Expression, Purification and Evaluation of Antigenicity of CagA Antigenic Fragment of Helicobacter pylori

Background: helicobacter pylori is a human pathogen that causes chronic gastritis, which playsrole in gastric and duodenal ulcers, is also involved in gastric carcinogenesis and may be regarded as a possible important factor in at least a subset of patients with functional dyspepsia.objectives: this study was aimed to construct a recombinant protein containing h. pylori antigenic caga region and determine its antigenicity as a vaccine candidate against h. pylori.materials and methods: the antigenic region of caga gene was detected by bioinformatics techniques. in this study, the h. pylori antigenic caga region was amplified by pcr and sub-cloned to prokaryotic expression vector pet32a. escherichia coli bl21 (de3) plyss was transformed with pet32a- caga and gene expression was induced by iptg. the expressed protein was purified by affinity chromatography using ni-nta resin. the integrity of the product was confirmed by western-blot analysis using sera of infected individual. finally antigenicity was studied by western-blot analysis using human sera infected with h. pylori.results: enzyme digestion analysis, pcr and sequencing showed that the target gene (1245 bp) was correctly inserted into the recombinant vector. the expressed protein was purified using affinity chromatography by ni-nta resin. the data also indicated that caga protein from h. pylori detected from patients' sera.conclusions: results indicates that antigenic region of recombinant caga protein were recognized as an antigen , so it might be a candidate for the development of h. pylori vaccine, elisa kit designs and serological diagnosis of h. pylori infections.