NKT cell subsets as key participants in liver physiology and pathology

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Bandyopadhyay, Keya; Marrero, Idania; Kumar, Vipin

2016-01-01

Natural killer T (NKT) cells are innate-like lymphocytes that generally recognize lipid antigens and are enriched in microvascular compartments of the liver. NKT cells can be activated by self- or microbial-lipid antigens and by signaling through toll-like receptors. Following activation, NKT cells rapidly secrete pro-inflammatory or anti-inflammatory cytokines and chemokines, and thereby determine the milieu for subsequent immunity or tolerance. It is becoming clear that two different subsets of NKT cells—type I and type II—have different modes of antigen recognition and have opposing roles in inflammatory liver diseases. Here we focus mainly on the roles of both NKT cell subsets in the maintenance of immune tolerance and inflammatory diseases in liver. Furthermore, how the differential activation of type I and type II NKT cells influences other innate cells and adaptive immune cells to result in important consequences for tissue integrity is discussed. It is crucial that better reagents, including CD1d tetramers, be used in clinical studies to define the roles of NKT cells in liver diseases in patients. PMID:26972772

Pro-inflammatory activated Kupffer cells by lipids induce hepatic NKT cells deficiency through activation-induced cell death.

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Tongfang Tang

Full Text Available BACKGROUND: Dietary lipids play an important role in the progression of non-alcoholic fatty liver disease (NAFLD through alternation of liver innate immune response. AIMS: The present study was to investigate the effect of lipid on Kupffer cells phenotype and function in vivo and in vitro. And further to investigate the impact of lipid on ability of Kupffer cell lipid antigen presentation to activate NKT cells. METHODS: Wild type male C57BL/6 mice were fed either normal or high-fat diet. Hepatic steatosis, Kupffer cell abundance, NKT cell number and cytokine gene expression were evaluated. Antigen presentation assay was performed with Kupffer cells treated with certain fatty acids in vitro and co-cultured with NKT cells. RESULTS: High-fat diet induced hepatosteatosis, significantly increased Kupffer cells and decreased hepatic NKT cells. Lipid treatment in vivo or in vitro induced increase of pro-inflammatory cytokines gene expression and toll-like receptor 4 (TLR4 expression in Kupffer cells. Kupffer cells expressed high levels of CD1d on cell surface and only presented exogenous lipid antigen to activate NKT cells. Ability of Kupffer cells to present antigen and activate NKT cells was enhanced after lipid treatment. In addition, pro-inflammatory activated Kupffer cells by lipid treatment induced hepatic NKT cells activation-induced apoptosis and necrosis. CONCLUSION: High-fat diet increase Kupffer cells number and induce their pro-inflammatory status. Pro-inflammatory activated Kupfffer cells by lipid promote hepatic NKT cell over-activation and cell death, which lead to further hepatic NKT cell deficiency in the development of NAFLD.

Pro-inflammatory activated Kupffer cells by lipids induce hepatic NKT cells deficiency through activation-induced cell death.

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Tang, Tongfang; Sui, Yongheng; Lian, Min; Li, Zhiping; Hua, Jing

2013-01-01

Dietary lipids play an important role in the progression of non-alcoholic fatty liver disease (NAFLD) through alternation of liver innate immune response. The present study was to investigate the effect of lipid on Kupffer cells phenotype and function in vivo and in vitro. And further to investigate the impact of lipid on ability of Kupffer cell lipid antigen presentation to activate NKT cells. Wild type male C57BL/6 mice were fed either normal or high-fat diet. Hepatic steatosis, Kupffer cell abundance, NKT cell number and cytokine gene expression were evaluated. Antigen presentation assay was performed with Kupffer cells treated with certain fatty acids in vitro and co-cultured with NKT cells. High-fat diet induced hepatosteatosis, significantly increased Kupffer cells and decreased hepatic NKT cells. Lipid treatment in vivo or in vitro induced increase of pro-inflammatory cytokines gene expression and toll-like receptor 4 (TLR4) expression in Kupffer cells. Kupffer cells expressed high levels of CD1d on cell surface and only presented exogenous lipid antigen to activate NKT cells. Ability of Kupffer cells to present antigen and activate NKT cells was enhanced after lipid treatment. In addition, pro-inflammatory activated Kupffer cells by lipid treatment induced hepatic NKT cells activation-induced apoptosis and necrosis. High-fat diet increase Kupffer cells number and induce their pro-inflammatory status. Pro-inflammatory activated Kupfffer cells by lipid promote hepatic NKT cell over-activation and cell death, which lead to further hepatic NKT cell deficiency in the development of NAFLD.

Invariant NKT cells with chimeric antigen receptor provide a novel platform for safe and effective cancer immunotherapy.

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Heczey, Andras; Liu, Daofeng; Tian, Gengwen; Courtney, Amy N; Wei, Jie; Marinova, Ekaterina; Gao, Xiuhua; Guo, Linjie; Yvon, Eric; Hicks, John; Liu, Hao; Dotti, Gianpietro; Metelitsa, Leonid S

2014-10-30

Advances in the design of chimeric antigen receptors (CARs) have improved the antitumor efficacy of redirected T cells. However, functional heterogeneity of CAR T cells limits their therapeutic potential and is associated with toxicity. We proposed that CAR expression in Vα24-invariant natural killer T (NKT) cells can build on the natural antitumor properties of these cells while their restriction by monomorphic CD1d limits toxicity. Primary human NKT cells were engineered to express a CAR against the GD2 ganglioside (CAR.GD2), which is highly expressed by neuroblastoma (NB). We compared CAR.GD2 constructs that encoded the CD3ζ chain alone, with CD28, 4-1BB, or CD28 and 4-1BB costimulatory endodomains. CAR.GD2 expression rendered NKT cells highly cytotoxic against NB cells without affecting their CD1d-dependent reactivity. We observed a striking T helper 1-like polarization of NKT cells by 4-1BB-containing CARs. Importantly, expression of both CD28 and 4-1BB endodomains in the CAR.GD2 enhanced in vivo persistence of NKT cells. These CAR.GD2 NKT cells effectively localized to the tumor site had potent antitumor activity, and repeat injections significantly improved the long-term survival of mice with metastatic NB. Unlike T cells, CAR.GD2 NKT cells did not induce graft-versus-host disease. These results establish the potential of NKT cells to serve as a safe and effective platform for CAR-directed cancer immunotherapy. © 2014 by The American Society of Hematology.

[NKT cells and graft-versus-host disease-review].

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Zhao, Lei; Hao, Sha; Yuan, Wei-Ping; Cheng, Tao

2013-10-01

NKT cells (nature killer T cells), as a regulatory cellular compartment in the immune system, express cell surface markers of T cells and NK cells. It secretes a variety of cytokines that stimulate specific antigens. Through regulating the balance of Th1/Th2, the NKT cells play an important role in prevention and treatment of graft-versus-host disease (GVHD). Its antitumor and anti-infectious effects serve as a basis of its application in allogeneic hematopoietic stem cell transplantation. A better understanding of the biological and immunological features of NKT cell, as well as its specific immune regulatory mechanisms, will further justify the rationales of using NKT cells in the management of GVHD for patients. In this review, the biologic properties, classification, differentiation and development, immune activation of NKT cells as well as the NKT cells and GVHD including the related mechanisms of prevention and treatment of GVHD with NKT cells, NKT cells and tumors, NKT cells and infection, and NKT cells and clinical GVHD are summarized.

Stimulation of Natural Killer T Cells by Glycolipids

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Brian L. Anderson

2013-12-01

Full Text Available Natural killer T (NKT cells are a subset of T cells that recognize glycolipid antigens presented by the CD1d protein. The initial discovery of immunostimulatory glycolipids from a marine sponge and the T cells that respond to the compounds has led to extensive research by chemists and immunologists to understand how glycolipids are recognized, possible responses by NKT cells, and the structural features of glycolipids necessary for stimulatory activity. The presence of this cell type in humans and most mammals suggests that it plays critical roles in antigen recognition and the interface between innate and adaptive immunity. Both endogenous and exogenous natural antigens for NKT cells have been identified, and it is likely that glycolipid antigens remain to be discovered. Multiple series of structurally varied glycolipids have been synthesized and tested for stimulatory activity. The structural features of glycolipids necessary for NKT cell stimulation are moderately well understood, and designed compounds have proven to be much more potent antigens than their natural counterparts. Nevertheless, control over NKT cell responses by designed glycolipids has not been optimized, and further research will be required to fully reveal the therapeutic potential of this cell type.

Harnessing Invariant NKT Cells to Improve Influenza Vaccines: A Pig Perspective

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Guan Yang

2017-12-01

Full Text Available Invariant natural killer T (iNKT cells are an “innate-like” T cell lineage that recognize glycolipid rather than peptide antigens by their semi-invariant T cell receptors. Because iNKT cells can stimulate an extensive array of immune responses, there is considerable interest in targeting these cells to enhance human vaccines against a wide range of microbial pathogens. However, long overlooked is the potential to harness iNKT cell antigens as vaccine adjuvants for domestic animal species that express the iNKT cell–CD1d system. In this review, we discuss the prospect of targeting porcine iNKT cells as a strategy to enhance the efficiency of swine influenza vaccines. In addition, we compare the phenotype and tissue distribution of porcine iNKT cells. Finally, we discuss the challenges that must be overcome before iNKT cell agonists can be contemplated for veterinary use in livestock.

CD1d-Restricted Type II NKT Cells Reactive With Endogenous Hydrophobic Peptides.

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Nishioka, Yusuke; Masuda, Sakiko; Tomaru, Utano; Ishizu, Akihiro

2018-01-01

NKT cells belong to a distinct subset of T cells that recognize hydrophobic antigens presented by major histocompatibility complex class I-like molecules, such as CD1d. Because NKT cells stimulated by antigens can activate or suppress other immunocompetent cells through an immediate production of a large amount of cytokines, they are regarded as immunological modulators. CD1d-restricted NKT cells are classified into two subsets, namely, type I and type II. CD1d-restricted type I NKT cells express invariant T cell receptors (TCRs) and react with lipid antigens, including the marine sponge-derived glycolipid α-galactosylceramide. On the contrary, CD1d-restricted type II NKT cells recognize a wide variety of antigens, including glycolipids, phospholipids, and hydrophobic peptides, by their diverse TCRs. In this review, we focus particularly on CD1d-restricted type II NKT cells that recognize endogenous hydrophobic peptides presented by CD1d. Previous studies have demonstrated that CD1d-restricted type I NKT cells usually act as pro-inflammatory cells but sometimes behave as anti-inflammatory cells. It has been also demonstrated that CD1d-restricted type II NKT cells play opposite roles to CD1d-restricted type I NKT cells; thus, they function as anti-inflammatory or pro-inflammatory cells depending on the situation. In line with this, CD1d-restricted type II NKT cells that recognize type II collagen peptide have been demonstrated to act as anti-inflammatory cells in diverse inflammation-induction models in mice, whereas pro-inflammatory CD1d-restricted type II NKT cells reactive with sterol carrier protein 2 peptide have been demonstrated to be involved in the development of small vessel vasculitis in rats.

B Cells Promote Th1- Skewed NKT Cell Response by CD1d-TCR Interaction

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Shin, Jung Hoon; Park, Se-Ho

2013-01-01

CD1d expressing dendritic cells (DCs) are good glyco-lipid antigen presenting cells for NKT cells. However, resting B cells are very weak stimulators for NKT cells. Although ?-galactosylceramide (?-GalCer) loaded B cells can activate NKT cells, it is not well defined whether B cells interfere NKT cell stimulating activity of DCs. Unexpectedly, we found in this study that B cells can promote Th1-skewed NKT cell response, which means a increased level of IFN-? by NKT cells, concomitant with a d...

Co-stimulatory signaling determines tumor antigen sensitivity and persistence of CAR T cells targeting PSCA+ metastatic prostate cancer.

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Priceman, Saul J; Gerdts, Ethan A; Tilakawardane, Dileshni; Kennewick, Kelly T; Murad, John P; Park, Anthony K; Jeang, Brook; Yamaguchi, Yukiko; Yang, Xin; Urak, Ryan; Weng, Lihong; Chang, Wen-Chung; Wright, Sarah; Pal, Sumanta; Reiter, Robert E; Wu, Anna M; Brown, Christine E; Forman, Stephen J

2018-01-01

Advancing chimeric antigen receptor (CAR)-engineered adoptive T cells for the treatment of solid cancers is a major focus in the field of immunotherapy, given impressive recent clinical responses in hematological malignancies. Prostate cancer may be amenable to T cell-based immunotherapy since several tumor antigens, including prostate stem-cell antigen (PSCA), are widely over-expressed in metastatic disease. While antigen selectivity of CARs for solid cancers is crucial, it is problematic due to the absence of truly restricted tumor antigen expression and potential safety concerns with "on-target off-tumor" activity. Here, we show that the intracellular co-stimulatory signaling domain can determine a CAR's sensitivity for tumor antigen expression. A 4-1BB intracellular co-stimulatory signaling domain in PSCA-CARs confers improved selectivity for higher tumor antigen density, reduced T cell exhaustion phenotype, and equivalent tumor killing ability compared to PSCA-CARs containing the CD28 co-stimulatory signaling domain. PSCA-CARs exhibit robust in vivo anti-tumor activity in patient-derived bone-metastatic prostate cancer xenograft models, and 4-1BB-containing CARs show superior T cell persistence and control of disease compared with CD28-containing CARs. Our study demonstrates the importance of co-stimulation in defining an optimal CAR T cell, and also highlights the significance of clinically relevant models in developing solid cancer CAR T cell therapies.

Co-stimulatory signaling determines tumor antigen sensitivity and persistence of CAR T cells targeting PSCA+ metastatic prostate cancer

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Priceman, Saul J.; Gerdts, Ethan A.; Tilakawardane, Dileshni; Kennewick, Kelly T.; Murad, John P.; Park, Anthony K.; Jeang, Brook; Yamaguchi, Yukiko; Urak, Ryan; Weng, Lihong; Chang, Wen-Chung; Wright, Sarah; Pal, Sumanta; Reiter, Robert E.; Brown, Christine E.; Forman, Stephen J.

2018-01-01

ABSTRACT Advancing chimeric antigen receptor (CAR)-engineered adoptive T cells for the treatment of solid cancers is a major focus in the field of immunotherapy, given impressive recent clinical responses in hematological malignancies. Prostate cancer may be amenable to T cell-based immunotherapy since several tumor antigens, including prostate stem-cell antigen (PSCA), are widely over-expressed in metastatic disease. While antigen selectivity of CARs for solid cancers is crucial, it is problematic due to the absence of truly restricted tumor antigen expression and potential safety concerns with “on-target off-tumor” activity. Here, we show that the intracellular co-stimulatory signaling domain can determine a CAR's sensitivity for tumor antigen expression. A 4-1BB intracellular co-stimulatory signaling domain in PSCA-CARs confers improved selectivity for higher tumor antigen density, reduced T cell exhaustion phenotype, and equivalent tumor killing ability compared to PSCA-CARs containing the CD28 co-stimulatory signaling domain. PSCA-CARs exhibit robust in vivo anti-tumor activity in patient-derived bone-metastatic prostate cancer xenograft models, and 4-1BB-containing CARs show superior T cell persistence and control of disease compared with CD28-containing CARs. Our study demonstrates the importance of co-stimulation in defining an optimal CAR T cell, and also highlights the significance of clinically relevant models in developing solid cancer CAR T cell therapies. PMID:29308300

Differential surface phenotype and context-dependent reactivity of functionally diverse NKT cells.

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Cameron, Garth; Godfrey, Dale I

2018-03-05

Natural Killer T (NKT) cells are a functionally diverse population that recognizes lipid-based antigens in association with the antigen-presenting molecule CD1d. Here, we define a technique to separate the functionally distinct thymic NKT1, NKT2 and NKT17 cell subsets by their surface expression of CD278 (ICOS) and the activation-associated glycoform of CD43, enabling the investigation of subset-specific effector-functions. We report that all three subsets express the transcription factor GATA-3 and the potential to produce IL-4 and IL-10 following activation. This questions the notion that NKT2 cells are the predominant source of IL-4 within the NKT cell pool, and suggests that IL-10-production may be more indicative of NKT cell plasticity than the existence of a distinct regulatory lineage or subset. We also show that many NKT17 cells are CD4 + and are biased toward Vβ8.3 TCR gene usage. Lastly, we demonstrate that the toll-like receptor (TLR) ligand lipopolysaccharide (LPS) can induce a NKT17 cell-biased response, even in the absence of exogenous antigen, and that combining LPS with α-GalCer resulted in enhanced IL-17A-production, and reduced levels of the immunosuppressive cytokine IL-10. This study provides a novel means to examine the context-dependent reactivity of the functionally heterogeneous NKT cell population and provides important new insight into the functional biology of these subsets. © 2018 Australasian Society for Immunology Inc.

CD1d expression and invariant NKT cell responses in herpesvirus infections

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Rusung eTan

2015-06-01

Full Text Available Invariant natural killer T (iNKT cells are a highly conserved subset of unconventional T lymphocytes that express a canonical, semi-invariant T cell receptor (TCR and surface markers shared with the natural killer cell lineage. iNKT cells recognize exogenous and endogenous glycolipid antigens restricted by non-polymorphic CD1d molecules, and are highly responsive to the prototypical agonist, α-galactosylceramide. Upon activation, iNKT cells rapidly coordinate signaling between innate and adaptive immune cells through the secretion of proinflammatory cytokines, leading to the maturation of antigen-presenting cells and expansion of antigen-specific CD4+ and CD8+ T cells. Because of their potent immunoregulatory properties, iNKT cells have been extensively studied and are known to play a pivotal role in mediating immune responses against microbial pathogens including viruses. Here, we review evidence that herpesviruses manipulate CD1d expression to escape iNKT cell surveillance and establish lifelong latency in humans. Collectively, published findings suggest that iNKT cells play critical roles in anti-herpesvirus immune responses and could be harnessed therapeutically to limit viral infection and viral-associated disease.

Regulation of NKT Cell Localization in Homeostasis and Infection

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Slauenwhite, Drew; Johnston, Brent

2015-01-01

Natural killer T (NKT) cells are a specialized subset of T lymphocytes that regulate immune responses in the context of autoimmunity, cancer, and microbial infection. Lipid antigens derived from bacteria, parasites, and fungi can be presented by CD1d molecules and recognized by the canonical T cell receptors on NKT cells. Alternatively, NKT cells can be activated through recognition of self-lipids and/or pro-inflammatory cytokines generated during infection. Unlike conventional T cells, only a small subset of NKT cells traffic through the lymph nodes under homeostatic conditions, with the largest NKT cell populations localizing to the liver, lungs, spleen, and bone marrow. This is thought to be mediated by differences in chemokine receptor expression profiles. However, the impact of infection on the tissue localization and function of NKT remains largely unstudied. This review focuses on the mechanisms mediating the establishment of peripheral NKT cell populations during homeostasis and how tissue localization of NKT cells is affected during infection. PMID:26074921

Regulation of NKT Cell Localization in Homeostasis and Infection.

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Slauenwhite, Drew; Johnston, Brent

2015-01-01

Natural killer T (NKT) cells are a specialized subset of T lymphocytes that regulate immune responses in the context of autoimmunity, cancer, and microbial infection. Lipid antigens derived from bacteria, parasites, and fungi can be presented by CD1d molecules and recognized by the canonical T cell receptors on NKT cells. Alternatively, NKT cells can be activated through recognition of self-lipids and/or pro-inflammatory cytokines generated during infection. Unlike conventional T cells, only a small subset of NKT cells traffic through the lymph nodes under homeostatic conditions, with the largest NKT cell populations localizing to the liver, lungs, spleen, and bone marrow. This is thought to be mediated by differences in chemokine receptor expression profiles. However, the impact of infection on the tissue localization and function of NKT remains largely unstudied. This review focuses on the mechanisms mediating the establishment of peripheral NKT cell populations during homeostasis and how tissue localization of NKT cells is affected during infection.

The effect of intracellular trafficking of CD1d on the formation of TCR repertoire of NKT cells.

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Shin, Jung Hoon; Park, Se-Ho

2014-05-01

CD1 molecules belong to non-polymorphic MHC class I-like proteins and present lipid antigens to T cells. Five different CD1 genes (CD1a-e) have been identified and classified into two groups. Group 1 include CD1a-c and present pathogenic lipid antigens to αβ T cells reminiscence of peptide antigen presentation by MHC-I molecules. CD1d is the only member of Group 2 and presents foreign and self lipid antigens to a specialized subset of αβ T cells, NKT cells. NKT cells are involved in diverse immune responses through prompt and massive production of cytokines. CD1d-dependent NKT cells are categorized upon the usage of their T cell receptors. A major subtype of NKT cells (type I) is invariant NKT cells which utilize invariant Vα14-Jα18 TCR alpha chain in mouse. The remaining NKT cells (type II) utilize diverse TCR alpha chains. Engineered CD1d molecules with modified intracellular trafficking produce either type I or type II NKT cell-defects suggesting the lipid antigens for each subtypes of NKT cells are processed/generated in different intracellular compartments. Since the usage of TCR by a T cell is the result of antigen-driven selection, the intracellular metabolic pathways of lipid antigen are a key in forming the functional NKT cell repertoire.

Design of a potent CD1d-binding NKT cell ligand as a vaccine adjuvant.

