New approaches to mucosal immunization

Every year more than 17 million deaths worldwide are caused by infectious d iseases. The great majority of these deaths occur in underdeveloped countri es and are attributed to diseases preventable by existing vaccines, or dise ases that could potentially be prevented with new vaccines. The fact that m ost human and veterinary pathogens establish infection in the host by initi ating contact at a mucosal surface, provide the rationale for the developme nt of mucosal vaccines. An increasing number of strategies have been propos ed to facilitate mucosal immunization. Among the most widely investigated s trategies are the use of attenuated microorganisms; the inclusion of immuni zing antigens in lipid-based carriers, the genetic creation of transgenic p lants and the use of mucosal adjuvants derived from bacterial toxins. This review provides a brief summary of the most recent advances in the field of mucosal immunization with an special emphasis on a promising genetically d etoxified mucosal adjuvant, LT(R192G), derived from the heat-labile toxin o f enterotoxigenic E. coli. We present evidence regarding the safety, immuno genicity, and efficacy of LT(R192G) for the development of a new generation of mucosal vaccines.