krn-7000 and Inflammation

Natural killer T (NKT) cells are CD1d-restricted, lipid antigen-reactive T cells with powerful immunoregulatory potential. The prototypic antigen for NKT cells is a marine sponge-derived glycolipid, α-galactosylceramide (α-GalCer), but this is not normally encountered in the mammalian environment. Thus, there is great interest in the identification of more physiological stimuli for NKT cells, and numerous studies have shown that NKT cells are capable of responding to a range of microbial lipid-based antigens. Two new studies expand our understanding of environmental NKT cell stimuli, with one showing that CD1d-restricted NKT cell antigens are present within common house dust extract (HDE), whereas the other shows that NKT cells can respond to innate stimuli irrespective of the presence of foreign microbial antigens. Collectively, these two investigations indicate that NKT cells are far more likely to encounter foreign antigens, or innate activating signals, than previously recognized, suggesting a more central role for these cells in the immune system.

Topics: Animals; Antigens, CD1d; Cytokines; Galactosylceramides; Glycolipids; Humans; Immune System; Inflammation; Lipids; Lymphocyte Activation; Mice; Models, Biological; Natural Killer T-Cells

NKT cells that express the semi-invariant TCR are innate-like lymphocytes whose functions are regulated by self and foreign glycolipid ligands presented by the Ag-presenting, MHC class I-like molecule CD1d. Activation of NKT cells in vivo results in rapid release of copious amounts of effector cytokines and chemokines with which they regulate innate and adaptive immune responses to pathogens, certain types of cancers, and self-antigens. The nature of CD1d-restricted ligands, the manner in which they are recognized, and the unique effector functions of NKT cells suggest an immunoregulatory role for this T cell subset. Their ability to respond fast and our ability to steer NKT cell cytokine response to altered lipid ligands make them an important target for vaccine design and immunotherapies against autoimmune diseases. This review summarizes our current understanding of CD1d-restricted ligand recognition by NKT cells and how these innate-like lymphocytes regulate inflammation.

Topics: Animals; Antigen Presentation; Galactosylceramides; Glycolipids; Humans; Immunological Synapses; Inflammation; Inflammation Mediators; Ligands; Lipid Metabolism; Natural Killer T-Cells

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

Invariant natural killer T (

Topics: Animals; Antibodies, Antinuclear; Autoimmunity; B-Lymphocytes; Chronic Disease; Disease Models, Animal; Female; Galactosylceramides; Humans; Inflammation; Injections, Intraperitoneal; Interleukin-18; Male; Mice; Mice, Transgenic; Natural Killer T-Cells; Recombinant Proteins

Immunotherapies for cancers may cause severe and life-threatening cardiotoxicities. The underlying mechanisms are complex and largely elusive. Currently, there are several ongoing clinical trials based on the use of activated invariant natural killer T (iNKT) cells. The potential cardiotoxicity commonly associated with this particular immunotherapy has yet been carefully evaluated. The present study aims to determine the effect of activated iNKT cells on normal and β-adrenergic agonist (isoproterenol, ISO)-stimulated hearts. Mice were treated with iNKT stimulants, α-galactosylceramide (αGC) or its analog OCH, respectively, to determine their effect on ISO-induced cardiac injury. We showed that administration of αGC (activating both T helper type 1 (Th1)- and T helper type 2 (Th2)-liked iNKT cells) significantly accelerated the progressive cardiac injury, leading to enhanced cardiac hypertrophy and cardiac fibrosis with prominent increases in collagen deposition and TGF-β1, IL-6, and alpha smooth muscle actin expression. In contrast to αGC, OCH (mainly activating Th2-liked iNKT cells) significantly attenuated the progression of cardiac injury and cardiac inflammation induced by repeated infusion of ISO. Flow cytometry analysis revealed that αGC promoted inflammatory macrophage infiltration in the heart, while OCH was able to restrain the infiltration. In vitro coculture of αGC- or OCH-pretreated primary peritoneal macrophages with primary cardiac fibroblasts confirmed the profibrotic effect of αGC and the antifibrotic effect of OCH. Our results demonstrate that activating both Th1- and Th2-liked iNKT cells is cardiotoxic, while activating Th2-liked iNKT cells is likely cardiac protective, which has implied key differences among subpopulations of iNKT cells in their response to cardiac pathological stimulation.

Topics: Animals; Cardiomegaly; Cardiotonic Agents; Cytokines; Fibrosis; Galactosylceramides; Glycolipids; Inflammation; Isoproterenol; Lymphocyte Activation; Macrophages; Male; Mice, Inbred C57BL; Natural Killer T-Cells

Invariant natural killer T (iNKT) cells are innate-like T lymphocytes. They quickly respond to antigenic stimulation by producing copious amounts of cytokines and chemokines. iNKT precursors differentiate into three subsets iNKT1, iNKT2, and iNKT17 with specific cytokine production signatures. While key transcription factors drive subset differentiation, factors that regulate iNKT subset homeostasis remain incompletely defined. Transcriptomic analyses of thymic iNKT subsets indicate that

Topics: Animals; Cell Differentiation; Cytokines; Dendritic Cells; Female; Galactosylceramides; Homeostasis; Inflammation; Liver; Lung; Lymphocyte Activation; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Models, Animal; Natural Killer T-Cells; Neutrophils; Serpins; Signal Transduction; Spleen

The glycosphingolipid, α-galactosylceramide (αGalCer), when presented by CD1d on antigen-presenting cells, efficiently activates invariant natural killer T (

