Cloning and expression of UreB-Omp18 recombinant protein from Iranian H. pylori strain

Helicobacter pylori (H. pylori) infection is accepted of chronic gastritis. Among the diagnostic methods, serological tests are widely available and relatively sensitive to detect H. pylori infection. However, the low specificity limits its application. The present study was aimed for designing, cloning and expression of UreB - Omp18 protein from Iranian H. pylori  strain as a promising diagnostic candidate with high specificity.

After extraction of genomic DNA from focal Helicobacter pylori strain, ureB and omp18 genes were amplified by primers designed for these genes by PCR reaction and cloned into pET-22b expression vector after enzymatic cleavage. The expression of the resulting recombinant protein was induced by IPTG and purified with high purity by affinity chromatography. The antigenic properties of the purified recombinant protein were confirmed by Western blotting.

In this study, two ureB and omp18 gene fragments were amplified by PCR as 597 and 479 bp fragments, respectively, and cloned as a hybrid fragment in the pET-22b vector. The expression of the recombinant protein in E. coli BL21 (DE3) appeared as a fragment of about 60 kDa on SDS-PAGE and was purified by Ni-NTA column. Western blot results of purified chimeric antigen with sera of H. pylori infected patients showed the antigenic properties of the recombinant protein.

In the present study, for the first time, the recombinant UreB-Omp18 protein was produced from the native strain of Helicobacter pylori, which can be a suitable candidate for designing a Helicobacter pylori diagnostic kit in the region.