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Li, Xiangming; Fujio, Masakazu; Imamura, Masakazu; Wu, Douglass; Vasan, Sandhya; Wong, Chi-Huey; Ho, David D; Tsuji, Moriya

2010-07-20

The glycolipid alpha-galactosylceramide (alpha-GalCer) has been shown to bind CD1d molecules to activate invariant natural killer T (iNKT) cells, and subsequently induce activation of various immune-competent cells, including dendritic cells, thereby providing a significant adjuvant effect for various vaccines. However, in phase I clinical trials, alpha-GalCer was shown to display only marginal biological activity. In our search for a glycolipid that can exert more potent stimulatory activity against iNKT cells and dendritic cells and produce an adjuvant effect superior to alpha-GalCer, we performed step-wise screening assays on a focused library of 25 alpha-GalCer analogues. Assays included quantification of the magnitude of stimulatory activity against human iNKT cells in vitro, binding affinity to human and murine CD1d molecules, and binding affinity to the invariant t cell receptor of human iNKT cells. Through this rigorous and iterative screening process, we have identified a lead candidate glycolipid, 7DW8-5, that exhibits a superior adjuvant effect than alpha-GalCer on HIV and malaria vaccines in mice.

Type II NKT Cells in Inflammation, Autoimmunity, Microbial Immunity, and Cancer.

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Marrero, Idania; Ware, Randle; Kumar, Vipin

2015-01-01

Natural killer T cells (NKT) recognize self and microbial lipid antigens presented by non-polymorphic CD1d molecules. Two major NKT cell subsets, type I and II, express different types of antigen receptors (TCR) with distinct mode of CD1d/lipid recognition. Though type II NKT cells are less frequent in mice and difficult to study, they are predominant in human. One of the major subsets of type II NKT cells reactive to the self-glycolipid sulfatide is the best characterized and has been shown to induce a dominant immune regulatory mechanism that controls inflammation in autoimmunity and in anti-cancer immunity. Recently, type II NKT cells reactive to other self-glycolipids and phospholipids have been identified suggesting both promiscuous and specific TCR recognition in microbial immunity as well. Since the CD1d pathway is highly conserved, a detailed understanding of the biology and function of type II NKT cells as well as their interplay with type I NKT cells or other innate and adaptive T cells will have major implications for potential novel interventions in inflammatory and autoimmune diseases, microbial immunity, and cancer.

The Janus Face of NKT Cell Function in Autoimmunity and Infectious Diseases

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Alessandra Torina

2018-02-01

Full Text Available Natural killer T cells (NKT are a subset of T lymphocytes bridging innate and adaptive immunity. These cells recognize self and microbial glycolipids bound to non-polymorphic and highly conserved CD1d molecules. Three NKT cell subsets, type I, II, and NKT-like expressing different antigen receptors (TCR were described and TCR activation promotes intracellular events leading to specific functional activities. NKT can exhibit different functions depending on the secretion of soluble molecules and the interaction with other cell types. NKT cells act as regulatory cells in the defense against infections but, on the other hand, their effector functions can be involved in the pathogenesis of several inflammatory disorders due to their exposure to different microbial or self-antigens, respectively. A deep understanding of the biology and functions of type I, II, and NKT-like cells as well as their interplay with cell types acting in innate (neuthrophils, innate lymphoid cells, machrophages, and dendritic cells and adaptive immunity (CD4+,CD8+, and double negative T cells should be important to design potential immunotherapies for infectious and autoimmune diseases.

SAP expression in invariant NKT cells is required for cognate help to support B-cell responses.

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Detre, Cynthia; Keszei, Marton; Garrido-Mesa, Natividad; Kis-Toth, Katalin; Castro, Wilson; Agyemang, Amma F; Veerapen, Natacha; Besra, Gurdyal S; Carroll, Michael C; Tsokos, George C; Wang, Ninghai; Leadbetter, Elizabeth A; Terhorst, Cox

2012-07-05

One of the manifestations of X-linked lymphoproliferative disease (XLP) is progressive agammaglobulinemia, caused by the absence of a functional signaling lymphocyte activation molecule (SLAM)-associated protein (SAP) in T, invariant natural killer T (NKT) cells and NK cells. Here we report that α-galactosylceramide (αGalCer) activated NKT cells positively regulate antibody responses to haptenated protein antigens at multiple checkpoints, including germinal center formation and affinity maturation. Whereas NKT cell-dependent B cell responses were absent in SAP(-/-).B6 mice that completely lack NKT cells, the small number of SAP-deficient NKT cells in SAP(-/-).BALB/c mice adjuvated antibody production, but not the germinal center reaction. To test the hypothesis that SAP-deficient NKT cells can facilitate humoral immunity, SAP was deleted after development in SAP(fl/fl).tgCreERT2.B6 mice. We find that NKT cell intrinsic expression of SAP is dispensable for noncognate helper functions, but is critical for providing cognate help to antigen-specific B cells. These results demonstrate that SLAM-family receptor-regulated cell-cell interactions are not limited to T-B cell conjugates. We conclude that in the absence of SAP, several routes of NKT cell-mediated antibody production are still accessible. The latter suggests that residual NKT cells in XLP patients might contribute to variations in dysgammaglobulinemia.

NKT cells in cardiovascular diseases.

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van Puijvelde, Gijs H M; Kuiper, Johan

2017-12-05

Despite life-style advice and the prescription of cholesterol-lowering and anti-thrombotic drugs, cardiovascular diseases are still the leading cause of death worldwide. Therefore, there is an urgent need for new therapeutic strategies focussing on atherosclerosis, the major underlying pathology of cardiovascular diseases characterized by an accumulation of lipids in an inflamed arterial/vessel wall. CD1d-restricted lipid-sensing natural killer T (NKT) cells, bridging the innate and adaptive immunity, and CD1d-expressing antigen-presenting cells are detected in atherosclerotic lesions of mice and humans. In this review we will summarize studies that point to a critical role for NKT cells in the pathogenesis of atherosclerosis and other cardiovascular diseases by the secretion of pro-atherogenic cytokines and cytotoxins. These pro-atherogenic NKT cells are potential targets for new therapeutic strategies in the prevention and treatment of cardiovascular diseases. Additionally, proteins transferring lipids during atherosclerosis, which are also important in the loading of lipids onto CD1d and possible endogenous ligands responsible for the activation of NKT cells during atherosclerosis will be discussed. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

B Cells Promote Th1- Skewed NKT Cell Response by CD1d-TCR Interaction.

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Shin, Jung Hoon; Park, Se-Ho

2013-10-01

CD1d expressing dendritic cells (DCs) are good glyco-lipid antigen presenting cells for NKT cells. However, resting B cells are very weak stimulators for NKT cells. Although α-galactosylceramide (α-GalCer) loaded B cells can activate NKT cells, it is not well defined whether B cells interfere NKT cell stimulating activity of DCs. Unexpectedly, we found in this study that B cells can promote Th1-skewed NKT cell response, which means a increased level of IFN-γ by NKT cells, concomitant with a decreased level of IL-4, in the circumstance of co-culture of DCs and B Cells. Remarkably, the response promoted by B cells was dependent on CD1d expression of B cells.

A potent adjuvant effect of a CD1d-binding NKT cell ligand in human immune system mice.

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Li, Xiangming; Huang, Jing; Kaneko, Izumi; Zhang, Min; Iwanaga, Shiroh; Yuda, Masao; Tsuji, Moriya

2017-01-01

A CD1d-binding invariant natural killer T (iNKT)-cell stimulatory glycolipid, namely 7DW8-5, is shown to enhance the efficacy of radiation-attenuated sporozoites (RAS)-based malaria vaccine in mice. In the current study, we aim to determine whether 7DW8-5 can display a potent adjuvant effect in human immune system (HIS) mice. HIS-A2/hCD1d mice, which possess both functional human iNKT cells and CD8+ T cells, were generated by the transduction of NSG mice with adeno-associated virus serotype 9 expressing genes that encode human CD1d molecules and HLA-A*0201, followed by the engraftment of human hematopoietic stem cells. The magnitudes of human iNKT-cell response against 7DW8-5 and HLA-A*0201-restricted human CD8+ T-cell response against a human malaria antigen in HIS-A2/hCD1d mice were determined by using human CD1d tetramer and human HLA-A*0201 tetramer, respectively. We found that 7DW8-5 stimulates human iNKT cells in HIS-A2/hCD1d mice, as well as those derived from HIS-A2/hCD1d mice in vitro. We also found that 7DW8-5 significantly increases the level of a human malarial antigen-specific HLA-A*0201-restricted human CD8+ T-cell response in HIS-A2/hCD1d mice. Our study indicates that 7DW8-5 can display a potent adjuvant effect on RAS vaccine-induced anti-malarial immunity by augmenting malaria-specific human CD8+ T-cell response.

DOCK8 is critical for the survival and function of NKT cells.

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Crawford, Greg; Enders, Anselm; Gileadi, Uzi; Stankovic, Sanda; Zhang, Qian; Lambe, Teresa; Crockford, Tanya L; Lockstone, Helen E; Freeman, Alexandra; Arkwright, Peter D; Smart, Joanne M; Ma, Cindy S; Tangye, Stuart G; Goodnow, Christopher C; Cerundolo, Vincenzo; Godfrey, Dale I; Su, Helen C; Randall, Katrina L; Cornall, Richard J

2013-09-19

Patients with the dedicator of cytokinesis 8 (DOCK8) immunodeficiency syndrome suffer from recurrent viral and bacterial infections, hyper-immunoglobulin E levels, eczema, and greater susceptibility to cancer. Because natural killer T (NKT) cells have been implicated in these diseases, we asked if these cells were affected by DOCK8 deficiency. Using a mouse model, we found that DOCK8 deficiency resulted in impaired NKT cell development, principally affecting the formation and survival of long-lived, differentiated NKT cells. In the thymus, DOCK8-deficient mice lack a terminally differentiated subset of NK1.1(+) NKT cells expressing the integrin CD103, whereas in the liver, DOCK8-deficient NKT cells express reduced levels of the prosurvival factor B-cell lymphoma 2 and the integrin lymphocyte function-associated antigen 1. Although the initial NKT cell response to antigen is intact in the absence of DOCK8, their ongoing proliferative and cytokine responses are impaired. Importantly, a similar defect in NKT cell numbers was detected in DOCK8-deficient humans, highlighting the relevance of the mouse model. In conclusion, our data demonstrate that DOCK8 is required for the development and survival of mature NKT cells, consistent with the idea that DOCK8 mediates survival signals within a specialized niche. Accordingly, impaired NKT cell numbers and function are likely to contribute to the susceptibility of DOCK8-deficient patients to recurrent infections and malignant disease.

DOCK8 is critical for the survival and function of NKT cells

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Crawford, Greg; Enders, Anselm; Gileadi, Uzi; Stankovic, Sanda; Zhang, Qian; Lambe, Teresa; Crockford, Tanya L.; Lockstone, Helen E.; Freeman, Alexandra; Arkwright, Peter D.; Smart, Joanne M.; Ma, Cindy S.; Tangye, Stuart G.; Goodnow, Christopher C.; Cerundolo, Vincenzo; Godfrey, Dale I.; Su, Helen C.; Randall, Katrina L.

2013-01-01

Patients with the dedicator of cytokinesis 8 (DOCK8) immunodeficiency syndrome suffer from recurrent viral and bacterial infections, hyper–immunoglobulin E levels, eczema, and greater susceptibility to cancer. Because natural killer T (NKT) cells have been implicated in these diseases, we asked if these cells were affected by DOCK8 deficiency. Using a mouse model, we found that DOCK8 deficiency resulted in impaired NKT cell development, principally affecting the formation and survival of long-lived, differentiated NKT cells. In the thymus, DOCK8-deficient mice lack a terminally differentiated subset of NK1.1+ NKT cells expressing the integrin CD103, whereas in the liver, DOCK8-deficient NKT cells express reduced levels of the prosurvival factor B-cell lymphoma 2 and the integrin lymphocyte function-associated antigen 1. Although the initial NKT cell response to antigen is intact in the absence of DOCK8, their ongoing proliferative and cytokine responses are impaired. Importantly, a similar defect in NKT cell numbers was detected in DOCK8-deficient humans, highlighting the relevance of the mouse model. In conclusion, our data demonstrate that DOCK8 is required for the development and survival of mature NKT cells, consistent with the idea that DOCK8 mediates survival signals within a specialized niche. Accordingly, impaired NKT cell numbers and function are likely to contribute to the susceptibility of DOCK8-deficient patients to recurrent infections and malignant disease. PMID:23929855

The Janus Face of NKT Cell Function in Autoimmunity and Infectious Diseases.

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Torina, Alessandra; Guggino, Giuliana; La Manna, Marco Pio; Sireci, Guido

2018-02-01

Natural killer T cells (NKT) are a subset of T lymphocytes bridging innate and adaptive immunity. These cells recognize self and microbial glycolipids bound to non-polymorphic and highly conserved CD1d molecules. Three NKT cell subsets, type I, II, and NKT-like expressing different antigen receptors (TCR) were described and TCR activation promotes intracellular events leading to specific functional activities. NKT can exhibit different functions depending on the secretion of soluble molecules and the interaction with other cell types. NKT cells act as regulatory cells in the defense against infections but, on the other hand, their effector functions can be involved in the pathogenesis of several inflammatory disorders due to their exposure to different microbial or self-antigens, respectively. A deep understanding of the biology and functions of type I, II, and NKT-like cells as well as their interplay with cell types acting in innate (neuthrophils, innate lymphoid cells, machrophages, and dendritic cells) and adaptive immunity (CD4⁺,CD8⁺, and double negative T cells) should be important to design potential immunotherapies for infectious and autoimmune diseases.

Natural Killer T Cells in Cancer Immunotherapy

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Nair, Shiny; Dhodapkar, Madhav V.

2017-01-01

Natural killer T (NKT) cells are specialized CD1d-restricted T cells that recognize lipid antigens. Following stimulation, NKT cells lead to downstream activation of both innate and adaptive immune cells in the tumor microenvironment. This has impelled the development of NKT cell-targeted immunotherapies for treating cancer. In this review, we provide a brief overview of the stimulatory and regulatory functions of NKT cells in tumor immunity as well as highlight preclinical and clinical studies based on NKT cells. Finally, we discuss future perspectives to better harness the potential of NKT cells for cancer therapy. PMID:29018445

Inhibition of type I NKT cells by retinoids or following sulfatide-mediated activation of type II NKT cells attenuates alcoholic liver disease

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Maricic, Igor; Sheng, Huiming; Marrero, Idania; Seki, Ehikiro; Kisseleva, Tatiana; Chaturvedi, Som; Molle, Natasha; Mathews, K. Stephanie; Gao, Bin; Kumar, Vipin

2015-01-01

Innate immune mechanisms leading to liver injury following chronic alcohol ingestion are poorly understood. Natural killer T (NKT) cells, enriched in the liver and comprised of at least two distinct subsets, type I and type II, recognize different lipid antigens presented by CD1d molecules. We have investigated whether differential activation of NKT cell subsets orchestrates inflammatory events leading to alcoholic liver disease (ALD). We found that following chronic plus binge feeding of Lieber-DeCarli liquid diet in male C57BL/6 mice, type I but not type II NKT cells are activated leading to recruitment of inflammatory Gr-1highCD11b+ cells into liver. A central finding is that liver injury following alcohol feeding is dependent upon type I NKT cells. Thus liver injury is significantly inhibited in Jα18−/− mice deficient in type I NKT cells as well as following their inactivation by sulfatide-mediated activation of type II NKT cells. Furthermore we have identified a novel pathway involving all-trans retinoic acid (ATRA) and its receptor RARγ signaling that inhibits type I NKT cells and consequently ALD. A semi-quantitative PCR analysis of hepatic gene expression of some of the key proinflammatory molecules shared in human disease indicated that their upregulation in ALD is dependent upon type I NKT cells. Conclusion Type I but not type II NKT cells become activated following alcohol feeding. Type I NKT cells-induced inflammation and neutrophil recruitment results in liver tissue damage while type II NKT cells protect from injury in ALD. Inhibition of type I NKT cells by retinoids or by sulfatide prevents ALD. Since the CD1d pathway is highly conserved between mice and humans, NKT cell subsets might be targeted for potential therapeutic intervention in ALD. PMID:25477000

Mycobacterium tuberculosis-specific memory NKT cells in patients with tuberculous pleurisy.

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Li, Zitao; Yang, Binyan; Zhang, Yannan; Ma, Jiangjun; Chen, Xinchun; Lao, Suihua; Li, Baiqing; Wu, Changyou

2014-11-01

Natural killer T (NKT) cells from mouse and human play a protective role in the immune responses against the infection of Mycobacterium tuberculosis. However, the characteristic of CD3(+)TCRvβ11(+) NKT cells at the local site of M. tuberculosis infection remains poorly defined. In the present study, we found that the numbers of CD3(+)TCRvβ11(+) NKT cells in pleural fluid mononuclear cells (PFMCs) were significantly lower than those in peripheral blood mononuclear cells (PBMCs). However, CD3(+)TCRvβ11(+) NKT cells from PFMCs spontaneously expressed high levels of CD69 and CD25 and effector memory phenotypes of CD45RO(high)CD62L(low)CCR7(low). After stimulation with the antigens of M. tuberculosis, CD3(+)TCRvβ11(+) NKT cells from PFMCs produced high levels of IFN-γ. Sorted CD3(+)TCRvβ11(+) NKT cells from PFMCs cultured with antigen presenting cells (APCs) produced IFN-γ protein and mRNA. The production of IFN-γ could be completely inhibited by AG490 and Wortmannin. In addition, CD3(+)TCRvβ11(+) NKT cells from PFMCs expressed higher levels of Fas (CD95), FasL (CD178) and perforin but lower levels of granzyme B compared with those from PBMCs. Taken together, our data demonstrated for the first time that M. tuberculosis-specific CD3(+)TCRvβ11(+) NKT cells participated in the local immune responses against M. tuberculosis through the production of IFN-γ and the secretion of cytolytic molecules.

TET proteins regulate the lineage specification and TCR-mediated expansion of iNKT cells.

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Tsagaratou, Ageliki; González-Avalos, Edahí; Rautio, Sini; Scott-Browne, James P; Togher, Susan; Pastor, William A; Rothenberg, Ellen V; Chavez, Lukas; Lähdesmäki, Harri; Rao, Anjana

2017-01-01

TET proteins oxidize 5-methylcytosine in DNA to 5-hydroxymethylcytosine and other oxidation products. We found that simultaneous deletion of Tet2 and Tet3 in mouse CD4 + CD8 + double-positive thymocytes resulted in dysregulated development and proliferation of invariant natural killer T cells (iNKT cells). Tet2-Tet3 double-knockout (DKO) iNKT cells displayed pronounced skewing toward the NKT17 lineage, with increased DNA methylation and impaired expression of genes encoding the key lineage-specifying factors T-bet and ThPOK. Transfer of purified Tet2-Tet3 DKO iNKT cells into immunocompetent recipient mice resulted in an uncontrolled expansion that was dependent on the nonclassical major histocompatibility complex (MHC) protein CD1d, which presents lipid antigens to iNKT cells. Our data indicate that TET proteins regulate iNKT cell fate by ensuring their proper development and maturation and by suppressing aberrant proliferation mediated by the T cell antigen receptor (TCR).

From Lysosomal Storage Diseases to NKT Cell Activation and Back

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Cátia S. Pereira

2017-02-01

Full Text Available Lysosomal storage diseases (LSDs are inherited metabolic disorders characterized by the accumulation of different types of substrates in the lysosome. With a multisystemic involvement, LSDs often present a very broad clinical spectrum. In many LSDs, alterations of the immune system were described. Special emphasis was given to Natural Killer T (NKT cells, a population of lipid-specific T cells that is activated by lipid antigens bound to CD1d (cluster of differentiation 1 d molecules at the surface of antigen-presenting cells. These cells have important functions in cancer, infection, and autoimmunity and were altered in a variety of LSDs’ mouse models. In some cases, the observed decrease was attributed to defects in either lipid antigen availability, trafficking, processing, or loading in CD1d. Here, we review the current knowledge about NKT cells in the context of LSDs, including the alterations detected, the proposed mechanisms to explain these defects, and the relevance of these findings for disease pathology. Furthermore, the effect of enzyme replacement therapy on NKT cells is also discussed.

NKT Cell Networks in the Regulation of Tumor Immunity

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Robertson, Faith C.; Berzofsky, Jay A.; Terabe, Masaki

2014-01-01

CD1d-restricted natural killer T (NKT) cells lie at the interface between the innate and adaptive immune systems and are important mediators of immune responses and tumor immunosurveillance. These NKT cells uniquely recognize lipid antigens, and their rapid yet specific reactions influence both innate and adaptive immunity. In tumor immunity, two NKT subsets (type I and type II) have contrasting roles in which they not only cross-regulate one another, but also impact innate immune cell populations, including natural killer, dendritic, and myeloid lineage cells, as well as adaptive populations, especially CD8+ and CD4+ T cells. The extent to which NKT cells promote or suppress surrounding cells affects the host’s ability to prevent neoplasia and is consequently of great interest for therapeutic development. Data have shown the potential for therapeutic use of NKT cell agonists and synergy with immune response modifiers in both pre-clinical studies and preliminary clinical studies. However, there is room to improve treatment efficacy by further elucidating the biological mechanisms underlying NKT cell networks. Here, we discuss the progress made in understanding NKT cell networks, their consequent role in the regulation of tumor immunity, and the potential to exploit that knowledge in a clinical setting. PMID:25389427

NKT cell networks in the regulation of tumor immunity.

