Mucosal vaccination is finding a place among the current vaccine strategies

Among the many vaccine approaches developed in the recent past, mucosal vac cination has been a major focus. Oral vaccination has been particularly stu died for the development of vaccines against enteric pathogens. To induce a local immune response, protective antigens have to be targeted to the inte stinal mucosa-associated lymphoid follicles. Two types of approaches are cu rrently being developed: (1) live attenuated strains constructed by specifi c inactivation of virulence factors; (2) subunit Vaccines using the purifie d protective antigens combined to a delivery system. Several vaccine candid ates are promising (live attenuated strains for shigellosis; killed bacteri a combined to the B subunit of cholera toxin, a potent mucosal adjuvant, fo r cholera). However, recent disappointing results (intussuception occurring following vaccination in children with a live rhesus-human reassortant rot avirus tetravalent vaccine; low immunogenicity of live bacterial attenuated strains tested in endemic areas...) emphasize some limitations that remain to be solved. Innovative strategies are being investigated : intranasal va ccination inducing both systemic and local immune responses at different mu cosal sites, edible plant vaccines... The future remains full of promise.