INVOLVEMENT OF E-CADHERIN IN THYMUS ORGANOGENESIS AND THYMOCYTE MATURATION

We examined the role of E-cadherin expressed by thymic epithelial cell s and immature thymocytes in thymus organogenesis and thymocyte develo pment. ECCD-1 MAb, which blocks homotypic E-cadherin interactions, inh ibited epithelial organization and thymocyte development in reaggregat e fetal thymic organ cultures. It also interfered with the differentia tion of fetal liver cells or fetal thymocytes within deoxyguanosine-tr eated thymic lobes, but did not affect thymocyte development in intact cultured fetal thymic lobes. In contrast, antibodies that selectively inhibit interactions between E-cadherin and alpha(E) beta(7) integrin s did not perturb thymic epithelial organization or thymocyte developm ent, suggesting that homotypic E-cadherin interactions play an importa nt role in thymus development and function.