VACCINATION AGAINST ENTEROBACTERIACEAE RE SPONSIBLE FOR ENTERIC INFECTIONS

Development of vaccines against enterobacterial species responsible fo r enteric infections sounds like an unrealistic project. On the other hand, based on our growing understanding of the pathogenesis of infect ions caused by the major species (i.e. Salmonella typhi, Shigella flex neri and Shigella dysenteriae 1, Enterotoxigenic Escherichia coli) and on our better characterization of the immunological parameters of muc osal protection, it is likely that a limited number of vaccines contro ling diseases such as typhoid fever, bacillary dysentery and cholera-l ike E. coli infections will become available. There are three major pr oblems that still need to be solved: the variety of antigens and antig enic specificities, the nature of protective antigens and, provided th at these prerequisites are fulfilled, the presentation of the vaccine and the immunization route. With the exception of typhoid fever, which has a systemic phase that probably makes immunization attempts by pur ified Vi antigen successful, experimental strategies rely very much on induction of a mucosal immunity. Either subunit vaccines, or genetica lly manipulated strains which attenuated virulence are currently consi dered.