Topics: Animals; Bacteroides fragilis; Diet; Galactosylceramides; Inflammation; Intestine, Large; Mice; Mice, Inbred Strains

Topics: Animals; Diet; Galactosylceramides; Gastrointestinal Microbiome; Immunologic Factors; Inflammation; Intestine, Large; Mice

The role of iNKT cells was investigated in chronic adipose tissue inflammation in obese mice after administration of α-GalCer in different pathways.. C57BL/6J mice were fed high-fat diet (HFD) for 12 weeks to establish the obese mouse model. The pathology of adipose tissue was observed by H&E staining. The rates of iNKT cells, macrophages and cell subsets in adipose tissue were detected by FCM. Cytokine levels in serum and adipose tissue lymphocyte-stimulated supernatants were assessed with the CBA kit. The expression levels of related transcription factor in adipose tissue were detected by Western blot.. The proportions of iNKT cells, iNKT10 cells and M2 macrophages were decreased, while those of iNKT1 and M1 macrophages were increased in adipose tissue of HFD-fed mice. The expression levels of the related transcriptional proteins E4BP4 and Arg-1 were decreased while iNOS expression was increased in adipose tissue. Administration of α-GalCer by subcutaneous injection resulted in increased rates of iNKT10 cells and M2 macrophages, and decreased amounts of M1 macrophages in adipose tissue of HFD-fed mice. The expression of E4BP4 and Arg-1 were up-regulated, but iNOS was down-regulated. Meanwhile, infiltration of inflammatory cells into adipose tissue was further reduced.. The imbalance between the proportions of iNKT1 and iNKT10 cells may be involved in the development of chronic inflammation in obese adipose tissue. Administration of α-GalCer by subcutaneous injection in HFD-fed mice activates adipose tissue iNKT10 cells, which promote M2 macrophage polarization and improve chronic inflammation in obese adipose tissue.

Topics: Adipocytes; Adipose Tissue; Animals; Basic-Leucine Zipper Transcription Factors; Diet, High-Fat; Disease Models, Animal; Galactosylceramides; Inflammation; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Obese; Nitric Oxide Synthase Type II; Obesity

The glycosphingolipid α-galactosylceramide (α-GalCer) is a well-described immune activator with strong anti-tumor properties in animal models. It is presented on CD1d and acts by stimulating the invariant, type I, natural killer T (iNKT) lymphocytes to rapidly secrete TH1 and TH2 associated cytokines. This in turn promotes activation of a diversity of immune cells including natural killer (NK) cells with anti-tumor functions. Prior to tumor development, iNKT cells can also perform tumor surveillance and naturally protect from emergence of cancer. In contrast, we have recently demonstrated that iNKT cells naturally promote polyps in the spontaneous murine adenomatous polyposis coli (Apc)

Topics: Animals; Antigens, CD1d; CD8-Positive T-Lymphocytes; Cytokines; Female; Galactosylceramides; Immunosuppression Therapy; Immunotherapy; Inflammation; Intestinal Polyps; Ligands; Lymphocyte Activation; Male; Mice; Mice, Inbred C57BL; Natural Killer T-Cells; Neoplasms; Th1 Cells; Th2 Cells; Tumor Microenvironment

Pulmonary fibrosis is a result of an abnormal wound healing in lung tissue triggered by an excessive accumulation of extracellular matrix proteins, loss of tissue elasticity, and debit of ventilatory function. NKT cells are a major source of Th1 and Th2 cytokines and may be crucial in the polarization of M1/M2 macrophages in pulmonary fibrogenesis. Although there appears to be constant scientific progress in that field, pulmonary fibrosis still exhibits no current cure. From these facts, we hypothesized that NKT cells could influence the development of pulmonary fibrosis via modulation of macrophage activation. Wild type (WT) and NKT type I cell-deficient mice (Jα18

Topics: Animals; Bleomycin; Collagen; Cytokines; Disease Models, Animal; Galactosylceramides; Inflammation; Lung; Macrophages; Mice; Mice, Inbred C57BL; Mice, Knockout; Natural Killer T-Cells; Phenotype; Pulmonary Fibrosis; Th1 Cells; Th2 Cells; Transforming Growth Factor beta; Vimentin

Sepsis is the third leading cause of death in the neonatal population, due to susceptibility to infection conferred by immaturity of both the innate and adaptive components of the immune system. Invariant natural killer T (iNKT) cells are specialized adaptive immune cells that possess important innate-like characteristics and have not yet been well-studied in septic neonates. We hypothesized that iNKT cells would play an important role in mediating the neonatal immune response to sepsis. To study this, we subjected 5- to 7-day-old neonatal C57BL/6 mice to sepsis by intraperitoneal (i.p.) cecal slurry (CS) injection. Thirty hours prior to or immediately following sepsis induction, pups received i.p. injection of the iNKT stimulator KRN7000 (KRN, 0.2 µg/g) or vehicle. Ten hours after CS injection, blood and tissues were collected for various analyses. Thirty-hour pretreatment with KRN resulted in better outcomes in inflammation, lung injury, and survival, while immediate treatment with KRN resulted in worse outcomes compared to vehicle treatment. We further analyzed the activation status of neonatal iNKT cells for 30 h after KRN administration, and showed a peak in frequency of CD69 expression on iNKT cells and serum IFN-γ levels at 5 and 10 h, respectively. We then used CD1d knockout neonatal mice to demonstrate that KRN acts through the major histocompatibility complex-like molecule CD1d to improve outcomes in neonatal sepsis. Finally, we identified that KRN pretreatment exerts its protective effect by increasing systemic levels of TGF-β1. These findings support the importance of iNKT cells for prophylactic immunomodulation in neonates susceptible to sepsis.

