Phenotypic characterization of murine thymic microenvironments

The thymus provides the necessary microenvironments for the differentiation of T lymphocytes. Thymic non-lymphoid cells, such as epithelial cells, macrophages and interdigitating cells are thought to promote sequential stages in T cell differentiation. However, their specific role in each step of T cell differentiation remains to be established. With the development of new monoclonal antibodies it has now become possible to characterize the different thymic stromal cell types. In this review, various aspects of thymic stromal cells and their functions in T cell differentiation are discussed, such as: (1) phenotypic analysis of stromal cells in situ; (2) the application of new "chimeric' monoclonal antibodies which "link' developing thymocytes and stromal cells; (3) perturbation of thymic microenvironments after cyclosporin-A treatment; (4) perturbation of thymic microenvironments in new transgenic mouse lines; (5) phenotypic analysis of in vitro growing stromal cell lines.