ABSTRACT
T cell anergy is an important mechanism in the induction of peripheral tolerance against autoimmune diseases, yet no surface marker unique to anergic T cells in these diseases has been identified. In this study we induced in vivo anergy by i.v. tolerance against experimental autoimmune encephalomyelitis in myelin basic protein TCR transgenic mice, and showed that the hyporesponsiveness of autoantigen-reactive T cells from tolerized mice was associated with a dramatic loss of 3G11, a cell surface molecule on the surface of CD4+ T cells. Purified 3G11-CD4+ T cells lost autoantigen-induced proliferation and IL-2 production, whereas 3G11+CD4+ T cells retained responsiveness. Furthermore, 3G11- T cells actively suppressed proliferation and Th1 cytokine production of 3G11+ T cells and splenocytes of nontolerized mice. Active suppression by 3G11- T cells was at least partially due to soluble immunoregulatory factors, including IL-10. The T regulatory property of 3G11- T cells was confirmed in vivo because the transfer of purified 3G11- T cells effectively suppressed clinical experimental autoimmune encephalomyelitis. We conclude that loss of the surface molecule 3G11 characterizes a distinct population of anergic/regulatory T cells. This is the first demonstration of the ability to identify and purify anergic T cells by a distinct cell surface marker in an autoimmune disease and paves the way for a better understanding of the mechanism of tolerance in autoimmune diseases.
Subject(s)
Antigens, Surface/immunology , Antigens, Surface/metabolism , Clonal Anergy/immunology , Encephalomyelitis, Autoimmune, Experimental/immunology , Encephalomyelitis, Autoimmune, Experimental/metabolism , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/metabolism , Adoptive Transfer , Animals , Cell Proliferation , Cells, Cultured , Disease Models, Animal , Down-Regulation , Encephalomyelitis, Autoimmune, Experimental/chemically induced , Encephalomyelitis, Autoimmune, Experimental/pathology , Female , Immunosuppressive Agents/pharmacology , Interleukin-10/pharmacology , Interleukin-4/pharmacology , L-Selectin/metabolism , Mice , Mice, Transgenic , Myelin Basic Protein/pharmacology , Peptide Fragments/pharmacology , T-Lymphocytes, Regulatory/drug effects , T-Lymphocytes, Regulatory/pathologyABSTRACT
To characterize T cell and antibody responses in remitting-relapsing experimental autoimmune encephalomyelitis (RR-EAE), we compared myelin oligodendrocyte glycoprotein (MOG)-induced RR-EAE in C57BL/6 (B6) x SJL (F1) mice and chronic-progressive EAE (CP-EAE) in B6 mice at week 8 p.i. when clinical scores were comparable. Although these two strains exhibited similar inflammation/demyelination pattern and MOG-induced T cell responses, RR-EAE mice produced significantly higher levels of anti-MOG IgG1/IgG2a antibodies. Further, lymphocytes of RR-EAE mice proliferated vigorously to the secondary epitope myelin basic protein (MBP) 1-11. These results support a potential involvement of anti-MOG antibodies and epitope spreading in T cell responses in the development of MOG-induced RR-EAE model.
Subject(s)
Antibodies/immunology , Disease Models, Animal , Encephalomyelitis, Autoimmune, Experimental/immunology , Multiple Sclerosis, Relapsing-Remitting/immunology , T-Lymphocytes/immunology , Analysis of Variance , Animals , Cells, Cultured , Cytokines/metabolism , Encephalomyelitis, Autoimmune, Experimental/etiology , Encephalomyelitis, Autoimmune, Experimental/pathology , Enzyme-Linked Immunosorbent Assay/methods , Flow Cytometry/methods , Glycoproteins/immunology , Histological Techniques , Immunization/methods , Immunoglobulin G/blood , Lymphocyte Activation , Mice , Mice, Inbred Strains , Multiple Sclerosis, Chronic Progressive/etiology , Multiple Sclerosis, Chronic Progressive/immunology , Multiple Sclerosis, Chronic Progressive/pathology , Multiple Sclerosis, Relapsing-Remitting/etiology , Multiple Sclerosis, Relapsing-Remitting/pathology , Myelin Basic Protein/immunology , Myelin Basic Protein/toxicity , Myelin Proteolipid Protein , Myelin-Oligodendrocyte Glycoprotein , Peptide Fragments/immunology , Peptide Fragments/toxicity , Spinal Cord/pathology , Time FactorsABSTRACT
