Involvement of E-cadherin in thymus organogenesis and thymocyte maturation.

We examined the role of E-cadherin expressed by thymic epithelial cells and immature thymocytes in thymus organogenesis and thymocyte development. ECCD-1 MAb, which blocks homotypic E-cadherin interactions, inhibited epithelial organization and thymocyte development in reaggregate fetal thymic organ cultures. It also interfered with the differentiation of fetal liver cells or fetal thymocytes within deoxyguanosine-treated 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)beta7 integrins did not perturb thymic epithelial organization or thymocyte development, suggesting that homotypic E-cadherin interactions play an important role in thymus development and function.