title: Population kinetics of precursors of IL 2-producing peripheral T lymphocytes: evidence for short life expectancy, continuous renewal, and post-thymic expansion.
abstract: The fate of spleen T cell populations able to produce IL 2 after stimulation with Con A (IL 2p) was evaluated at different times after injection into IL 2p-deficient, syngeneic nude recipients. Precise enumeration of transferred cell populations in recipient organs was performed by limiting dilution analysis. The results obtained confirm previous findings on the short life-span of IL 2p cells. They also demonstrate that: the transferred populations containing IL 2p were capable of continuous renewal and expansion in the host; IL 2p cell expansion, a transient event that takes place predominantly in lymph nodes, is much reduced when injected cells are depleted of recent thymus migrants; in steady-state conditions, IL 2p T cells do not lose their self-renewal ability and maintain population sizes by continuous cell production and death in peripheral pools. The self-renewal capacity, the expansion potential of peripheral IL 2p T cells and, in particular, of recent thymus migrants may allow extensive post-thymic modulation of peripheral T cell specificities, suggesting that post-thymic selection may have a major role in the establishment of the available and actual mature IL 2p T cell repertoire.
mesh_terms: D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte; D000950:Antigens, Ly / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis; D002453:Cell Cycle; D002454:Cell Differentiation; D002470:Cell Survival; D006918:Hydroxyurea / Q000494:pharmacology; D007376:Interleukin-2 / Q000096:biosynthesis*; D051379:Mice; D008819:Mice, Nude; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000502:physiology*; D013934:Thymectomy; D013950:Thymus Gland / Q000276:immunology
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000950:Antigens, Ly; D000954:Antigens, Surface; D007376:Interleukin-2; D006918:Hydroxyurea