Infection of T84 cells with enteropathogenic Escherichia coli alters barrier and transport functions

The effect of enteropathogenic Escherichia coli (EPEC) infection on electrophysiology of T84 cell monolayers was examined. After 18 h of infection with EPEC (E2348), transepithelial electrical resistance was decreased (30 +/- 5% of uninfected values) compared with monolayers infected with a nonpathogenic E. coli strain (104 +/- 13%). Resistance of monolayers infected with EPEC mutant strain CVD206, deficient in attaching and effacing lesion formation, was partially reduced (66 +/- 10%). In addition, permeability of EPEC-infected T84 monolayers increased compared with uninfected cells. Associated with these changes was an altered distribution of the tight junction protein, ZO-1. Taken together, these findings suggest that the barrier defect induced by EPEC was at the level of the tight junction. Adenosine 3'5'-cyclic monophosphate-stimulated chloride secretion was also diminished in EPEC-infected cells, whereas Ca2+ -dependent chloride secretion was not different from uninfected cells. These findings indicate that EPEC infection alters intestinal epithelial barrier and transport functions. Furthermore, these results provide a possible mechanism for EPEC-induced diarrheal disease.