title: Thymocyte-directed enhancement of apoptosis via soluble factor(s) derived from a cortical and a medullary thymic epithelial cell line.
abstract: Apoptosis of murine thymocytes was examined either in intact fetal thymus lobes or in thymus cell suspensions, both cultured alone or in the presence of either a cortical (TEC 1.4) or a medullary (TEC 2.3) thymic epithelial cell line. Both TECs induced a pronounced increase of apoptosis in 24-h cultivated single thymus cell suspensions but not in spleen or bone marrow cell cultures. Co-culture of thymocytes with murine fibroblasts did not enhance apoptosis of the thymus cells. A similar enhancement of thymocyte apoptosis was observed with dialysed culture supernatants derived from both TEC lines, the active component(s) having a molecular weight of > 30 kDa. In contrast, the cortical TEC 1.4 had a pronounced apoptosis inducing effect on intact fetal thymus lobes cultivated for six days, whereas the medullary TEC 2.3 had only a marginal influence. TEC 1.4 also induced a significant alteration in the ratio of CD4+CD8+ to CD4-CD8- cells. It is concluded that both the cortical and medullary epithelial cell lines are able to induce thymocyte apoptosis but that a large proportion of the cells within the intact thymus stroma is refractory to the respective signal(s) of the medullary epithelial cell line.
authors.affiliation: Institute of General and Experimental Pathology, University of of Graz, Austria.
authors.forename: I
authors.initials: I
authors.lastname: Rinner
authors.forename: R
authors.initials: R
authors.lastname: Eren
authors.forename: E
authors.initials: E
authors.lastname: Skreiner
authors.forename: T
authors.initials: T
authors.lastname: Kukulansky
authors.forename: M
authors.initials: M
authors.lastname: Kasai
authors.forename: K
authors.initials: K
authors.lastname: Hirokawa
authors.forename: A
authors.initials: A
authors.lastname: Globerson
authors.forename: K
authors.initials: K
authors.lastname: Schauenstein
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002460:Cell Line / Q000166:cytology / Q000378:metabolism; D016922:Cellular Senescence / Q000502:physiology; D017077:Culture Media, Conditioned / Q000737:chemistry* / Q000494:pharmacology; D004847:Epithelial Cells; D005333:Fetus / Q000166:cytology; D005434:Flow Cytometry; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D012995:Solubility; D013950:Thymus Gland / Q000166:cytology*
chemical_list: D017077:Culture Media, Conditioned