Thymus, T-Cell Differentiation and the T-Cell System

Abstract

Although it is not possible to say that passage through the thymus is the exclusive pathway that all T-lineage cells must follow, there is ample evidence that the thymus has a profound influence on the development of a fully competent T-cell system (reviewed in Cantor and Weissman, 1976; Stutman, 1978). Thus, for most T-cells, during their development from a stem cell precursor there is a pre-, intra- and post-thymic phase. In the course of this developmental history a number of events take place. These include the emergence of the receptor repertoire (van Boehmer et al., 1978) and the acquisition of MHC restriction and self tolerance (Zinkernagel, 1978) as well as phenotypic differentiation in terms of Lyt antigen defined and functionally defined (helper, effector, suppressor) subpopulations (Cantor and Boyse, 1977).