T-lymphocyte-epithelial-cell interactions: integrin alpha(E)(CD103)beta(7), LEEP-CAM and chemokines

The epithelia are the avascular layers of cells that cover the environment- exposed surfaces of the body. It appears that T cells localize to selected sites in or adjacent to epithelia via the selective expression of adhesion molecules and chemokine receptors on T cells. These bind to counter-recepto rs and to chemokines expressed by epithelial cells. Recently, there has bee n an advance in our understanding of the interaction of the alpha(E)beta(7) integrin with its epithelial cell ligand, E-cadherin. In addition, a new a dhesion molecule has been identified on non-intestinal epithelial cells, te rmed lymphocyte-endothelial-epithelial-cell adhesion molecule (LEEP-CAM). F inally, there have been advances in our understanding of the role of skin- or gut-epithelia-derived chemokines in regulating activated T cell homing t o these sites.