湖南省2004年流感病毒优势流行毒株甲3亚型基因特性分析

An analysis on genetic characterizations of group A influenza virus(H3N2) preponderant prevalent strains in Hunan Province in 2004

目的：了解2004年湖南省流感病毒优势流行毒株甲3亚型的基因特性变异特征。方法：取病原学监测中分离到的13株甲3亚型流感病毒毒株，经鉴定后用鸡胚传代，收获尿囊液提取病毒RNA，进行逆转录-聚合酶链反应（RT-PCR），扩增产物用纯化试剂盒纯化后测序；测序结果使用Flu Sequence DatasetExplorer工具进行比较，通过与NCBI数据库中2000-2005年中国的流感病毒H3N2株同源比对后，绘制种系发生树。结果：所测13株甲3（H3N2）亚型毒株的HA1区的320个氨基酸，与甲3亚型国际疫苗株A／wuhan／359／1995相比，抗原决定簇E区、A区、D区、B区及受体结合位点（RBS）后壁和左壁均有多个位点发生氨基酸替换。与2002年流行的A／Fujian／411／2002甲3亚型代表株相比，抗原决定簇及受体结合位点亦有单个或多个位点氨基酸发生了替换。种系发生树显示，13株甲3亚型人流感病毒中有9株同源性较大，独立形成一簇，与A／Fujiart／52／2004较为接近。另外1株与我省2002年分离的毒株最为接近。最后3株则整合进2003～2004年其他省分离到的毒株所形成的簇中。结论：湖南省2004年流感优势流行毒株甲3亚型流感病毒的HA1基因特性发生了变异，可能是导致其流行的主要原因。在HA1基因进化上，时间比地理分布起着更重要的作用。

Objective ：To understand the genetic variation characterizations of group A influenza virus （H3N2） preponderant prevalent strains in Hunan Province in 2004. nethods：Embrayonated chicken eggs inoculated with the group A influenza viruses （H3N2） isolated from etiology surveillance after being identified. Virion RNA was extracted from harvesting egg allantoie fluids and subjected to reverse transcription -polymerase chain reaction （RT -PCR）. The product of PCR was purified by QIAgen purification kits, and then sequenced and analyzed phylogenetically by Sequence DatasetExplorer software. Finally the phylogenetic trees were drawn according to deduced amino acid sequences of influenza viruses in China from 2000 to 2005 in the NCBI database. Results ：The 13 sequences of 320 amino acids on HA1 domain had been analyzed. Compared with A/wuhan/359/1995, several positions had amino acid substitution in antigenic determinant E, A, D, B and back and left wall of the receptor binding site （RBS）. Compared with A/fujian/411/2002, one or several positions also had amino acid substitution. Phylogenetic trees showed 9 out of 13 strains were similar to A/Fujian/52/2004 -like virus and grouped together to form an independent cluster. One out of 13 was close to a strain isolated in Hunan Province in 2002. And last 3 out of 13 were incorporated into the sublineage of strains isolated from other provinces. Conclusion： HA1 gene variation of influenza A （H3N2） viruses in Hunan Province in 2004 is recorded, suggesting it is the main cause leading to the spread of influenza. Time plays a more important role than geographical distribution in the evolution of the HA1 gene of influenza viruses.