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目的研究中山市2010-2013年流行的H3N2亚型流感病毒的血凝素基因特征,分析其基因变异情况。方法选取2010-2013年中山市流行的H3N2亚型流感病毒6株,用MDCK细胞分离病毒,提取病毒RNA,RT-PCR扩增HA基因并测定序列,利用BLASTn对序列进行相似性检索,分析其与疫苗株,不同年份、区域流行株的进化变异情况。结果共分离鉴定到6株H3N2亚型流感病毒,其中2株为2010年流行株,2株为2012年流行株,2株为2013年流行株。各年流行株与其他国家或地区当年大部分流行株在一个分支上,其进化距离随着进化时间变长而变远。2012年流行株相对2010年流行株在HA1区发生12个氨基酸位点变异,有3个位于B、C区。2013年流行株相对2012年流行株发生4个氨基酸位点变异,有2个位于A区。2012年、2013年流行株相对于疫苗株分别发生6、8个氨基酸位点变异,分别有2、4个位于A、B、C区。受体结合位点未发生变异。结论中山市H3N2亚型流感病毒流行株在年度之间存在一定程度变异,进化距离随着进化时间变长而变远,相对于疫苗株也存在一定程度上的变异。
Objective To study the hemagglutinin gene characteristics of H3N2 subtype influenza virus circulating in Zhongshan city from 2010 to 2013 and analyze its genetic variation. Methods Six strains of H3N2 influenza viruses were selected from Zhongshan City in 2010-2013. Virus was isolated from MDCK cells and the viral RNA was extracted. The HA gene was amplified by RT-PCR and sequenced. The similarity of the sequences was analyzed by BLASTn, And vaccine strains, different years, the evolution of endemic strains of variation. Results A total of 6 strains of H3N2 influenza viruses were isolated and identified. Among them, 2 strains were epidemic strains in 2010, 2 strains were epidemic strains in 2012 and 2 strains were epidemic strains in 2013. The epidemic strains of all the year and most other endemic countries in the year were on a branch, and their evolutionary distance became longer as the evolutionary time became longer. In 2012, the epidemic strains had 12 amino acid site mutations in the HA1 region relative to the strains in 2010, and 3 strains were located in the B and C regions. There were 4 amino acid site mutations in the 2013 epidemic strains compared with the 2012 epidemic strains, two in the A region. In 2012 and 2013, 6 and 8 amino acid site mutations occurred in the epidemic strains respectively against the vaccine strains, with 2,4 and 4 loci in A, B and C regions respectively. Receptor binding sites did not mutate. Conclusion There is a certain degree of variation in epidemic strains of H3N2 subtype influenza in Zhongshan City between years. The evolutionary distance becomes longer with the evolutionary time longer. There is a certain degree of variation with respect to the vaccine strains.