krn-7000 and Autoimmune-Diseases

Invariant NKT (iNKT) cells are a unique subset of lymphocytes that recognize glycolipid antigens presented by a monomorphic glycoprotein CD1d. Numerous works have shown that iNKT cells may serve as regulatory cells in autoimmune diseases including multiple sclerosis (MS). However, recent studies have revealed that the presence of iNKT cells accelerates some inflammatory conditions, implying that their protective role against autoimmunity is not predetermined. Here we review recent information concerning the mechanism of how iNKT cells intervene or promote autoimmune inflammation. Although iNKT cells are thought to be specific for a limited set of glycolipids, they may cross-react to self and non-self ligands. Regarding the response to non-self, it is now known that iNKT cells produce enormous amounts of proinflammatory cytokines during the course of infectious diseases, which is triggered by TCR ligation by microbial lipids, cytokines produced from APCs or both. Whereas the strongly activated iNKT cells play a beneficial role in combating environmental pathogens, they could play a deleterious role in autoimmunity by producing disease-promoting cytokines. However, iNKT cells in the steady state would retain an ability to produce anti-inflammatory cytokines, which is needed for terminating the ongoing inflammation. Though an initial trigger for their regulatory responses remains elusive, our recent work indicates that iNKT cells may start regulating inflammation after sensing the presence of IL-2 in addition to recognizing a ubiquitous endogenous ligand. Understanding of how iNKT cells regulate autoimmunity should lead to a more sophisticated strategy for controlling autoimmune diseases.

Topics: Animals; Antigen-Presenting Cells; Autoimmune Diseases; Autoimmunity; Cytokines; Galactosylceramides; Globosides; Humans; Killer Cells, Natural; Th1 Cells; Th2 Cells; Trihexosylceramides

Autoimmune responses are normally kept in check by immune-tolerance mechanisms, which include regulatory T cells. In recent years, research has focused on the role of a subset of natural killer T (NKT) cells - invariant NKT (iNKT) cells, which are a population of glycolipid-reactive regulatory T cells - in controlling autoimmune responses. Because iNKT cells strongly react with a marine-sponge-derived glycolipid, alpha-galactosylceramide (alpha-GalCer), it has been possible to specifically target and track these cells. As I discuss here, although preclinical studies have shown considerable promise for the development of treatment with alpha-GalCer as a therapeutic modality for autoimmune diseases, several obstacles need to be overcome before moving alpha-GalCer therapy from the bench to the bedside.

Topics: Animals; Autoimmune Diseases; Autoimmunity; Galactosylceramides; Humans; Immunologic Factors; Killer Cells, Natural; T-Lymphocyte Subsets

Topics: Adjuvants, Immunologic; Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Autoimmune Diseases; Cytokines; Disease Models, Animal; Drug Evaluation, Preclinical; Galactosylceramides; Glycolipids; Humans; Immunotherapy, Adoptive; Killer Cells, Natural; Lymphocyte Activation; Mice; Mice, Inbred C57BL; Receptors, Antigen, T-Cell, alpha-beta; Receptors, Neurokinin-1; T-Lymphocyte Subsets; Transforming Growth Factor beta; Transforming Growth Factor beta1

Invariant natural killer T (iNKT) cells are an unusual group of T lymphocytes that recognize glycolipid antigens presented by the major histocompatibility complex class I-related protein CD1d. Because iNKT cells play a regulatory role in the immune system, they are attractive targets for immunotherapy. The marine-sponge-derived glycolipid alpha-galactosylceramide (alpha-GalCer) potently activates iNKT cells. In vivo administration of alpha-GalCer to mice or humans results in rapid and robust cytokine secretion by iNKT cells, followed by the activation of a variety of cell types of the innate and adaptive immune systems. These potent immunomodulatory activities of alpha-GalCer are being exploited for therapeutic purposes. Preclinical studies in mice have demonstrated that alpha-GalCer and related glycolipids can protect mice against a variety of diseases, including cancer, infections, and several autoimmune and inflammatory conditions. Although alpha-GalCer treatment of mice is associated with unwanted side-effects, it has been proven safe in clinical trials with cancer patients. These studies have raised significant enthusiasm for the development of effective and safe iNKT-cell-based immunotherapies for a variety of human diseases.

