摘要
目的研究我国结核分枝杆菌复合群(Mycobacterium tuberculosis complex,MTBC)菌株中pstS1基因及其中的人T细胞和B细胞表位区的序列多态性。方法选取180株临床分离MTBC菌株及11株世界不同来源的BCG疫苗株,PCR扩增其pstS1基因并测序后,结合已经公布的1株牛分枝杆菌(Mycobacterium bovis)及3株BCG菌株的pstS1基因序列,与从免疫表位数据库(Immune Epitope Database,IEDB)中查询到的表位序列进行比对和分析,总结该基因序列中的变异特征。结果在所有菌株中,共发现2个单碱基插入造成的移码突变(Frame-shift mutation)和4个单核苷酸多态性(Single nucleotide polymorphism,SNP)位点,共造成79.17%(19/24)的B细胞表位和65.22%(15/23)T细胞表位区的序列变异。pstS1基因的dN值为0.000 14,其中T细胞表位区与非T细胞表位区的dN值分别为0.000 17和0.000 05,B细胞表位区与非B细胞表位区的dN值分别为0.000 23和0,由于未发现同义突变位点,所有序列区的dS值均为零。结论 MTBC菌株的pstS1基因具有较高的序列多态性,且其中的T、B细胞表位区具有更高的多态性水平。
Objective To study the polymorphisms in pstS1 and its human T and B cell epitopes of Mycobacterium tuberculosis complex （MTBC） strains in China. Methods The pstS1 sequences of the 180 clinical MTBC isolates and 11 BCG strains were obtained by PCR and first generation sequencing, and together with the published data of one Mycobacterium bovis and 3 BCG trains, the sequences were compared with the human T and B cell epitope sequences from Immune Epitope Database （IEDB）. The dN and dS values were calculated with Mega 5 software. Results Two kinds of insertion and 4 single nucleotide polymorphism （SNP） mutations were found in pstS1 gene of the studied samples, which affected 79. 17% （19/24） of B cell epitopes and 65.22% （15/23） of T cell epitopes area. The dN value of whole pstS1 gene was 0. 000 14, those of T epitopes and non-T epitopes areas were 0. 000 17 and 0. 000 05 respectively and those of B cell epitopes and non-B epitopes areas were 0. 000 23 and zero. The dS value of all sequence types were zero as there was no synonymous mutation. Conclusion The polymorphisms exist in the pstSl and its human T and B cell epitopes of the MTBC strains selected in China, and the T and B epitope regions have relatively high levels of mutation.
出处
《疾病监测》
CAS
2014年第4期260-265,共6页
Disease Surveillance
基金
国家科技重大专项课题(No.2013ZX10003006-002-001)~~
