ABSTRACT
This chapter is limited to fimbrial vaccines to prevent human diseases and to a few infections, such as enterotoxigenic E. coli (ETEC), where there exists considerable information including clinical trials of candidate vaccines in humans. A few prospective epidemiological field studies provide direct evidence that acquired immunity is largely directed at fimbrial colonization factors of ETEC. To explore the safety, immunogenicity, and efficacy of a simple-to-prepare killed whole-cell vaccine, Tacket et al. (unpublished data) administered formalin-inactivated ETEC to volunteers. It is now recognized that there exist uropathogenic strains of E. coli that manifest certain specific vimlence characteristics. These uropathogenic strains: fall into a restricted set of 0:K:H serotypes; elaborate hemolysin; exhibit resistance to human serum; produce colicin V; and express P fimbriae that allow them to adhere to uroepithelial cells. Pili represent an important virulence property of N. gonorrhoeae, an extremely host-restricted pathogen for which there exists no relevant animal model of infection.
