中国莱姆病螺旋体菌株bmpA基因中人B细胞表位多态性分析

Polymorphisms of human B cell epitopes in bmpAof Borrelia burgdorferi sensu lato in China

目的研究我国伯氏疏螺旋体(Borrelia burgdorferi sensu lato),即莱姆病螺旋体菌株中bmpA基因及其人B细胞表位区的序列多态性。方法选取61株莱姆病螺旋体分离株,PCR扩增其bmpA基因并测序后,结合4种基因型参考菌株序列,与从免疫表位数据库(Immune Epitope Database,IEDB)中查询到的B细胞表位序列进行比对分析。结果中国B.garinii基因型菌株的cluster2、cluster3以及B.afzelii和B.valaisiana基因型所有菌株与参考序列比对后发现分别有3、9、5和18个异义突变。B细胞表位改变主要发生在B.afzelii基因型全部分离株和B.garinii基因型的cluster3及5株非成簇菌株。B.afzelii基因型菌株在B细胞表位区的异义突变A125S影响了2个B细胞表位;B.garinii基因型的cluster3和5株非成簇菌株B细胞表位区的3个异义突变导致5个B细胞表位均发生改变。结论中国莱姆病螺旋体bmpA基因在4种基因型间和B.garinii基因型内存在较大多态性。

To study the polymorphism in bmpAand its human B cell epitopes of Borrelia burgdorferi strains in China,the bmpAsequences of 61 B.burgdorferi strains were obtained by PCR and sequencing.They were compared with the human B cell epitope sequences from Immune Epitope Database（IEDB）based on the reference strain of each genotype.The 3,9,5and18 nonsynonymous mutations were seperately found in cluster2 and cluster3of B.garinii,B.afzelii and B.valaisianastrains in China.The changed B cell epitopes were mainly found in cluster3 and five non-clustered strains of B.garinii and B.afzelii strains.The nonsynonymous mutation of A125 Sin B.afzelii strains affected two B cell epitopes.Three nonsynonymous mutations in cluster3 and five non-clustered strains in B.garinii affected all of five B cell epitopes.The polymorphysims were widely existed in bmpAand its B cell epitopes in B.garinii and between four genotypes of B.burgdorferi strains selected in China.