摘要目的 研究我国结核分枝杆菌复合群(MTBC)抗原mpt83、mpt70、lpqH、pstS3、groES及其人B细胞表位的多态性.方法 从中国疾病预防控制中心传染病所结核室菌株库随机选取我国的179株MTBC临床分离株,培养后提取DNA,基因扩增并测序,根据H37Rv标准序列和免疫表位数据库(IEDB)的抗原表位信息,比较、分析各基因B细胞表位序列的变异情况,最后用MEGA6软件计算各基因的非同义突变率(dN)、同义突变率(dS)及其比值.结果 在179株MTBC菌株中,mpt83基因有7个单核苷酸多态性(SNP)位点,该基因及其表位区、非表位区的dN/dS分别为0.88、0.34和0.14;mpt70基因有1个SNP位点,为非同义突变;lpqH基因及其B细胞表位区dN/dS均为0.38,非表位区dN、dS均为0;pstS3基因及B细胞非表位区的dN/dS分别为1.74和1.40;groES基因未发现突变位点.结论 结核分枝杆菌mpt83、lpqH、pstS3的基因序列及B细胞表位具有较高的多态性,而mpt70和groE基因B细胞表位较保守.

abstractsObjective To study the diversities of human B cell epitopes of five proteins (Mpt83,Mpt70,LpqH,PstS3,GroES) in Mycobacterium tuberculosis isolates from China.Methods We selected 179 strains isolated from patients with tuberculosis in different regions of China,and cultured these strains by L-J medium.The gene sequences of these 5 proteins were amplified and sequenced by PCR.The variations (single nucleotide polymorphisms,SNP) of the DNA sequences were compared and analyzed according to the immune epitope database (IEDB).The synonymous mutation rate (dS),non-synonymous mutation rate (dN) and dN/dS values were calculated with MEGA6 software.Results Among the 179 clinical MTBC isolates,7 SNP mutations were found in the mpt83gene.The dN/dS value of the whole mpt83 gene was 0.88.One SNP mutation was found in the mpt70 gene.The dN/dS values of the whole pstS3 gene and non-B epitopes areas were 1.74 and 1.40 respectively.But no mutation was found in the groES gene.Conclusion The mpt83,lpqH and pstS3 genes of 179 MTBC strains contain gene SNPs and human B cell epitopes diversities,while the coding gene and human B cell epitopes of protein mpt70 and groES were conservative.