title: A mechanism for the major histocompatibility complex-linked resistance to autoimmunity.
abstract: Certain major histocompatibility complex (MHC) class II haplotypes encode elements providing either susceptibility or dominant resistance to the development of spontaneous autoimmune diseases via mechanisms that remain undefined. Here we show that a pancreatic beta cell-reactive, I-Ag7-restricted, transgenic TCR that is highly diabetogenic in nonobese diabetic mice (H-2(g7)) undergoes thymocyte negative selection in diabetes-resistant H-2(g7/b), H-2(g7/k), H-2(g7/q), and H-2(g7/nb1) NOD mice by engaging antidiabetogenic MHC class II molecules on thymic bone marrow-derived cells, independently of endogenous superantigens. Thymocyte deletion is complete in the presence of I-Ab, I-Ak + I-Ek or I-Anb1 + I-Enb1 molecules, partial in the presence of I-Aq or I-Ak molecules alone, and absent in the presence of I-As molecules. Mice that delete the transgenic TCR develop variable degrees of insulitis that correlate with the extent of thymocyte deletion, but are invariably resistant to diabetes development. These results provide an explanation as to how protective MHC class II genes carried on one haplotype can override the genetic susceptibility to an autoimmune disease provided by allelic MHC class II genes carried on a second haplotype.
authors.affiliation: Department of Microbiology and Infectious Diseases and Julia McFarlane Diabetes Research Centre, Faculty of Medicine, Health Sciences Centre, The University of Calgary, Calgary, Alberta T2N 4N1, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Schmidt
authors.forename: J
authors.initials: J
authors.lastname: Verdaguer
authors.forename: N
authors.initials: N
authors.lastname: Averill
authors.forename: P
authors.initials: P
authors.lastname: Santamaria
mesh_terms: D000818:Animals; D001327:Autoimmune Diseases / Q000235:genetics* / Q000276:immunology; D001853:Bone Marrow / Q000276:immunology; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics* / Q000276:immunology; D004198:Disease Susceptibility; D005260:Female; D005786:Gene Expression Regulation; D005802:Genes, MHC Class II; D006183:H-2 Antigens / Q000235:genetics / Q000276:immunology; D006239:Haplotypes / Q000235:genetics; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000276:immunology; D007113:Immunity, Innate; D007515:Islets of Langerhans / Q000276:immunology*; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D008822:Mice, Transgenic; D011948:Receptors, Antigen, T-Cell / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology
chemical_list: D006183:H-2 Antigens; D000949:Histocompatibility Antigens Class II; D011948:Receptors, Antigen, T-Cell