Strategies for developing a Helicobacter pylori vaccine

Novel strategies are needed to control infection with Helicobacter pylori. Prophylactic and therapeutic immunization against this gastric pathogen is possible in animal models, and initial human studies in H. pylori-infected subjects showed that immunization with H. pylori urease is both safe and im munogenic. In rodents, gastric protection against Helicobacter species infe ction does not depend on the humoral immune response, and a prominent role of the major histocompatibility complex II-restricted CD4(+) T-cell respons e is recognized; however, much remains to be learned about the mechanisms o f effective bactericidal response. A clear understanding of the basic mecha nisms of gastric immune protection in humans is of the utmost importance fo r the development of an effective human vaccine. More potent Vaccines are l ikely to be required to induce protection in humans. The availability of tw o complete genome sequences of H. pylori represents a unique opportunity to identify novel vaccine antigens. Multivalent vaccines delivered by recombi nant attenuated bacteria or administered with nontoxic adjuvants need to be evaluated in relevant models. (C) 1999 Lippincott Williams & Wilkins, Inc.