The Intrathymic Environment

Hormone-Like Activity of a Thymus Humoral Factor on the Induction of Immune Competence in Lymphoid Cells

“…Previous observations suggest that an active substance is released by the reticular epithelial cells of the thymus medulla (34)(35)(36) and is present in the blood in measurable small quantities (37). The present results indicate that induction of competence by THF involves activation of adenyl cyclase and a rise in cellular cAMP levels.…”

Cellular Differentiation of Lymphoid Subpopulations and Their Microenvironments in the Human Thymus

“…The subcapsular region contains epithelium (Thy-1 +, HLA-DR -or weakly positive), which is most probably capable of initiating very powerful proliferative signals (CLARK 1976) and secretes the thymic hormones thymopoietin, thymosin alpha!, and thymosin beta3 . These biological modulators have been shown to induce TdT positivity in TdT-bone marrow prothymocytes (GOLDSCHNEIDER et al 1981).…”

Functions of Rat T‐Lymphocyte Subsets Isolated by Means of Monoclonal Antibodies

“…It is not known at present if the cortical thymocytes that express MRC OX-22 antigen are also strongly Class 1 antigen-positive, but if this is so then these cells appear to have a mature T ceil phenotype. With regard to the intramedullary MRC OX-22* cells, it seems very likely that these are mature thymocytes about to leave the thymus since these cells are close to the cortico-medullary junction which is considered to be the region where thymocytes migrate into the bloodstream (Clark 1973).…”