湖北省2007~2012年 H3N2流感病毒 HA基因及抗原性分析

摘要

目的：研究湖北省2007~2012年 H3N2流感病毒 HA 基因变异及抗原性变化情况。方法选取2007~2012年分离的湖北省各地区 H3N2流感病毒39株,提取病毒 RNA,运用 RT-PCR技术扩增 HA基因并测定序列,软件导出其核苷酸、氨基酸序列,采用 MEGA5.2构建进化树,用红细胞凝集抑制实验检测病毒的抗原性。结果14株毒株红细胞凝集抑制结果显示效价与参照抗原有4倍以上的差异,提示 H3N2流感病毒存在抗原性变异；核苷酸有较高的同源性,为97%~99%；HA1区共有50个氨基酸发生改变,其中37个在抗原位点,受体结合位点有2个(194、225位),抗原决定簇 A区4个,B区6个,C区2个,D、E区各1个；糖基化位点有明显的地域差异,不同地区糖基化位点的数量和位置均不相同。结论湖北省2007~2012年间 H3N2流感病毒抗原性和 HA基因存在变异。%Objective To investigate the variation of HA gene and antigenicity of influenza H3N2 viruses in Hubei province during 2007-2012.Methods RNA was extracted from 39 strains of influenza H3N2 viruses obtained from different areas in Hubei province during 2007-2012.The HA gene was amplified with RT-PCR and sequenced.The amino acid and nucleotide sequences were obtained by using the software.Then the evolutionary tree was constructed via MEGA 5.2.The antigenicity of the strains was determined by hemagglutination inhibition(HI)test.Results HI test results showed that there was a difference of more than 4 times in the antibody titer between the samples and the standard antigen,suggesting the antigenic variation of H3N2 flu viruses.The nucleotide homology was high,and reached 97%-99%.Fifty amino acids changed in the HA1 segment, including 37 in antigen sites,2 in receptor binding sites(194,225),4 in the antigenic determinant area A,6 in area B,2 in area C and 1 in area D and E each.There were significant differences in the number and position of glycosylation sites between different regions.Conclusion There were variations in HA gene and antigenicity in H3N2 virus in Hubei province during 2007-2012.