ABSTRACT
Systemic lupus erythematosus is characterized by the spontaneous production of IgG autoantibodies in patients and lupus-prone mice. In this study, we investigated the effect of the Sle1 lupus susceptibility locus on the peripheral development of 56R(+) anti-DNA transgenic B cells by tracking 56R(+) B cells in mice without (B6.56R) or with (B6.Sle1.56R) the Sle1 locus. Compared with B6.56R mice, B6.Sle1.56R mice exhibited increased class-switched IgG2a anti-DNA Abs in their serum, encoded by the transgene. Interestingly, within the spleen, Sle1 facilitated the development of these cells into clusters of IgG2a class-switched B cells juxtaposed to CD4(+) T cells within extrafollicular sites. Through sequence analysis of B cell hybridomas, we also found that B cells from B6.Sle1.56R mice are inefficient at Ig H and L chain editing. Thus, the Ig H chains in Sle1.56R(+) B cells are partnered more often with cationic L chains that facilitate DNA binding. Taken together, these findings indicate that the Sle1 lupus-susceptibility locus may facilitate the emergence of anti-DNA B cells by subduing BCR revision and possibly by shaping the extrafollicular development of effector B cells, although the precise molecular mechanisms await further study.
Subject(s)
Antibodies, Antinuclear/immunology , B-Lymphocytes/immunology , Genetic Loci/immunology , Genetic Predisposition to Disease , Immunoglobulin G/immunology , Lupus Erythematosus, Systemic/immunology , Receptors, Antigen, B-Cell/immunology , Animals , Antibodies, Antinuclear/genetics , B-Lymphocytes/pathology , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/pathology , Immunoglobulin G/genetics , Lupus Erythematosus, Systemic/genetics , Lupus Erythematosus, Systemic/pathology , Mice , Mice, Mutant Strains , Receptors, Antigen, B-Cell/geneticsABSTRACT
Catheters are implanted into the peritoneal cavity during the process of peritoneal dialysis. Though these catheters may be effective and beneficial, the impact of catheters on the immune system is poorly understood. Catheters and other devices implanted in the peritoneal cavity elicit a foreign body reaction. However, the immunological consequences of this remain uncharacterized. To model this, catheters were implanted into the peritoneal cavity of healthy mice. Catheter implantation induced rapid cellular changes within the peritoneal cavity. Whereas B-cells and T-cells were reduced, catheter implantation was associated with the rapid expansion of F4/80-low-positive, CD11b-positive macrophages that elaborated IL-10, and suppressed T-cell division and Th1 skewing in co-culture assays. Peritoneal catheter elicited macrophages had increased Jmjd3 but reduced NF-κB activation, and their emergence was MyD88-dependent. Collectively, these studies indicate that foreign body implantation into the peritoneal cavity is associated with the expansion of suppressor macrophages. Whether peritoneal cavity catheter implantation may have systemic immunoregulatory roles remains to be explored.
Subject(s)
Interleukin-10/immunology , Macrophages, Peritoneal/immunology , Myeloid Differentiation Factor 88/immunology , Signal Transduction/immunology , Animals , Antigens, Differentiation/immunology , Antigens, Differentiation/metabolism , B-Lymphocytes/cytology , B-Lymphocytes/immunology , B-Lymphocytes/metabolism , CD11b Antigen/immunology , CD11b Antigen/metabolism , CD5 Antigens/immunology , CD5 Antigens/metabolism , Catheters, Indwelling , Cell Count , Flow Cytometry , Foreign-Body Reaction/immunology , Humans , Interleukin-10/metabolism , Jumonji Domain-Containing Histone Demethylases/immunology , Jumonji Domain-Containing Histone Demethylases/metabolism , Macrophage Activation/immunology , Macrophages, Peritoneal/cytology , Macrophages, Peritoneal/metabolism , Mice , Mice, Inbred C57BL , Microscopy, Confocal , Myeloid Differentiation Factor 88/metabolism , Peritoneal Cavity/cytology , Peritoneal Dialysis , T-Lymphocytes/cytology , T-Lymphocytes/immunology , T-Lymphocytes/metabolismABSTRACT
In oral tolerance, locally instigated tolerance in the gut propagate to systemic tolerance. In order to investigate the mechanism, we analyzed indoleamine 2,3-dioxygenase (IDO) expression in splenic dendritic cell (DC) subsets and tested whether DCs suppress collagen-induced arthritis (CIA) by inducing regulatory T cells (Tregs). The proportion of IDO-expressing cells was higher in the CD11b(+) subset of splenic DCs from orally tolerized CIA mice. These DCs suppressed type II collagen-specific T cell proliferation and promoted Treg induction from CD4(+)CD25(-) T cells using transforming growth factor-ß. These DCs also increased the expression of cytotoxic T lymphocyte antigen-4 and programmed death-1 on Tregs. When adoptively transferred, spenic IDO-expressing CD11b(+) DCs from tolerized animals suppressed the development of arthritis, increased the Treg/Th17 cell ratio, and decreased the production of inflammatory cytokines in the spleen. Taken together, a distinct subset of splenic IDO(+)CD11b(+)DCs is responsible for the systemic immune regulation in oral tolerance.