Topics: Adjuvants, Immunologic; Animals; Animals, Newborn; Antigens, CD; Antigens, CD1d; Antigens, Differentiation, T-Lymphocyte; Female; Galactosylceramides; Immunomodulation; Inflammation; Interferon-gamma; Lectins, C-Type; Mice; Mice, Inbred C57BL; Mice, Knockout; Natural Killer T-Cells; Neonatal Sepsis; Transforming Growth Factor beta1

Graphene oxide (GO) modulates the functions of antigen-presenting cells including dendritic cells (DCs). Although carbon nanotubes affect expression of the MHC class I-like CD1d molecule, whether GO can influence immune responses of CD1d-dependent invariant natural killer T (iNKT) cells remains unclear. Here, we investigated the impact of GO on inflammatory responses mediated by α-galactosylceramide (α-GalCer), an iNKT cell agonist. We found that in vivo GO treatment substantially inhibited the capacity of α-GalCer to induce the iNKT cell-mediated trans-activation of and cytokine production by innate and innate-like cells, including DCs, macrophages, NK cells, and γδ T cells. Such effects of GO on α-GalCer-induced inflammatory responses closely correlated with iNKT cell polarization towards TGFβ production, which also explains the capacity of GO to expand regulatory T cells. Interestingly, the absence of TLR4, a receptor for GO, failed to downregulate, and instead partially enhanced the anti-inflammatory activity of GO against α-GalCer-elicited responses, implying negative effects of TLR4 signaling on the anti-inflammatory properties of GO. By employing an α-GalCer-induced sepsis model, we further demonstrated that GO treatment significantly protected mice from α-GalCer-induced lethality. Taken together, we provide strong evidence that GO holds promise as an adjuvant to modulate iNKT cell responses for immunotherapy.

Topics: Animals; Antigens, CD1d; Cell Polarity; Dendritic Cells; Disease Models, Animal; Galactosylceramides; Graphite; Humans; Inflammation; Intraepithelial Lymphocytes; Lymphocyte Activation; Mice; Nanotubes, Carbon; Natural Killer T-Cells; Sepsis; Toll-Like Receptor 4; Transforming Growth Factor beta

Natural killer T (NKT) cells are activated by lipid antigens presented by CD1d molecules and represent a major lymphocyte subset of the liver. NODc3c4 mice spontaneously develop biliary inflammation in extra- and intrahepatic bile ducts. We demonstrated by flow cytometry that invariant NKT (iNKT) cells were more abundant in the thymus, spleen, and liver of NODc3c4 mice compared to NOD mice. iNKT cells in NODc3c4 mice displayed an activated phenotype. Further, NOD and NOD

Topics: Animals; Antigens, CD1d; Bile Duct Diseases; Disease Models, Animal; Galactosylceramides; Inflammation; Liver; Mice; Mice, Knockout; Natural Killer T-Cells; Spleen; Thymus Gland

Chronic obstructive pulmonary disease (COPD) is characterized by chronic airway inflammation, mucus hypersecretion, and emphysema, which lead to reduced lung function and breathlessness. The pathologies of COPD are due to an abnormal immune response. Invariant natural killer T (iNKT) cells are an important population of innate lymphocytes and have been implicated in the regulation of immune responses associated with a broad range of diseases including COPD. We have here analyzed the role of iNKT cells in a model of COPD induced by repeated intranasal administration of iNKT cell agonist α-galactosylceramide (α-GalCer). Our results demonstrated that mice that received repeated intranasal administration of α-GalCer had molecular and inflammatory features of COPD including airway inflammation with significant increases in infiltration of macrophages and lymphocytes, CD8+ T cells, as well as proinflammatory cytokines IL-6 and TNF-α. In particular, these mice also showed the presence of pulmonary emphysema, mucus production, and pulmonary fibrosis. Furthermore, neutralization of IL-4 reduced α-GalCer induced emphysema. This study indicates the importance of iNKT cells in the pathogenesis of COPD by an IL-4 dependent mechanism.

Topics: Administration, Intranasal; Animals; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Female; Galactosylceramides; Inflammation; Interleukin-4; Interleukin-6; Lung; Lymphocyte Activation; Macrophages; Matrix Metalloproteinase 12; Mice; Mice, Inbred BALB C; Natural Killer T-Cells; Pulmonary Disease, Chronic Obstructive; Tumor Necrosis Factor-alpha

Invariant natural killer T cells (iNKT cells) are a unique subset of T lymphocytes and are considered to play an important role in the development of allergic bronchial asthma. Recently, iNKT cells were shown to play an immunoregulatory role in CD4+ and CD8+ T cell-mediated adaptive immune response. Allergen-specific Th2 inflammatory responses are an important part of the adaptive immune response in asthma. However, the regulatory functions of the Th2 inflammatory response in asthma have not been studied in detail.. In this study, we have investigated the regulatory functions of iNKT cells on the Th2 inflammatory response in an ovalbumin (OVA)-induced murine model of asthma.. Our results demonstrate that α-Galactosylceramide (α-GalCer) administration activated iNKT cells but could not induce the Th2 inflammatory response in wild-type (WT) mice. In the OVA-induced asthma model, α-GalCer administration and adoptive transfer of iNKT cells significantly augmented the Th2 inflammatory responses, including elevated inflammatory cell infiltration in the lung and bronchoalveolar lavage fluid (BALF); increased levels of IL-4, IL-5, and IL-13 in the BALF and splenocyte culture supernatant; and increased serum levels of OVA-specific IgE and IgG1. In addition, the Th2 inflammatory response was reduced, but not completely abrogated in CD1d-/- mice immunized and challenged with OVA, compared with WT mice.. These results suggest that iNKT cells may serve as an adjuvant to enhance Th2 inflammatory response in an OVA-induced murine model of asthma.

