title: L3T4+, B2A2+ thymocytes from infant mice produce IL 2 after interaction with accessory cells expressing self class II antigens.
abstract: The presence of a thymocyte population in infant (3 to 10 day old), but not adult mice, that produces IL 2 after self class II MHC antigen stimulation is described. The responding thymocyte expresses the antigenic phenotype: Thy-1+, Ly-1+, Ly-2-, L3T4+, B2A2+. Cell-cell mixing experiments and limiting dilution analysis were consistent with a loss of the self-Ia-reactive IL 2-producing thymocyte in the adult, with no evidence for active suppression found. Although thymocytes from adult animals failed to generate IL 2 after self class II stimulation, a similar frequency of IL 2-producing cells was demonstrated in both infant and adult after allo stimulation. These findings, taken with the recent demonstration of IL 2 receptors on neonatal thymocyte subpopulations, demonstrate a mechanism for IL 2 production in the thymus that may play a role in intrathymic differentiation of T cells.
mesh_terms: D000375:Aging; D000818:Animals; D000938:Antigen-Presenting Cells / Q000502:physiology*; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology*; D002450:Cell Communication; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D007376:Interleukin-2 / Q000096:biosynthesis*; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008819:Mice, Nude; D013154:Spleen; D013234:Stem Cells / Q000145:classification / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000145:classification / Q000378:metabolism* / Q000502:physiology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D000949:Histocompatibility Antigens Class II; D007376:Interleukin-2