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Robertson, Faith C; Berzofsky, Jay A; Terabe, Masaki

2014-01-01

CD1d-restricted natural killer T (NKT) cells lie at the interface between the innate and adaptive immune systems and are important mediators of immune responses and tumor immunosurveillance. These NKT cells uniquely recognize lipid antigens, and their rapid yet specific reactions influence both innate and adaptive immunity. In tumor immunity, two NKT subsets (type I and type II) have contrasting roles in which they not only cross-regulate one another, but also impact innate immune cell populations, including natural killer, dendritic, and myeloid lineage cells, as well as adaptive populations, especially CD8(+) and CD4(+) T cells. The extent to which NKT cells promote or suppress surrounding cells affects the host's ability to prevent neoplasia and is consequently of great interest for therapeutic development. Data have shown the potential for therapeutic use of NKT cell agonists and synergy with immune response modifiers in both pre-clinical studies and preliminary clinical studies. However, there is room to improve treatment efficacy by further elucidating the biological mechanisms underlying NKT cell networks. Here, we discuss the progress made in understanding NKT cell networks, their consequent role in the regulation of tumor immunity, and the potential to exploit that knowledge in a clinical setting.

NKT cell networks in the regulation of tumor immunity

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Faith C Robertson

2014-10-01

Full Text Available CD1d-restricted natural killer T (NKT cells lie at the interface between the innate and adaptive immune systems and are important mediators of immune responses and tumor immunosurveillance. These NKT cells uniquely recognize lipid antigens, and their rapid yet specific reactions influence both innate and adaptive immunity. In tumor immunity, two NKT subsets (type I and type II have contrasting roles in which they not only cross-regulate one another, but also impact innate immune cell populations, including natural killer, dendritic and myeloid lineage cells, as well as adaptive populations, especially CD8+ and CD4+ T cells. The extent to which NKT cells promote or suppress surrounding cells affects the host’s ability to prevent neoplasia and is consequently of great interest for therapeutic development. Data have shown the potential for therapeutic use of NKT cell agonists and synergy with immune response modifiers in both pre-clinical studies and preliminary clinical studies. However, there is room to improve treatment efficacy by further elucidating the biological mechanisms underlying NKT cell networks. Here, we discuss the progress made in understanding NKT cell networks, their consequent role in the regulation of tumor immunity, and the potential to exploit that knowledge in a clinical setting.

Critical role of NKT cells in posttransplant alloantibody production.

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Zimmerer, J M; Swamy, P; Sanghavi, P B; Wright, C L; Abdel-Rasoul, M; Elzein, S M; Brutkiewicz, R R; Bumgardner, G L

2014-11-01

We previously reported that posttransplant alloantibody production in CD8-deficient hosts is IL-4+ CD4+ T cell-dependent and IgG1 isotype-dominant. The current studies investigated the hypothesis that IL-4-producing natural killer T cells (NKT cells) contribute to maximal alloantibody production. To investigate this, alloantibody levels were examined in CD8-deficient WT, CD1d KO and Jα18 KO transplant recipients. We found that the magnitude of IgG1 alloantibody production was critically dependent on the presence of type I NKT cells, which are activated by day 1 posttransplant. Unexpectedly, type I NKT cell contribution to enhanced IgG1 alloantibody levels was interferon-γ-dependent and IL-4-independent. Cognate interactions between type I NKT and B cells alone do not stimulate alloantibody production. Instead, NKT cells appear to enhance maturation of IL-4+ CD4+ T cells. To our knowledge, this is the first report to substantiate a critical role for type I NKT cells in enhancing in vivo antibody production in response to endogenous antigenic stimuli. © Copyright 2014 The American Society of Transplantation and the American Society of Transplant Surgeons.

Adjuvant effects of therapeutic glycolipids administered to a cohort of NKT cell-diverse pigs.

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Artiaga, Bianca L; Whitener, Robert L; Staples, Charles R; Driver, John P

2014-11-15

CD1d-restricted natural killer T (NKT) cells are a unique lymphocyte population that makes important contributions to host defense against numerous microbial pathogens. The powerful immunomodulatory effects of these cells can be exploited in mice by cognate antigens for multiple therapeutic purposes, including for protection from infectious diseases and as adjuvants to improve vaccines against microbial organisms. These applications have potential to treat and prevent infectious diseases in livestock species that express NKT cells, including pigs. In this study, immune tissues from commercial swine of mixed genetic background were compared for NKT cell frequency, cytokine secretion and subset ratios. Pigs were also injected with the model antigen hen-egg lysozyme (HEL) in conjunction with one of three glycosphingolipids, alpha-galactosylceramide (αGC), OCH and C-glycoside that selectively activate NKT cells, to assess the adjuvant potential of each. There was significant variation between individual pigs for all NKT cell parameters measured. The NKT cell agonists elicited HEL-specific immune responses of different quality, but only αGC increased the systemic concentration of NKT cells. Peripheral blood NKT cell frequency measured prior to treatment was a poor predictor of how individual animals responded to NKT cell therapy. However, our results show that although NKT cells vary considerably between pigs, there exists considerable potential to harness these cells to protect swine from infectious diseases. Copyright © 2014 Elsevier B.V. All rights reserved.

NKT-cell glycolipid agonist as adjuvant in synthetic vaccine.

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Liu, Zheng; Guo, Jun

2017-11-27

NKT cells are CD1d-restricted, glycolipid antigen-reactive, immunoregulatory T lymphocytes that can serve as a bridge between the innate and adaptive immunities. NKT cells have a wide range of therapeutic application in autoimmunity, transplant biology, infectious disease, cancer, and vaccinology. Rather than triggering "danger signal" and eliciting an innate immune response, αGalCer-based NKT-cell agonist act via a unique mechanism, recruiting NKT cells which play a T helper-like role even without peptide as Th epitope. Importantly, the non-polymorphism of CD1d render glycolipid a universal helper epitope, offering the potential to simplify the vaccine construct capable of eliciting consistent immune response in different individuals. This review details recent advances in the design of synthetic vaccines using NKT-cell agonist as adjuvant, highlighting the role of organic synthesis and conjugation technique to enhance the immunological actives and to simplify the vaccine constructs. Copyright © 2017 Elsevier Ltd. All rights reserved.

EBV promotes human CD8 NKT cell development.

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Yuling He

2010-05-01

reaggregated thymic organ cultures. Thymic antigen-presenting EBV-infected dendritic cells are required for this process. IL-7, produced mainly by thymic dendritic cells, is a major and essential factor for CD8(+ NKT cell differentiation in EBV-challenged human-thymus/liver-SCID chimeras and fetal thymic organ cultures. Additionally, these EBV-induced CD8(+ NKT cells produce remarkably more perforin than that in counterpart CD4(+ NKT cells, and predominately express CD8alphaalpha homodimer in their co-receptor. Thus, upon interaction with certain viruses, CD8 lineage-specific NKT cells are developed, differentiated and matured intrathymically, a finding with potential therapeutic importance against viral infections and tumors.

TCRα-TCRβ pairing controls recognition of CD1d and directs the development of adipose NKT cells.

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Vieth, Joshua A; Das, Joy; Ranaivoson, Fanomezana M; Comoletti, Davide; Denzin, Lisa K; Sant'Angelo, Derek B

2017-01-01

The interaction between the T cell antigen receptor (TCR) expressed by natural killer T cells (NKT cells) and the antigen-presenting molecule CD1d is distinct from interactions between the TCR and major histocompatibility complex (MHC). Our molecular modeling suggested that a hydrophobic patch created after TCRα-TCRβ pairing has a role in maintaining the conformation of the NKT cell TCR. Disruption of this patch ablated recognition of CD1d by the NKT cell TCR but not interactions of the TCR with MHC. Partial disruption of the patch, while permissive to the recognition of CD1d, significantly altered NKT cell development, which resulted in the selective accumulation of adipose-tissue-resident NKT cells. These results indicate that a key component of the TCR is essential for the development of a distinct population of NKT cells.

TLR4 and NKT cell synergy in immunotherapy against visceral leishmaniasis.

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Subir Karmakar

Full Text Available NKT cells play an important role in autoimmune diseases, tumor surveillance, and infectious diseases, providing in most cases protection against infection. NKT cells are reactive to CD1d presented glycolipid antigens. They can modulate immune responses by promoting the secretion of type 1, type 2, or immune regulatory cytokines. Pathogen-derived signals to dendritic cells mediated via Toll like Receptors (TLR can be modulated by activated invariant Natural Killer T (iNKT cells. The terminal β-(1-4-galactose residues of glycans can modulate host responsiveness in a T helper type-1 direction via IFN-γ and TLRs. We have attempted to develop a defined immunotherapeutic, based on the cooperative action of a TLR ligand and iNKT cell using a mouse model of visceral leishmaniasis. We evaluated the anti-Leishmania immune responses and the protective efficacy of the β-(1-4-galactose terminal NKT cell ligand glycosphingophospholipid (GSPL antigen of L. donovani parasites. Our results suggest that TLR4 can function as an upstream sensor for GSPL and provoke intracellular inflammatory signaling necessary for parasite killing. Treatment with GSPL was able to induce a strong effective T cell response that contributed to effective control of acute parasite burden and led to undetectable parasite persistence in the infected animals. These studies for the first time demonstrate the interactions between a TLR ligand and iNKT cell activation in visceral leishmaniasis immunotherapeutic.

Generation of induced pluripotent stem cell-derived mice by reprogramming of a mature NKT cell.

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Ren, Yue; Dashtsoodol, Nyambayar; Watarai, Hiroshi; Koseki, Haruhiko; Quan, Chengshi; Taniguchi, Masaru

2014-10-01

NKT cells are characterized by their expression of an NKT-cell-specific invariant antigen-receptor α chain encoded by Vα14Jα18 gene segments. These NKT cells bridge the innate and acquired immune systems to mediate effective and augmented responses; however, the limited number of NKT cells in vivo hampers their analysis. Here, two lines of induced pluripotent stem cell-derived mice (NKT-iPSC-derived mice) were generated by reprogramming of mature NKT cells, where one harbors both rearranged Vα14Jα18 and Vβ7 genes and the other carries rearranged Vα14Jα18 on both alleles but germline Vβ loci. The analysis of NKT-iPSC-derived mice showed a significant increase in NKT cell numbers with relatively normal frequencies of functional subsets, but significantly enhanced in some cases, and acquired functional NKT cell maturation in peripheral lymphoid organs. NKT-iPSC-derived mice also showed normal development of other immune cells except for the absence of γδT cells and disturbed development of conventional CD4 αβT cells. These results suggest that the NKT-iPSC-derived mice are a better model for NKT cell development and function study rather than transgenic mouse models reported previously and also that the presence of a pre-rearranged Vα14Jα18 in the natural chromosomal context favors the developmental fate of NKT cells. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society for Immunology.

The split personality of NKT cells in malignancy, autoimmune and allergic disorders

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Subleski, Jeff J; Jiang, Qun; Weiss, Jonathan M; Wiltrout, Robert H

2011-01-01

NKT cells are a heterogeneous subset of specialized, self-reactive T cells, with innate and adaptive immune properties, which allow them to bridge innate and adaptive immunity and profoundly influence autoimmune and malignant disease outcomes. NKT cells mediate these activities through their ability to rapidly express pro- and anti-inflammatory cytokines that influence the type and magnitude of the immune response. Not only do NKT cells regulate the functions of other cell types, but experimental evidence has found NKT cell subsets can modulate the functions of other NKT subsets. Depending on underlying mechanisms, NKT cells can inhibit or exacerbate autoimmunity and malignancy, making them potential targets for disease intervention. NKT cells can respond to foreign and endogenous antigenic glycolipid signals that are expressed during pathogenic invasion or ongoing inflammation, respectively, allowing them to rapidly react to and influence a broad array of diseases. In this article we review the unique development and activation pathways of NKT cells and focus on how these attributes augment or exacerbate autoimmune disorders and malignancy. We also examine the growing evidence that NKT cells are involved in liver inflammatory conditions that can contribute to the development of malignancy. PMID:21995570

The split personality of NKT cells in malignancy, autoimmune and allergic disorders.

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Subleski, Jeff J; Jiang, Qun; Weiss, Jonathan M; Wiltrout, Robert H

2011-10-01

NKT cells are a heterogeneous subset of specialized, self-reactive T cells, with innate and adaptive immune properties, which allow them to bridge innate and adaptive immunity and profoundly influence autoimmune and malignant disease outcomes. NKT cells mediate these activities through their ability to rapidly express pro- and anti-inflammatory cytokines that influence the type and magnitude of the immune response. Not only do NKT cells regulate the functions of other cell types, but experimental evidence has found NKT cell subsets can modulate the functions of other NKT subsets. Depending on underlying mechanisms, NKT cells can inhibit or exacerbate autoimmunity and malignancy, making them potential targets for disease intervention. NKT cells can respond to foreign and endogenous antigenic glycolipid signals that are expressed during pathogenic invasion or ongoing inflammation, respectively, allowing them to rapidly react to and influence a broad array of diseases. In this article we review the unique development and activation pathways of NKT cells and focus on how these attributes augment or exacerbate autoimmune disorders and malignancy. We also examine the growing evidence that NKT cells are involved in liver inflammatory conditions that can contribute to the development of malignancy.

Cellular Adjuvant Properties, Direct Cytotoxicity of Re-differentiated Vα24 Invariant NKT-like Cells from Human Induced Pluripotent Stem Cells

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Shuichi Kitayama

2016-02-01

Full Text Available Vα24 invariant natural killer T (iNKT cells are a subset of T lymphocytes implicated in the regulation of broad immune responses. They recognize lipid antigens presented by CD1d on antigen-presenting cells and induce both innate and adaptive immune responses, which enhance effective immunity against cancer. Conversely, reduced iNKT cell numbers and function have been observed in many patients with cancer. To recover these numbers, we reprogrammed human iNKT cells to pluripotency and then re-differentiated them into regenerated iNKT cells in vitro through an IL-7/IL-15-based optimized cytokine combination. The re-differentiated iNKT cells showed proliferation and IFN-γ production in response to α-galactosylceramide, induced dendritic cell maturation and downstream activation of both cytotoxic T lymphocytes and NK cells, and exhibited NKG2D- and DNAM-1-mediated NK cell-like cytotoxicity against cancer cell lines. The immunological features of re-differentiated iNKT cells and their unlimited availability from induced pluripotent stem cells offer a potentially effective immunotherapy against cancer.

Intravascular Immune Surveillance by CXCR6+ NKT Cells Patrolling Liver Sinusoids

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Geissmann Frederic

2005-01-01

Full Text Available We examined the in vivo behavior of liver natural killer T cells (NKT cells by intravital fluorescence microscopic imaging of mice in which a green fluorescent protein cDNA was used to replace the gene encoding the chemokine receptor CXCR6. NKT cells, which account for most CXCR6+ cells in liver, were found to crawl within hepatic sinusoids at 10-20 µm/min and to stop upon T cell antigen receptor activation. CXCR6-deficient mice exhibited a selective and severe reduction of CD1d-reactive NKT cells in the liver and decreased susceptibility to T-cell-dependent hepatitis. CXCL16, the cell surface ligand for CXCR6, is expressed on sinusoidal endothelial cells, and CXCR6 deficiency resulted in reduced survival, but not in altered speed or pattern of patrolling of NKT cells. Thus, NKT cells patrol liver sinusoids to provide intravascular immune surveillance, and CXCR6 contributes to liver-based immune responses by regulating their abundance.

Endogenous collagen peptide activation of CD1d-restricted NKT cells ameliorates tissue-specific inflammation in mice.

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Liu, Yawei; Teige, Anna; Mondoc, Emma; Ibrahim, Saleh; Holmdahl, Rikard; Issazadeh-Navikas, Shohreh

2011-01-01

NKT cells in the mouse recognize antigen in the context of the MHC class I-like molecule CD1d and play an important role in peripheral tolerance and protection against autoimmune and other diseases. NKT cells are usually activated by CD1d-presented lipid antigens. However, peptide recognition in the context of CD1 has also been documented, although no self-peptide ligands have been reported to date. Here, we have identified an endogenous peptide that is presented by CD1d to activate mouse NKT cells. This peptide, the immunodominant epitope from mouse collagen type II (mCII707-721), was not associated with either MHC class I or II. Activation of CD1d-restricted mCII707-721-specific NKT cells was induced via TCR signaling and classical costimulation. In addition, mCII707-721-specific NKT cells induced T cell death through Fas/FasL, in an IL-17A-independent fashion. Moreover, mCII707-721-specific NKT cells suppressed a range of in vivo inflammatory conditions, including delayed-type hypersensitivity, antigen-induced airway inflammation, collagen-induced arthritis, and EAE, which were all ameliorated by mCII707-721 vaccination. The findings presented here offer new insight into the intrinsic roles of NKT cells in health and disease. Given the results, endogenous collagen peptide activators of NKT cells may offer promise as novel therapeutics in tissue-specific autoimmune and inflammatory diseases.

NKG2D performs two functions in invariant NKT cells: direct TCR-independent activation of NK-like cytolysis and co-stimulation of activation by CD1d.

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Kuylenstierna, Carlotta; Björkström, Niklas K; Andersson, Sofia K; Sahlström, Peter; Bosnjak, Lidija; Paquin-Proulx, Dominic; Malmberg, Karl-Johan; Ljunggren, Hans-Gustaf; Moll, Markus; Sandberg, Johan K

2011-07-01

Invariant NKT cells are important in the activation and regulation of immune responses. They can also function as CD1d-restricted killer cells. However, the role of activating innate NK-cell receptors expressed on NKT cells in triggering cytolytic function is poorly characterized. Here, we initially confirmed that the cellular stress-ligand receptor NKG2D is expressed on CD4- NKT cells, whereas most CD4+ NKT cells lack this receptor. Interestingly, NKG2D+ NKT cells frequently expressed perforin, and both NKG2D and perforin localized at the site of contact with NKG2D ligand-expressing target cells. CD4- NKT cells degranulated in response to NKG2D engagement in a redirected activation assay independent of stimulation via their invariant TCR. NKT cells killed P815 cells coated with anti-NKG2D mAb and CD1d-negative K562 tumor target cells in an NKG2D-dependent manner. Furthermore, NKG2D engagement co-stimulated TCR-mediated NKT-cell activation in response to endogenous CD1d-presented ligands or suboptimal levels of anti-CD3 triggering. These data indicate that the CD4- subset of human NKT cells can mediate direct lysis of target cells via NKG2D engagement independent of CD1d, and that NKG2D also functions as a co-stimulatory receptor in these cells. NKG2D thus plays both a direct and a co-stimulatory role in the activation of NKT cells. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Antigen Specificity of Type I NKT Cells Is Governed by TCR β-Chain Diversity.

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Cameron, Garth; Pellicci, Daniel G; Uldrich, Adam P; Besra, Gurdyal S; Illarionov, Petr; Williams, Spencer J; La Gruta, Nicole L; Rossjohn, Jamie; Godfrey, Dale I

2015-11-15

NKT cells recognize lipid-based Ags presented by CD1d. Type I NKT cells are often referred to as invariant owing to their mostly invariant TCR α-chain usage (Vα14-Jα18 in mice, Vα24-Jα18 in humans). However, these cells have diverse TCR β-chains, including Vβ8, Vβ7, and Vβ2 in mice and Vβ11 in humans, joined to a range of TCR Dβ and Jβ genes. In this study, we demonstrate that TCR β-chain composition can dramatically influence lipid Ag recognition in an Ag-dependent manner. Namely, the glycolipids α-glucosylceramide and isoglobotrihexosylceramide were preferentially recognized by Vβ7(+) NKT cells from mice, whereas the α-galactosylceramide analog OCH, with a truncated sphingosine chain, was preferentially recognized by Vβ8(+) NKT cells from mice. We show that the influence of the TCR β-chain is due to a combination of Vβ-, Jβ-, and CDR3β-encoded residues and that these TCRs can recapitulate the selective Ag reactivity in TCR-transduced cell lines. Similar observations were made with human NKT cells where different CDR3β-encoded residues determined Ag preference. These findings indicate that NKT TCR β-chain diversity results in differential and nonhierarchical Ag recognition by these cells, which implies that some Ags can preferentially activate type I NKT cell subsets. Copyright © 2015 by The American Association of Immunologists, Inc.

The response of CD1d-restricted invariant NKT cells to microbial pathogens and their products

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Luc eVan Kaer

2015-05-01

Full Text Available Invariant natural killer T (iNKT cells become activated during a wide variety of infections. This includes organisms lacking cognate CD1d-binding glycolipid antigens recognized by the semi-invariant T cell receptor of iNKT cells. Additional studies have shown that iNKT cells also become activated in vivo in response to microbial products such as bacterial lipopolysaccharide, a potent inducer of cytokine production in antigen-presenting cells (APCs. Other studies have shown that iNKT cells are highly responsive to stimulation by cytokines such as interleukin-12. These findings have led to the concept that microbial pathogens can activate iNKT cells either directly via glycolipids, or indirectly by inducing cytokine production in APCs. iNKT cells activated in this manner produce multiple cytokines that can influence the outcome of infection, usually in favor of the host, although potent iNKT cell activation may contribute to an uncontrolled cytokine storm and sepsis. One aspect of the response of iNKT cells to microbial pathogens is that it is short-lived and followed by an extended time period of unresponsiveness to reactivation. This refractory period may represent a means to avoid chronic activation and cytokine production by iNKT cells, thus protecting the host against some of the negative effects of iNKT cell activation, but potentially putting the host at risk for secondary infections. These effects of microbial pathogens and their products on iNKT cells are not only important for understanding the role of these cells in immune responses against infections but also for the development of iNKT cell-based therapies.