Topics: Adoptive Transfer; Animals; Antigens, CD1d; Asthma; Disease Models, Animal; Female; Galactosylceramides; Inflammation; Mice; Mice, Inbred BALB C; Natural Killer T-Cells; Ovalbumin; Th2 Cells

Topics: Animals; Antigens; Antigens, CD1d; Cell Line; Cytokines; Galactosylceramides; Humans; Immunity, Innate; Inflammation; Interferon-gamma; Mice; Natural Killer T-Cells; T-Lymphocyte Subsets

T and B cells are known to be involved in the disease process of periodontitis. However, the role of natural killer T cells in the pathogenesis of periodontitis has not been clarified.. To examine the role of these cells, C57BL/6J (wild-type), CD1d(-/-) and α-galactosylceramide (αGC)-stimulated wild-type mice were orally infected with Porphyromonas gingivalis strain W83.. Apart from CD1d(-/-) mice, the level of alveolar bone resorption was elevated by the infection and was further accelerated in αGC-stimulated mice. The infection induced elevated levels of serum amyloid A and P. gingivalis-specific IgG in the sera, although the degree of elevation was much smaller in the CD1d(-/-) mice. Infection-induced RANKL elevation was only observed in αGC-stimulated mice. Although the cytokines produced by splenocytes were mainly T-helper 1 type in wild-type mice, those in αGC-stimulated mice were predominantly T-helper 2 type. In the liver, the infection demonstrated no effect on the gene expression for interferon-γ, interleukin-4 and RANKL except αGC-stimulated mice in which the infection upregulated the gene expressions.. This study is the first to show that natural killer T cells upregulated systemic and local inflammatory responses induced by oral infection with P. gingivalis, thereby contributing to the progression of alveolar bone resorption.

Topics: Alveolar Bone Loss; Animals; Antibodies, Bacterial; Antigens, CD1d; Bacteroidaceae Infections; Galactosylceramides; Immunoglobulin G; Inflammation; Interferon-gamma; Interleukin-4; Killer Cells, Natural; Liver; Male; Mice, Inbred C57BL; Mice, Inbred Strains; Periodontitis; Porphyromonas gingivalis; RANK Ligand; Serum Amyloid A Protein; Spleen; Th1 Cells; Th2 Cells

Many hematopoietic cell types express CD1d and are capable of presenting glycolipid antigens to invariant natural killer T cells (iNKT cells). However, the question of which cells are the principal presenters of glycolipid antigens in vivo remains controversial, and it has been suggested that this might vary depending on the structure of a particular glycolipid antigen. Here we have shown that a single type of cell, the CD8α(+) DEC-205(+) dendritic cell, was mainly responsible for capturing and presenting a variety of different glycolipid antigens, including multiple forms of α-galactosylceramide that stimulate widely divergent cytokine responses. After glycolipid presentation, these dendritic cells rapidly altered their expression of various costimulatory and coinhibitory molecules in a manner that was dependent on the structure of the antigen. These findings show flexibility in the outcome of two-way communication between CD8α(+) dendritic cells and iNKT cells, providing a mechanism for biasing toward either proinflammatory or anti-inflammatory responses.

Topics: Animals; Antigen Presentation; Antigens; Antigens, CD; Antigens, CD1d; CD8 Antigens; Cell Communication; Cytokines; Dendritic Cells; Galactosylceramides; Gene Expression Regulation; Homeostasis; Inflammation; Lectins, C-Type; Lymphocyte Activation; Mice; Mice, Inbred C57BL; Mice, Knockout; Minor Histocompatibility Antigens; Natural Killer T-Cells; Receptors, Cell Surface

The NLRP3 inflammasome plays a crucial role in the innate immune response to pathogens and exogenous or endogenous danger signals. Its activity must be precisely and tightly regulated to generate tailored immune responses. However, the immune cell subsets and cytokines controlling NLRP3 inflammasome activity are still poorly understood. Here, we have shown a link between NKT-cell-mediated TNF-α and NLRP3 inflammasome activity. The NLRP3 inflammasome in APCs was critical to potentiate NKT-cell-mediated immune responses, since C57BL/6 NLRP3 inflammasome-deficient mice exhibited reduced responsiveness to α-galactosylceramide. Importantly, NKT cells were found to act as regulators of NLRP3 inflammasome signaling, as NKT-cell-derived TNF-α was required for optimal IL-1β and IL-18 production by myeloid cells in response to α-galactosylceramide, by acting on the NLRP3 inflammasome priming step. Thus, NKT cells play a role in the positive regulation of NLRP3 inflammasome priming by mediating the production of TNF-α, thus demonstrating another means by which NKT cells control early inflammation.

