Effect of Recombinant Helicobacter Outer Membrane Protein H (HopH) on Nitric Oxide Production by Peripheral Macrophage in BALB/c Mice

Some products of bacteria are reported as an immunomodulator. The Helicobacter pylori (H. pylori) outer membrane proteins play an important role in stimulation of immune system. The present study was performed to determine the in vitro effect of recombinant HopH of H. pylori on Nitric Oxide (NO) production and viability of mouse peritoneal macrophages. H. pylori recombinant HopH was produced in this study. Mice peritoneal macrophages were purified and cultured. Different concentrations of recombinant HopH were used for stimulation of macrophages in order to evaluate NO production. The cell viability was detected by MTT assay. NO amounts released in to the supernatants of cultured macrophages and LPS-stimulated macrophages (10 μg/ml) were detected by Griess reagent. Results demonstrated that the suppressive effect of high concentrations of recombinant HopH on NO release and the stimulation effect of protein was shown in 15 µg/ml, compared to the control group. NO stimulation was significant in all the concentrations of LPS stimulated with HopH groups. According to our findings, recombinant HopH has a toxic effect in high concentration on cell. So it can be an anticancer candidate.