IL-12 was thought to be involved in the development of experimental autoimmune encephalomyelitis (EAE), a Th1 cell-mediated autoimmune disorder of the CNS. However, we have recently found that IL-12 responsiveness, via IL-12Rbeta2, is not required in the induction of EAE. To determine the role of IL-12Rbeta1, a key subunit for the responsiveness to both IL-12 and IL-23, in the development of autoimmune diseases, we studied EAE in mice deficient in this subunit of IL-12R. IL-12Rbeta1(-/-) mice are completely resistant to myelin oligodendrocyte glycoprotein (MOG)-induced EAE, with an autoantigen-specific Th2 response. To study the mechanism underlying this Th2 bias, we cocultured purified CD4(+) T cells and APCs of MOG-immunized mice. We demonstrate that IL-12Rbeta1(-/-) APCs drive CD4(+) T cells of both wild-type and IL-12Rbeta1(-/-) mice to an Ag-induced Th2 phenotype, whereas wild-type APCs drive these CD4(+) T cells toward a Th1 type. IL-12Rbeta1(-/-) CD4(+) T cells, in turn, appear to exert an immunoregulatory effect on the capacity of wild-type APCs to produce IFN-gamma and TNF-alpha. Furthermore, decreased levels of IL-12p40, p35, and IL-23p19 mRNA expression were found in IL-12Rbeta1(-/-) APCs, indicating an autocrine pathway of IL-12/IL-23 via IL-12Rbeta1. IL-18 production and IL-18Ralpha expression are also significantly decreased in IL-12Rbeta1(-/-) mice immunized with MOG. We conclude that in the absence of IL-12Rbeta1, APCs play a prominent regulatory role in the induction of autoantigen-specific Th2 cells.
Subject(s)
Antigen-Presenting Cells/immunology , CD4-Positive T-Lymphocytes/immunology , Encephalomyelitis, Autoimmune, Experimental/immunology , Interleukin-12/metabolism , Receptors, Interleukin/physiology , Animals , Antigen-Presenting Cells/metabolism , CD4-Positive T-Lymphocytes/metabolism , CD4-Positive T-Lymphocytes/pathology , Cell Differentiation/genetics , Cell Differentiation/immunology , Cell Movement/genetics , Cell Movement/immunology , Cells, Cultured , Coculture Techniques , Down-Regulation/genetics , Down-Regulation/immunology , Encephalomyelitis, Autoimmune, Experimental/genetics , Encephalomyelitis, Autoimmune, Experimental/pathology , Female , Glycoproteins/antagonists & inhibitors , Glycoproteins/immunology , Immunity, Innate/genetics , Interleukin-12/biosynthesis , Interleukin-12/genetics , Interleukin-12 Subunit p35 , Interleukin-23 , Interleukin-23 Subunit p19 , Interleukins/biosynthesis , Interleukins/genetics , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Monocytes/immunology , Monocytes/pathology , Myelin-Oligodendrocyte Glycoprotein , Peptide Fragments/antagonists & inhibitors , Peptide Fragments/immunology , Protein Subunits/biosynthesis , Protein Subunits/genetics , RNA, Messenger/biosynthesis , Receptors, Interleukin/deficiency , Receptors, Interleukin/genetics , Receptors, Interleukin-12 , Spinal Cord/immunology , Spinal Cord/pathology , Th1 Cells/immunology , Th1 Cells/metabolism , Th2 Cells/cytology , Th2 Cells/immunologyABSTRACT
Intravenous administration of autoantigen is an effective method to induce Ag-specific tolerance against experimental autoimmune encephalomyelitis (EAE). IL-12 is a potent Th1 stimulator and an essential cytokine in the induction of EAE. The role of IL-12 in the induction of i.v. tolerance is not clear. In this study, we induced tolerance by i.v. administering myelin basic protein (MBP) peptide Ac1-11 (MBP1-11) in EAE. We observed significant suppression of IL-12 production by the lymph node cells of MBP1-11-injected mice. To see whether the low level of IL-12 is the cause or effect of tolerance, we administered IL-12 to the EAE mice at the time of i.v. MBP1-11 injection. Exogenous IL-12 abrogated the suppression of clinical and pathological EAE by i.v. tolerance. IL-12 blocked the suppressive effect of i.v. tolerance on the proliferative response to MBP1-11 and MBP1-11-induced production of IL-12 and IFN-gamma. Furthermore, IL-12 completely blocked the i.v. tolerance-induced type 1 T regulatory cell response. These data suggest that i.v. administration of autoantigen results in the suppression of endogenous IL-12 and the consequent switching of the immune response from an immunogenic to a tolerogenic form.