Topics: Animals; Antigen-Presenting Cells; Carrier Proteins; Cytokines; Galactosylceramides; Inflammation; Male; Mice; Mice, Inbred C57BL; Natural Killer T-Cells; NLR Family, Pyrin Domain-Containing 3 Protein; Tumor Necrosis Factor-alpha

Epitope-based peptide vaccines encompass minimal immunogenic regions of protein antigens to allow stimulation of precisely targeted adaptive immune responses. However, because efficacy is largely determined by the functional status of antigen-presenting cells (APCs) that acquire and present peptides to cells of the adaptive immune system, adjuvant compounds are needed to enhance immunogenicity. We present here a vaccine consisting of an allergen-derived peptide conjugated to a prodrug of the natural killer-like T (NKT) cell agonist α-galactosylceramide, which is highly effective in reducing inflammation in a mouse model of allergic airway inflammation. Unlike other peptide-adjuvant conjugates that directly activate APCs through pattern recognition pathways, this vaccine encourages third-party interactions with NKT cells to enhance APC function. Therapeutic efficacy was correlated with marked increases in the number and functional activity of allergen-specific cytotoxic T lymphocytes (CTLs), leading to suppression of immune infiltration into the lungs after allergen challenge in sensitized hosts.

Topics: Adjuvants, Immunologic; Allergens; Animals; Anti-Inflammatory Agents; Antigen-Presenting Cells; Disease Models, Animal; Female; Galactosylceramides; Hypersensitivity; Immunoglobulin E; Inflammation; Male; Mice; Mice, Inbred C57BL; Molecular Conformation; Natural Killer T-Cells; Peptides; Prodrugs; T-Lymphocytes, Cytotoxic; Vaccines

Little is known about the function of natural IgM autoantibodies, especially that of IgM anti-leukocyte autoantibodies (IgM-ALA). Natural IgM-ALA are present at birth and characteristically increase during inflammatory and infective conditions. Our prior clinical observations and those of other investigators showing fewer rejections in renal and cardiac allografts transplanted into recipients with high levels of IgM-ALA led us to investigate whether IgM-ALA regulate the inflammatory response. In this article, we show that IgM, in physiologic doses, inhibit proinflammatory cells from proliferating and producing IFN-γ and IL-17 in response to alloantigens (MLR), anti-CD3, and the glycolipid α-galactosyl ceramide. We showed in an IgM knockout murine model, with intact B cells and regulatory T cells, that there was more severe inflammation and loss of function in the absence of IgM after renal ischemia reperfusion injury and cardiac allograft rejection. Replenishing IgM in IgM knockout mice or increasing the levels of IgM-ALA in wild-type B6 mice significantly attenuated the inflammation in both of these inflammatory models that involve IFN-γ and IL-17. The protective effect on renal ischemia reperfusion injury was not observed using IgM preadsorbed with leukocytes to remove IgM-ALA. We provide data to show that the anti-inflammatory effect of IgM is mediated, in part, by inhibiting TLR-4-induced NF-κB translocation into the nucleus and inhibiting differentiation of activated T cells into Th-1 and Th-17 cells. These observations highlight the importance of IgM-ALA in regulating excess inflammation mediated by both innate and adaptive immune mechanisms and where the inflammatory response involves Th-17 cells that are not effectively regulated by regulatory T cells.

Topics: Adaptive Immunity; Animals; Autoantibodies; CD3 Complex; Cell Differentiation; Galactosylceramides; Immunity, Innate; Immunoglobulin M; Inflammation; Interferon-gamma; Interleukin-17; Isoantigens; Leukocytes; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; NF-kappa B; Th1 Cells; Th17 Cells; Toll-Like Receptor 4

Obesity triggers a low-grade systemic inflammation, which plays an important role in the development of obesity-associated metabolic diseases. In searching for links between lipid accumulation and chronic inflammation, we examined invariant natural killer T (iNKT) cells, a subset of T lymphocytes that react with lipids and regulate inflammatory responses. We show that iNKT cells respond to dietary lipid excess and become activated before or at the time of tissue recruitment of inflammatory leukocytes, and that these cells progressively increase proinflammatory cytokine production in obese mice. Such iNKT cells skew other leukocytes toward proinflammatory cytokine production and induce an imbalanced proinflammatory cytokine environment in multiple tissues. Further, iNKT cell deficiency ameliorates tissue inflammation and provides protection against obesity-induced insulin resistance and hepatic steatosis. Conversely, chronic iNKT cell stimulation using a canonical iNKT cell agonist exacerbates tissue inflammation and obesity-associated metabolic disease. These findings place iNKT cells into the complex network linking lipid excess to inflammation in obesity and suggest new therapeutic avenues for obesity-associated metabolic disorders.

Topics: Adipose Tissue, White; Animals; Antigens, CD1d; CD8-Positive T-Lymphocytes; Cells, Cultured; Cytokines; Dietary Fats; Fatty Liver; Female; Flow Cytometry; Galactosylceramides; Inflammation; Inflammation Mediators; Insulin Resistance; Lipids; Lymphocyte Activation; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Natural Killer T-Cells; Obesity

α-Galactosylceramide (α-GalCer) is the prototypical lipid ligand for invariant NKT cells. Recent studies have proposed that α-GalCer is an effective adjuvant in vaccination against a range of immune challenges, however its mechanism of action has not been completely elucidated. A variety of delivery methods have been examined including pulsing dendritic cells with α-GalCer to optimize the potential of α-GalCer. These methods are currently being used in a variety of clinical trials in patients with advanced cancer but cannot be used in the context of vaccine development against pathogens due to their complexity. Using a simple delivery method, we evaluated α-GalCer adjuvant properties, using the mouse model for cytomegalovirus (MCMV). We measured several key parameters of the immune response to MCMV, including inflammation, effector, and central memory CD8(+) T cell responses. We found that α-GalCer injection at the time of the infection decreases viral titers, alters the kinetics of the inflammatory response, and promotes both increased frequencies and numbers of virus-specific memory CD8(+) T cells. Overall, our data suggest that iNKT cell activation by α-GalCer promotes the development of long-term protective immunity through increased fitness of central memory CD8(+) T cells, as a consequence of reduced inflammation.

