Molecular mechanisms of cell migration during T-lymphocyte development

点击翻译按钮获取中文摘要

This study was aimed to identify the molecules that govern cellular migration during T-lymphocyte development in the thymus. Our results showed that (1)two chemokines CCL21 and CCL25, which are secreted by thymic epithelial cells, play a major role in attracting T-lymphoid progenitor cells to fetal thymus. We also showed that (2)chemokine signals via CCL19/CCL21 and CCR7 essentially regulate the migration of positively selected thymocytes from the thymic cortex to the thymic medulla. It was identified that the chemokine-dependent cortex-to-medulla migration of developing thymocytes was essential for establishment of central tolerance to tissue-specific antigens and not for T-cell maturation or T-cell export from adult thymus. Furthermore, our study showed that the emigration of mature T lymphocytes from the thymus was dependent on CCR7 chemokine signals in newborn mice but not in adult mice. These results have contributed to better understanding of molecular mechanisms that govern cellular migration during T-lymphocyte development in the thymus.