Endogenous collagen peptide activation of CD1d-restricted NKT cells ameliorates tissue-specific inflammation in mice

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Liu, Yawei; Teige, Anna; Mondoc, Emma

2011-01-01

NKT cells in the mouse recognize antigen in the context of the MHC class I-like molecule CD1d and play an important role in peripheral tolerance and protection against autoimmune and other diseases. NKT cells are usually activated by CD1d-presented lipid antigens. However, peptide recognition...... in the context of CD1 has also been documented, although no self-peptide ligands have been reported to date. Here, we have identified an endogenous peptide that is presented by CD1d to activate mouse NKT cells. This peptide, the immunodominant epitope from mouse collagen type II (mCII707-721), was not associated...... with either MHC class I or II. Activation of CD1d-restricted mCII707-721-specific NKT cells was induced via TCR signaling and classical costimulation. In addition, mCII707-721-specific NKT cells induced T cell death through Fas/FasL, in an IL-17A-independent fashion. Moreover, mCII707-721-specific NKT cells...

Differential Role of Cathepsins S and B In Hepatic APC-Mediated NKT Cell Activation and Cytokine Secretion.

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de Mingo Pulido, Álvaro; de Gregorio, Estefanía; Chandra, Shilpi; Colell, Anna; Morales, Albert; Kronenberg, Mitchell; Marí, Montserrat

2018-01-01

Natural killer T (NKT) cells exhibit a specific tissue distribution, displaying the liver the highest NKT/conventional T cell ratio. Upon antigen stimulation, NKT cells secrete Th1 cytokines, including interferon γ (IFNγ), and Th2 cytokines, including IL-4 that recruit and activate other innate immune cells to exacerbate inflammatory responses in the liver. Cysteine cathepsins control hepatic inflammation by regulating κB-dependent gene expression. However, the contribution of cysteine cathepsins other than Cathepsin S to NKT cell activation has remained largely unexplored. Here we report that cysteine cathepsins, cathepsin B (CTSB) and cathepsin S (CTSS), regulate different aspects of NKT cell activation. Inhibition of CTSB or CTSS reduced hepatic NKT cell expansion in a mouse model after LPS challenge. By contrast, only CTSS inhibition reduced IFNγ and IL-4 secretion after in vivo α-GalCer administration. Accordingly, in vitro studies reveal that only CTSS was able to control α-GalCer-dependent loading in antigen-presenting cells (APCs), probably due to altered endolysosomal protein degradation. In summary, our study discloses the participation of cysteine cathepsins, CTSB and CTSS, in the activation of NKT cells in vivo and in vitro .

Differential Role of Cathepsins S and B In Hepatic APC-Mediated NKT Cell Activation and Cytokine Secretion

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Álvaro de Mingo Pulido

2018-02-01

Full Text Available Natural killer T (NKT cells exhibit a specific tissue distribution, displaying the liver the highest NKT/conventional T cell ratio. Upon antigen stimulation, NKT cells secrete Th1 cytokines, including interferon γ (IFNγ, and Th2 cytokines, including IL-4 that recruit and activate other innate immune cells to exacerbate inflammatory responses in the liver. Cysteine cathepsins control hepatic inflammation by regulating κB-dependent gene expression. However, the contribution of cysteine cathepsins other than Cathepsin S to NKT cell activation has remained largely unexplored. Here we report that cysteine cathepsins, cathepsin B (CTSB and cathepsin S (CTSS, regulate different aspects of NKT cell activation. Inhibition of CTSB or CTSS reduced hepatic NKT cell expansion in a mouse model after LPS challenge. By contrast, only CTSS inhibition reduced IFNγ and IL-4 secretion after in vivo α-GalCer administration. Accordingly, in vitro studies reveal that only CTSS was able to control α-GalCer-dependent loading in antigen-presenting cells (APCs, probably due to altered endolysosomal protein degradation. In summary, our study discloses the participation of cysteine cathepsins, CTSB and CTSS, in the activation of NKT cells in vivo and in vitro.

Ex-vivo α-galactosylceramide activation of NKT cells in humans and macaques.

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Fernandez, Caroline S; Cameron, Garth; Godfrey, Dale I; Kent, Stephen J

2012-08-31

NKT cells are key mediators of antiviral and anticancer immunity. Experiments in mice have demonstrated that activation of NKT cells in vivo induces the expression of multiple effector molecules critical to successful immunity. Human clinical trials have shown similar responses, although in vivo activation of NKT cells in humans or primate models are far more limited in number and scope. Measuring ex vivo activation of NKT cells by the CD1d-restricted glycolipid ligand α-Galactosylceramide (α-GalCer) through cytokine expression profiles is a useful marker of NKT cell function, but for reasons that are unclear, this approach does not appear to work as well in humans and non-human primate macaque models in comparison to mice. We performed a series of experiments on human and macaque (Macaca nemestrina) fresh whole blood samples to define optimal conditions to detect NKT cell cytokine (TNF, IFNγ, IL-2) and degranulation marker (CD107a) expression by flow cytometry. We found that conditions previously described for mouse splenocyte NKT cell activation were suboptimal on human or macaque blood NKT cells. In contrast, a 6h incubation with brefeldin A added for the last 4h, in a 96-well plate based assay, and using an α-GalCer concentration of 1 μg/ml were optimal methods to stimulate NKT cells in fresh blood from both humans and macaques. Unexpectedly, we noted that blood NKT cells from macaques infected with SIV were more readily activated by α-GalCer than NKT cells from uninfected macaques, suggesting that SIV infection may have primed the NKT cells. In conclusion, we describe optimized methods for the ex vivo antigen-specific activation of human and macaque blood NKT cells. These assays should be useful in monitoring NKT cells in disease and in immunotherapy studies. Copyright © 2012 Elsevier B.V. All rights reserved.

Sublingual injection of microparticles containing glycolipid ligands for NKT cells and subunit vaccines induces antibody responses in oral cavity.

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DeLyria, Elizabeth S; Zhou, Dapeng; Lee, Jun Soo; Singh, Shailbala; Song, Wei; Li, Fenge; Sun, Qing; Lu, Hongzhou; Wu, Jinhui; Qiao, Qian; Hu, Yiqiao; Zhang, Guodong; Li, Chun; Sastry, K Jagannadha; Shen, Haifa

2015-03-20

Natural Killer T (NKT) cells are a unique type of innate immune cells which exert paradoxical roles in animal models through producing either Th1 or Th2 cytokines and activating dendritic cells. Alpha-galactosylceramide (αGalCer), a synthetic antigen for NKT cells, was found to be safe and immune stimulatory in cancer and hepatitis patients. We recently developed microparticle-formulated αGalCer, which is selectively presented by dendritic cells and macrophages, but not B cells, and thus can avoid the anergy of NKT cells. In this study, we have examined the immunogenicity of microparticles containing αGalCer and protein vaccine components through sublingual injection in mice. The results showed that sublingual injection of microparticles containing αGalCer and ovalbumin triggered IgG responses in serum (titer >1:100,000), which persisted for more than 3months. Microparticles containing ovalbumin alone also induced comparable level of IgG responses. However, immunoglobulin subclass analysis showed that sublingually injected microparticles containing αGalCer and ovalbumin induced 20 fold higher Th1 biased antibody (IgG2c) than microparticles containing OVA alone (1:20,000 as compared to 1:1000 titer). Sublingual injection of microparticles containing αGalCer and ovalbumin induced secretion of both IgG (titer >1:1000) and IgA (titer=1:80) in saliva secretion, while microparticles containing ovalbumin alone only induced secretion of IgG in saliva. Our results suggest that sublingual injection of microparticles and their subsequent trafficking to draining lymph nodes may induce adaptive immune responses in mucosal compartments. Ongoing studies are focused on the mechanism of antigen presentation and lymphocyte biology in the oral cavity, as well as the toxicity and efficacy of these candidate microparticles for future applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

Immunologic glycosphingolipidomics and NKT cell development in mouse thymus

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Li, Yunsen; Thapa, Prakash; Hawke, David

2009-01-01

Invariant NKT cells are a hybrid cell type of Natural Killer cells and T cells, whose development is dependent on thymic positive selection mediated by double positive thymocytes through their recognition of natural ligands presented by CD1d, a nonpolymorphic, non-MHC, MHC-like antigen presenting...

iNKT Cells and Their potential Lipid Ligands during Viral Infection

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Anunya eOpasawatchai

2015-07-01

Full Text Available Invariant natural killer T (iNKT cells are a unique population of lipid reactive CD1d restricted innate-like T lymphocytes. Despite being a minor population, they serve as an early source of cytokines and promote immunological crosstalk thus bridging innate and adaptive immunity. Diseases ranging from allergy, autoimmunity, and cancer as well as infectious diseases, including viral infection, have been reported to be influenced by iNKT cells. However, it remains unclear how iNKT cells are activated during viral infection, as virus derived lipid antigens have not been reported. Cytokines may activate iNKT cells during infections from influenza and murine cytomegalovirus (MCMV, although CD1d dependent activation is evident in other viral infections. Several viruses, such as dengue virus (DENV, induce CD1d upregulation which correlates with iNKT cell activation. In contrast, Herpes simplex virus type 1 (HSV-1, Human immunodeficiency virus (HIV, Epstein-Barr virus (EBV and Human papiloma virus (HPV promote CD1d downregulation as a strategy to evade iNKT cell recognition. These observations suggest the participation of a CD1d-dependent process in the activation of iNKT cells in response to viral infection. Endogenous lipid ligands, including phospholipids as well as glycosphingolipids, such as glucosylceramide have been proposed to mediate iNKT cell activation. Pro-inflammatory signals produced during viral infection may stimulate iNKT cells through enhanced CD1d dependent endogenous lipid presentation. Furthermore, viral infection may alter lipid composition and inhibit endogenous lipid degradation. Recent advances in this field are reviewed.

Fine tuning a well-oiled machine: Influence of NK1.1 and NKG2D on NKT cell development and function.

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Joshi, Sunil K; Lang, Mark L

2013-10-01

Natural killer T cells (NKT) represent a group of CD1d-restricted T-lineage cells that provide a functional interface between innate and adaptive immune responses in infectious disease, cancer, allergy and autoimmunity. There have been remarkable advances in understanding the molecular events that underpin NKT development in the thymus and in the complex array of functions in the periphery. Most functional studies have focused on activation of T cell antigen receptors expressed by NKT cells and their responses to CD1d presentation of glycolipid and related antigens. Receiving less attention has been several molecules that are hallmarks of Natural Killer (NK) cells, but nonetheless expressed by NKT cells. These include several activating and inhibitory receptors that may fine-tune NKT development and survival, as well as activation via antigen receptors. Herein, we review the possible roles of the NK1.1 and NKG2D receptors in regulating development and function of NKT cells in health and disease. We suggest that pharmacological alteration of NKT activity should consider the potential complexities commensurate with NK1.1 and NKG2D expression. Published by Elsevier B.V.

NKT Cell Subsets Can Exert Opposing Effects in Autoimmunity, Tumor Surveillance and Inflammation

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Viale, Rachael; Ware, Randle; Maricic, Igor; Chaturvedi, Varun; Kumar, Vipin

2014-01-01

The innate-like natural killer T (NKT) cells are essential regulators of immunity. These cells comprise at least two distinct subsets and recognize different lipid antigens presented by the MHC class I like molecules CD1d. The CD1d-dependent recognition pathway of NKT cells is highly conserved from mouse to humans. While most type I NKT cells can recognize αGalCer and express a semi-invariant T cell receptor (TCR), a major population of type II NKT cells reactive to sulfatide utilizes an oligoclonal TCR. Furthermore TCR recognition features of NKT subsets are also distinctive with almost parallel as opposed to perpendicular footprints on the CD1d molecules for the type I and type II NKT cells respectively. Here we present a view based upon the recent studies in different clinical and experimental settings that while type I NKT cells are more often pathogenic, they may also be regulatory. On the other hand, sulfatide-reactive type II NKT cells mostly play an inhibitory role in the control of autoimmune and inflammatory diseases. Since the activity and cytokine secretion profiles of NKT cell subsets can be modulated differently by lipid ligands or their analogs, novel immunotherapeutic strategies are being developed for their differential activation for potential intervention in inflammatory diseases. PMID:25288922

B Cell Help by CD1d-Rectricted NKT Cells

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Livia Clerici

2015-10-01

Full Text Available B cell activation and antibody production against foreign antigens is a central step of host defense. This is achieved via highly regulated multi-phase processes that involve a variety of cells of both innate and adaptive arms of the immune system. MHC class II-restricted CD4+ T cells specific for peptide antigens, which acquire professional follicular B cell helper functions, have been long recognized as key players in this process. Recent data, however, challenge this paradigm by showing the existence of other helper cell types. CD1d restricted NKT cells specific for lipid antigens are one such new player and can coopt bona fide follicular helper phenotypes. Their role in helping antigen-specific B cell response to protein antigens, as well as to the so called “help-less” antigens that cannot be recognized by T follicular helper cells, is being increasingly elucidated, highlighting their potential pathophysiological impact on the immune response, as well as on the design of improved vaccine formulations.

IL-15 protects NKT cells from inhibition by tumor-associated macrophages and enhances antimetastatic activity

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Liu, Daofeng; Song, Liping; Wei, Jie; Courtney, Amy N.; Gao, Xiuhua; Marinova, Ekaterina; Guo, Linjie; Heczey, Andras; Asgharzadeh, Shahab; Kim, Eugene; Dotti, Gianpietro; Metelitsa, Leonid S.

2012-01-01

Vα24-invariant NKT cells inhibit tumor growth by targeting tumor-associated macrophages (TAMs). Tumor progression therefore requires that TAMs evade NKT cell activity through yet-unknown mechanisms. Here we report that a subset of cells in neuroblastoma (NB) cell lines and primary tumors expresses membrane-bound TNF-α (mbTNF-α). These proinflammatory tumor cells induced production of the chemokine CCL20 from TAMs via activation of the NF-κB signaling pathway, an effect that was amplified in hypoxia. Flow cytometry analyses of human primary NB tumors revealed selective accumulation of CCL20 in TAMs. Neutralization of the chemokine inhibited in vitro migration of NKT cells toward tumor-conditioned hypoxic monocytes and localization of NKT cells to NB grafts in mice. We also found that hypoxia impaired NKT cell viability and function. Thus, CCL20-producing TAMs served as a hypoxic trap for tumor-infiltrating NKT cells. IL-15 protected antigen-activated NKT cells from hypoxia, and transgenic expression of IL-15 in adoptively transferred NKT cells dramatically enhanced their antimetastatic activity in mice. Thus, tumor-induced chemokine production in hypoxic TAMs and consequent chemoattraction and inhibition of NKT cells represents a mechanism of immune escape that can be reversed by adoptive immunotherapy with IL-15–transduced NKT cells. PMID:22565311

IL-15 protects NKT cells from inhibition by tumor-associated macrophages and enhances antimetastatic activity.

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Liu, Daofeng; Song, Liping; Wei, Jie; Courtney, Amy N; Gao, Xiuhua; Marinova, Ekaterina; Guo, Linjie; Heczey, Andras; Asgharzadeh, Shahab; Kim, Eugene; Dotti, Gianpietro; Metelitsa, Leonid S

2012-06-01

Vα24-invariant NKT cells inhibit tumor growth by targeting tumor-associated macrophages (TAMs). Tumor progression therefore requires that TAMs evade NKT cell activity through yet-unknown mechanisms. Here we report that a subset of cells in neuroblastoma (NB) cell lines and primary tumors expresses membrane-bound TNF-α (mbTNF-α). These proinflammatory tumor cells induced production of the chemokine CCL20 from TAMs via activation of the NF-κB signaling pathway, an effect that was amplified in hypoxia. Flow cytometry analyses of human primary NB tumors revealed selective accumulation of CCL20 in TAMs. Neutralization of the chemokine inhibited in vitro migration of NKT cells toward tumor-conditioned hypoxic monocytes and localization of NKT cells to NB grafts in mice. We also found that hypoxia impaired NKT cell viability and function. Thus, CCL20-producing TAMs served as a hypoxic trap for tumor-infiltrating NKT cells. IL-15 protected antigen-activated NKT cells from hypoxia, and transgenic expression of IL-15 in adoptively transferred NKT cells dramatically enhanced their antimetastatic activity in mice. Thus, tumor-induced chemokine production in hypoxic TAMs and consequent chemoattraction and inhibition of NKT cells represents a mechanism of immune escape that can be reversed by adoptive immunotherapy with IL-15-transduced NKT cells.

Critical role for invariant chain in CD1d-mediated selection and maturation of Vα14-invariant NKT cells.

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Sillé, Fenna C M; Martin, Constance; Jayaraman, Pushpa; Rothchild, Alissa; Besra, Gurdyal S; Behar, Samuel M; Boes, Marianne

2011-09-30

The development and maturation of Vα14 invariant (i)NKT cells in mice requires CD1d-mediated lipid antigen presentation in the thymus and the periphery. Cortical thymocytes mediate positive selection, while professional APCs are involved in thymic negative selection and in terminal maturation of iNKT cells in the periphery. CD1d requires entry in the endosomal pathway to allow antigen acquisition for assembly as lipid/CD1d complexes for display to iNKT cells. This process involves tyrosine-based sorting motifs in the CD1d cytoplasmic tail and invariant chain (Ii) that CD1d associates with in the endoplasmic reticulum. The function of Ii in iNKT cell thymic development and peripheral maturation had not been fully understood. Using mice deficient in Ii and the Ii-processing enzyme cathepsin S (catS), we addressed this question. Ii(-/-) mice but not catS(-/-) mice developed significantly fewer iNKT cells in thymus, that were less mature as measured by CD44 and NK1.1 expression. Ii(-/-) mice but not catS(-/-) mice developed fewer Vβ7(+) cells in their iNKT TCR repertoire than WT counterparts, indicative of a change in endogenous glycolipid antigen/CD1d-mediated iNKT cell selection. Finally, using a Mycobacterium tuberculosis infection model in macrophages, we show that iNKT developed in Ii(-/-) but not catS(-/-) mice have defective effector function. Our data support a role for professional APCs expressing Ii, but no role for catS in the thymic development and peripheral terminal maturation of iNKT cells. Copyright © 2011 Elsevier B.V. All rights reserved.

Development of a qPCR method to rapidly assess the function of NKT cells.

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Sohn, Silke; Tiper, Irina; Japp, Emily; Sun, Wenji; Tkaczuk, Katherine; Webb, Tonya J

2014-05-01

NKT cells comprise a rare, but important subset of T cells which account for ~0.2% of the total circulating T cell population. NKT cells are known to have anti-tumor functions and rapidly produce high levels of cytokines following activation. Several clinical trials have sought to exploit the effector functions of NKT cells. While some studies have shown promise, NKT cells are approximately 50% lower in cancer patients compared to healthy donors of the same age and gender, thus limiting their therapeutic efficacy. These studies indicate that baseline levels of activation should be assessed before initiating an NKT cell based immunotherapeutic strategy. The goal of this study was to develop a sensitive method to rapidly assess NKT cell function. We utilized artificial antigen presenting cells in combination with qPCR in order to determine NKT cell function in peripheral blood mononuclear cells from healthy donors and breast cancer patients. We found that NKT cell activation can be detected by qPCR, but not by ELISA, in healthy donors as well as in breast cancer patients following four hour stimulation. This method utilizing CD1d-expressing aAPCs will enhance our knowledge of NKT cell biology and could potentially be used as a novel tool in adoptive immunotherapeutic strategies. Copyright © 2014 Elsevier B.V. All rights reserved.

NKT cells as an ideal anti-tumor immunotherapeutic.

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Fujii, Shin-Ichiro; Shimizu, Kanako; Okamoto, Yoshitaka; Kunii, Naoki; Nakayama, Toshinori; Motohashi, Shinichiro; Taniguchi, Masaru

2013-12-02

Human natural killer T (NKT) cells are characterized by their expression of an invariant T cell antigen receptor α chain variable region encoded by a Vα24Jα18 rearrangement. These NKT cells recognize α-galactosylceramide (α-GalCer) in conjunction with the MHC class I-like CD1d molecule and bridge the innate and acquired immune systems to mediate efficient and augmented immune responses. A prime example of one such function is adjuvant activity: NKT cells augment anti-tumor responses because they can rapidly produce large amounts of IFN-γ, which acts on NK cells to eliminate MHC negative tumors and also on CD8 cytotoxic T cells to kill MHC positive tumors. Thus, upon administration of α-GalCer-pulsed DCs, both MHC negative and positive tumor cells can be effectively eliminated, resulting in complete tumor eradication without tumor recurrence. Clinical trials have been completed in a cohort of 17 patients with advanced non-small cell lung cancers and 10 cases of head and neck tumors. Sixty percent of advanced lung cancer patients with high IFN-γ production had significantly prolonged median survival times of 29.3 months with only the primary treatment. In the case of head and neck tumors, 10 patients who completed the trial all had stable disease or partial responses 5 weeks after the combination therapy of α-GalCer-DCs and activated NKT cells. We now focus on two potential powerful treatment options for the future. One is to establish artificial adjuvant vector cells containing tumor mRNA and α-GalCer/CD1d. This stimulates host NKT cells followed by DC maturation and NK cell activation but also induces tumor-specific long-term memory CD8 killer T cell responses, suppressing tumor metastasis even 1 year after the initial single injection. The other approach is to establish induced pluripotent stem (iPS) cells that can generate unlimited numbers of NKT cells with adjuvant activity. Such iPS-derived NKT cells produce IFN-γ in vitro and in vivo upon

Cross-talk between cd1d-restricted nkt cells and γδ cells in t regulatory cell response

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Huber Sally A

2011-01-01

Full Text Available Abstract CD1d is a non-classical major histocompatibility class 1-like molecule which primarily presents either microbial or endogenous glycolipid antigens to T cells involved in innate immunity. Natural killer T (NKT cells and a subpopulation of γδ T cells expressing the Vγ4 T cell receptor (TCR recognize CD1d. NKT and Vγ4 T cells function in the innate immune response via rapid activation subsequent to infection and secrete large quantities of cytokines that both help control infection and modulate the developing adaptive immune response. T regulatory cells represent one cell population impacted by both NKT and Vγ4 T cells. This review discusses the evidence that NKT cells promote T regulatory cell activation both through direct interaction of NKT cell and dendritic cells and through NKT cell secretion of large amounts of TGFβ, IL-10 and IL-2. Recent studies have shown that CD1d-restricted Vγ4 T cells, in contrast to NKT cells, selectively kill T regulatory cells through a caspase-dependent mechanism. Vγ4 T cell elimination of the T regulatory cell population allows activation of autoimmune CD8+ effector cells leading to severe cardiac injury in a coxsackievirus B3 (CVB3 myocarditis model in mice. CD1d-restricted immunity can therefore lead to either immunosuppression or autoimmunity depending upon the type of innate effector dominating during the infection.

