目的 分析3株甲肝病毒(hepatitis A virus,HAV)流行株全基因组和准种序列特征.方法 收集某地3例急性期甲肝患者血清标本,经病毒核酸提取、逆转录、分段巢式PCR,获得HAV近全长序列,并对全长VP1-2 A区进行克隆测序.结果 VP1-2 A连接区分型结果表明3株HAV均属于IA亚型,3株序列在此区核苷酸和氨基酸同源性为100％;全基因组核苷酸和氨基酸同源性分别为99.9％ ～ 100％和100％,与GenBank中日本AH2株同源性最高(核苷酸、氨基酸同源性为98.5％和99.7％);在已发表的抗原中和位点处未出现氨基酸变异.每株流行株全长VP1-2 A区克隆序列内、以及所有克隆序列间,核苷酸和氨基酸同源性分别为99.0％ ～ 100％、98.1％～100％和99.0％～100％、97.2％ ～ 100％,VP1-2 A连接区的核苷酸和氨基酸变异率高于部分VP1区.结论 3株流行株VP1-2 A连接区分型序列一致,全长基因组及准种序列间核苷酸、氨基酸序列同源性较高,推测可能为同源感染.本研究为甲肝病毒在传播过程中的遗传变异特点及溯源调查提供参考依据.%Objective To analyze the genetic characteristics of whole-genome and quasispecies sequences from three hepatitis A virus (HAV) strains in China.Methods Serum samples from acute hepatitis A patients were collected and viral RNA extraction,transcription,nested PCR,sequencing and assembling were performed to gain near full-length sequences;cloning-based sequencing of the full-length VP1-2 A region was also performed.Results Genotyping showed that the nucleotide and amino acid identities among three strains on VP1-2 A junction region were both 100％ and all belonged to subgenotype IA;the nucleotide and amino acid identities on whole-genome region were 99.9％-100％ and 100％ respectively,and shared the highest identities with AH2 strain from GenBank of 98.5％ in nucleotide and 99.7％ in amino acid level;no amino acid variation was found among published neutralizing antigenic sites.Within cloning sequences from each strain,the nucleotide and amino acid identities were 99.0％-100％ and 98.1％-100％,while among all cloning sequences were 99.0％-100％ and 97.2％-100％.The variation rate of nucleotide and amino acid in VP1-2 A junction region were both higher than that of partial VP1 region.Conclusions Sequences among three strains in VP1-2 A region were identical,the nucleotide and amino acid identities in both whole-genome region and among quasispecies sequences were relatively high to deduce that they were from the same outbreak.This study provides new insight for identification of HAV transmissions and tracing investigations.
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