wisconsin / 67/2005 independently formed a branch (group Ⅰ), A / Brisbane / 59/2007 and 2007 Strains (except 339) form group II, and in 2008 and 2009 the strains accumulate into group III. NA gene in the tail region, polar transmembrane region, the handle area individual strains of individual sites have been replaced. The substitution frequency of antigen region 328 ~ 336 is higher, and the strain antigenic site of 2008 is more active. A / nanning / 242/2007 D151E substitution at the enzyme active site may result in a slight resistance of NA to zanamivir and oseltamivir; A / nanning / 242/2007, A / 2008 respectively in the non-active site N234D, in the G286D replacement may affect NA-mediated release of virus particles thereby affecting the activity of NA protein. Conclusions The NA of the strains in Nanning from 2007 to 2009 had a great variation, when the vaccine strains lagged the epidemic strains of Nanning.