Subject(s)
Arthritis, Experimental/immunology , CD11b Antigen/immunology , Dendritic Cells/immunology , Immune Tolerance , Indoleamine-Pyrrole 2,3,-Dioxygenase/immunology , T-Lymphocytes, Regulatory/immunology , Administration, Oral , Adoptive Transfer , Animals , Antigens, Differentiation/genetics , Antigens, Differentiation/immunology , Arthritis, Experimental/chemically induced , Arthritis, Experimental/genetics , Arthritis, Experimental/metabolism , CD11b Antigen/genetics , Cell Differentiation/genetics , Cell Differentiation/immunology , Cell Proliferation , Collagen Type II , Cytokines/biosynthesis , Cytokines/immunology , Dendritic Cells/cytology , Dendritic Cells/metabolism , Dendritic Cells/transplantation , Gene Expression , Indoleamine-Pyrrole 2,3,-Dioxygenase/genetics , Integrin alpha4beta1/genetics , Integrin alpha4beta1/immunology , Lymphocyte Activation , Mice , Organ Specificity , Programmed Cell Death 1 Receptor , Signal Transduction , Spleen/cytology , Spleen/immunology , Spleen/metabolism , T-Lymphocytes, Regulatory/cytology , T-Lymphocytes, Regulatory/metabolism , Transforming Growth Factor beta/genetics , Transforming Growth Factor beta/immunologyABSTRACT
OBJECTIVE: Bone marrow-derived mesenchymal stem cells (MSCs) can prevent various autoimmune diseases. We examined the therapeutic potential of transforming growth factor ß (TGFß)-transduced MSCs in experimental autoimmune arthritis, using an accepted animal model of collagen-induced arthritis (CIA). METHODS: DBA/1J mice with CIA were treated with syngeneic TGFß-induced MSCs, whereas control mice received either vehicle or MSCs alone. Arthritis severity was assessed by clinical and histologic scoring. TGFß-transduced MSCs were tested for their immunosuppressive ability and differential regulation in mice with CIA. T cell responses to type II collagen were evaluated by determining proliferative capacity and cytokine levels. The effects of TGFß-transduced MSCs on osteoclast formation were analyzed in vitro and in vivo. RESULTS: Systemic infusion of syngeneic TGFß-transduced MSCs prevented arthritis development and reduced bone erosion and cartilage destruction. Treatment with TGFß-transduced MSCs potently suppressed type II collagen-specific T cell proliferation and down-regulated proinflammatory cytokine production. These therapeutic effects were associated with an increase in type II collagen-specific CD4+FoxP3+ Treg cells and inhibition of Th17 cell formation in the peritoneal cavity and spleen. Furthermore, TGFß-transduced MSCs inhibited osteoclast differentiation. CONCLUSION: TGFß-transduced MSCs suppressed the development of autoimmune arthritis and joint inflammation. These data suggest that enhancing the immunomodulatory activity of MSCs and modulating T cell-mediated immunity using gene-modified MSCs may be a gateway for new therapeutic approaches to clinical rheumatoid arthritis.
