Epitope mapping and antigenic evaluation of Helicobacter pylori Urease subunit beta fragment

Background: Helicobacter pylori (H.pylori) is one of the most common chronic infections worldwide. The H. pylori Urease is a high molecular mass (530 kDa) multimeric enzyme collected of two separate subunits, UreA (26.5 kDa) and UreB (61.7 kDa). Recently, many researchers are working in the expansion of a vaccine to prevent H. pylori infection, and of the various candidate antigens, the majority promising is the B subunit of the Urease protein (Urease B), for the reason that immunization of mice with purified Urease B has resulted in better immunogenicity and protection as contrast to the use of Urease A. The aim of this study was to high level expression and evaluation of antigenic property of recombinant UreB protein with infected human and mice sera as a vaccine candidate. Materials and Methods: In this experimental study, the highly antigenic region of UreB gene (609 base pair) was detected by best immunobioinformatics methods of epitope mapping, amplified by PCR method and was cloned into the cloning vector pBSK and then inserted into the expression vector pET-32a. The target protein was expressed and purified. Finally antigenicity was studied by western blotting using human sera infected with H. pylori UreB recombinant protein. Results: PCR and sequencing results showed the successful cloning of the target gene into the recombinant vector. The expression of protein was induced by IPTG and the expressed protein was purified with Ni-NTA kit and dialysis. The recombinant protein with molecular weight about 42 KDa was recognized by antibodies in western blotting. Conclusion: Evaluation of antibodies studies have shown that the predicted immunogenic fragment by best immunobioinformatics tools antigenic properties is high., so this Recombinant UreB protein is a good candidate for the design of H. pylori vaccine and diagnostic kits.