title: Detection of glutamic acid decarboxylase-activated T cells with I-Ag7 tetramers.
abstract: CD4(+) T cells selected by the type 1 diabetes associated class II MHC I-A(g7) molecules play a critical role in the disease process. Multivalent MHC/peptide tetramers have been used to directly detect antigen-specific T cells. Detection of autoantigen-activated CD4(+) T cells with tetramers should be very helpful in the study of the roles of these cells in diabetes. We report here the generation of tetramers of I-A(g7) covalently linked to two glutamic acid decarboxylase (GAD) peptides and the detection of GAD peptide-activated T cells from nonobese diabetic (NOD) mice. The I-A(g7) heterodimers can form stable complexes with a covalently bound GAD peptide and can stimulate antigen specific T cells. Furthermore, I-A(g7)/GAD peptide tetramer can detect most if not all of the antigen-specific CD4(+) T cells from immunized NOD mice. Antigen-specific T cells detected by the tetramers can up-regulate their CD4 expression on the cell surface after being restimulated with the GAD peptides in vitro. In contrast, the tetramers can detect a percentage of T cells in lymph nodes and spleens and T cells infiltrating islets from nonimmunized mice that is not significantly above the background. Therefore, T cells specific for the GAD peptides are present in NOD mice at a frequency too low to be detected, but immunization of NOD mice can facilitate their detection by tetramers.
authors: Division of Immunology, Beckman Research Institute, City of Hope, Duarte, CA 91010, USA. cliu@coh.org
authors: C P
authors: CP
authors: Liu
authors: K
authors: K
authors: Jiang
authors: C H
authors: CH
authors: Wu
authors: W H
authors: WH
authors: Lee
authors: W J
authors: WJ
authors: Lin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001324:Autoantigens / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology*; D005968:Glutamate Decarboxylase / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D016688:Mice, Inbred NOD; D008969:Molecular Sequence Data; D010455:Peptides / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000276:immunology
chemical_list: D001324:Autoantigens; D000949:Histocompatibility Antigens Class II; C407099:I-A g7 antigen; D010455:Peptides; D011993:Recombinant Fusion Proteins; D005968:Glutamate Decarboxylase