Subject(s)
Arthritis, Experimental/therapy , Arthritis, Rheumatoid/therapy , Mesenchymal Stem Cell Transplantation , Mesenchymal Stem Cells/immunology , Osteoclasts/immunology , T-Lymphocytes, Regulatory/immunology , Th17 Cells/immunology , Transforming Growth Factor beta/immunology , Animals , Cell Differentiation/immunology , Cytokines/biosynthesis , Cytokines/immunology , Forkhead Transcription Factors/immunology , Forkhead Transcription Factors/metabolism , Lymphocyte Activation/immunology , Male , Mice , Mice, Inbred DBA , Peritoneal Cavity , Severity of Illness Index , Spleen/immunology , Transduction, Genetic , Transforming Growth Factor beta/geneticsABSTRACT
N-tosyl-l-phenylalanine chloromethyl ketone (TPCK) is known to inhibit NF-kappaB activation and the expression of inflammation mediators in cultured cells. We measured the potential of TPCK to inhibit the pathogenesis of collagen-induced arthritis by blocking NF-kappaB activation. Arthritis was induced in DBA/1J mice by the injection of bovine type II collagen in adjuvant on days 0 and 14. Mice received either TPCK (3 or 10 mg/kg, i.p.) or vehicle three times a week for 3 weeks starting on day 21. TPCK moderately reduced clinical disease activity scores, whereas it markedly suppressed histological indications of joint destruction. In vitro production of tumor necrosis factor-alpha, interleukin-6, and monocyte chemotactic protein-1 from lipopolysaccharide-stimulated spleen cells was also reduced by in vivo treatment with TPCK. Proliferation of cells isolated from spleen or draining lymph nodes and production of interferon-gamma and interleukin-17 in response to stimulation with type II collagen was decreased by TPCK. Moreover, nuclear NF-kappaB activity induced by collagen immunization was significantly reduced in mice treated with TPCK. Finally, osteoclast differentiation of bone marrow cells induced by macrophage colony-stimulating factor and receptor activator of NF-kappaB ligand was completely inhibited by TPCK. These results indicate that TPCK attenuates collagen-induced arthritis and bone erosion by suppressing NF-kappaB activation and thus expression of inflammatory and osteoclastogenic genes.
Subject(s)
Anti-Inflammatory Agents/pharmacology , Arthritis, Experimental/drug therapy , Joints/drug effects , NF-kappa B/antagonists & inhibitors , Osteoclasts/drug effects , Tosylphenylalanyl Chloromethyl Ketone/pharmacology , Animals , Arthritis, Experimental/immunology , Arthritis, Experimental/pathology , Cell Differentiation/drug effects , Cell Proliferation/drug effects , Cells, Cultured , Cytokines/metabolism , Dose-Response Relationship, Drug , Joints/immunology , Joints/pathology , Lymphocyte Activation/drug effects , Male , Mice , Mice, Inbred DBA , NF-kappa B/metabolism , Osteoclasts/immunology , Osteoclasts/pathology , T-Lymphocytes/drug effects , T-Lymphocytes/immunologyABSTRACT
To investigate the role of CD8alpha(+) DCs in the development of collagen-induced arthritis (CIA). The immunogenic properties of CD8alpha(+) and CD8alpha(-) DC subsets were investigated by mixed-lymphocyte reaction and cytokine enzyme-linked immunoassay. CII-pulsed CD8alpha(+) DCs or CD8alpha(-) DCs with CD4(+) T cells from CIA mice were adoptively transferred onto the hind footpad of DBA mice. The onset of arthritis and the arthritis index were examined for 14 weeks after adoptive transfer. Expression of MHC-II and CD80 but not CD86 and CD40 was higher in CD8alpha(+) DCs than in CD8alpha(-) DCs from the spleens of CIA mice. Culturing CD8alpha(+) DCs with CD4(+) T cells significantly increased the proliferative response of CD4(+) T cells in the presence of CII. The production of interleukin (IL)-12p70, IL-17, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha was slightly increased in CD8alpha(+) DCs than in CD8alpha(-) DCs. DBA/1 mice that were adoptively transferred with CII-pulsed CD8alpha(+) DCs and CD4(+) T cells into the footpads showed accelerated onset of CIA compared to control group. By contrast, CD8alpha(-) DCs showed a partial inhibitory effect on CIA. These findings show that CD8alpha(+) DCs accelerated the onset of CIA when aoptively transferred with CD4(+) T cells and that CD8alpha(+) DCs provoke the development of CIA probably by stimulating the immune responses of CII-reactive CD4(+) T cells and by increasing the production of inflammatory cytokines.