Topics: Animals; Antigens, CD1; Autoimmune Diseases; Carbohydrate Sequence; Galactosylceramides; Glycolipids; Humans; Infections; Inflammation; Killer Cells, Natural; Mice; Molecular Sequence Data; Molecular Structure; Neoplasms; T-Lymphocyte Subsets

Natural killer T (NKT) cells are a conserved subpopulation of lymphocytes that recognize glycolipid antigens in a CD1d context. Upon activation through their semi-invariant T cell receptor, these cells rapidly release large amounts of immunomodulating Th1 and Th2 cytokines. NKT cells have therefore been implicated in immune responses controlling various diseases, including infection, cancer, transplantation, and autoimmunity. Stimulation of the immunoregulatory capacity of NKT cells by the prototypical antigen alpha-galactosylceramide results in amelioration of disease in several animal models. This review will focus on the current knowledge of human NKT cells and their role in autoimmune diseases. The features of these cells and their importance in regulation of autoimmunity suggest that NKT cell-based therapies might be an interesting approach for the treatment of autoimmune diseases.

Topics: Animals; Autoimmune Diseases; Autoimmunity; Diabetes Mellitus, Type 1; Encephalomyelitis, Autoimmune, Experimental; Galactosylceramides; Humans; Killer Cells, Natural; Lymphocyte Activation; Multiple Sclerosis; T-Lymphocyte Subsets; T-Lymphocytes; Thymus Gland

CD1d-restricted natural killer T (NKT) cells are innate lymphocytes that play a regulatory role during an immune response. The identification of alpha-galactosylceramide (alpha-GalCer), a marine sponge-derived glycosphingolipid, as a potent stimulator of NKT cells led many laboratories to investigate the effects of NKT cell activation on the regulation of immune responses. These studies revealed that alpha-GalCer induces rapid and robust cytokine production by NKT cells, secondary activation of a variety of innate and adaptive immune cells, and modulation of Th cell responses. Further, alpha-GalCer influences disease progression in a variety of experimental models of autoimmunity and inflammation in mice, including models for type 1 diabetes, multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, inflammatory bowel disease, and atherosclerosis. While these studies have raised significant enthusiasm for manipulation of NKT cells as a means of preventing autoimmunity in the clinical setting, there are significant concerns regarding the safety of repeated alpha-GalCer injections in human subjects.

Topics: Animals; Antigens, CD1; Antigens, CD1d; Autoimmune Diseases; Cytokines; Galactosylceramides; Humans; Immunotherapy; Killer Cells, Natural; Lymphocyte Activation; Mice; T-Lymphocytes

Natural killer T (NKT) cells constitute a T cell subpopulation that shares several characteristics with NK cells. NKT cells are characterized by a narrow T cell antigen receptor (TCR) repertoire, recognize glycolipid antigen in the context of the monomorphic CD1d antigen-presenting molecule, and have the unique capacity to rapidly produce large amounts of both T helper (Th) 1 and Th2 cytokines. Important roles of NKT cells have now been demonstrated in the regulation of autoimmune, allergic, antimicrobial, and antitumor immune responses. Here, we review the immunoregulatory role of NKT cells in disease and discuss NKT cell based immunotherapeutic strategies.