Improving Mycobacterium bovis bacillus Calmette-Guèrin as a vaccine delivery vector for viral antigens by incorporation of glycolipid activators of NKT cells.

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Venkataswamy, Manjunatha M; Ng, Tony W; Kharkwal, Shalu S; Carreño, Leandro J; Johnson, Alison J; Kunnath-Velayudhan, Shajo; Liu, Zheng; Bittman, Robert; Jervis, Peter J; Cox, Liam R; Besra, Gurdyal S; Wen, Xiangshu; Yuan, Weiming; Tsuji, Moriya; Li, Xiangming; Ho, David D; Chan, John; Lee, Sunhee; Frothingham, Richard; Haynes, Barton F; Panas, Michael W; Gillard, Geoffrey O; Sixsmith, Jaimie D; Korioth-Schmitz, Birgit; Schmitz, Joern E; Larsen, Michelle H; Jacobs, William R; Porcelli, Steven A

2014-01-01

Recombinant Mycobacterium bovis bacillus Calmette-Guèrin (rBCG) has been explored as a vector for vaccines against HIV because of its ability to induce long lasting humoral and cell mediated immune responses. To maximize the potential for rBCG vaccines to induce effective immunity against HIV, various strategies are being employed to improve its ability to prime CD8+ T cells, which play an important role in the control of HIV infections. In this study we adopted a previously described approach of incorporating glycolipids that activate CD1d-restricted natural killer T (NKT) cells to enhance priming of CD8+ T cells by rBCG strains expressing an SIV Gag antigen (rBCG-SIV gag). We found that the incorporation of the synthetic NKT activating glycolipid α-galactosylceramide (α-GC) into rBCG-SIV gag significantly enhanced CD8+ T cell responses against an immunodominant Gag epitope, compared to responses primed by unmodified rBCG-SIV gag. The abilities of structural analogues of α-GC to enhance CD8+ T cell responses to rBCG were compared in both wild type and partially humanized mice that express human CD1d molecules in place of mouse CD1d. These studies identified an α-GC analogue known as 7DW8-5, which has previously been used successfully as an adjuvant in non-human primates, as a promising compound for enhancing immunogenicity of antigens delivered by rBCG.vectors. Our findings support the incorporation of synthetic glycolipid activators of NKT cells as a novel approach to enhance the immunogenicity of rBCG-vectored antigens for induction of CD8+ T cell responses. The glycolipid adjuvant 7DW8-5 may be a promising candidate for advancing to non-human primate and human clinical studies for the development of HIV vaccines based on rBCG vectors.

Improving Mycobacterium bovis bacillus Calmette-Guèrin as a vaccine delivery vector for viral antigens by incorporation of glycolipid activators of NKT cells.

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Manjunatha M Venkataswamy

Full Text Available Recombinant Mycobacterium bovis bacillus Calmette-Guèrin (rBCG has been explored as a vector for vaccines against HIV because of its ability to induce long lasting humoral and cell mediated immune responses. To maximize the potential for rBCG vaccines to induce effective immunity against HIV, various strategies are being employed to improve its ability to prime CD8+ T cells, which play an important role in the control of HIV infections. In this study we adopted a previously described approach of incorporating glycolipids that activate CD1d-restricted natural killer T (NKT cells to enhance priming of CD8+ T cells by rBCG strains expressing an SIV Gag antigen (rBCG-SIV gag. We found that the incorporation of the synthetic NKT activating glycolipid α-galactosylceramide (α-GC into rBCG-SIV gag significantly enhanced CD8+ T cell responses against an immunodominant Gag epitope, compared to responses primed by unmodified rBCG-SIV gag. The abilities of structural analogues of α-GC to enhance CD8+ T cell responses to rBCG were compared in both wild type and partially humanized mice that express human CD1d molecules in place of mouse CD1d. These studies identified an α-GC analogue known as 7DW8-5, which has previously been used successfully as an adjuvant in non-human primates, as a promising compound for enhancing immunogenicity of antigens delivered by rBCG.vectors. Our findings support the incorporation of synthetic glycolipid activators of NKT cells as a novel approach to enhance the immunogenicity of rBCG-vectored antigens for induction of CD8+ T cell responses. The glycolipid adjuvant 7DW8-5 may be a promising candidate for advancing to non-human primate and human clinical studies for the development of HIV vaccines based on rBCG vectors.

Type II Natural Killer T (NKT) Cells And Their Emerging Role In Health And Disease

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Dhodapkar, Madhav V.; Kumar, Vipin

2016-01-01

Natural killer T (NKT) cells recognize lipid antigens presented by a class I MHC-like molecule CD1d, a member of the CD1 family. While most of the initial studies on NKT cells focused on a subset with semi-invariant T cell receptor (TCR) termed iNKT cells, majority of CD1d-restricted lipid-reactive human T cells express diverse TCRs and are termed as type II NKT cells. These cells constitute a distinct population of circulating and tissue-resident effector T cells with immune-regulatory properties. They react to a growing list of self- as well as non-self lipid ligands, and share some properties with both iNKT as well as conventional T cells. Emerging body of evidence points to their role in the regulation of immunity to pathogens/tumors and in autoimmune/metabolic disorders. Improved understanding of the biology of these cells and the ability to manipulate their function may be of therapeutic benefit in diverse disease conditions. PMID:28115591

iNKT cell cytotoxic responses control T-lymphoma growth in vitro and in vivo

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Bassiri, Hamid; Das, Rupali; Guan, Peng; Barrett, David M.; Brennan, Patrick J.; Banerjee, Pinaki P.; Wiener, Susan J.; Orange, Jordan S.; Brenner, Michael B.; Grupp, Stephan A.; Nichols, Kim E.

2013-01-01

Invariant natural killer T (iNKT) cells comprise a lineage of CD1d-restricted glycolipid-reactive T lymphocytes with important roles in host immunity to cancer. iNKT cells indirectly participate in antitumor responses by inducing dendritic cell maturation and producing cytokines that promote tumor clearance by CD8+ T and NK cells. Although iNKT cells thereby act as potent cellular adjuvants, it is less clear whether they directly control the growth of tumors. To gain insights into the direct contribution of iNKT cells to tumor immune surveillance, we developed in vitro and in vivo systems to selectively examine the antitumor activity of iNKT cells in the absence of other cytolytic effectors. Using the EL4 T-lymphoma cell line as a model, we find that iNKT cells exert robust and specific lysis of tumor cells in vitro in a manner that is differentially-induced by iNKT cell agonists of varying TCR affinities, such as OCH, α-galactosyl ceramide and PBS44. In vitro blockade of CD1d-mediated lipid antigen presentation, disruption of T cell receptor (TCR) signaling, or loss of perforin expression significantly reduce iNKT cell killing. Consistent with these findings, iNKT cell reconstitution of T, B, and NK cell-deficient mice slows EL4 growth in vivo via TCR-CD1d and perforin-dependent mechanisms. Together, these observations establish that iNKT cells are sufficient to control the growth of T-lymphoma in vitro and in vivo. They also suggest that the induction of iNKT cell cytotoxic responses in situ might serve as a more effective strategy to prevent and/or treat CD1d+ cancers, such as T-lymphoma. PMID:24563871

Pathogen-expanded CD11b+ invariant NKT cells feedback inhibit T cell proliferation via membrane-bound TGF-β1.

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Han, Yanmei; Jiang, Zhengping; Chen, Zhubo; Gu, Yan; Liu, Yanfang; Zhang, Xiang; Cao, Xuetao

2015-04-01

Natural killer T cells (NKT cells) are effector cells, but also regulator of immune response, which either promote or suppress immune response through production of different cytokines. However, the subsets of NKT cells with definite phenotype and regulatory function need to be further identified. Furthermore, the mechanisms for NKT cells to regulate immune response remain to be fully elucidated. Here we identified CD11b(+) invariant NKT (CD11b(+) iNKT) cells as a new subset of regulatory NKT cells in mouse models with infection. αGalCer:CD1d complex(+)TCRβ(+)NK1.1(+) NKT cells could be categorized to CD11b(+) and CD11b(-) subsets. NKT cells are enriched in liver. During Listeria monocytogenes infection, hepatic CD11b(+) iNKT cells were significantly induced and expanded, with peak expansion on day 8. CD11b(+) iNKT cells were also expanded significantly in spleen and mesenteric lymph nodes. As compared to CD11b(-) iNKT cells, CD11b(+) iNKT cells expressed higher levels of CD27, FasL, B7H1, CD69, and particularly higher level of membrane-bound TGF-β1 (mTGF-β1), but produced less IFN-γ, IL-4, IL-10 and TGF-β1. Hepatic CD11b(+) iNKT cells suppressed antigen-nonspecific and OVA-specific CD4 and CD8 T cell proliferation through mTGF-β1 both in vitro and in vivo, meanwhile, they did not interfere with activation of CD4 T cells and cytotoxicity of the activated CD8 T cells. Thus, we have identified a new subset of pathogen-expanded CD11b(+) invariant NKT cells which can feedback inhibit T cell response through cell-to-cell contact via cell surface (membrane-bound) TGF-β1, especially at the late stage of immune response against infection. CD11b(+) regulatory iNKT cells may contribute to protect host from pathological injure by preventing immune overactivation. Copyright © 2015 Elsevier Ltd. All rights reserved.

iNKT cell cytotoxic responses control T-lymphoma growth in vitro and in vivo .

Science.gov (United States)

Bassiri, Hamid; Das, Rupali; Guan, Peng; Barrett, David M; Brennan, Patrick J; Banerjee, Pinaki P; Wiener, Susan J; Orange, Jordan S; Brenner, Michael B; Grupp, Stephan A; Nichols, Kim E

2014-01-01

Invariant natural killer T (iNKT) cells comprise a lineage of CD1d-restricted glycolipid-reactive T lymphocytes with important roles in host immunity to cancer. iNKT cells indirectly participate in antitumor responses by inducing dendritic cell maturation and producing cytokines that promote tumor clearance by CD8+ T and NK cells. Although iNKT cells thereby act as potent cellular adjuvants, it is less clear whether they directly control the growth of tumors. To gain insights into the direct contribution of iNKT cells to tumor immune surveillance, we developed in vitro and in vivo systems to selectively examine the antitumor activity of iNKT cells in the absence of other cytolytic effectors. Using the EL4 T-lymphoma cell line as a model, we found that iNKT cells exert robust and specific lysis of tumor cells in vitro in a manner that is differentially induced by iNKT cell agonists of varying T-cell receptor (TCR) affinities, such as OCH, α-galactosyl ceramide, and PBS44. In vitro blockade of CD1d-mediated lipid antigen presentation, disruption of TCR signaling, or loss of perforin expression significantly reduce iNKT cell killing. Consistent with these findings, iNKT cell reconstitution of T, B, and NK cell–deficient mice slows EL4 growth in vivo via TCR-CD1d and perforin-dependent mechanisms. Together, these observations establish that iNKT cells are sufficient to control the growth of T lymphoma in vitro and in vivo. They also suggest that the induction of iNKT cell cytotoxic responses in situ might serve as a more effective strategy to prevent and/or treat CD1d+ cancers, such as T lymphoma. ©2013 AACR.

Raising the Roof: The Preferential Pharmacological Stimulation of Th1 and Th2 Responses Mediated by NKT Cells

Science.gov (United States)

East, James E.; Kennedy, Andrew J.; Webb, Tonya J.

2014-01-01

Natural killer T (NKT) cells serve as a bridge between the innate and adaptive immune systems, and manipulating their effector functions can have therapeutic significances in the treatment of autoimmunity, transplant biology, infectious disease, and cancer. NKT cells are a subset of T cells that express cell-surface markers characteristic of both natural killer cells and T cells. These unique immunologic cells have been demonstrated to serve as a link between the innate and adaptive immune systems through their potent cytokine production following the recognition of a range of lipid antigens, mediated through presentation of the major histocompatibility complex (MHC) class I like CD1d molecule, in addition to the NKT cell′s cytotoxic capabilities upon activation. Although a number of glycolipid antigens have been shown to complex with CD1d molecules, most notably the marine sponge derived glycolipid alpha-galactosylceramide (α-GalCer), there has been debate as to the identity of the endogenous activating lipid presented to the T-cell receptor (TCR) via the CD1d molecule on antigen-presenting cells (APCs). This review aims to survey the use of pharmacological agents and subsequent structure–activity relationships (SAR) that have given insight into the binding interaction of glycolipids with both the CD1d molecules as well as the TCR and the subsequent immunologic response of NKT cells. These studies not only elucidate basic binding interactions but also pave the way for future pharmacological modulation of NKT cell responses. PMID:23239102

Innate-like control of human iNKT cell autoreactivity via the hypervariable CDR3beta loop.

Directory of Open Access Journals (Sweden)

Gediminas Matulis

2010-06-01

Full Text Available Invariant Natural Killer T cells (iNKT are a versatile lymphocyte subset with important roles in both host defense and immunological tolerance. They express a highly conserved TCR which mediates recognition of the non-polymorphic, lipid-binding molecule CD1d. The structure of human iNKT TCRs is unique in that only one of the six complementarity determining region (CDR loops, CDR3beta, is hypervariable. The role of this loop for iNKT biology has been controversial, and it is unresolved whether it contributes to iNKT TCR:CD1d binding or antigen selectivity. On the one hand, the CDR3beta loop is dispensable for iNKT TCR binding to CD1d molecules presenting the xenobiotic alpha-galactosylceramide ligand KRN7000, which elicits a strong functional response from mouse and human iNKT cells. However, a role for CDR3beta in the recognition of CD1d molecules presenting less potent ligands, such as self-lipids, is suggested by the clonal distribution of iNKT autoreactivity. We demonstrate that the human iNKT repertoire comprises subsets of greatly differing TCR affinity to CD1d, and that these differences relate to their autoreactive functions. These functionally different iNKT subsets segregate in their ability to bind CD1d-tetramers loaded with the partial agonist alpha-linked glycolipid antigen OCH and structurally different endogenous beta-glycosylceramides. Using surface plasmon resonance with recombinant iNKT TCRs and different ligand-CD1d complexes, we demonstrate that the CDR3beta sequence strongly impacts on the iNKT TCR affinity to CD1d, independent of the loaded CD1d ligand. Collectively our data reveal a crucial role for CDR3beta for the function of human iNKT cells by tuning the overall affinity of the iNKT TCR to CD1d. This mechanism is relatively independent of the bound CD1d ligand and thus forms the basis of an inherent, CDR3beta dependent functional hierarchy of human iNKT cells.

Functional Invariant NKT Cells in Pig Lungs Regulate the Airway Hyperreactivity: A Potential Animal Model

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Manickam, Cordelia; Khatri, Mahesh; Rauf, Abdul; Li, Xiangming; Tsuji, Moriya; Rajashekara, Gireesh; Dwivedi, Varun

2015-01-01

Important roles played by invariant natural killer T (iNKT) cells in asthma pathogenesis have been demonstrated. We identified functional iNKT cells and CD1d molecules in pig lungs. Pig iNKT cells cultured in the presence of α-GalCer proliferated and secreted Th1 and Th2 cytokines. Like in other animal models, direct activation of pig lung iNKT cells using α-GalCer resulted in acute airway hyperreactivity (AHR). Clinically, acute AHR-induced pigs had increased respiratory rate, enhanced mucus secretion in the airways, fever, etc. In addition, we observed petechial hemorrhages, infiltration of CD4+ cells, and increased Th2 cytokines in AHR-induced pig lungs. Ex vivo proliferated iNKT cells of asthma induced pigs in the presence of C-glycoside analogs of α-GalCer had predominant Th2 phenotype and secreted more of Th2 cytokine, IL-4. Thus, baby pigs may serve as a useful animal model to study iNKT cell-mediated AHR caused by various environmental and microbial CD1d-specific glycolipid antigens. PMID:21042929

NKAP regulates iNKT cell proliferation and differentiation into ROR-��t expressing NKT17 cells

OpenAIRE

Thapa, Puspa; Chen, Meibo W.; McWilliams, Douglas C.; Belmonte, Paul; Constans, Megan; Sant���Angelo, Derek B.; Shapiro, Virginia Smith

2016-01-01

Invariant Natural Killer T (iNKT) cells are a unique lineage with characteristics of both adaptive and innate lymphocytes, and recognize glycolipid presented by an MHC Class I-like CD1d molecule. During thymic development, iNKT cells also differentiate into NKT1, NKT2 and NKT17 functional subsets that preferentially produce cytokines IFN-��, IL-4 and IL-17, respectively, upon activation. Newly selected iNKT cells undergo a burst of proliferation, which is defective in mice with a specific del...

Initiation of Antiviral B Cell Immunity Relies on Innate Signals from Spatially Positioned NKT Cells.

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Gaya, Mauro; Barral, Patricia; Burbage, Marianne; Aggarwal, Shweta; Montaner, Beatriz; Warren Navia, Andrew; Aid, Malika; Tsui, Carlson; Maldonado, Paula; Nair, Usha; Ghneim, Khader; Fallon, Padraic G; Sekaly, Rafick-Pierre; Barouch, Dan H; Shalek, Alex K; Bruckbauer, Andreas; Strid, Jessica; Batista, Facundo D

2018-01-25

B cells constitute an essential line of defense from pathogenic infections through the generation of class-switched antibody-secreting cells (ASCs) in germinal centers. Although this process is known to be regulated by follicular helper T (TfH) cells, the mechanism by which B cells initially seed germinal center reactions remains elusive. We found that NKT cells, a population of innate-like T lymphocytes, are critical for the induction of B cell immunity upon viral infection. The positioning of NKT cells at the interfollicular areas of lymph nodes facilitates both their direct priming by resident macrophages and the localized delivery of innate signals to antigen-experienced B cells. Indeed, NKT cells secrete an early wave of IL-4 and constitute up to 70% of the total IL-4-producing cells during the initial stages of infection. Importantly, the requirement of this innate immunity arm appears to be evolutionarily conserved because early NKT and IL-4 gene signatures also positively correlate with the levels of neutralizing antibodies in Zika-virus-infected macaques. In conclusion, our data support a model wherein a pre-TfH wave of IL-4 secreted by interfollicular NKT cells triggers the seeding of germinal center cells and serves as an innate link between viral infection and B cell immunity. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Roquin Paralogs Differentially Regulate Functional NKT Cell Subsets.

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Drees, Christoph; Vahl, J Christoph; Bortoluzzi, Sabrina; Heger, Klaus D; Fischer, Julius C; Wunderlich, F Thomas; Peschel, Christian; Schmidt-Supprian, Marc

2017-04-01

NKT cells represent a small subset of glycolipid-recognizing T cells that are heavily implicated in human allergic, autoimmune, and malignant diseases. In the thymus, precursor cells recognize self-glycolipids by virtue of their semi-invariant TCR, which triggers NKT cell lineage commitment and maturation. During their development, NKT cells are polarized into the NKT1, NKT2, and NKT17 subsets, defined through their cytokine-secretion patterns and the expression of key transcription factors. However, we have largely ignored how the differentiation into the NKT cell subsets is regulated. In this article, we describe the mRNA-binding Roquin-1 and -2 proteins as central regulators of murine NKT cell fate decisions. In the thymus, T cell-specific ablation of the Roquin paralogs leads to a dramatic expansion of NKT17 cells, whereas peripheral mature NKT cells are essentially absent. Roquin-1/2-deficient NKT17 cells show exaggerated lineage-specific expression of nearly all NKT17-defining proteins tested. We show through mixed bone marrow chimera experiments that NKT17 polarization is mediated through cell-intrinsic mechanisms early during NKT cell development. In contrast, the loss of peripheral NKT cells is due to cell-extrinsic factors. Surprisingly, Roquin paralog-deficient NKT cells are, in striking contrast to conventional T cells, compromised in their ability to secrete cytokines. Altogether, we show that Roquin paralogs regulate the development and function of NKT cell subsets in the thymus and periphery. Copyright © 2017 by The American Association of Immunologists, Inc.

