title: Studies on the mechanism of action of human thymic epithelial conditioned medium on mouse thymocytes. Evidence for induction of immune competence.
abstract: It has been shown that addition of human thymic epithelial conditioned medium (HTECM) leads to an increased response of mouse thymocytes to concanavalin A and phytohemagglutinin. HTECM caused a maximal potentiating effect when added to thymocyte cultures at the time of their initiation. Addition at later times had a smaller enhancing effect and after 24 hr no effect of HTECM could be measured. Responses to mitogen were higher at all time periods measured and peak responses were shifted to later times in the presence of HTECM.  Determination of cell viability made it highly unlikely that the effect of HTECM was simple due to enhanced numbers of viable cells in culture. These data support the view that HTECM induces T-lymphocyte maturation.
mesh_terms: D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D003470:Culture Media; D004848:Epithelium / Q000276:immunology; D006801:Humans; D007121:Immunocompetence; D051379:Mice; D008934:Mitogens / Q000494:pharmacology; D013936:Thymidine / Q000378:metabolism; D013950:Thymus Gland / Q000276:immunology*
chemical_list: D003470:Culture Media; D008934:Mitogens; D013936:Thymidine