Topics: Adjuvants, Immunologic; Animals; Antigens, CD1; Antigens, CD1d; Autoimmune Diseases; Communicable Diseases; Galactosylceramides; Graft Survival; Humans; Hypersensitivity; Immunotherapy; Killer Cells, Natural; Mice; Neoplasms; T-Lymphocytes

Therapeutic strategies focused on restoring immune tolerance remain the main avenue to prevent type 1 diabetes (T1D). Because estrogens potentiate FoxP3+ regulatory T cells (Treg) and invariant natural killer T (iNKT) cells, two regulatory lymphocyte populations that are functionally deficient in nonobese diabetic (NOD) mice, we investigated whether estradiol (E2) therapy influences the course of T1D in this model. To this end, female NOD mice were sc implanted with E2- or placebo-delivering pellets to explore the course of spontaneous and cyclophosphamide-induced diabetes. Treg-depleted and iNKT-cell-deficient (Jα18(-/-)) NOD mice were used to assess the respective involvement of these lymphocyte populations in E2 effects. Early E2 administration (from 4 wk of age) was found to preserve NOD mice from both spontaneous and cyclophosphamide-induced diabetes, and a complete protection was also observed throughout treatment when E2 treatment was initiated after the onset of insulitis (from 12 wk of age). This delayed E2 treatment remained fully effective in Treg-depleted mice but failed to entirely protect Jα18(-/-) mice. Accordingly, E2 administration was shown to restore the cytokine production of iNKT cells in response to in vivo challenge with the cognate ligand α-galactosylceramide. Finally, transient E2 administration potentiated the previously described protective action of α-galactosylceramide treatment in NOD females. This study provides original evidence that E2 therapy strongly protects NOD mice from T1D and reveals the estrogen/iNKT cell axis as a new effective target to counteract diabetes onset at the stage of insulitis. Estrogen-based therapy should thus be considered for T1D prevention.

Topics: Animals; Autoimmune Diseases; Cytokines; Diabetes Mellitus, Type 1; Drug Implants; Estradiol; Estrogen Replacement Therapy; Estrogens; Female; Galactosylceramides; Immune Tolerance; Killer Cells, Natural; Lymphocyte Activation; Lymphocyte Depletion; Mice, Inbred C57BL; Mice, Inbred NOD; Mice, Mutant Strains; Ovariectomy; Prediabetic State; T-Lymphocytes, Regulatory

There remain significant obstacles in developing biologics to treat primary biliary cholangitis (PBC). Although a number of agents have been studied both in murine models and human patients, the results have been relatively disappointing. IL-22 is a member of the IL-10 family and has multiple theoretical reasons for predicting successful usage in PBC. We have taken advantage of an IL-22 expressing adeno-associated virus (AAV-IL-22) to address the potential role of IL-22 in not only protecting mice from autoimmune cholangitis, but also in treating animals with established portal inflammation. Using our established mouse model of 2-OA-OVA immunization, including α-galactosylceramide (α-GalCer) stimulation, we treated mice both before and after the onset of clinical disease with AAV-IL-22. Firstly, AAV-IL-22 treatment given prior to 2-OA-OVA and α-GalCer exposure, i.e. before the onset of disease, significantly reduces the portal inflammatory response, production of Th1 cytokines and appearance of liver fibrosis. It also reduced the liver lymphotropic chemokines CCL5, CCL19, CXCL9, and CXCL10. Secondly, and more importantly, therapeutic use of AAV-IL-22, administered after the onset of disease, achieved a greater hurdle and significantly improved portal pathology. Further the improvements in inflammation were negatively correlated with levels of CCL5 and CXCL10 and positively correlated with levels of IL-22. In conclusion, we submit that the clinical use of IL-22 has a potential role in modulating the inflammatory portal process in patients with PBC.

Topics: Animals; Autoimmune Diseases; Biological Therapy; Chemokine CCL19; Chemokine CCL5; Chemokine CXCL10; Chemokine CXCL9; Cholangitis; Dependovirus; Disease Models, Animal; Female; Galactosylceramides; Genetic Vectors; Interleukin-22; Interleukins; Liver; Liver Cirrhosis, Biliary; Mice; Mice, Inbred C57BL; Portal System

