棘球蚴AgB抗原家族基因的克隆及抗原表位的预测分析  

Cloning and Epitope Prediction of AgB Antigen Gene Family of Echinococcus granulosus and Echinococcus multilocularis

作　　者：江莉[1] 冯正[2] 胡薇[2] 张耀光[1] 

机构地区：[1]上海市疾病预防控制中心,上海市预防医学研究院 [2]中国疾病预防控制中心寄生虫病预防控制所,世界卫生组织疟疾,血吸虫病和丝虫病合作中心,上海200336

出　　处：《中国寄生虫学与寄生虫病杂志》2010年第5期368-371,376,共5页Chinese Journal of Parasitology and Parasitic Diseases

基　　金：国家自然科学基金(No30872211)~~

摘　　要：目的对棘球蚴AgB抗原家族的不同亚单位基因进行克隆,并对序列进行生物信息学分析和抗原表位预测分析。方法根据GenBank中的参考序列设计特异性引物,以我国新疆、甘肃和四川来源的细粒棘球蚴(Eg)和多房棘球蚴(Em)虫体DNA为模板扩增目的基因,将PCR产物克隆到TA载体中测序。用Bioedit分析软件和Blastn、NPS@和IEDB等在线分析系统对序列进行分析。结果分别从细粒棘球蚴和多房棘球蚴中克隆获得AgB抗原的全部5个亚单位基因,经测序确定为正确的目的序列;序列比对分析表明,EmAgB的5个亚单位基因序列高度保守,而EgAgB的亚单位基因变异性较大。细粒棘球蚴和多房棘球蚴种间差异分析显示,相同亚单位基因的序列一致性为87.69%～100%。AgB各亚单位抗原主要的二级结构包括α-螺旋、β-折叠和无规卷曲等3个类型。其中,AgB1、AgB2和AgB4等3个亚单位抗原中无规卷曲所占比例较高。AgB各亚单位抗原预测表位区共10个,分别是AgB1:1～7和21～27,AgB2:1～7和29～36,AgB3:1～11和18～28,AgB4:1～13、27～37和39～60,AgB5:1～11。结论 EgAgB和EmAgB亚单位抗原表位区的大部分序列一致或相似,预测的10个表位区主要位于序列N端。在5个亚单位抗原中,AgB1、AgB2和AgB4的抗原性较高。Objective To clone the subunits of AgB antigen gene family of Echinococcus granulosus （Eg） and Echinococcus multilocularis （Em）, analyze the gene sequences by bioinformatics methods, and predict the potential antigen epitopes. Methods Specific primers were designed based on the reference sequences from GenBank database. Total DNA was extracted from E. granulosus and E. multilocularis, which collected from the endemic areas of Xinjiang, Gansu and Sichuan. The PCR products were cloned into TA vector for sequencing. The online bioinformatics systems such as Bioedit software, Blastn, NPS@ and IEDB were used for the analysis. Results A total of five AgB gene subunits were cloned from E. granulosus and E. multilocularis, respectively, and identified by sequencing. Sequence homology analysis indicated that EmAgB subunits were highly conserved, while the EgAgB subunits were variable. Sequence alignment of AgB subunit genes from E. granulosus and E. multilocularis showed that the identity ranged from 87.69% to 100%. Three major types of secondary structure in the AgB subunits were alpha helix, extended strand, and random coil. Compared with other subunits, the higher percentages of random coil were found in AgB1, AgB2 and AgB4. Ten epitope areas were predicted from the five AgB subunits which were located in AgB1： 1-7 and 21-27, AgB2： 1-7 and 29-36, AgB3： 1-11 and 18- 28, AgB4： 1-13, 27-37 and 39-60, AgB5： 1-11, repectively. Conclusion The majority of epitopes in EgAgB and EmAgB subunits have the same or similar sequences. Ten predicted epitopes are mainly located at the N-terminal sequences. Among the five subunits, AgB1, AgB2 and AgB4 display higher antigenicity.

关 键 词：细粒棘球蚴 多房棘球蚴 AgB基因家族 抗原亚单位 基因克隆 表位预测 

分 类 号：R383.33[医药卫生—医学寄生虫学]