Figure 3.

Increased paracellular permeability of T84 monolayers to fluorescein isothiocyanate (FITC)–labeled markers by heat-labile enterotoxin (LT)–producing enterotoxigenic Escherichia coli (ETEC) and purified catalytically active LT. A, Cells were treated for three hours, washed, and incubated. At 18-hours post-infection, FITC-dextran was added to the apical side of each well. Six hours later, fluorescence in the basolateral compartment was measured by using a fluorimeter. Values are the mean ± SEM. The Mann-Whitney test was used to determine significance. B, Penetration of FITC–bovine serum albumin through monolayers treated with ETEC strains or LT. Detection of the marker was not significantly above the negative control for any of the treatments (mean and 95% confidence intervals are shown).