Although primary biliary cirrhosis (PBC) is considered a model autoimmune disease, it has not responded therapeutically to traditional immunosuppressive agents. In addition, PBC may recur following liver transplantation, despite the absence of major histocompatibility complex (MHC) matching, in sharp contrast to the well-known paradigm of MHC restriction. We have suggested previously that invariant natural killer T (iNK T) cells are critical to the initiation of PBC. In this study we have taken advantage of our ability to induce autoimmune cholangitis with 2-octynoic acid, a common component of cosmetics, conjugated to bovine serum albumin (2-OA-BSA), and studied the natural history of pathology in mice genetically deleted for CD4 or CD8 following immunization with 2-OA-BSA in the presence or absence of α-galactosylceramide (α-GalCer). In particular, we address whether autoimmune cholangitis can be induced in the absence of traditional CD4 and CD8 responses. We report herein that CD4 and CD8 knock-out mice immunized with 2-OA-BSA/PBS or 2-OA-BSA/α-GalCer develop anti-mitochondrial antibodies (AMAs), portal infiltrates and fibrosis. Indeed, our data suggest that the innate immunity is critical for immunopathology and that the pathology is exacerbated in the presence of α-GalCer. In conclusion, these data provide not only an explanation for the recurrence of PBC following liver transplantation in the absence of MHC compatibility, but also suggest that effective therapies for PBC must include blocking of both innate and adaptive pathways.

Topics: Animals; Autoantibodies; Autoimmune Diseases; CD4 Antigens; CD8 Antigens; Cholangitis; Dihydrolipoyllysine-Residue Acetyltransferase; Disease Models, Animal; Fatty Acids, Monounsaturated; Female; Galactosylceramides; Immunity, Innate; Liver; Liver Cirrhosis, Biliary; Mice; Mice, Knockout; Mitochondrial Proteins; Serum Albumin, Bovine; Xenobiotics

Mucosal-associated invariant T (MAIT) cells contribute to protection against certain microorganism infections and play an important role in mucosal immunity. However, the role of MAIT cells remains enigmatic in autoimmune diseases. In this study, we examined the level and function of MAIT cells in patients with rheumatic diseases. MAIT cell, cytokine, and programmed death-1 (PD-1) levels were measured by flow cytometry. Circulating MAIT cell levels were significantly reduced in systemic lupus erythematosus (SLE) and rheumatoid arthritis patients. In particular, this MAIT cell deficiency was more prominent in CD8(+) and double-negative T cell subsets, and significantly correlated with disease activity, such as SLE disease activity index and 28-joint disease activity score. Interestingly, MAIT cell frequency was significantly correlated with NKT cell frequency in SLE patients. IFN-γ production in MAIT cells was impaired in SLE patients, which was due to an intrinsic defect in the Ca(2+)/calcineurin/NFAT1 signaling pathway. In SLE patients, MAIT cells were poorly activated by α-galactosylceramide-stimulated NKT cells, thereby showing the dysfunction between MAIT cells and NKT cells. Notably, an elevated expression of PD-1 in MAIT cells and NKT cells was associated with SLE. In rheumatoid arthritis patients, MAIT cell levels were significantly higher in synovial fluid than in peripheral blood. Our study primarily demonstrates that MAIT cells are numerically and functionally deficient in SLE. In addition, we report a novel finding that this MAIT cell deficiency is associated with NKT cell deficiency and elevated PD-1 expression. These abnormalities possibly contribute to dysregulated mucosal immunity in SLE.

Topics: Active Transport, Cell Nucleus; Adult; Arthritis, Rheumatoid; Autoimmune Diseases; Calcineurin; Calcium Signaling; CD8-Positive T-Lymphocytes; Cytokines; Escherichia coli; Escherichia coli Infections; Female; Galactosylceramides; Humans; Immunity, Mucosal; Interferon-gamma; Lupus Erythematosus, Systemic; Lymphocyte Activation; Lymphocyte Count; Male; Middle Aged; Natural Killer T-Cells; NFATC Transcription Factors; Programmed Cell Death 1 Receptor; Synovial Fluid; T-Lymphocyte Subsets

Topics: Animals; Antigens, Ly; Autoimmune Diseases; Galactosylceramides; Immunity, Cellular; Mice; Mice, Inbred BALB C; Myocarditis; NK Cell Lectin-Like Receptor Subfamily B

