Intestinal epithelia are in intimate contact with subepithelial and intraepithelial lymphocytes. When stimulated, mucosal lymphocytes generate inflammatory cytokines such as IL-4 and IFN-gamma. We have shown that IFN-gamma directly regulates epithelial function. It is unknown whether IL-4 might influence epithelial function and, if so, whether such influences are similar to or differ from those exerted by IFN-gamma. In this study, we examine the effect of human IL-4 on barrier function, ion transport, and immune accessory ligand expression on T84 cells, a crypt-like epithelial cell line. Basolateral exposure of epithelial monolayers to IL-4 attenuated epithelial barrier function by greater than 65% in a dose (50% of effective dose = 1 U/ml)- and time (t1/2 = 24 h)-dependent fashion, and was inhibitable by neutralizing anti-IL-4 and anti-IL-4R Ab. Stimulated Cl- secretion, as measured by epithelial short circuit current, was diminished by as much as 70% by IL-4. Epithelial preexposure to IL-4 brought about a greater than twofold increase in beta 2 integrin-dependent neutrophil adhesion to epithelial, but retarded neutrophil migration into and across epithelial monolayers. ELISAs revealed that epithelial exposure to IL-4 had no effect on cell surface expression of MHC class I, MHC class II, or ICAM-1. These results indicate that IL-4, like IFN-gamma, may serve to regulate intestinal epithelial function, but that resulting phenotypes may be cytokine specific. We speculate from these data that activation of the basolateral receptor for IL-4 potentially provides a new strategy for damping the cellular component of active inflammation in the intestine.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.