辽宁省甲3亚型流感病毒HAl基因特性分析

摘要

目的 了解2001-2006年间辽宁省甲3亚型流感病毒HAl基因变异特征.方法 采用辽宁省流感监测的咽拭分离株,对其中的7株甲3病毒核酸提取,经逆转录-聚合酶链反应(RT-PCR),扩增产物测序,推导出其氨基酸序列,并用DNA MAN软件包中的Alignment做了差异和同源性比较,用Mega软件包中的Neighbor Joining方法 ,通过与NCBI数据库中2000-2006年28株H3N2流感病毒同源比对后,制作种系进化树,进行基因进化特征分析.结果 序列分析发现,甲3亚型流感病毒与WHO当年的疫苗株M/California/7/2004比较,在其HA1核酸序列上有12处碱基不同,4个氨基酸位点发生了替换.基因及氨基酸序列同源性下降.与WHO北半球疫苗株A/Wisconsirn/67/2005序列更接近,但仍有4处碱基不同.结论 甲3亚型流感病毒基因序列发生了变异,与甲3亚型疫苗株A/California/7/2004同源性有下降趋势,提示其抗原可能发生部分漂移或更换,与南方浙江2005年株、WHO北半球2006-2007疫苗株A/Wiseonsin/6712005序列接近,提示南方春夏季流感流行株极有可能在北方秋冬季流行,对流感流行病学监测,疫苗株使用指导都具有重要意义.%Objective To understand the HA1 genetic variation characterization of influenza virus subtype H3N2 circulated from 2001 to 2006 in Liaoning local area. Methods Viral RNA was extracted and transcribed into cDNA by reverse transcriptase and amplified by PCR. The product of PCR was purified by QIAgen purification kits,and sequenced by ABI 3100avant. The sequence data were analyzed phylngeneticaUy by Sequence software with epidemic records. Finally, the phylngenetic trees were drawn according to deduced amino acid sequences of influenza vires H3N2 from 2000 to 2006 in the NCBI database. Results The seven HAldomain sequences of H3N2 influenza viruses circulated from 2001 to 2006 in Liaoning local area had been analyzed. Compared with WHO 2004-2006 H3N2 vaccine A/California/7/2004, 12 bases had changed, 4 positions had amino acid substitution in 62 *>E, 182 T>1,224 S>A ,225 C>Y. 224 and 225 are RBS (Receptor binding site). The homology is lower than 98%. Phylogenetic tree showed Liaoning H3N2 2006 strains and Zhejiang 2005 strains were similar to WHO Northern hemisphere winter 2006-2007 Vaccine A/Wisconsin/67/2005 (H3N2)-like virus and grouped together to form an independent cluster even though several bases were still different. Conclusion The HA1 domain of HA gene of influenza viruses (H3N2) isolated from 2001-2006 in Liaoning local area showed base mutation, amino acid sequence difference compared to A/California/7/2004 (2005-2006 vaccine), suggesting it might be the main cause leading to the spread of influenza. The sequence analysis showed Liaoning 2006 H3N2 strains were similar to those from Southern area which suggested that furher surveullance should be conducted to monitor the virus mutation in circulation.