Perspectives of anti-H. pylori vaccination.

Mucosal vaccination using different antigens in conjunction with adjuvants has been used for the prevention and even cure of Helicobacter infection in animal models. A phase I-II trial was recently performed on infected volunteers with urease and the heat labile enterotoxin from E. coli (LT). A significant decrease in bacterial density but no cure of infection was observed in some patients. The immune effectors which prevent or cure infection with Helicobacter are not well understood and will need to be more clearly defined in order to improve vaccination strategies. Future developments will likely include the following: generation of new mucosal adjuvants without gastrointestinal toxicity; combination of two or three different antigens in order to ensure broader efficacy; use of different routes of administration such as nasal or rectal; coadministration of anti-Helicobacter treatment and vaccine; development of alternate vaccine methods which do not require a mucosal adjuvant, i.e. antigen expression by live carriers or by DNA vaccination; combination of different vaccination methods, for instance DNA vaccination followed by a mucosal boost.