Transfer of mRNA Encoding Invariant NKT Cell Receptors Imparts Glycolipid Specific Responses to T Cells and γδT Cells.

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Shimizu, Kanako; Shinga, Jun; Yamasaki, Satoru; Kawamura, Masami; Dörrie, Jan; Schaft, Niels; Sato, Yusuke; Iyoda, Tomonori; Fujii, Shin-Ichiro

2015-01-01

Cell-based therapies using genetically engineered lymphocytes expressing antigen-specific T cell receptors (TCRs) hold promise for the treatment of several types of cancers. Almost all studies using this modality have focused on transfer of TCR from CD8 cytotoxic T lymphocytes (CTLs). The transfer of TCR from innate lymphocytes to other lymphocytes has not been studied. In the current study, innate and adaptive lymphocytes were transfected with the human NKT cell-derived TCRα and β chain mRNA (the Vα24 and Vβ11 TCR chains). When primary T cells transfected with NKT cell-derived TCR were subsequently stimulated with the NKT ligand, α-galactosylceramide (α-GalCer), they secreted IFN-γ in a ligand-specific manner. Furthermore when γδT cells were transfected with NKT cell-derived TCR mRNA, they demonstrated enhanced proliferation, IFN-γ production and antitumor effects after α-GalCer stimulation as compared to parental γδT cells. Importantly, NKT cell TCR-transfected γδT cells responded to both NKT cell and γδT cell ligands, rendering them bi-potential innate lymphocytes. Because NKT cell receptors are unique and universal invariant receptors in humans, the TCR chains do not yield mispaired receptors with endogenous TCR α and β chains after the transfection. The transfection of NKT cell TCR has the potential to be a new approach to tumor immunotherapy in patients with various types of cancer.

Α-galactosylceramide analogs with weak agonist activity for human iNKT cells define new candidate anti-inflammatory agents.

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Gabriel Bricard

2010-12-01

Full Text Available CD1d-restricted natural killer T cells with invariant T cell receptor α chains (iNKT cells are a unique lymphocyte subset that responds to recognition of specific lipid and glycolipid antigens. They are conserved between mice and humans and exert various immunoregulatory functions through their rapid secretion of a variety of cytokines and secondary activation of dendritic cells, B cells and NK cells. In the current study, we analyzed the range of functional activation states of human iNKT cells using a library of novel analogs of α-galactosylceramide (αGalCer, the prototypical iNKT cell antigen. Measurement of cytokines secreted by human iNKT cell clones over a wide range of glycolipid concentrations revealed that iNKT cell ligands could be classified into functional groups, correlating with weak versus strong agonistic activity. The findings established a hierarchy for induction of different cytokines, with thresholds for secretion being consistently lowest for IL-13, higher for interferon-γ (IFNγ, and even higher for IL-4. These findings suggested that human iNKT cells can be intrinsically polarized to selective production of IL-13 by maintaining a low level of activation using weak agonists, whereas selective polarization to IL-4 production cannot be achieved through modulating the strength of the activating ligand. In addition, using a newly designed in vitro system to assess the ability of human iNKT cells to transactivate NK cells, we found that robust secondary induction of interferon-γ secretion by NK cells was associated with strong but not weak agonist ligands of iNKT cells. These results indicate that polarization of human iNKT cell responses to Th2-like or anti-inflammatory effects may best be achieved through selective induction of IL-13 and suggest potential discrepancies with findings from mouse models that may be important in designing iNKT cell-based therapies in humans.

Does an NKT-cell-based immunotherapeutic approach have a future in multiple myeloma?

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Favreau, Mérédis; Vanderkerken, Karin

2016-01-01

Natural killer T (NKT) cells constitute a unique subset of innate-like T lymphocytes which differ from conventional T cells by recognizing lipid antigens presented by the non-polymorphic major histocompatibility complex (MHC) I-like molecule CD1d. Despite being a relatively infrequent population of lymphocytes, NKT cells can respond rapidly upon activation with glycosphingolipids by production of cytokines which aim to polarize different axes of the immune system. Due to their dual effector capacities, NKT cells can play a vital role in cancer immunity, infection, inflammation and autoimmune diseases. It is believed that modulation of their activity towards immune activation can be a useful tool in anti-tumor immunotherapeutic strategies. Here we summarize the characteristics of NKT cells and discuss their involvement in immunosurveillance. Furthermore, an update is given about their role and the progress that has been made in the field of multiple myeloma (MM). Finally, some challenges are discussed that are currently hampering further progress. PMID:26895468

Raising the roof: the preferential pharmacological stimulation of Th1 and th2 responses mediated by NKT cells.

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East, James E; Kennedy, Andrew J; Webb, Tonya J

2014-01-01

Natural killer T (NKT) cells serve as a bridge between the innate and adaptive immune systems, and manipulating their effector functions can have therapeutic significances in the treatment of autoimmunity, transplant biology, infectious disease, and cancer. NKT cells are a subset of T cells that express cell-surface markers characteristic of both natural killer cells and T cells. These unique immunologic cells have been demonstrated to serve as a link between the innate and adaptive immune systems through their potent cytokine production following the recognition of a range of lipid antigens, mediated through presentation of the major histocompatibility complex (MHC) class I like CD1d molecule, in addition to the NKT cell's cytotoxic capabilities upon activation. Although a number of glycolipid antigens have been shown to complex with CD1d molecules, most notably the marine sponge derived glycolipid alpha-galactosylceramide (α-GalCer), there has been debate as to the identity of the endogenous activating lipid presented to the T-cell receptor (TCR) via the CD1d molecule on antigen-presenting cells (APCs). This review aims to survey the use of pharmacological agents and subsequent structure-activity relationships (SAR) that have given insight into the binding interaction of glycolipids with both the CD1d molecules as well as the TCR and the subsequent immunologic response of NKT cells. These studies not only elucidate basic binding interactions but also pave the way for future pharmacological modulation of NKT cell responses. © 2012 Wiley Periodicals, Inc.

Activation of glioma cells generates immune tolerant NKT cells.

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Tang, Bo; Wu, Wei; Wei, Xiaowei; Li, Yang; Ren, Gang; Fan, Wenhai

2014-12-12

Therapeutic outcomes of glioma are currently not encouraging. Tumor tolerance plays an important role in the pathogenesis of glioma. It is reported that micro RNAs (miR) are associated with tumor development. This study aims to investigate the role of miR-92a in the development of tolerant natural killer T (NKT) cells. In this study, U87 cells (a human glioma cell line) and primary glioma cells were prepared. The assessment of miR-92a was performed by real time RT-PCR. The expression of interleukin (IL)-10 and IL-6 in NKT cells was evaluated by flow cytometry. Results showed that abundant IL-6(+) IL-10(+) NKT cells were detected in glioma tissue. Cultures of glioma cells and NKT cells induced the expression of IL-6 and IL-10 in NKT cells. Glioma cells expressed miR-92a; the latter played a critical role in the induction of IL-6 and IL-10 expression in NKT cells. The expression of the antitumor molecules, including perforin, Fas ligand, and interferon-γ, was significantly attenuated compared with control NKT cells. The IL-6(+) IL-10(+) NKT cells showed less capability in the induction of apoptosis in glioma cells, but showed the immune suppressor functions on CD8(+) T cell activities. We conclude that glioma-derived miR-92a induces IL-6(+) IL-10(+) NKT cells; this fraction of NKT cells can suppress cytotoxic CD8(+) T cells. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Design of a potent CD1d-binding NKT cell ligand as a vaccine adjuvant

OpenAIRE

Li, Xiangming; Fujio, Masakazu; Imamura, Masakazu; Wu, Douglass; Vasan, Sandhya; Wong, Chi-Huey; Ho, David D.; Tsuji, Moriya

2010-01-01

The glycolipid α-galactosylceramide (α-GalCer) has been shown to bind CD1d molecules to activate invariant natural killer T (iNKT) cells, and subsequently induce activation of various immune-competent cells, including dendritic cells, thereby providing a significant adjuvant effect for various vaccines. However, in phase I clinical trials, α-GalCer was shown to display only marginal biological activity. In our search for a glycolipid that can exert more potent stimulatory activity against iNK...

The immunoregulatory role of type I and type II NKT cells in cancer and other diseases

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Terabe, Masaki; Berzofsky, Jay A.

2014-01-01

NKT cells are CD1d-restricted T cells that recognize lipid antigens. They also have been shown to play critical roles in the regulation of immune responses. In the immune responses against tumors, two subsets of NKT cells, type I and type II, play opposing roles and cross-regulate each other. As members of both the innate and adaptive immune systems, which form a network of multiple components, they also interact with other immune components. Here we discuss the function of NKT cells in tumor immunity and their interaction with other regulatory cells, especially CD4+CD25+Foxp3+ regulatory T cells. PMID:24384834

Discrete functions of mTOR signaling in iNKT cell development and NKT17 fate decision

OpenAIRE

Wei, Jun; Yang, Kai; Chi, Hongbo

2014-01-01

Invariant natural killer T (iNKT) cells have been recently classified into NKT1, NKT2 and NKT17 lineages with distinct transcription factor and cytokine profiles, but mechanisms underlying such fate decisions remain elusive. Here, we report crucial roles of mTOR signaling especially mTORC2 in iNKT cell development and fate determination of NKT17 cells. Loss of Rictor, an obligatory component of mTORC2, decreased thymic and peripheral iNKT cells, associated with defective survival. Strikingly,...

The Functions of Type I and Type II Natural Killer T (NKT) Cells in Inflammatory Bowel Diseases

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Liao, Chia-Min; Zimmer, Michael I.; Wang, Chyung-Ru

2013-01-01

CD1d-restricted natural killer T (NKT) cells are a distinct subset of T cells that rapidly produce an array of cytokines upon activation and play a critical role in regulating various immune responses. NKT cells are classified into two groups based on differences in T cell receptor (TCR) usage. Type I NKT cells have an invariant TCRα-chain and are readily detectable by α-galactosylceramide (α-GalCer)-loaded CD1d tetramers. Type II NKT cells have a more diverse TCR repertoire and cannot be directly identified. Both types of NKT cells as well as multiple CD1d-expressing cell types are present in the intestine and their interactions are likely to be modulated by pathogenic and commensal microbes, which in turn contribute to the intestinal immune responses in health and disease. Indeed, in several animal models of inflammatory bowel disease (IBD), Type I NKT cells have been shown to make both protective and pathogenic contributions to disease. In contrast, in human patients suffering from ulcerative colitis (UC), and a mouse model in which both CD1d expression and the frequency of Type II NKT cells are increased, Type II NKT cells appear to promote intestinal inflammation. In this review, we summarize present knowledge on the antigen recognition, activation and function of NKT cells with a particular focus on their role in IBD, and discuss factors that may influence the functional outcome of NKT cell responses in intestinal inflammation. PMID:23518808

Invariant NKT cells and CD1d(+) cells amass in human omentum and are depleted in patients with cancer and obesity.

LENUS (Irish Health Repository)

Lynch, Lydia

2012-02-01

Invariant NKT (iNKT) cells recognize lipid antigens presented by CD1d and respond rapidly by killing tumor cells and release cytokines that activate and regulate adaptive immune responses. They are essential for tumor rejection in various mouse models, but clinical trials in humans involving iNKT cells have been less successful, partly due to their rarity in humans compared with mice. Here we describe an accumulation of functional iNKT cells in human omentum, a migratory organ with healing properties. Analysis of 39 omental samples revealed that T cells are the predominant lymphoid cell type and of these, 10% expressed the invariant Valpha24Jalpha18 TCR chain, found on iNKT cells, higher than in any other human organ tested to date. About 15% of omental hematopoietic cells expressed CD1d, compared with 1% in blood (p<0.001). Enriched omental iNKT cells killed CD1d(+) targets and released IFN-gamma and IL-4 upon activation. Omental iNKT-cell frequencies were lower in patients with severe obesity (p=0.005), and with colorectal carcinoma (p=0.004) compared with lean healthy subjects. These data suggest a novel role for the omentum in immune regulation and tumor immunity and identify it as a potential source of iNKT cells for therapeutic use.

NKT Cell-TCR Expression Activates Conventional T Cells in Vivo, but Is Largely Dispensable for Mature NKT Cell Biology

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Vahl, J. Christoph; Heger, Klaus; Knies, Nathalie; Hein, Marco Y.; Boon, Louis; Yagita, Hideo; Polic, Bojan; Schmidt-Supprian, Marc

2013-01-01

Natural killer T (NKT) cell development depends on recognition of self-glycolipids via their semi-invariant Vα14i-TCR. However, to what extent TCR-mediated signals determine identity and function of mature NKT cells remains incompletely understood. To address this issue, we developed a mouse strain allowing conditional Vα14i-TCR expression from within the endogenous Tcrα locus. We demonstrate that naïve T cells are activated upon replacement of their endogenous TCR repertoire with Vα14i-restricted TCRs, but they do not differentiate into NKT cells. On the other hand, induced TCR ablation on mature NKT cells did not affect their lineage identity, homeostasis, or innate rapid cytokine secretion abilities. We therefore propose that peripheral NKT cells become unresponsive to and thus are independent of their autoreactive TCR. PMID:23853545

NKT cell-TCR expression activates conventional T cells in vivo, but is largely dispensable for mature NKT cell biology.

Directory of Open Access Journals (Sweden)

J Christoph Vahl

Full Text Available Natural killer T (NKT cell development depends on recognition of self-glycolipids via their semi-invariant Vα14i-TCR. However, to what extent TCR-mediated signals determine identity and function of mature NKT cells remains incompletely understood. To address this issue, we developed a mouse strain allowing conditional Vα14i-TCR expression from within the endogenous Tcrα locus. We demonstrate that naïve T cells are activated upon replacement of their endogenous TCR repertoire with Vα14i-restricted TCRs, but they do not differentiate into NKT cells. On the other hand, induced TCR ablation on mature NKT cells did not affect their lineage identity, homeostasis, or innate rapid cytokine secretion abilities. We therefore propose that peripheral NKT cells become unresponsive to and thus are independent of their autoreactive TCR.

Co-administration of α-GalCer analog and TLR4 agonist induces robust CD8+ T-cell responses to PyCS protein and WT-1 antigen and activates memory-like effector NKT cells

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Coelho-dos-Reis, Jordana G.; Huang, Jing; Tsao, Tiffany; Pereira, Felipe V.; Funakoshi, Ryota; Nakajima, Hiroko; Sugiyama, Haruo; Tsuji, Moriya

2016-01-01

In the present study, the combined adjuvant effect of 7DW8-5, a potent α-GalCer-analog, and monophosphoryl lipid A (MPLA), a TLR4 agonist, on the induction of vaccine-induced CD8+ T-cell responses and protective immunity was evaluated. Mice were immunized with peptides corresponding to the CD8+ T-cell epitopes of a malaria antigen, a circumsporozoite protein of Plasmodium yoelii, and a tumor antigen, a Wilms Tumor antigen-1 (WT-1), together with 7DW8-5 and MPLA, as an adjuvant. These immunization regimens were able to induce higher levels of CD8+ T-cell responses and, ultimately, enhanced levels of protection against malaria and tumor challenges compared to the levels induced by immunization with peptides mixed with 7DW8-5 or MPLA alone. Co-administration of 7DW8-5 and MPLA induces activation of memory-like effector natural killer T (NKT) cells, i.e. CD44+CD62L−NKT cells. Our study indicates that 7DW8-5 greatly enhances important synergistic pathways associated to memory immune responses when co-administered with MPLA, thus rendering this combination of adjuvants a novel vaccine adjuvant formulation. PMID:27132023

Dynamics of NKT-Cell Responses to Chlamydial Infection.

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Shekhar, Sudhanshu; Joyee, Antony George; Yang, Xi

2015-01-01

Natural killer T (NKT) cells have gained great attention owing to their critical functional roles in immunity to various pathogens. In this review, we provide an overview of the current knowledge on the role of NKT cells in host defense against and pathogenesis due to Chlamydia, which is an intracellular bacterial pathogen that poses a threat to the public health worldwide. Accumulating evidence has demonstrated that NKT cells, particularly invariant NKT (iNKT) cells, play a crucial role in host defense against chlamydial infections, especially in C. pneumoniae infection. iNKT cells can promote type-1 protective responses to C. pneumoniae by inducing enhanced production of IL-12 by dendritic cells (DCs), in particular CD8α+ DCs, which promote the differentiation of naive T cells into protective IFN-γ-producing Th1/Tc1 type CD4+/CD8+ T cells. This iNKT-cell-mediated modulation of DC function is largely dependent upon CD40-CD40L interaction, IFN-γ production, and cell-to-cell contact. In addition, iNKT cells modulate the function of natural killer cells. NKT cells may be also involved in the pathogenesis of some chlamydial diseases by inducing different patterns of cytokine production. A better understanding of NKT-cell biology will enable us to rationally design prophylactic and therapeutic tools to combat infectious diseases.

Invariant NKT cells: regulation and function during viral infection.

Directory of Open Access Journals (Sweden)

Jennifer A Juno

Full Text Available Natural killer T cells (NKT cells represent a subset of T lymphocytes that express natural killer (NK cell surface markers. A subset of NKT cells, termed invariant NKT cells (iNKT, express a highly restricted T cell receptor (TCR and respond to CD1d-restricted lipid ligands. iNKT cells are now appreciated to play an important role in linking innate and adaptive immune responses and have been implicated in infectious disease, allergy, asthma, autoimmunity, and tumor surveillance. Advances in iNKT identification and purification have allowed for the detailed study of iNKT activity in both humans and mice during a variety of chronic and acute infections. Comparison of iNKT function between non-pathogenic simian immunodeficiency virus (SIV infection models and chronic HIV-infected patients implies a role for iNKT activity in controlling immune activation. In vitro studies of influenza infection have revealed novel effector functions of iNKT cells including IL-22 production and modulation of myeloid-derived suppressor cells, but ex vivo characterization of human iNKT cells during influenza infection are lacking. Similarly, as recent evidence suggests iNKT involvement in dengue virus pathogenesis, iNKT cells may modulate responses to a number of emerging pathogens. This Review will summarize current knowledge of iNKT involvement in responses to viral infections in both human and mouse models and will identify critical gaps in knowledge and opportunities for future study. We will also highlight recent efforts to harness iNKT ligands as vaccine adjuvants capable of improving vaccination-induced cellular immune responses.

CD1d-unrestricted NKT cells are endowed with a hybrid function far superior than that of iNKT cells.

Science.gov (United States)

Farr, Alexander R; Wu, Weisheng; Choi, Bongkum; Cavalcoli, James D; Laouar, Yasmina

2014-09-02

Invariant natural killer T (iNKT) cells to date represent the best example of cells known to have a hybrid function, representing both innate and adaptive immunity. Shared phenotypic similarities with NK cells together with a rapid response to a cytokine stimulus and a productive TCR engagement are the features that underline the hybrid nature of iNKT cells. Using these criteria, we provide molecular and functional evidence demonstrating that CD1d-independent (CD1d(ind)) NKT cells, a population of CD1d-unrestricted NKT cells, are endowed with a hybrid function far superior to that of iNKT cells: (i) an extensive shared program with NK cells, (ii) a closer Euclidian distance with NK cells, and (iii) the ability to respond to innate stimuli (Poly:IC) with cytotoxic potential in the same manner as NK cells identify a hybrid feature in CD1d(ind)NKT cells that truly fulfills the dual function of an NK and a T cell. Our finding that CD1d(ind)NKT cells are programmed to act like NK cells in response to innate signals while being capable of adaptive responses is unprecedented, and thus might reemphasize CD1d-unrestricted NKT cells as a subset of lymphocytes that could affect biological processes of antimicrobial and tumor immunity in a unique way.

Extracellular adenosine controls NKT-cell-dependent hepatitis induction.

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Subramanian, Meenakshi; Kini, Radhika; Madasu, Manasa; Ohta, Akiko; Nowak, Michael; Exley, Mark; Sitkovsky, Michail; Ohta, Akio

2014-04-01

Extracellular adenosine regulates inflammatory responses via the A2A adenosine receptor (A2AR). A2AR deficiency results in much exaggerated acute hepatitis, indicating nonredundancy of adenosine-A2AR pathway in inhibiting immune activation. To identify a critical target of immunoregulatory effect of extracellular adenosine, we focused on NKT cells, which play an indispensable role in hepatitis. An A2AR agonist abolished NKT-cell-dependent induction of acute hepatitis by concanavalin A (Con A) or α-galactosylceramide in mice, corresponding to downregulation of activation markers and cytokines in NKT cells and of NK-cell co-activation. These results show that A2AR signaling can downregulate NKT-cell activation and suppress NKT-cell-triggered inflammatory responses. Next, we hypothesized that NKT cells might be under physiological control of the adenosine-A2AR pathway. Indeed, both Con A and α-galactosylceramide induced more severe hepatitis in A2AR-deficient mice than in WT controls. Transfer of A2AR-deficient NKT cells into A2AR-expressing recipients resulted in exaggeration of Con A-induced liver damage, suggesting that NKT-cell activation is controlled by endogenous adenosine via A2AR, and this physiological regulatory mechanism of NKT cells is critical in the control of tissue-damaging inflammation. The current study suggests the possibility to manipulate NKT-cell activity in inflammatory disorders through intervention to the adenosine-A2AR pathway. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Immunoregulation of NKT Cells in Systemic Lupus Erythematosus.