Subject(s)
Arthritis, Experimental/immunology , CD4-Positive T-Lymphocytes/immunology , CD8 Antigens/immunology , Cytokines/metabolism , Dendritic Cells/immunology , Adoptive Transfer , Animals , Antigens, CD/metabolism , Arthritis, Experimental/metabolism , CD4-Positive T-Lymphocytes/cytology , CD4-Positive T-Lymphocytes/metabolism , Cytokines/immunology , Dendritic Cells/cytology , Dendritic Cells/metabolism , Dendritic Cells/transplantation , Foot Joints/pathology , Lymphocyte Activation , Male , Mice , Mice, Inbred DBAABSTRACT
Interleukin (IL) 21 plays a key role in the development of acute graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation. Therapeutic manipulation of IL-21 activity may improve acute GVHD during the early-posttransplant period. We investigated the mechanisms regulating T- and B-cells during IL-21 blockade in acute GVHD. Interleukin 21 blockade enhanced regulatory T and T helper (Th) 2 cell differentiation and inhibited Th1- and Th17-derived transcription factors and cytokines as a modulator of activated T-cells. Interleukin 21(-/-) cell recipients showed increased mature B- and marginal-zone B-cells, but decreased memory B-cells, germinal center formation, and plasma cells that did not lead to immunoglobulin production. B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) are involved in the induction and maintenance of T- and B-cell responses. We observed decreased levels of only BAFF during acute GVHD and confirmed that mammalian target of rapamycin complex 1 was reduced by the BAFF/BAFF-receptor pathway. Therefore, this study suggests that IL-21 blockade modulates activated T- and B-cell homeostasis via BAFF-pathway-mediated inhibition in acute GVHD following murine allogeneic bone marrow transplantation.
Subject(s)
B-Cell Activating Factor/physiology , Graft vs Host Disease/immunology , Interleukins/deficiency , Acute Disease , Animals , B-Cell Activating Factor/biosynthesis , B-Lymphocyte Subsets/immunology , Bone Marrow Transplantation/adverse effects , Cell Transplantation , Gene Expression Regulation/immunology , Homeostasis , Immunologic Memory , Interferon-gamma/biosynthesis , Interleukins/biosynthesis , Interleukins/genetics , Interleukins/physiology , Lymphopoiesis , Mechanistic Target of Rapamycin Complex 1 , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Knockout , Multiprotein Complexes/antagonists & inhibitors , Plasma Cells/immunology , Radiation Chimera , Signal Transduction , Specific Pathogen-Free Organisms , Spleen/cytology , T-Lymphocyte Subsets/immunology , TOR Serine-Threonine Kinases/antagonists & inhibitors , Transcription Factors/physiology , Tumor Necrosis Factor Ligand Superfamily Member 13/biosynthesis , Tumor Necrosis Factor Ligand Superfamily Member 13/geneticsABSTRACT
Establishment of mixed chimerism is an ideal approach to induce donor-specific tolerance while expanding its potential in various clinical settings. Despite the developments in partial conditioning regimens, improvements are still needed in reducing toxicity and bone marrow transplantation-related complications. Recently, cell-based therapies, including mesenchymal stem cells (MSCs), have been incorporated in establishing noncytoreductive mixed chimerism protocols; however, its efficacy is only partial and shows reversed immunosuppressive properties. This study demonstrates a novel approach to induce mixed chimerism and tolerance through combinatory cell-based immune modulation (CCIM) of MSCs and regulatory T cells (Tregs). We hypothesize that the interaction between these cells may lead to greater inhibition of host immune responses. Compared with single cell therapy, CCIM induced a higher engraftment rate and robust donor-specific tolerance to skin allografts across full major histocompatibility complex barriers. These regulatory effects were associated with inhibition of natural killer cell cytotoxic activity, CD4(+)IL-17(+) cells, memory B cells, plasma cells, and immunoglobulin production levels along with increased frequencies of CD4(+)Foxp3(+) cells, IL-10-producing mature B cells, and myeloid-derived suppressor cells. Furthermore, CCIM was able to regulate mortality in a graft-versus-host disease model through reciprocal regulation of Treg/Th17. Taken together, we suggest CCIM as a clinically applicable strategy for facilitating the induction of mixed chimerism and permanent tolerance.
Subject(s)
Graft Survival/immunology , Graft vs Host Disease/immunology , Immune Tolerance , Mesenchymal Stem Cells/cytology , T-Lymphocytes, Regulatory/immunology , Transplantation Chimera/immunology , Animals , Bone Marrow Transplantation/methods , Female , Immune Tolerance/immunology , Mice, Inbred BALB C , Transplantation Conditioning/methodsABSTRACT
IL-17-producing CD4+ T cells (Th17) play important functions in autoimmune diseases and allograft rejection of solid organs. We examined the effects of IL 17 and its mechanism of action on arthritis in a murine collagen-induced arthritis (CIA) model using bone marrow transplantation (BMT) system. DBA/1J mice were administered a lethal radiation dose and then rescued with bone marrow derived from either wild-type (WT) or IL-17-/- mice on C57BL/6 background mice. CIA was induced after the bone marrow transplant, and disease progression was characterized. DBA/1J mice with CIA that received IL-17-/- donor bone marrow showed potently inhibited development and severity of clinical arthritis as compared with CIA mice that received WT bone marrow. Reduced secretion of the pro-inflammatory cytokines tumor necrosis factor-α, IL-1ß, and IL-6, and collagen-specific T cell responses were observed in mice that received IL-17-/- bone marrow. IL-17 blockade also inhibited effector T cell proliferation by reciprocally regulating the Treg/Th17 ratio. IL-17 blockade prevented joint destruction in mice with CIA. These findings suggest that CIA with BMT is a viable method of immunological manipulation and that IL-17 deficiency suppresses severe joint destruction and inflammation in CIA mice. There may be clinical benefits in blocking IL-17 and BMT in the treatment of rheumatoid arthritis.