Topics: Adjuvants, Immunologic; Animals; CD8-Positive T-Lymphocytes; Cell Differentiation; Cytokines; Cytomegalovirus Infections; Flow Cytometry; Galactosylceramides; Immunologic Memory; Inflammation; Lymphocyte Activation; Mice; Mice, Inbred C57BL; Natural Killer T-Cells; Statistics, Nonparametric

IL-17A is associated with different asthma phenotypes as virus-associated or steroid-resistant asthma. Invariant natural killer T (iNKT) cells play an important role in the pathogenesis of asthma. The aim of the study was to evaluate the activity of polyinosinic-polycytidylic acid [poly(I:C)] on IL-17A production by CD1d-activated iNKT cells.. We analysed the in vitro effect of poly(I:C) on the release of IL-17A by spleen and lung CD1d-activated iNKT cells with α-galactosylceramide (α-GalCer). Its activity was also investigated in an α-GalCer-induced murine models, including lung inflammation. The inhibition of IL-17A by Toll-like receptor (TLR) 7 agonists in the same in vitro and in vivo models has been analysed.. Poly(I:C) upregulated the in vitro IL-17A production by CD1d-activated NK1.1- CD4- iNKT subset, without modifying type 1 and type 2 cytokines. The two stimuli selectively upregulated IL-17A serum levels in vivo. Their intratracheal administration resulted in increased airway hyper-reactivity (AHR), neutrophilia in bronchoalveolar lavage and airway inflammation, which were inhibited by anti-IL-17A antibody. Poly(I:C) effects were attributable to IL1β and IL-23 release from dendritic cells, as showed by inhibition with neutralizing antibodies. TLR7 agonists inhibited the IL-17A production by poly(I:C) plus α-GalCer in the same models. Such effect was associated with the increased production by DC of IL-17A-inhibiting cytokines and the dampening of IL-1β and IL-23.. Synthetic dsRNA selectively expand a CD1d-driven IL-17A-producing iNKT cell subset, thus explaining the worsening of airway inflammation by some viral infections. TLR3- and TLR7-triggering viral sequences can exert variable and opposite effects on adaptive immune response.

Topics: Animals; Antigens, CD1d; Asthma; Bronchoalveolar Lavage Fluid; Galactosylceramides; Humans; Inflammation; Interleukin-17; Mice; Natural Killer T-Cells; Poly I-C

One experimental approach for the treatment of allergic reactions is the stimulation of immunoregulatory NKT cells with the synthetic glycolipid αgalactosylceramide. For a first evaluation of the immunomodulatory potential of αGalCerMPEG a human in vitro allergy model was exploited. Acting as an adjuvant, the glycolipid induced an enhanced Th1-biased allergen-specific immune response of autologous lymphocytes. In a mouse model of allergic airway inflammation, αGalCerMPEG-activated NKT cells promoted a cytokine environment in the spleen, leading to priming of Th1 cells. The shift towards a Th1-dominated allergen-specific immune response thus might mediate the abrogation of allergic airway inflammation and thereby might provide a valid option for therapeutic intervention.

Topics: Adolescent; Adult; Animals; Cells, Cultured; Cytokines; Female; Galactosylceramides; Humans; Hypersensitivity; Immunologic Factors; Inflammation; Male; Mice; Mice, Inbred BALB C; Middle Aged; Natural Killer T-Cells; Spleen; Th1 Cells; Young Adult

Lymph nodes (LNs) have been long considered as comprising few invariant NKT (iNKT) cells, and these cells have not been studied extensively. In this study, we unravel the existence of stable rather than transitional LN-resident NK1.1(-) iNKT cell populations. We found the one resident in peripheral LNs (PLNs) to comprise a major IL-17-producing population and to express the retinoic acid receptor-related orphan receptor (gamma)t (ROR(gamma)t). These cells respond to their ligand alpha-galactosylceramide (alpha-GalCer) in vivo by expanding dramatically in the presence of LPS, providing insight into how this rare population could have an impact in immune responses to infection. PLN-resident ROR(gamma)t(+) NK1.1(-) iNKT cells express concomitantly CCR6, the integrin alpha-chain alpha(E) (CD103), and IL-1R type I (CD121a), indicating that they might play a role in inflamed epithelia. Accordingly, skin epithelia comprise a major ROR(gamma)t(+) CCR6(+)CD103(+)CD121a(+) NK1.1(-) cell population, reflecting iNKT cell composition in PLNs. Importantly, both skin and draining PLN ROR(gamma)t(+) iNKT cells respond preferentially to inflammatory signals and independently of IL-6, indicating that they could play a nonredundant role during inflammation. Overall, our study indicates that ROR(gamma)t(+) iNKT cells could play a major role in the skin during immune responses to infection and autoimmunity.

