Identification of Helicobacter pylori strain cagPAI+ and cagPAI- Antigens by IgG antibodies from sera of experimentally colonized meriones unguiculatus (Mongolian gerbils)

Background: Mongolian gerbils that are experimentally infected with Helicobacter pylori develop a chronic inflammation that is similar to natural infections in humans. The aim of this study was to compare the antigens of H. pylori cagPAI+ and cagPAI? strains that are expressed during Meriones unguiculatus colonization. Materials and Methods: We identified H. pylori cagPAI+ and cagPAI? strain antigens via Western blotting of samples from Mongolian gerbils that were subjected to unique, mixed, and sequential bacterial infections. Results: The antigens from the J99/CG3 (cagPAI+) strain had a lower molecular weight than the antigens from the 251F/CG3 (cagPAI?) strain. There were fewer identified antigens in the single unique infections compared with the mixed and sequential infections. The number of recognized antigens that had a frequency of recognition >60% was higher for the simultaneous and sequential infection groups compared with the single infection group. A 57‐kDa antigen was present in >60% of the samples and four of the five experimental groups. Antigens specific to each bacterial strain were identified; the 190‐ and 158‐kDa antigens appear to be specific for cagPAI?, and the 70‐kDa antigen appears to be specific for cagPAI+. Conclusions: In this study, we identified antigens that are common and specific to the H. pylori cagPAI+ and cagPAI? strains.