目的　构建表达幽门螺杆菌 (Hp)细胞毒素相关蛋白 (CagA)及粘膜免疫佐剂霍乱毒素B亚单位 (CTB)的重组质粒 ,并在大肠杆菌中表达获得基因重组蛋白。方法　用PCR方法从幽门螺杆菌扩增CagA基因片段 ,从霍乱弧菌扩增CTB基因片段 ,将它们转入原核载体质粒pGEMEX 1,在大肠杆菌DH5α中克隆 ,并在JM10 9DE3中表达。结果　重组质粒pGEMEX CTB的全长序列经分析与Gen Bank公布的序列相符 ;各表达蛋白经SDS PAGE分析 ,相对分子量与文献相符 ;重组蛋白经Westernblot检测有较强的抗原性。结论　基因重组菌表达的融合蛋白有可能作为有效抗原用于幽门螺杆菌疫苗的研制及检测试剂盒的制备 OBJECTIVE: To construct a recombinant plasmid expressing Hp cytotoxin-related protein (CagA) and mucosal immune adjuvant cholera toxin B subunit (CTB) and obtain the recombinant protein in E. coli. Methods The CagA gene fragment was amplified from Helicobacter pylori by PCR and the CTB gene fragment was amplified from Vibrio cholera. The CTB gene fragment was transformed into prokaryotic vector pGEMEX 1, cloned in E. coli DH5α and expressed in JM10 9DE3. Results The full-length sequence of the recombinant plasmid pGEMEX CTB was identical with the sequence published by GenBank. The expressed proteins were analyzed by SDS PAGE. The relative molecular weights were consistent with those of the literature. The recombinant proteins were proved to be highly antigenic by Western blot. Conclusion The fusion protein expressed by recombinant DNA may be used as an effective antigen in the preparation of H. pylori vaccine and the preparation of test kit