Topics: Animals; Cell Proliferation; Epithelial Cells; Galactosylceramides; Inflammation; Interleukin-17; Interleukin-6; Lymph Nodes; Mice; Mice, Knockout; Natural Killer T-Cells; Nuclear Receptor Subfamily 1, Group F, Member 3; Receptors, Retinoic Acid; Receptors, Thyroid Hormone; Skin

IL-33 is an IL-1 family member recently identified as the ligand for T1/ST2 (ST2), a member of the IL-1 receptor family. ST2 is stably expressed on mast cells and T(h)2 effector T cells and its function has been studied in the context of T(h)2-associated inflammation. Indeed, IL-33 induces T(h)2 cytokines from mast cells and polarized mouse T cells and leads to pulmonary and mucosal T(h)2 inflammation when administered in vivo. To better understand how this pathway modulates inflammatory responses, we examined the activity of IL-33 on a variety of human immune cells. Human blood-derived basophils expressed high levels of ST2 receptor and responded to IL-33 by producing several pro-inflammatory cytokines including IL-1 beta, IL-4, IL-5, IL-6, IL-8, IL-13 and granulocyte macrophage colony-stimulating factor. Next, utilizing a human T(h)2-polarized T cell culture system derived from allergic donor blood cells, we found that IL-33 was able to enhance antigen-dependent and -independent T cell responses, including IL-5, IL-13 and IFN-gamma production. IL-33 activity was also tested on V alpha 24-positive human invariant NKT (iNKT) cells. In the presence of alpha-galactosylceramide antigen presentation, IL-33 dose dependently enhanced iNKT production of several cytokines, including both IL-4 and IFN-gamma. IL-33 also directly induced IFN-gamma production from both iNKT and human NK cells via cooperation with IL-12. Taken together, these results indicate that in addition to its activity on human mast cells, IL-33 is capable of activating human basophils, polarized T cells, iNKT and NK cells. Moreover, the nature of the responses elicited by IL-33 suggests that this axis may amplify both T(h)1- and T(h)2-oriented immune responses.

Topics: Antigens, Dermatophagoides; Asthma; Basophils; Cell Culture Techniques; Cytokines; Escherichia coli; Flow Cytometry; Galactosylceramides; Humans; Inflammation; Interleukin-1 Receptor-Like 1 Protein; Interleukin-33; Interleukins; Killer Cells, Natural; Lymphocyte Activation; Receptors, Cell Surface; Recombinant Proteins; Th2 Cells

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

The glycolipid alpha-galactosylceramide (alphaGalCer) has immunomodulatory properties, which have been exploited to combat cancer, chronic inflammatory diseases, and infections. However, its poor solubility makes alphaGalCer a suboptimal compound for in vivo applications. In this study, a pegylated derivative of alphaGalCer is characterized, which exhibits improved physical and biological properties. The new compound, alphaGalCerMPEG, is water-soluble and retains the specificity for the CD1d receptor of alphaGalCer. The in vitro stimulatory properties on immune cells (e.g., dendritic cells and splenocytes) are maintained intact, even when tested at a 33-fold lower concentration of the active moiety than alphaGalCer. NK cells isolated from mice treated with alphaGalCerMPEG also had stronger cytotoxic activity on YAC-1 cells than those obtained from animals receiving either alphaGalCer or CpG. Intranasal immunization studies performed in mice showed that alphaGalCerMPEG exerts stronger adjuvant activities than the parental compound alphaGalCer when tested at 0.35 vs 11.7 nM/dose. Coadministration of beta-galactosidase with alphaGalCerMPEG resulted not only in high titers of Ag-specific Abs in serum (i.e., 1:512,000), but also in the stimulation of stronger Th2 and secretory IgA responses, both at local and remote mucosal effector sites (i.e., nose, lung, and vagina). The new synthetic derivative alphaGalCerMPEG represents a promising tool for the development of immune interventions against infectious and noninfectious diseases.

Topics: Adjuvants, Immunologic; Administration, Intranasal; Animals; Antibody Specificity; Antigens; beta-Galactosidase; Cell Line; Chronic Disease; Dendritic Cells; Galactosylceramides; Humans; Immunity, Mucosal; Immunization; Immunoglobulin A; Immunologic Factors; Infections; Inflammation; Mice; Mucous Membrane; Neoplasms; Oligonucleotides; Polyethylene Glycols; Solubility; Spleen

CD1d-restricted NKT cells are reported to play a critical role in the host defense to pulmonary infection with Pseudomonas aeruginosa. However, the contribution of a major subset expressing a Valpha14-Jalpha18 gene segment remains unclear. In the present study, we re-evaluated the role of NKT cells in the neutrophilic inflammatory responses and host defense to this infection using mice genetically lacking Jalpha18 or CD1d (Jalpha18KO or CD1dKO mice). These mice cleared the bacteria in lungs at a comparable level to wild-type (WT) mice. There was no significant difference in the local neutrophilic responses, as shown by neutrophil counts and synthesis of MIP-2 and TNF-alpha, in either KO mice from those in WT mice. Administration of alpha-galactosylceramide, a specific activator of Valpha14+ NKT cells, failed to promote the bacterial clearance and neutrophilic responses, although the same treatment increased the synthesis of IFN-gamma, suggesting the involvement of this cytokine downstream of NKT cells. In agreement against this notion, these responses were not further enhanced by administration of recombinant IFN-gamma in the infected Jalpha18KO mice. Our data indicate that NKT cells play a limited role in the development of neutrophilic inflammatory responses and host defense to pulmonary infection with P. aeruginosa.