This study was designed to investigate the role of α-galactosylceramide (α-GalCer) on experimental autoimmune myocarditis (EAM), and to explore the underlying mechanisms. Balb/c mice were immunized with porcine cardiac myosin to establish the EAM model. All the immunized mice were divided into two groups, the α-GalCer group and the EAM group. α-GalCer or vehicle was given intraperitoneally at the time of immunization. Then α-GalCer or PBS was injected on alternate days for 6 weeks. Myocardial inflammation was evaluated by H & E staining and the expression levels of C/EBPβ and α-SMA were determined by immunohistochemistry. CD4(+)CD25(+)Foxp3(+) Tregs and iNKT cells were analyzed and sorted by flow cytometry. Western blot analysis was performed to detect MMP-2 and MMP-9 protein expression. Following α-GalCer treatment for 6 weeks, myocardial inflammation improved significantly in the α-GalCer treated group compared to the EAM group. The proportions of CD4(+)CD25(+)Foxp3(+) regulatory T cells and NK1.1(+) iNKT cells were statistically increased in the α-GalCer treated group compared to the EAM and normal control groups. In contrast to the EAM group, α-GalCer treatment significantly increased myocardial MMP-2 and MMP-9 expression. Expression of C/EBPβ increased significantly in the EAM group compared to the other two groups. In contrast, the expression of α-SMA did not differ significantly among the three groups. This study demonstrated that α-GalCer alleviates EAM. Thus, α-GalCer represents a potential therapeutic target for autoimmune-inflammation mediated cardiac damage. α-GalCer protects EAM through upregulation of the proportion of iNKT and Tregs and increased expression of myocardial MMP-2 and MMP-9.

Topics: Actins; Animals; Autoimmune Diseases; Blotting, Western; CCAAT-Enhancer-Binding Protein-alpha; Disease Models, Animal; Forkhead Transcription Factors; Galactosylceramides; Interleukin-2 Receptor alpha Subunit; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Myocarditis; Myocardium; Natural Killer T-Cells; Severity of Illness Index; T-Lymphocytes, Regulatory

Stimulated by an agonistic ligand, alpha-galactosylceramide (alphaGalCer), invariant NKT (iNKT) cells are capable of both eliciting antitumor responses and suppressing autoimmunity, while they become anergic after an initial phase of activation. It is unknown how iNKT cells act as either activators or regulators in different settings of cellular immunity. We examined effects of alphaGalCer administration on autoimmune inflammation and characterized phenotypes and functional status of iNKT cells and dendritic cells in alphaGalCer-treated NOD mice. Although iNKT cells became and remained anergic after the initial exposure to their ligand, anergic iNKT cells induce noninflammatory DCs in response to alphaGalCer restimulation, whereas activated iNKT cells induce immunogenic maturation of DCs in a small time window after the priming. Induction of noninflammatory DCs results in the activation and expansion of islet-specific T cells with diminished proinflammatory cytokine production. The noninflammatory DCs function at inflammation sites in an Ag-specific fashion, and the persistence of noninflammatory DCs critically inhibits autoimmune pathogenesis in NOD mice. Anergic differentiation is a regulatory event that enables iNKT cells to transform from promoters to suppressors, down-regulating the ongoing inflammatory responses, similar to other regulatory T cells, through a ligand-dependent mechanism.

Topics: Animals; Autoimmune Diseases; CD8-Positive T-Lymphocytes; Cell Differentiation; Clonal Anergy; Dendritic Cells; Diabetes Mellitus, Type 1; Dose-Response Relationship, Immunologic; Galactosylceramides; Immunophenotyping; Inflammation; Islets of Langerhans; Killer Cells, Natural; Ligands; Lymphocyte Activation; Mice; Mice, Inbred NOD; Mice, Knockout; Mice, Transgenic; Self Tolerance; T-Lymphocyte Subsets; T-Lymphocytes, Regulatory