Subject(s)
Arthritis, Experimental/prevention & control , Bone Marrow Transplantation , Interleukin-17/deficiency , Animals , Antigens, Differentiation/metabolism , Arthritis, Experimental/pathology , Cell Differentiation , Cell Proliferation , Cells, Cultured , Collagen Type II , Cytokines/metabolism , Humans , Interleukin-17/genetics , Joints/pathology , Male , Mice , Mice, Inbred C57BL , Mice, Inbred DBA , Mice, Knockout , Osteoclasts/metabolism , Osteoclasts/physiology , Signal Transduction , T-Lymphocytes/metabolism , T-Lymphocytes/physiology , Transplantation, HomologousABSTRACT
Maintaining an appropriate balance between subsets of CD4(+) helper T cells and T regulatory cells (Tregs) is a critical process in immune homeostasis and a protective mechanism against autoimmunity and inflammation. To identify the role of vitamin A-related compounds, we investigated the regulation of interleukin (IL)-17-producing helper T cells (Th17 cells) and Tregs treated with all-trans-retinal (retinal). CD4(+)T cells or total cells from the spleens of C57BL/6 mice were stimulated under Treg-polarizing (anti-CD3/CD28 and TGF-ß) or Th17-polarizing (anti-CD3/CD28, TGF-ß, and IL-6) conditions in the presence or absence of retinal. To analyze their suppressive abilities, retinal-induced Tregs or TGF-ß-induced Tregs were co-cultured with responder T cells. Collagen-induced arthritis (CIA) was established in interferon (IFN)-γ knockout mice. On day 13, retinal-induced Tregs were adoptively transferred to mice with established CIA after second immunizations. Compared with TGF-ß-induced Treg cells, retinal-induced Tregs showed increased Foxp3 expression and mediated stronger suppressive activity. Under Th17-polarizing conditions, retinal inhibited the production of IL-17 and increased the expression of Foxp3.Retinal-induced Tregs showed therapeutic effects in IFN-γ knockout CIA mice. Thus, we demonstrated that retinal reciprocally regulates Foxp3(+) Tregs and Th17 cells. These findings suggest that retinal, a vitamin A metabolite, can regulate the balance between pro- and anti-inflammatory immunity. A better understanding of the manipulation of Foxp3 and Tregs may enable the application of this tremendous therapeutic potential in various autoimmune diseases.
Subject(s)
Adoptive Transfer , Arthritis, Experimental/therapy , Autoimmune Diseases/therapy , Interferon-gamma/genetics , Retinaldehyde/immunology , T-Lymphocytes, Regulatory/transplantation , Th17 Cells/immunology , Animals , Arthritis, Experimental/immunology , Autoimmune Diseases/immunology , Female , Forkhead Transcription Factors/metabolism , Interleukin-17/metabolism , Lymphocyte Activation , Mice , Mice, Inbred C57BL , Mice, KnockoutABSTRACT
Grape seed proanthocyanidin extract (GSPE), which is the antioxidant derived from grape seeds, has been reported to possess a variety of potent properties. We have previously shown that GSPE attenuates collagen-induced arthritis. However the mechanism by which GSPE regulates the immune response remains unclear, although it may involve effects on the regulation of pathogenic T cells in autoimmune arthritis. To clarify this issue, we have assessed the effects of GSPE on differential regulation of Th17 and regulatory T (Treg) cells subsets in vitro in mouse and human CD4(+) T cells. We observed that GSPE decreased the frequency of IL-17(+)CD4(+)Th17 cells and increased induction of CD4(+)CD25(+)forkhead box protein 3 (Foxp3)(+) Treg cells. In vivo, GSPE effectively attenuated clinical symptoms of established collagen-induced arthritis in mice with concomitant suppression of IL-17 production and enhancement of Foxp3 expression (type II collagen-reactive Treg cells) in CD4(+) T cells of joints and splenocytes. The presence of GSPE decreased the levels of IL-21, IL-22, IL-26 and IL-17 production by human CD4(+) T cells in a STAT3-dependent manner. In contrast, GSPE induces Foxp3(+) Treg cells in humans. Our results suggest that GSPE possesses a reciprocal control over IL-17 and Foxp3. By potently regulating inflammatory T cell differentiation, GSPE may serve as a possible novel therapeutic agent for inflammatory and autoimmune diseases, including rheumatoid arthritis.
