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.