G1型轮状病毒中和抗原VP7基因变异特点

Study on the genetic variations of the major neutralization antigen VP7 of group A rotavirus type G1 in China

目的 研究我国G1型轮状病毒主要中和抗原VP7基因的变异特点。方法 对 1988～1998年收集自北京、沈阳、新乡、上海、深圳、广州、重庆等 7个城市的 2 3份G1型轮状病毒毒株VP7cDNA序列进行测定 ,并结合核酸电泳带型和G1型单抗的ELISA检测结果分析VP7基因的变异特点。结果 我国G1型轮状病毒VP7变异有一定规律 ,主要集中在aa41、49、5 7、65、68、74、94、97、147、170、2 17、2 18、2 68、2 81、2 91,即VR3～ 5、VR7～ 8以及多肽C端的部分区域内。各地区之间没有明显差别 ,虽然随时间不同个别氨基酸可能发生替换 ,但仍同属Jpn 417支系 ;aa91位可能参与构成G1型VP7的抗原表位 ,某些位点的氨基酸变异可能与核酸带型改变有关。结论 在研制疫苗时 ,应采用基因和抗原性具有代表性的近期毒株 。

Objective To study the genetic variations of the major neutralization antigen VP7 of group A rotavirus,type G1 in China.Methods Twenty three isolates derived from seven cities (Beijing,Shenyang,Xinxiang,Shanghai,Shenzhen,Guangzhou and Chongqing)during the period of 1988 1998 were analyzed for the VP7 cDNA sequences.Results An obvious homology was observed in amino acid sequences of VP7 in the 23 isolates.Compared with the standard strain Wa,the variations were found at the position of aa 41,49,57,65,68,74,94,97,147,170,217,218,268,281 and 291,respectively,and all of these were located in the variable region(VR)3,4,5,7,8 as well as in the C terminal of the peptide.There seemed to be no remarkable divergence among the samples collected from different cities and all of them shared the same genetic lineage with the strain Jpn 417,though there might be one or two amino acid substitutions as time passed.When detected simultaneously with ELISA using G1 serotype specific monoclonal antibody,the location of amino acid 91 was found presumably related to the neutralization epitope in VP7 of the type G1.Variations at some position may be resulted in the change of electropherotype.Conclusion The results indicated that the recent isolates with representative genetic and antigenic features should be used to develop effective vaccines,and the antigenic variations should be monitored periodically.