CATALASE, A NOVEL ANTIGEN FOR HELICOBACTER-PYLORI VACCINATION

The efficacy of an orogastric vaccine comprised of purified Helicobact er pylori catalase plus the mucosal adjuvant cholera toxin (CT) was ex amined with both the Helicobacter felis and H. pylori mouse models wit h BALB/c mice. Native H. pylori catalase (290 mu g) plus CT was initia lly used as a vaccine antigen in the H. felis mouse model and protecte d 80% (8 of 10) of the challenged animals, while all control animals w ere infected (20 of 20). In a follow-up experiment, recombinant H. pyl ori catalase plus CT was used for immunization, and groups of mice wer e challenged with the Sydney strain of H. pylori. Immunization with re combinant catalase protected a significant proportion (9 of 10) of the mice from H. pylori challenge, indicating that this enzyme should be considered as a candidate for a future vaccine. This study provides th e first available data on the efficacy of protective immunization with the new Sydney strain of H. pylori in a mouse model. These data also provide indirect evidence that proteins which are normally intracellul ar, such as catalase, may be present on the surface of N. pylori and t hus may provide targets for immunization.