Topics: Animals; Cell Count; Chemokine CXCL2; Chemokines; Galactosylceramides; Immunologic Factors; Inflammation; Interferon-gamma; Killer Cells, Natural; Lung; Lymphocyte Subsets; Mice; Mice, Knockout; Neutrophils; Pneumonia, Bacterial; Pseudomonas aeruginosa; Pseudomonas Infections; T-Lymphocytes; Tumor Necrosis Factor-alpha

CD1d-restricted NKT cells expressing invariant TCR alpha-chains (iNKT cells) produce both proinflammatory and anti-inflammatory cytokines rapidly upon activation, and are believed to play an important role in both host defense and immunoregulation. To address the potential implications of iNKT cell responses for infectious or inflammatory diseases of the nervous system, we investigated the expression of CD1d in human peripheral nerve. We found that CD1d was expressed on the surface of Schwann cells in situ and on primary or immortalized Schwann cell lines in culture. Schwann cells activated iNKT cells in a CD1d-dependent manner in the presence of alpha-galactosylceramide. Surprisingly, the cytokine production of iNKT cells stimulated by alpha-galactosylceramide presented by CD1d+ Schwann cells showed a predominance of Th2-associated cytokines such as IL-5 and IL-13 with a marked deficiency of proinflammatory Th1 cytokines such as IFN-gamma or TNF-alpha. Our findings suggest a mechanism by which iNKT cells may restrain inflammatory responses in peripheral nerves, and raise the possibility that the expression of CD1d by Schwann cells could be relevant in the pathogenesis of infectious and inflammatory diseases of the peripheral nervous system.

Topics: Antigens, CD1; Antigens, CD1d; Cell Communication; Cells, Cultured; Coculture Techniques; Cytokines; Galactosylceramides; Humans; Immunity; Inflammation; Killer Cells, Natural; Nervous System Diseases; Schwann Cells; T-Lymphocytes

alpha-Galactosylceramide (alpha-GalCer) is a specific ligand of natural killer T cells (NKT cells) that regulates the immune responses such as tumor rejection and autoimmunity by producing interferon (IFN)-gamma and interleukin (IL)-4. However, it has not been determined whether alpha-GalCer-activated NKT cells modulate allergic inflammation. Because alpha-GalCer induces a large amount of IFN-gamma production by NKT cells, we hypothesized that an in vivo administration of alpha-GalCer could inhibit allergic airway inflammation in mice. Strikingly, a single intraperitoneal injection of alpha-GalCer almost completely abrogated an infiltrate with eosinophils in the lung tissue as well as in the bronchoalveolar lavage. This inhibition of allergic inflammation was associated with a significant decrease in the levels of IL-4, IL-5, and IL-13 in bronchoalveolar lavage fluid and in the number of goblet cells. In addition, this ligand significantly inhibited airway hyperresponsiveness to inhaled methacholine and raised the serum levels of ovalbumin-specific IgG2a with a decrease in those of ovalbumin-specific IgE. In IFN-gamma knockout mice, however, alpha-GalCer failed to exert such inhibitory effects in this asthma model. These results indicate that alpha-GalCer prevents allergic airway inflammation possibly through IFN-gamma production by ligand-activated NKT cells, suggesting the potential therapeutic application of alpha-GalCer in asthma.

Topics: Animals; Antigens; Asthma; Bronchoalveolar Lavage Fluid; Cytotoxicity, Immunologic; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Galactosylceramides; Goblet Cells; Hyperplasia; Hypersensitivity; Immunoglobulin E; Immunoglobulin G; Inflammation; Interferon-gamma; Killer Cells, Natural; Ligands; Lung; Mice; Mice, Inbred BALB C; Mice, Knockout; Ovalbumin; T-Lymphocytes; Th2 Cells; Time Factors

Non-obese diabetic (NOD) mice develop diabetes mediated by pathogenic T-helper type 1 (Th1) cells. V alpha 14 Natural killer (NKT) cells are a unique lymphocyte subtype implicated in the regulation of autoimmunity and a good source of protective Th2 cytokines. We recently developed a Th2-skewing NKT cell ligand, OCH. OCH, a sphingosine truncated derivative of alpha-galactosylceramide (alpha-GC), stimulates NKT cells to selectively produce Th2 cytokines. Here we show that OCH prevented the development of diabetes and insulitis in NOD mice. The suppression of insulitis by OCH was more profound compared to alpha-GC. Infiltration of T cells, B cells and macrophages into islets is inhibited in OCH-treated NOD mice. OCH-mediated suppression of diabetes is associated with Th2 bias of anti-islet antigen response and increased IL-10 producing cells among islet-infiltrating leukocytes. Considering the non-polymorphic and well conserved features of the CD1d molecule in mice and humans, these findings not only support the proposed role of NKT cells in the regulation of self-tolerance but also highlight the potential use of OCH for therapeutic intervention in type I diabetes.

Topics: Animals; Autoantibodies; Autoantigens; Cytokines; Diabetes Mellitus, Type 1; Female; Galactosylceramides; Glutamate Decarboxylase; Glycolipids; Immunoglobulin G; Inflammation; Islets of Langerhans; Killer Cells, Natural; Ligands; Mice; Mice, Inbred NOD; Self Tolerance; Th2 Cells