Subject(s)
Antioxidants/pharmacology , Arthritis, Experimental/drug therapy , Arthritis, Rheumatoid/drug therapy , Plant Extracts/pharmacology , Proanthocyanidins/pharmacology , Seeds/chemistry , Vitis/chemistry , Animals , Antioxidants/chemistry , Arthritis, Experimental/immunology , Arthritis, Rheumatoid/immunology , Cytokines/immunology , Humans , Male , Mice , Plant Extracts/chemistry , Proanthocyanidins/chemistry , T-Lymphocytes, Regulatory , Th17 CellsABSTRACT
BACKGROUND/AIMS: The bone marrow functions not only as the primary B-lymphocyte-producing organ but also as a secondary lymphoid organ for CD4 and CD8 cell responses and a site of preferential homing and persistence for memory T cells. Bone marrow T (BM-T) cells are distinguished from peripheral blood T cells by surface phenotype, cytokine secretion profile, and immune functions. In this study, we evaluated the alloreactive potential of donor lymphocyte infusion (DLI) using BM-T cells in mixed chimerism compared to that using spleen T (SP-T) cells. METHODS: Cells were prepared using established procedures. BM-T cells were obtained as a by-product of T-cell depletion in BM grafting and then cryopreserved for subsequent DLI. We performed DLI using BM-T cells in allogeneic mixed chimera mice on post-BMT day 21. RESULTS: When the same dose of T cells, 5-10x10(5) (Thy1.2+), fractionated from BM and spleen were administered into mixed chimeras, the BM-T group showed complete chimeric conversion, with self-limited graft-versus-host disease (GVHD) and no pathological changes. However, the SP-T group showed persistent mixed chimerism, with pathological signs of GVHD in the liver and intestine. CONCLUSIONS: Our results suggest that DLI using BM-T cells, even in small numbers, is more potent at inducing chimeric conversion in mixed chimerism than DLI using SP-T cells. Further study is needed to determine whether cryopreserved BM-T cells are an effective cell source for DLI to consolidate donor-dominant chimerism in clinical practice without concerns about GVHD.
Subject(s)
Bone Marrow Cells/physiology , Bone Marrow Transplantation , Lymphocyte Transfusion , Spleen/cytology , T-Lymphocytes/physiology , Animals , Female , Graft vs Host Disease/prevention & control , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Tissue Donors , Transplantation Chimera , Transplantation, HomologousABSTRACT
INTRODUCTION: The present study was devised to understand the role of systemic indoleamine 2,3-dioxygenase (IDO) in the tolerance induction for orally tolerized mice in collagen-induced arthritis (CIA). We examined whether IDO-expressing dendritic cells (DCs) are involved in the generation of CD4+CD25+ regulatory T cells during the induction of oral tolerance in a murine CIA model. METHODS: Type II collagen was fed six times to DBA/1 mice beginning 2 weeks before immunization, and the effect on arthritis was assessed. To examine the IDO expression, the DCs of messenger RNA and protein were analyzed by RT-PCR and Flow cytometry. In addition, a proliferative response assay was also carried out to determine the suppressive effects of DCs through IDO. The ability of DCs expressing IDO to induce CD4+CD25+ T regulatory cells was examined. RESULTS: CD11c+ DCs in Peyer's patches from orally tolerized mice expressed a higher level of IDO than DCs from nontolerized CIA mice. IDO-expressing CD11c+ DCs were involved in the suppression of type II collagen-specific T-cell proliferation and in the downregulation of proinflammatory T helper 1 cytokine production. The suppressive effect of IDO-expressing CD11c+ DCs was mediated by Foxp3+CD4+CD25+ regulatory T cells. CONCLUSION: Our data suggest that tolerogenic CD11c+ DCs are closely linked with the induction of oral tolerance through an IDO-dependent mechanism and that this pathway may provide a new therapeutic modality to treat autoimmune arthritis.