Vaccination against Helicobacter pylori.

The initial steps have been taken towards the development of a vaccine against the human gastroduodenal pathogen, Helicobacter pylori. Proof of principle was achieved when mice were protected against challenge with living Helicobacter felis, a close relative of the human pathogen, following oral immunization with H. felis sonicate and the mucosal adjuvant, cholera toxin. Similar results with H. pylori antigen have allowed development of possible human vaccines. Recombinant urease protein has been proposed as a major vaccine candidate, together with the heat-labile toxin of Escherichia coli as the adjuvant. Probably the most significant finding in the early vaccine studies was that immunization of already infected mice resulted in a cure of Helicobacter infection. The possibility of a therapeutic vaccine makes commercial development more attractive, as large populations could be immunized without the potential for development of drug-resistant strains that currently restricts widespread antibiotic use. For advanced societies with powerful economies yet a high prevalence of H. pylori, such as Japan, vaccine development should become a high national health priority.