Therapeutic vaccination against Helicobacter pylori infection with attenuated recombinant Salmonella typhimurium urease B subunit and catalase in mice

Abstract

To investigate the effects of oral immunization with attenuated recombinant Salmonella typhimurium urease B subunit and catalase vaccines in the treatment of Helicobacter pylori infection in a H. pylori infected mouse model. Thirty C57BL/6 mice were randomized into three groups and challenged twice with oral administration of H. pylori within 3 days. Four weeks after the second challenge, the mice were immunized by oral administration of attenuated recombinant S. typhimurium urease B subunit (group A), attenuated recombinant S. typhimurium catalase (group B) or saline (group C), and all mice were killed 4 weeks later. The stomachs were collected for a rapid urease test, modified Giemsa staining and quantitative culture to observe the density of H. pylori, hematoxylin-eosin staining was performed to assess the presence of inflammation and lymphocytes from the spleen were used for the lymphoproliferation assay. The gastric H. pylori density of groups A, B and C was 1.58 x 10(5) c.f.u./g, 4.88 x 10(5) c.f.u./g and 1.92 x 10(6) c.f.u./g, respectively. The H. pylori density was significantly decreased in the therapeutic groups (P < 0.05). No significant inflammation was found in any group of mice. The lymphoproliferation assays of groups A and B were positive. Immunization with oral attenuated recombinant S. typhimurium urease B subunit and catalase vaccines is effective in reducing the density of H. pylori colonization.