ADHESION BETWEEN EPITHELIAL-CELLS AND T-LYMPHOCYTES MEDIATED BY E-CADHERIN AND THE ALPHA(E)BETA(7) INTEGRIN

IN contrast to sessile cell types, lymphocytes migrate through the vas culature to become diffusely distributed in tissues or organized in ly mphoid structures. A complex array of adhesion molecules including sel ectins, integrins and their counter-receptors mediate lymphocyte homin g and migration into tissues and may be constitutively expressed or in duced(1,2). However, the molecules that mediate the tissue-specific re tention of lymphocytes within the parenchyma have not been identified. Along the epithelium at the basolateral surface of enterocytes, intes tinal intraepithelial lymphocytes are found. These T cells of the muco sal immune system serve as a model for the tissue-specific compartment alization of lymphocytes. We investigated whether the localization of these intestinal intraepithelial lymphocytes could be mediated by spec ific interactions between adhesion molecules expressed selectively on this subpopulation of T cells and tissue-restricted adhesion molecules on epithelial cells. Here we show that heterotypic adhesive interacti ons between epithelial cells and intraepithelial lymphocytes in vitro are mediated by E-cadherin and the alpha(E) beta(7) integrin.