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Chen, Junwei; Wu, Meng; Wang, Jing; Li, Xiaofeng

2015-01-01

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease with different variety of clinical manifestations. Natural killer T (NKT) cells are innate lymphocytes that play a regulatory role during broad range of immune responses. A number of studies demonstrated that the quantity and quality of invariant NKT (iNKT) cells showed marked defects in SLE patients in comparison to healthy controls. This finding suggests that iNKT cells may play a regulatory role in the occurrence and development of this disease. In this review, we mainly summarized the most recent findings about the behavior of NKT cells in SLE patients and mouse models, as well as how NKT cells affect the proportion of T helper cells and the production of autoreactive antibodies in the progress of SLE. This will help people better understand the role of NKT cells in the development of SLE and improve the therapy strategy.

Zbtb7b (Th-POK) regulates the development of IL-17 producing CD1d-restricted mouse NKT-cells

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Enders, Anselm; Stankovic, Sanda; Teh, Charis; Uldrich, Adam P.; Yabas, Mehmet; Juelich, Torsten; Altin, John A.; Frankenreiter, Sandra; Bergmann, Hannes; Roots, Carla M.; Kyparissoudis, Konstantinos; Goodnow, Chris C.; Godfrey, Dale I.

2012-01-01

CD1d-dependent NKT-cells represent a heterogeneous family of effector T-cells including CD4+CD8− and CD4−CD8− subsets, that respond to glycolipid antigens with rapid and potent cytokine production. NKT-cell development is regulated by a unique combination of factors, however very little is known about factors that control the development of NKT subsets. Here, we analyze a novel mouse strain (helpless) with a mis-sense mutation in the BTB-POZ domain of Zbtb7b and demonstrate that this mutation has dramatic, intrinsic effects on development of NKT-cell subsets. Although NKT-cell numbers are similar in Zbtb7b mutant mice, these cells are hyperproliferative and most lack CD4 and instead express CD8. Moreover, the majority of Zbtb7b mutant NKT-cells in the thymus are RORγt+ and a high frequency produce IL-17 while very few produce IFN-γ or other cytokines, sharply contrasting the profile of normal NKT-cells. Mice heterozygous for the helpless mutation also have reduced numbers of CD4+ NKT-cells and increased production of IL-17 without an increase in CD8+ cells, suggesting that Zbtb7b acts at multiple stages of NKT-cell development. These results reveal Zbtb7b as a critical factor genetically pre-determining the balance of effector subsets within the NKT-cell population. PMID:23105140

Peptide-Conjugated Nanoparticles Reduce Positive Co-stimulatory Expression and T Cell Activity to Induce Tolerance.

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Kuo, Robert; Saito, Eiji; Miller, Stephen D; Shea, Lonnie D

2017-07-05

Targeted approaches to treat autoimmune diseases would improve upon current therapies that broadly suppress the immune system and lead to detrimental side effects. Antigen-specific tolerance was induced using poly(lactide-co-glycolide) nanoparticles conjugated with disease-relevant antigen to treat a model of multiple sclerosis. Increasing the nanoparticle dose and amount of conjugated antigen both resulted in more durable immune tolerance. To identify active tolerance mechanisms, we investigated downstream cellular and molecular events following nanoparticle internalization by antigen-presenting cells. The initial cell response to nanoparticles indicated suppression of inflammatory signaling pathways. Direct and functional measurement of surface MHC-restricted antigen showed positive correlation with both increasing particle dose from 1 to 100 μg/mL and increasing peptide conjugation by 2-fold. Co-stimulatory analysis of cells expressing MHC-restricted antigen revealed most significant decreases in positive co-stimulatory molecules (CD86, CD80, and CD40) following high doses of nanoparticles with higher peptide conjugation, whereas expression of a negative co-stimulatory molecule (PD-L1) remained high. T cells isolated from mice immunized against myelin proteolipid protein (PLP 139-151 ) were co-cultured with antigen-presenting cells administered PLP 139-151 -conjugated nanoparticles, which resulted in reduced T cell proliferation, increased T cell apoptosis, and a stronger anti-inflammatory response. These findings indicate several potential mechanisms used by peptide-conjugated nanoparticles to induce antigen-specific tolerance. Copyright © 2017 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.

Cross-activating invariant NKT cells and kupffer cells suppress cholestatic liver injury in a mouse model of biliary obstruction.

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Caroline C Duwaerts

Full Text Available Both Kupffer cells and invariant natural killer T (iNKT cells suppress neutrophil-dependent liver injury in a mouse model of biliary obstruction. We hypothesize that these roles are interdependent and require iNKT cell-Kupffer cell cross-activation. Female, wild-type and iNKT cell-deficient C57Bl/6 mice were injected with magnetic beads 3 days prior to bile duct ligation (BDL in order to facilitate subsequent Kupffer cell isolation. On day three post-BDL, the animals were euthanized and the livers dissected. Necrosis was scored; Kupffer cells were isolated and cell surface marker expression (flow cytometry, mRNA expression (qtPCR, nitric oxide (NO (. production (Griess reaction, and protein secretion (cytometric bead-array or ELISAs were determined. To address the potential role of NO (. in suppressing neutrophil accumulation, a group of WT mice received 1400W, a specific inducible nitric oxide synthase (iNOS inhibitor, prior to BDL. To clarify the mechanisms underlying Kupffer cell-iNKT cell cross-activation, WT animals were administered anti-IFN-γ or anti-lymphocyte function-associated antigen (LFA-1 antibody prior to BDL. Compared to their WT counterparts, Kupffer cells obtained from BDL iNKT cell-deficient mice expressed lower iNOS mRNA levels, produced less NO (. , and secreted more neutrophil chemoattractants. Both iNOS inhibition and IFN-γ neutralization increased neutrophil accumulation in the livers of BDL WT mice. Anti-LFA-1 pre-treatment reduced iNKT cell accumulation in these same animals. These data indicate that the LFA-1-dependent cross-activation of iNKT cells and Kupffer cells inhibits neutrophil accumulation and cholestatic liver injury.

NKT cell depletion in humans during early HIV infection.

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Fernandez, Caroline S; Kelleher, Anthony D; Finlayson, Robert; Godfrey, Dale I; Kent, Stephen J

2014-08-01

Natural killer T (NKT) cells bridge across innate and adaptive immune responses and have an important role in chronic viral infections such as human immunodeficiency virus (HIV). NKT cells are depleted during chronic HIV infection, but the timing, drivers and implications of this NKT cell depletion are poorly understood. We studied human peripheral blood NKT cell levels, phenotype and function in 31 HIV-infected subjects not on antiretroviral treatment from a mean of 4 months to 2 years after HIV infection. We found that peripheral CD4(+) NKT cells were substantially depleted and dysfunctional by 4 months after HIV infection. The depletion of CD4(+) NKT cells was more marked than the depletion of total CD4(+) T cells. Further, the early depletion of NKT cells correlated with CD4(+) T-cell decline, but not HIV viral levels. Levels of activated CD4(+) T cells correlated with the loss of NKT cells. Our studies suggest that the early loss of NKT cells is associated with subsequent immune destruction during HIV infection.

Co-administration of α-GalCer analog and TLR4 agonist induces robust CD8(+) T-cell responses to PyCS protein and WT-1 antigen and activates memory-like effector NKT cells.

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Coelho-Dos-Reis, Jordana G; Huang, Jing; Tsao, Tiffany; Pereira, Felipe V; Funakoshi, Ryota; Nakajima, Hiroko; Sugiyama, Haruo; Tsuji, Moriya

2016-07-01

In the present study, the combined adjuvant effect of 7DW8-5, a potent α-GalCer-analog, and monophosphoryl lipid A (MPLA), a TLR4 agonist, on the induction of vaccine-induced CD8(+) T-cell responses and protective immunity was evaluated. Mice were immunized with peptides corresponding to the CD8(+) T-cell epitopes of a malaria antigen, a circumsporozoite protein of Plasmodium yoelii, and a tumor antigen, a Wilms Tumor antigen-1 (WT-1), together with 7DW8-5 and MPLA, as an adjuvant. These immunization regimens were able to induce higher levels of CD8(+) T-cell responses and, ultimately, enhanced levels of protection against malaria and tumor challenges compared to the levels induced by immunization with peptides mixed with 7DW8-5 or MPLA alone. Co-administration of 7DW8-5 and MPLA induces activation of memory-like effector natural killer T (NKT) cells, i.e. CD44(+)CD62L(-)NKT cells. Our study indicates that 7DW8-5 greatly enhances important synergistic pathways associated to memory immune responses when co-administered with MPLA, thus rendering this combination of adjuvants a novel vaccine adjuvant formulation. Copyright © 2016 Elsevier Inc. All rights reserved.

Sulfatide-activated type II NKT cells prevent allergic airway inflammation by inhibiting type I NKT cell function in a mouse model of asthma.

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Zhang, Guqin; Nie, Hanxiang; Yang, Jiong; Ding, Xuhong; Huang, Yi; Yu, Hongying; Li, Ruyou; Yuan, Zhuqing; Hu, Suping

2011-12-01

Asthma is a common chronic inflammatory disease involving many different cell types. Recently, type I natural killer T (NKT) cells have been demonstrated to play a crucial role in the development of asthma. However, the roles of type II NKT cells in asthma have not been investigated before. Interestingly, type I and type II NKT cells have been shown to have opposing roles in antitumor immunity, antiparasite immunity, and autoimmunity. We hypothesized that sulfatide-activated type II NKT cells could prevent allergic airway inflammation by inhibiting type I NKT cell function in asthma. Strikingly, in our mouse model, activation of type II NKT cells by sulfatide administration and adoptive transfer of sulfatide-activated type II NKT cells result in reduced-inflammation cell infiltration in the lung and bronchoalveolar lavage fluid, decreased levels of IL-4 and IL-5 in the BALF; and decreased serum levels of ovalbumin-specific IgE and IgG1. Furthermore, it is found that the activation of sulfatide-reactive type II NKT cells leads to the functional inactivation of type I NKT cells, including the proliferation and cytokine secretion. Our data reveal that type II NKT cells activated by glycolipids, such as sulfatide, may serve as a novel approach to treat allergic diseases and other disorders characterized by inappropriate type I NKT cell activation.

Chronic alcohol consumption enhances iNKT cell maturation and activation

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Zhang, Hui, E-mail: hzhang@wsu.edu; Zhang, Faya; Zhu, Zhaohui; Luong, Dung; Meadows, Gary G.

2015-01-15

Alcohol consumption exhibits diverse effects on different types of immune cells. NKT cells are a unique T cell population and play important immunoregulatory roles in different types of immune responses. The effects of chronic alcohol consumption on NKT cells remain to be elucidated. Using a mouse model of chronic alcohol consumption, we found that alcohol increases the percentage of NKT cells, especially iNKT cells in the thymus and liver, but not in the spleen or blood. Alcohol consumption decreases the percentage of NK1.1{sup −} iNKT cells in the total iNKT cell population in all of the tissues and organs examined. In the thymus, alcohol consumption increases the number of NK1.1{sup +}CD44{sup hi} mature iNKT cells but does not alter the number of NK1.1{sup −} immature iNKT cells. A BrdU incorporation assay shows that alcohol consumption increases the proliferation of thymic NK1.1{sup −} iNKT cells, especially the NK1.1{sup −}CD44{sup lo} Stage I iNKT cells. The percentage of NKG2A{sup +} iNKT cells increases in all of the tissues and organs examined; whereas CXCR3{sup +} iNKT cells only increases in the thymus of alcohol-consuming mice. Chronic alcohol consumption increases the percentage of IFN-γ-producing iNKT cells and increases the blood concentration of IFN-γ and IL-12 after in vivo α-galactosylceramide (αGalCer) stimulation. Consistent with the increased cytokine production, the in vivo activation of iNKT cells also enhances the activation of dendritic cells (DC) and NK, B, and T cells in the alcohol-consuming mice. Taken together the data indicate that chronic alcohol consumption enhances iNKT cell maturation and activation, which favors the Th1 immune response. - Highlights: • Chronic alcohol consumption increases iNKT cells in the thymus and liver • Chronic alcohol consumption enhances thymic Stage I iNKT cell proliferation • Chronic alcohol consumption enhances iNKT cell maturation in thymus and periphery • Chronic alcohol

Chronic alcohol consumption enhances iNKT cell maturation and activation

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Zhang, Hui; Zhang, Faya; Zhu, Zhaohui; Luong, Dung; Meadows, Gary G.

2015-01-01

Alcohol consumption exhibits diverse effects on different types of immune cells. NKT cells are a unique T cell population and play important immunoregulatory roles in different types of immune responses. The effects of chronic alcohol consumption on NKT cells remain to be elucidated. Using a mouse model of chronic alcohol consumption, we found that alcohol increases the percentage of NKT cells, especially iNKT cells in the thymus and liver, but not in the spleen or blood. Alcohol consumption decreases the percentage of NK1.1 − iNKT cells in the total iNKT cell population in all of the tissues and organs examined. In the thymus, alcohol consumption increases the number of NK1.1 + CD44 hi mature iNKT cells but does not alter the number of NK1.1 − immature iNKT cells. A BrdU incorporation assay shows that alcohol consumption increases the proliferation of thymic NK1.1 − iNKT cells, especially the NK1.1 − CD44 lo Stage I iNKT cells. The percentage of NKG2A + iNKT cells increases in all of the tissues and organs examined; whereas CXCR3 + iNKT cells only increases in the thymus of alcohol-consuming mice. Chronic alcohol consumption increases the percentage of IFN-γ-producing iNKT cells and increases the blood concentration of IFN-γ and IL-12 after in vivo α-galactosylceramide (αGalCer) stimulation. Consistent with the increased cytokine production, the in vivo activation of iNKT cells also enhances the activation of dendritic cells (DC) and NK, B, and T cells in the alcohol-consuming mice. Taken together the data indicate that chronic alcohol consumption enhances iNKT cell maturation and activation, which favors the Th1 immune response. - Highlights: • Chronic alcohol consumption increases iNKT cells in the thymus and liver • Chronic alcohol consumption enhances thymic Stage I iNKT cell proliferation • Chronic alcohol consumption enhances iNKT cell maturation in thymus and periphery • Chronic alcohol consumption induces Th1 immune response upon iNKT

Natural killer T (NKT cells accelerate Shiga toxin type 2 (Stx2 pathology in mice

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Fumiko eObata

2015-04-01

Full Text Available Shiga toxin-producing Escherichia coli (STEC is a leading cause of childhood renal disease He-molytic Uremic Syndrome (HUS. The involvement of renal cytokines and chemokines is sus-pected to play a critical role in disease progression. In current article, we tested the hypothesis that NKT cells are involved in Stx2-induced pathology in vivo. To address this hypothesis we compared Stx2 toxicity in WT and CD1 knockout (KO mice. In CD1KO mice, which lack nat-ural killer T (NKT cells, Stx2-induced pathologies such as weight loss, renal failure, and death were delayed. In WT mice, Stx2-specific selective increase in urinary albumin occurs in later time points, and this was also delayed in NKT cell deficient mice. NKT cell-associated cytokines such as IL-2, IL-4, IFN-γ and IL-17 were detected in kidney lysates of Stx2-injected WT mice with the peak around 36 h after Stx2 injection. In CD1KO, there was a delay in the kinetics, and increases in these cytokines were observed 60 h post Stx2 injection. These data suggest that NKT cells accelerate Stx2-induced pathology in mouse kidneys. To determine the mechanism by which NKT cells promote Stx2-associated disease, in vitro studies were performed using murine renal cells. We found that murine glomerular endothelial cells and podocytes express functional CD1d molecules and can present exogenous antigen to NKT cells. Moreover, we observed the direct interaction between Stx2 and the receptor Gb3 on the surface of mouse renal cells by 3D STORM-TIRF which provides single molecule imaging. Collectively, these data suggest that Stx2 binds to Gb3 on renal cells and leads to aberrant CD1d-mediated NKT cell activation. Therefore, strategies targeting NKT cells could have a significant impact on Stx2-associated renal pathology in STEC disease.

Natural killer T (NKT) cells accelerate Shiga toxin type 2 (Stx2) pathology in mice.

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Obata, Fumiko; Subrahmanyam, Priyanka B; Vozenilek, Aimee E; Hippler, Lauren M; Jeffers, Tynae; Tongsuk, Methinee; Tiper, Irina; Saha, Progyaparamita; Jandhyala, Dakshina M; Kolling, Glynis L; Latinovic, Olga; Webb, Tonya J

2015-01-01

Shiga toxin-producing Escherichia coli (STEC) is a leading cause of childhood renal disease Hemolytic Uremic Syndrome (HUS). The involvement of renal cytokines and chemokines is suspected to play a critical role in disease progression. In current article, we tested the hypothesis that NKT cells are involved in Stx2-induced pathology in vivo. To address this hypothesis we compared Stx2 toxicity in WT and CD1 knockout (KO) mice. In CD1KO mice, which lack natural killer T (NKT) cells, Stx2-induced pathologies such as weight loss, renal failure, and death were delayed. In WT mice, Stx2-specific selective increase in urinary albumin occurs in later time points, and this was also delayed in NKT cell deficient mice. NKT cell-associated cytokines such as IL-2, IL-4, IFN-γ, and IL-17 were detected in kidney lysates of Stx2-injected WT mice with the peak around 36 h after Stx2 injection. In CD1KO, there was a delay in the kinetics, and increases in these cytokines were observed 60 h post Stx2 injection. These data suggest that NKT cells accelerate Stx2-induced pathology in mouse kidneys. To determine the mechanism by which NKT cells promote Stx2-associated disease, in vitro studies were performed using murine renal cells. We found that murine glomerular endothelial cells and podocytes express functional CD1d molecules and can present exogenous antigen to NKT cells. Moreover, we observed the direct interaction between Stx2 and the receptor Gb3 on the surface of mouse renal cells by 3D STORM-TIRF which provides single molecule imaging. Collectively, these data suggest that Stx2 binds to Gb3 on renal cells and leads to aberrant CD1d-mediated NKT cell activation. Therefore, strategies targeting NKT cells could have a significant impact on Stx2-associated renal pathology in STEC disease.

Choline Deficiency Causes Colonic Type II Natural Killer T (NKT) Cell Loss and Alleviates Murine Colitis under Type I NKT Cell Deficiency.

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Sagami, Shintaro; Ueno, Yoshitaka; Tanaka, Shinji; Fujita, Akira; Niitsu, Hiroaki; Hayashi, Ryohei; Hyogo, Hideyuki; Hinoi, Takao; Kitadai, Yasuhiko; Chayama, Kazuaki

2017-01-01

Serum levels of choline and its derivatives are lower in patients with inflammatory bowel disease (IBD) than in healthy individuals. However, the effect of choline deficiency on the severity of colitis has not been investigated. In the present study, we investigated the role of choline deficiency in dextran sulfate sodium (DSS)-induced colitis in mice. Methionine-choline-deficient (MCD) diet lowered the levels of type II natural killer T (NKT) cells in the colonic lamina propria, peritoneal cavity, and mesenteric lymph nodes, and increased the levels of type II NKT cells in the livers of wild-type B6 mice compared with that in mice fed a control (CTR) diet. The gene expression pattern of the chemokine receptor CXCR6, which promotes NKT cell accumulation, varied between colon and liver in a manner dependent on the changes in the type II NKT cell levels. To examine the role of type II NKT cells in colitis under choline-deficient conditions, we assessed the severity of DSS-induced colitis in type I NKT cell-deficient (Jα18-/-) or type I and type II NKT cell-deficient (CD1d-/-) mice fed the MCD or CTR diets. The MCD diet led to amelioration of inflammation, decreases in interferon (IFN)-γ and interleukin (IL)-4 secretion, and a decrease in the number of IFN-γ and IL-4-producing NKT cells in Jα18-/- mice but not in CD1d-/- mice. Finally, adaptive transfer of lymphocytes with type II NKT cells exacerbated DSS-induced colitis in Jα18-/- mice with MCD diet. These results suggest that choline deficiency causes proinflammatory type II NKT cell loss and alleviates DSS-induced colitis. Thus, inflammation in DSS-induced colitis under choline deficiency is caused by type II NKT cell-dependent mechanisms, including decreased type II NKT cell and proinflammatory cytokine levels.

Bacillus anthracis lethal toxin disrupts TCR signaling in CD1d-restricted NKT cells leading to functional anergy.

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Sunil K Joshi

2009-09-01

Full Text Available Exogenous CD1d-binding glycolipid (alpha-Galactosylceramide, alpha-GC stimulates TCR signaling and activation of type-1 natural killer-like T (NKT cells. Activated NKT cells play a central role in the regulation of adaptive and protective immune responses against pathogens and tumors. In the present study, we tested the effect of Bacillus anthracis lethal toxin (LT on NKT cells both in vivo and in vitro. LT is a binary toxin known to suppress host immune responses during anthrax disease and intoxicates cells by protective antigen (PA-mediated intracellular delivery of lethal factor (LF, a potent metalloprotease. We observed that NKT cells expressed anthrax toxin receptors (CMG-2 and TEM-8 and bound more PA than other immune cell types. A sub-lethal dose of LT administered in vivo in C57BL/6 mice decreased expression of the activation receptor NKG2D by NKT cells but not by NK cells. The in vivo administration of LT led to decreased TCR-induced cytokine secretion but did not affect TCR expression. Further analysis revealed LT-dependent inhibition of TCR-stimulated MAP kinase signaling in NKT cells attributable to LT cleavage of the MAP kinase kinase MEK-2. We propose that Bacillus anthracis-derived LT causes a novel form of functional anergy in NKT cells and therefore has potential for contributing to immune evasion by the pathogen.

