title: Early signaling defects in human T cells anergized by T cell presentation of autoantigen.
abstract: Major histocompatibility complex class II-positive human T cell clones are nontraditional antigen-presenting cells (APCs) that are able to simultaneously present and respond to peptide or degraded antigen, but are unable to process intact protein. Although T cell presentation of peptide antigen resulted in a primary proliferative response, T cells that had been previously stimulated by T cells presenting antigen were completely unresponsive to antigen but not to interleukin 2 (IL-2). In contrast, peptide antigen presented by B cells or DR2+ L cell transfectants resulted in T cell activation and responsiveness to restimulation. The anergy induced by T cell presentation of peptide could not be prevented by the addition of either autologous or allogeneic B cells or B7+ DR2+ L cell transfectants, suggesting that the induction of anergy could occur in the presence of costimulation. T cell anergy was induced within 24 h of T cell presentation of antigen and was long lasting. Anergized T cells expressed normal levels of T cell receptor/CD3 but were defective in their ability to release [Ca2+]i to both alpha CD3 and APCs. Moreover, anergized T cells did not proliferate to alpha CD2 monoclonal antibodies or alpha CD3 plus phorbol myristate acetate (PMA), nor did they synthesize IL-2, IL-4, or interferon gamma mRNA in response to either peptide or peptide plus PMA. In contrast, ionomycin plus PMA induced both normal proliferative responses and synthesis of cytokine mRNA, suggesting that the signaling defect in anergized cells occurs before protein kinase C activation and [Ca2+]i release.
authors.affiliation: Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: J M
authors.initials: JM
authors.lastname: LaSalle
authors.forename: P J
authors.initials: PJ
authors.lastname: Tolentino
authors.forename: G J
authors.initials: GJ
authors.lastname: Freeman
authors.forename: L M
authors.initials: LM
authors.lastname: Nadler
authors.forename: D A
authors.initials: DA
authors.lastname: Hafler
mesh_terms: D000938:Antigen-Presenting Cells / Q000502:physiology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D001324:Autoantigens / Q000276:immunology*; D017252:CD3 Complex; D002118:Calcium / Q000378:metabolism; D016207:Cytokines / Q000096:biosynthesis; D006684:HLA-DR Antigens / Q000276:immunology; D006801:Humans; D007108:Immune Tolerance; D011948:Receptors, Antigen, T-Cell / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D001324:Autoantigens; D017252:CD3 Complex; D016207:Cytokines; D006684:HLA-DR Antigens; D011948:Receptors, Antigen, T-Cell; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium