title: Interleukin-2 in the ontogeny of human lymphoid tissues.
abstract: Cells from different fetal and adult lymphoid organs were tested for the capacity to (a) react to the T-cell growth factor interleukin-2 (IL-2) and (b) to produce IL-2 under appropriate conditions. IL-2 was determined as growth promoting activity for mouse T blasts. Optimal conditions for IL-2 production were: 5 X 10(6) cells/ml; 4-6 micrograms mitogen, 24 h incubation time. Concanavalin A was preferable for fetal thymus, whereas phytohemagglutinin was the appropriate mitogen for lymphocytes from blood and lymph node. Fetal and adult spleen cells produced equal activities of IL-2 irrespective of the mitogen used. Cells from thymus and spleen of 17-21-week-old fetuses produced IL-2 activities like adult cells. Fetal liver cells from the same fetuses produced no IL-2. A comparison of IL-2 activities released from cells of 26 donors showed that within individual variations there was no decrease of the capacity to produce IL-2 with old age. An activity present in culture media of mitogen treated lymphocytes which increased thymidine uptake in fetal liver cells could be distinguished from IL-2 by its different molecular weight and by a heat treatment which abolished IL-2 but not fetal liver cell growth promoting activity. This latter activity is discussed to be colony-stimulating activity. It is concluded that IL-2 is produced by and reacts with T cells only after they have reached or passed the thymus.
mesh_terms: D000328:Adult; D003208:Concanavalin A / Q000494:pharmacology; D005333:Fetus / Q000276:immunology*; D006133:Growth Substances / Q000302:isolation & purification; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000096:biosynthesis / Q000276:immunology* / Q000494:pharmacology; D008099:Liver / Q000276:immunology; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology; D008221:Lymphoid Tissue / Q000276:immunology*; D008222:Lymphokines / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D006133:Growth Substances; D007376:Interleukin-2; D008222:Lymphokines; D003208:Concanavalin A