title: Immunopathology of interleukin (IL) 2-deficient mice: thymus dependence and suppression by thymus-dependent cells with an intact IL-2 gene.
abstract: Interleukin (IL) 2-deficient mice develop a fatal immunopathology characterized by lymphoadenopathy, splenomegaly, T cell infiltration of the bone marrow, loss of B cells, anemia, and inflammation of the gut. The thymus dependence of these disease symptoms was tested by introducing the IL-2 mutation into athymic mice. With the exception of an increase in CD8+ intrahepatic alpha/beta T cells, IL-2 deficiency had no detectable effect on leukocyte composition or health of athymic mice, indicating a key role for thymus-derived T cells in the initiation of disease and demonstrating that B cell development and survival are independent of IL-2. In adoptive transfer studies, lymph node and spleen cells from euthymic IL-2-deficient mice induced disease in athymic mice with an intact IL-2 gene, suggesting that thymus-independent IL-2-expressing cells are unable to control the development of immune pathology. Both IL-2+ and IL-2-/- bone marrow cells repopulated the thymus and the peripheral T cell compartment of the recombination activator gene 2-deficient recipients, and chimeras that had received IL-2-deficient bone marrow developed immune pathology. Disease development was, however, fully or at least partially prevented when 30% of the bone marrow inoculum was derived from mice able to express IL-2. These results demonstrate that the IL-2 deficiency syndrome depends on the intrathymic differentiation of T cells carrying the IL-2 mutation, and that the abnormal activation of IL-2-deficient lymphocytes can be controlled by thymus-derived but not thymus-independent lymphocytes.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D001853:Bone Marrow / Q000473:pathology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D004268:DNA-Binding Proteins; D007153:Immunologic Deficiency Syndromes / Q000276:immunology* / Q000473:pathology; D007376:Interleukin-2 / Q000172:deficiency / Q000502:physiology*; D008099:Liver / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D008819:Mice, Nude; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013950:Thymus Gland / Q000502:physiology*
chemical_list: D004268:DNA-Binding Proteins; D007376:Interleukin-2; C499308:Rag2 protein, mouse; C064655:V(D)J recombination activating protein 2