Molecular mechanisms for lineage commitment in T cell development.

Thymocyte development is characterized by the ordered expression of T cell receptors as well as the accessory molecules, CD4 and CD8. Interactions of these critical surface molecules with MHC ligands expressed on thymic stromal cells mediate additional developmental processes. Now that the stages of thymic differentiation have been delineated, current investigations are addressing the mechanisms that underlie T cell lineage commitment and selection.