Interactions between enteropathogenic Escherichia coli and epithelial cells

Enteropathogenic Escherichia coli (EPEC) may be considered a paradigm for a multistage interaction between pathogen and host cell. EPEC strains produc e a type IV pilus that is associated with initial adherence to host cells, and these strains possess a type III secretion apparatus that is necessary for transducing signals to host cells. Secretion of three Esp proteins is r equired for activation of a phosphotyrosine-containing receptor that allows EPEC to bind intimately to host cells via the bacterial outer membrane pro tein intimin. Intimately attached bacteria rest upon a pedestal composed of host cytoskeletal proteins in an arrangement recognized as the attaching a nd effacing phenotype. The precise molecular interactions that lead to thes e dramatic alterations in the host cell cytoskeleton remain to be elucidate d.