title: Anti-TCR antibody treatment activates a novel population of nonintestinal CD8 alpha alpha+ TCR alpha beta+ regulatory T cells and prevents experimental autoimmune encephalomyelitis.
abstract: CD8alphaalpha+CD4-TCRalphabeta+ T cells are a special lineage of T cells found predominantly within the intestine as intraepithelial lymphocytes and have been shown to be involved in the maintenance of immune homeostasis. Although these cells are independent of classical MHC class I (class Ia) molecules, their origin and function in peripheral lymphoid tissues are unknown. We have recently identified a novel subset of nonintestinal CD8alphaalpha+CD4-TCRalphabeta+ regulatory T cells (CD8alphaalpha Tregs) that recognize a TCR peptide from the conserved CDR2 region of the TCR Vbeta8.2-chain in the context of a class Ib molecule, Qa-1a, and control- activated Vbeta8.2+ T cells mediating experimental autoimmune encephalomyelitis. Using flow cytometry, spectratyping, and real-time PCR analysis of T cell clones and short-term lines, we have determined the TCR repertoire of the CD8alphaalpha regulatory T cells (Tregs) and found that they predominantly use the TCR Vbeta6 gene segment. In vivo injection of anti-TCR Vbeta6 mAb results in activation of the CD8alphaalpha Tregs, inhibition of the Th1-like pathogenic response to the immunizing Ag, and protection from experimental autoimmune encephalomyelitis. These data suggest that activation of the CD8alphaalpha Tregs present in peripheral lymphoid organs other than the gut can be exploited for the control of T cell-mediated autoimmune diseases.
authors.affiliation: Laboratory of Autoimmunity, Torrey Pines Institute for Molecular Studies, San Diego, CA 92121, USA.
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Tang
authors.forename: Igor
authors.initials: I
authors.lastname: Maricic
authors.forename: Vipin
authors.initials: V
authors.lastname: Kumar
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage*; D016827:CD8 Antigens / Q000096:biosynthesis* / Q000502:physiology; D002460:Cell Line; D002999:Clone Cells; D015536:Down-Regulation / Q000276:immunology; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control*; D005260:Female; D019674:Genes, T-Cell Receptor beta / Q000276:immunology; D007413:Intestinal Mucosa / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000145:classification / Q000276:immunology* / Q000378:metabolism; D018417:Th1 Cells / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D016827:CD8 Antigens; C431698:CD8alpha antigen; D016693:Receptors, Antigen, T-Cell, alpha-beta