INTERACTION OF ENTEROPATHOGENIC ESCHERICHIA-COLI WITH HOST EPITHELIAL-CELLS

Enteropathogenic Escherichia coli (EPEC) causes severe diarrhea in you ng children. Upon infection, EPEC induces the assembly of highly organ ized pedestal-like actin structures in host epithelial cells. All the EPEC genes that are involved in inducing formation of actin pedestals are located in a unique 35 kbp chromosomal pathogenicity island, terme d LEE. These genes include the sep genes that encode components of typ e III protein secretion system, and genes that encode proteins secrete d by this system, the esp genes. This protein secretion system is acti vated upon contact with the host cell, resulting in increased secretio n of Esp proteins. Some of these Esp proteins form the translocation a pparatus while others are translocated into the cytoplasm of the host cell. Concerted activity of the LEE genes including the eae, esp and t he sep genes is needed to trigger signal transduction in the host cell which results in formation of an actin pedestal.