摘要
目的了解2008—2009年南宁市人季节性H1N1流感病毒神经氨酸酶(NA)基因的遗传进化特征,探讨NA基因潜在的抗原位点和活性位点(抑制剂耐药性位点)变异规律。方法提取2008—2009年20株H1N1流感病毒RNA,采用RT-PCR扩增病毒NA基因后进行序列测定,通过CTLPred软件预测NA基因上潜在的抗原位点,并对NA分子进化和其重要功能位点的遗传变异进行分析。结果将20株H1N1流感病毒毒株与北半球疫苗推荐株A/Solomon/3/2006和A/Bris-bane/59/2007构建进化树,NA进化树共分成3个类群,10株2008年H1N1流感病毒毒株聚集成分支Ⅱ,10株2009年毒株与疫苗株A/Brisbane/59/2007聚集成分支Ⅰ,A/Solomon/3/2006则独立形成1个分支(Ⅲ)。2008年毒株抗原位点替换频率较高,相对于A/Solomon/3/2006氨基酸替换分布在不同的3个区域的3个位点,分别是N64H、Y100H、L367I;2009年度的毒株抗原决定簇位点相对保守。在已知NA的酶活性位点中,2009年所有毒株均在275位点发生了H>Y的突变,而这种变异在2008年的毒株中未有出现。结论 A/Solomon/3/2006落后于2008年毒株,A/Brisbane/59/2007对应的疫苗在2009年能起到较好的保护作用;大量H275Y耐药株的出现提示在流感病毒监测中应密切关注其耐药位点的变异。
Objective To investigate the genetic variation and evolution characteristics of influen- za virus and understand the potential antigenic sites and active sites （ inhibitor resistance sites） of NA gene of human seasonal influenza H1 N1 viruses circulating in Nanning City during 2008 - 2009. Methods 20 samples that isolated from influenza surveillance between 2008 and 2009 were tested. RNAs were extrac- ted, and NA genes were amplified by RT-PCR and then sequenced. CTLPred software was used to predict potential antigenic sites in the NA gene. The genetic variation and important functional sites of NA genes were analyzed based on amino acid sequences. Results The NA phylogenetic tree constructed showed that the strains were divided into three branches, strains in 2008 were located in branch II , strains in 2009 with A/Brisbane/59/2007 were located in branch I , and A/Solomon/3/2006 was located in branch Ill. The substitutions of antigenic sites were relatively active in 2008. Compared to the vaccine strain A/Solomon / 3/2006, there were 3 different substitutions in antigenic sites of strains in 2008,i. e. , N64H,Y100H, and L367I,which located in 3 regions. The antigenic sites of strains in 2009 were more conserved. Among the known active sites of NA, all strains in 2009 showed mutation in site H275 changed to Y,while such muta- tion was not appeared in 2008. Conclusion A/Solomon/3/2006 lagged behind the circulating strains in2008,and the vaccine that base on A/Brisbane/59/2007 might provide a better protection for human in Nanning during 2009. Numbers of H275Y resistant strains appearing indicated that we should pay attention to the variation of resistance sites during the influenza surveillance.
出处
《华南预防医学》
2012年第5期6-10,共5页
South China Journal of Preventive Medicine
基金
广西南宁科学研究与技术开发计划项目(200802127C)
