Background: Helicobacter pylori (H. pylori) is a gram negative bacilli that causes the stomach and duodenum diseases in human. An important virulence factor of H. pylori is a CagA gene that increases of colonization it in stomach epithelial cells and lead to inflammation and peptic ulcers. The aim of the present study was to production of recombinant protein containing highly antigenic region of CagA in E. coli.

Materials and Methods: In this experimental study, the antigenic region (1245 base pair) of CagA gene was detected by bioinformatics methods, proliferated by PCR method, digested by BamHI and XhoI restriction enzymes and cloned into pET32a plasmid and was expressed in the E. coli BL21 (DE3) pLysS with induced by IPTG. The expressed protein was purified with Ni-NTA kit and its antigenicity was studied by western blotting method.

Results: Data showed the successful cloning and expression of the target gene. Recombinant CagA protein purified by Ni-NTA kit and dialysis with concentration of 1.5 mg/ml. In western blotting, the produced protein was interacted with infected human and mice sera.

Conclusion: Results indicated that recombinant CagA protein (65 KDa) maintains its antigenicity, so could be used for serological diagnosis of H. pylori diseases and production of vaccine.