title: A functional analysis of the T-cell defect in MRL-lpr mice.
abstract: Autoimmune MRL-lpr mice have a defect in antigen-specific T-cell proliferation. Our studies indicate that this defect is caused by the massive expansion in MRL-lpr mice of a unique T-cell subset which is unresponsive to antigenic signals. Pharmacologic doses of PGE1 suppress this lymphoid hyperplasia and thus prevent loss of T-cell functions by preventing numeric dilution of normal T cells by defective T cells. The inability of the unique subset of T cells to respond to antigenic signals cannot be corrected by the addition of interleukin 2 (IL-2), implying that additional cellular properties are required to initiate proliferation. While the vast majority of freshly harvested MRL-lpr T cells lack IL-2 receptors (R) as measured by anti-IL-2R monoclonal antibody staining, a large fraction of nonstimulated, cultured (48 hr) MRL-lpr T cells, but not MRL-++ T cells, express IL-2R. These experiments suggest that MRL-lpr cells are activated in vivo but an undefined suppressive influence prevents detection or expression of IL-2R until these cells are explanted and cultured.
mesh_terms: D000367:Age Factors; D000527:Alprostadil / Q000494:pharmacology*; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D000941:Antigens; D001327:Autoimmune Diseases / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D007376:Interleukin-2 / Q000502:physiology; D008213:Lymphocyte Activation / Q000187:drug effects*; D051379:Mice; D008817:Mice, Mutant Strains / Q000276:immunology*; D011971:Receptors, Immunologic / Q000502:physiology; D015375:Receptors, Interleukin-2; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000941:Antigens; D000949:Histocompatibility Antigens Class II; D007376:Interleukin-2; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D000527:Alprostadil