TNF-α production in NKT cell hybridoma is regulated by sphingosine-1-phosphate: implications for inflammation in atherosclerosis.

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Ito, Shiori; Iwaki, Soichiro; Kondo, Rie; Satoh, Masashi; Iwabuchi, Kazuya; Ohkawa, Ryunosuke; Mishima, Yuko; Yatomi, Yutaka; Furumoto, Tomoo; Tsutsui, Hiroyuki; Fujii, Satoshi

2014-06-01

Natural killer T (NKT) cells are unique T lymphocytes that recognize glycolipid antigen and produce various cytokines. NKT cells accelerate atherosclerosis in mice. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid and regulates T-lymphocyte trafficking. We aimed to determine the effects of S1P on the production of proinflammatory cytokine, tumor necrosis factor (TNF)-α, in NKT cell hybridomas and mouse NKT cells. NKT cell hybridomas and sorted mouse NKT cells were stimulated with S1P and α-galactosylceramide (α-GalCer), the major ligand to produce cytokines in NKT cells. TNF-α mRNA expression and protein production were determined by real-time PCR and ELISA, respectively. Cell migration was assayed using chemotaxicell. Plasma S1P was measured using HPLC. Hybridomas expressed S1P receptors, S1P1, S1P2, and S1P4. S1P and α-GalCer increased TNF-α mRNA expression and protein production. S1P enhanced TNF-α induction by α-GalCer. S1P receptor antagonists decreased the TNF-α mRNA expression induced by S1P. FTY720, an immunosuppressive S1P receptor modulator, also decreased the TNF-α mRNA expression. The migration of NKT cell hybridomas was increased by S1P. FTY720 reduced the migration induced by S1P. S1P also increased the TNF-α mRNA expression in mouse NKT cells. Plasma TNF-α levels in patients with high plasma S1P (≥500 nmol/l) were higher than those in patients with low S1P (NKT cells and enhances TNF-α production. TNF-α overproduction may induce atherogenic inflammatory responses. S1P may serve as a novel therapeutic target for amelioration of vascular inflammatory diseases.

The percentage of iNKT cells among other immune cells at various clinical stages of laryngeal cancer

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Janusz Klatka

2016-04-01

Full Text Available Introduction: Invariant natural killer T (iNKT cells constitute a small population of immune cells that share functional and phenotypic characteristics of T lymphocytes and NK cells. Due to their involvement in specific and non-specific immune responses, iNKT cells may represent an important component of antitumor and anti-infectious immunity. Material and methods: Using flow cytometry, we analyzed the percentages of iNKT cells as well as T and B lymphocytes in peripheral blood of 50 laryngeal cancer patients at various clinical stages in comparison to healthy controls (n=15. Moreover, we determined the expression of CD25, CD69 and CD95 antigens on T lymphocytes.Results: The percentage of CD4+/CD3+ T lymphocytes in the controls was higher than in laryngeal cancer patients, both with early and late stages of the disease. The percentage of CD8+/CD3+ T lymphocytes in healthy controls was lower than in patients with early and late clinical stages of laryngeal cancer. Patients with advanced laryngeal cancer showed a lower percentage of iNKT cells and higher frequencies of T regulatory cells (Tregs than the controls. Advanced clinical stages of laryngeal cancer are associated with impaired activation of lymphocytes.Conclusions: Our study confirmed that laryngeal cancer cells exert a strong suppressor effect on the immune system of the host. This is reflected by a decrease in the percentage of iNKT cells that are capable of cancer cell elimination, and a concomitant increase in the percentage of Tregs. However, further studies are needed in order to explain the underlying mechanisms of immunosuppression and understand interactions between immune and cancer cells.

Activated NKT cells imprint NK-cell differentiation, functionality and education.

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Riese, Peggy; Trittel, Stephanie; May, Tobias; Cicin-Sain, Luka; Chambers, Benedict J; Guzmán, Carlos A

2015-06-01

NK cells represent a vital component of the innate immune system. The recent discoveries demonstrating that the functionality of NK cells depends on their differentiation and education status underscore their potential as targets for immune intervention. However, to exploit their full potential, a detailed understanding of the cellular interactions involved in these processes is required. In this regard, the cross-talk between NKT cells and NK cells needs to be better understood. Our results provide strong evidence for NKT cell-induced effects on key biological features of NK cells. NKT-cell activation results in the generation of highly active CD27(high) NK cells with improved functionality. In this context, degranulation activity and IFNγ production were mainly detected in the educated subset. In a mCMV infection model, we also demonstrated that NKT-cell stimulation induced the generation of highly functional educated and uneducated NK cells, crucial players in viral control. Thus, our findings reveal new fundamental aspects of the NKT-NK cell axis that provide important hints for the manipulation of NK cells in clinical settings. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

NKT cells contribute to basal IL-4 production but are not required to induce experimental asthma.

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McKnight, Christopher G; Morris, Suzanne C; Perkins, Charles; Zhu, Zhenqi; Hildeman, David A; Bendelac, Albert; Finkelman, Fred D

2017-01-01

CD1d-deficiency results in a selective deletion of NKT cells in mice that is reported to prevent murine allergic airway disease (AAD). Because we find 2-3 fold lower basal IL-4 production in CD1d- mice than in wild-type (WT) mice, we hypothesized that the contribution made by NKT cells to AAD would depend on the strength of the stimulus used to induce the disease. Consequently, we compared CD1d-deficient mice to WT mice in the development of AAD, using several models of disease induction that differed in the type and dose of allergen, the site of sensitization and the duration of immunization. Surprisingly we found equivalent allergic inflammation and airway disease in WT and CD1d- mice in all models investigated. Consistent with this, NKT cells constituted only ~2% of CD4+ T cells in the lungs of mice with AAD, and IL-4-transcribing NKT cells did not expand with disease induction. Concerned that the congenital absence of NKT cells might have caused a compensatory shift within the immune response, we administered an anti-CD1d monoclonal Ab (mAb) to block NKT function before airway treatments, before or after systemic sensitization to antigen. Such Ab treatment did not affect disease severity. We suggest that the differences reported in the literature regarding the significance of NKT cells in the induction of allergic airway disease may have less to do with the methods used to study the disease and more to do with the animals themselves and/or the facilities used to house them.

NKT cells contribute to basal IL-4 production but are not required to induce experimental asthma.

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Christopher G McKnight

Full Text Available CD1d-deficiency results in a selective deletion of NKT cells in mice that is reported to prevent murine allergic airway disease (AAD. Because we find 2-3 fold lower basal IL-4 production in CD1d- mice than in wild-type (WT mice, we hypothesized that the contribution made by NKT cells to AAD would depend on the strength of the stimulus used to induce the disease. Consequently, we compared CD1d-deficient mice to WT mice in the development of AAD, using several models of disease induction that differed in the type and dose of allergen, the site of sensitization and the duration of immunization. Surprisingly we found equivalent allergic inflammation and airway disease in WT and CD1d- mice in all models investigated. Consistent with this, NKT cells constituted only ~2% of CD4+ T cells in the lungs of mice with AAD, and IL-4-transcribing NKT cells did not expand with disease induction. Concerned that the congenital absence of NKT cells might have caused a compensatory shift within the immune response, we administered an anti-CD1d monoclonal Ab (mAb to block NKT function before airway treatments, before or after systemic sensitization to antigen. Such Ab treatment did not affect disease severity. We suggest that the differences reported in the literature regarding the significance of NKT cells in the induction of allergic airway disease may have less to do with the methods used to study the disease and more to do with the animals themselves and/or the facilities used to house them.

Differential pulmonic NK and NKT cell responses in Schistosoma japonicum-infected mice.

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Cha, Hefei; Qin, Wenjuan; Yang, Quan; Xie, Hongyan; Qu, Jiale; Wang, Mei; Chen, Daixiong; Wang, Fang; Dong, Nuo; Chen, Longhua; Huang, Jun

2017-02-01

Natural killer cells (NK cells) and natural killer T cells (NKT cells) play a role in anti-infection, anti-tumor, transplantation immunity, and autoimmune regulation. However, the role of NK and NKT cells during Schistosoma japonicum (S. japonicum) infection has not been widely reported, especially regarding lung infections. The aim of this study was to research the NK and NKT cell response to S. japonicum infection in the lungs of mice. Using immunofluorescent histological analysis, NK and NKT cells were found near pulmonary granulomas. Moreover, flow cytometry revealed that the percentage and number of pulmonic NK cells in S. japonicum-infected mice were significantly increased (P cell number of NKT cells were decreased compared to those of normal mice (P NKT cells was increased after infection (P NKT cells (P cells (P NKT cells significantly increased (P NKT cells (P NKT cell activation during S. japonicum infection.

Invariant NKT cells as novel targets for immunotherapy in solid tumors.

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Pilones, Karsten A; Aryankalayil, Joseph; Demaria, Sandra

2012-01-01

Natural killer T (NKT) cells are a small population of lymphocytes that possess characteristics of both innate and adaptive immune cells. They are uniquely poised to respond rapidly to infection and inflammation and produce cytokines that critically shape the ensuing adaptive cellular response. Therefore, they represent promising therapeutic targets. In cancer, NKT cells are attributed a role in immunosurveillance. NKT cells also act as potent activators of antitumor immunity when stimulated with a synthetic agonist in experimental models. However, in some settings, NKT cells seem to act as suppressors and regulators of antitumor immunity. Here we briefly review current data supporting these paradoxical roles of NKT cells and their regulation. Increased understanding of the signals that determine the function of NKT cells in cancer will be essential to improve current strategies for NKT-cell-based immunotherapeutic approaches.

Invariant NKT Cells as Novel Targets for Immunotherapy in Solid Tumors

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Karsten A. Pilones

2012-01-01

Full Text Available Natural killer T (NKT cells are a small population of lymphocytes that possess characteristics of both innate and adaptive immune cells. They are uniquely poised to respond rapidly to infection and inflammation and produce cytokines that critically shape the ensuing adaptive cellular response. Therefore, they represent promising therapeutic targets. In cancer, NKT cells are attributed a role in immunosurveillance. NKT cells also act as potent activators of antitumor immunity when stimulated with a synthetic agonist in experimental models. However, in some settings, NKT cells seem to act as suppressors and regulators of antitumor immunity. Here we briefly review current data supporting these paradoxical roles of NKT cells and their regulation. Increased understanding of the signals that determine the function of NKT cells in cancer will be essential to improve current strategies for NKT-cell-based immunotherapeutic approaches.

Tissue specific distribution of iNKT cells impacts their cytokine response

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Lee, You Jeong; Wang, Haiguang; Starrett, Gabriel J.; Phuong, Vanessa; Jameson, Stephen C.; Hogquist, Kristin A.

2015-01-01

Three subsets of invariant natural killer T (iNKT) cells have been identified, NKT1, NKT2 and NKT17, which produce distinct cytokines when stimulated, but little is known about their localization. Here, we have defined the anatomic localization and systemic distribution of these subsets and measured their cytokine production. Thymic NKT2 cells that produced interleukin-4 (IL-4) at steady state were located in the medulla and conditioned medullary thymocytes. NKT2 cells were abundant in the me...

Impact of NKT Cells and LFA-1 on Liver Regeneration under Subseptic Conditions.

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Ann-Kathrin Jörger

Full Text Available Activation of the immune system in terms of subseptic conditions during liver regeneration is of paramount clinical importance. However, little is known about molecular mechanisms and their mediators that control hepatocyte proliferation. We sought to determine the functional role of immune cells, especially NKT cells, in response to partial hepatectomy (PH, and to uncover the impact of the integrin lymphocyte function-associated antigen-1 (LFA-1 on liver regeneration in a subseptic setting.Wild-type (WT and LFA-1-/- mice underwent a 2/3 PH and low-dose lipopolysaccharid (LPS application. Hepatocyte proliferation, immune cell infiltration, and cytokine profile in the liver parenchyma were determined.Low-dose LPS application after PH results in a significant delay of liver regeneration between 48h and 72h, which is associated with a reduced number of CD3+ cells within the regenerating liver. In absence of LFA-1, an impaired regenerative capacity was observed under low-dose LPS application. Analysis of different leukocyte subpopulations showed less CD3+NK1.1+ NKT cells in the liver parenchyma of LFA-1-/- mice after PH and LPS application compared to WT controls, while CD3-NK1.1+ NK cells markedly increased. Concordantly with this observation, lower levels of NKT cell related cytokines IL-12 and IL-23 were expressed in the regenerating liver of LFA-1-/- mice, while the expression of NK cell-associated CCL5 and IL-10 was increased compared to WT mice.A subseptic situation negatively alters hepatocyte proliferation. Within this scenario, we suggest an important impact of NKT cells and postulate a critical function for LFA-1 during processes of liver regeneration.

IL-15 regulates homeostasis and terminal maturation of NKT cells1

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Gordy, Laura E.; Bezbradica, Jelena S.; Flyak, Andrew I.; Spencer, Charles T.; Dunkle, Alexis; Sun, Jingchun; Stanic, Aleksandar K.; Boothby, Mark R.; He, You-Wen; Zhao, Zhongming; Van Kaer, Luc; Joyce, Sebastian

2011-01-01

Semi-invariant natural killer T (NKT) cells are thymus-derived innate lymphocytes that modulate microbial and tumour immunity as well as autoimmune diseases. These immunoregulatory properties of NKT cells are acquired during their development. Much has been learnt regarding the molecular and cellular cues that promote NKT cell development, yet how these cells are maintained in the thymus and the periphery and how they acquire functional competence are incompletely understood. We found that IL-15 induced several Bcl-2 family survival factors in thymic and splenic NKT cells in vitro. Yet, IL15-mediated thymic and peripheral NKT cell survival critically depended on Bcl-xL expression. Additionally, IL-15 regulated thymic developmental stage 2 (ST2) to ST3 lineage progression and terminal NKT cell differentiation. Global gene expression analyses and validation revealed that IL-15 regulated Tbx21 (T-bet) expression in thymic NKT cells. The loss of IL15 also resulted in poor expression of key effector molecules such as IFN-γ, granzyme A and C as well as several NK cell receptors in NKT cells. Taken together, our findings reveal a critical role for IL-15 in NKT cell survival, which is mediated by Bcl-xL, and effector differentiation, which is consistent with a role of T-bet in regulating terminal maturation. PMID:22084435

Targeted disruption of CD1d prevents NKT cell development in pigs.

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Yang, Guan; Artiaga, Bianca L; Hackmann, Timothy J; Samuel, Melissa S; Walters, Eric M; Salek-Ardakani, Shahram; Driver, John P

2015-06-01

Studies in mice genetically lacking natural killer T (NKT) cells show that these lymphocytes make important contributions to both innate and adaptive immune responses. However, the usefulness of murine models to study human NKT cells is limited by the many differences between mice and humans, including that their NKT cell frequencies, subsets, and distribution are dissimilar. A more suitable model may be swine that share many metabolic, physiological, and growth characteristics with humans and are also similar for NKT cells. Thus, we analyzed genetically modified pigs made deficient for CD1d that is required for the development of Type I invariant NKT (iNKT) cells that express a semi-invariant T-cell receptor (TCR) and Type II NKT cells that use variable TCRs. Peripheral blood analyzed by flow cytometry and interferon-γ enzyme-linked immuno spot assays demonstrated that CD1d-knockout pigs completely lack iNKT cells, while other leukocyte populations remain intact. CD1d and NKT cells have been shown to be involved in shaping the composition of the commensal microbiota in mice. Therefore, we also compared the fecal microbiota profile between pigs expressing and lacking NKT cells. However, no differences were found between pigs lacking or expressing CD1d. Our results are the first to show that knocking-out CD1d prevents the development of NKT cells in a non-rodent species. CD1d-deficient pigs should offer a useful model to more accurately determine the contribution of NKT cells for human immune responses. They also have potential for understanding how NKT cells impact the health of commercial swine.

Alternative pathway for the development of Vα14+ NKT cells directly from CD4-CD8- thymocytes that bypasses the CD4+CD8+ stage.

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Dashtsoodol, Nyambayar; Shigeura, Tomokuni; Aihara, Minako; Ozawa, Ritsuko; Kojo, Satoshi; Harada, Michishige; Endo, Takaho A; Watanabe, Takashi; Ohara, Osamu; Taniguchi, Masaru

2017-03-01

Although invariant V α 14 + natural killer T cells (NKT cells) are thought to be generated from CD4 + CD8 + double-positive (DP) thymocytes, the developmental origin of CD4 - CD8 - double-negative (DN) NKT cells still remains unresolved. Here we provide definitive genetic evidence obtained, through studies of mice with DP-stage-specific ablation of expression of the gene encoding the recombinase component RAG-2 (Rag2) and by a fate-mapping approach, that supports the proposal of the existence of an alternative developmental pathway through which a fraction of DN NKT cells with strong T-helper-type-1 (T H 1)-biased and cytotoxic characteristics develop from late DN-stage thymocytes, bypassing the DP stage. These findings provide new insight into understanding of the development of NKT cells and propose a role for timing of expression of the invariant T cell antigen receptor in determining the functional properties of NKT cells.

Suppression of Natural Killer Cell Activity by Regulatory NKT10 Cells Aggravates Alcoholic Hepatosteatosis

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Kele Cui

2017-10-01

Full Text Available We and others have found that the functions of hepatic natural killer (NK cells are inhibited but invariant NKT (iNKT cells become activated after alcohol drinking, leaving a possibility that there exists interplay between NK cells and iNKT cells during alcoholic liver disease. Here, in a chronic plus single-binge ethanol consumption mouse model, we observed that NK cells and interferon-γ (IFN-γ protected against ethanol-induced liver steatosis, as both wild-type (WT mice treated with anti-asialo GM1 antibody and IFN-γ-deficient GKO mice developed more severe alcoholic fatty livers. As expected, IFN-γ could directly downregulate lipogenesis in primary hepatocytes in vitro. On the contrary, iNKT cell-deficient Jα18−/− or interleukin-10 (IL-10−/− mice showed fewer alcoholic steatosis, along with the recovered number and IFN-γ release of hepatic NK cells, and exogenous IL-10 injection was sufficient to compensate for iNKT cell deficiency. Furthermore, NK cell depletion in Jα18−/− or IL-10−/− mice caused more severe hepatosteatosis, implying NK cells are the direct effector cells to inhibit liver steatosis. Importantly, adoptive transfer of iNKT cells purified from normal but not IL-10−/− mice resulted in suppression of the number and functions of NK cells and aggravated alcoholic liver injury in Jα18−/− mice, indicating that IL-10-producing iNKT (NKT10 cells are the regulators on NK cells. Conclusion: Ethanol exposure-triggered NKT10 cells antagonize the protective roles of NK cells in alcoholic hepatosteatosis.

Diacylglycerol kinase zeta positively controls the development of iNKT-17 cells.

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Jinhong Wu

Full Text Available Invariant natural killer T (iNKT cells play important roles in bridging innate and adaptive immunity via rapidly producing a variety of cytokines. A small subset of iNKT cells produces IL-17 and is generated in the thymus during iNKT-cell ontogeny. The mechanisms that control the development of these IL-17-producing iNKT-17 cells (iNKT-17 are still not well defined. Diacylglycerol kinase ζ (DGKζ belongs to a family of enzymes that catalyze the phosphorylation and conversion of diacylglycerol to phosphatidic acid, two important second messengers involved in signaling from numerous receptors. We report here that DGKζ plays an important role in iNKT-17 development. A deficiency of DGKζ in mice causes a significant reduction of iNKT-17 cells, which is correlated with decreased RORγt and IL-23 receptor expression. Interestingly, iNKT-17 defects caused by DGKζ deficiency can be corrected in chimeric mice reconstituted with mixed wild-type and DGKζ-deficient bone marrow cells. Taken together, our data identify DGKζ as an important regulator of iNKT-17 development through iNKT-cell extrinsic mechanisms.

β-Catenin is required for the differentiation of iNKT2 and iNKT17 cells that augment IL-25-dependent lung inflammation

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Berga-Bolaños, Rosa; Sharma, Archna; Steinke, Farrah C.; Pyaram, Kalyani; Kim, Yeung-Hyen; Sultana, Dil A.; Fang, Jessie X.; Chang, Cheong-Hee; Xue, Hai-Hui; Heller, Nicola M.; Sen, Jyoti Misra

2015-01-01

Background Invariant Natural Killer T (iNKT) cells have been implicated in lung inflammation in humans and also shown to be a key cell type in inducing allergic lung inflammation in mouse models. iNKT cells differentiate and acquire functional characteristics during development in the thymus. However, the correlation between development of iNKT cells in the thymus and role in lung inflammation remains unknown. In addition, transcriptional control of differentiation of iNKT cells into iNKT cel...

iNKT cells suppress the CD8+ T cell response to a murine Burkitt's-like B cell lymphoma.

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Ryan L Bjordahl

Full Text Available The T cell response to B cell lymphomas differs from the majority of solid tumors in that the malignant cells themselves are derived from B lymphocytes, key players in immune response. B cell lymphomas are therefore well situated to manipulate their surrounding microenvironment to enhance tumor growth and minimize anti-tumor T cell responses. We analyzed the effect of T cells on the growth of a transplantable B cell lymphoma and found that iNKT cells suppressed the anti-tumor CD8(+ T cell response. Lymphoma cells transplanted into syngeneic wild type (WT mice or Jalpha18(-/- mice that specifically lack iNKT cells grew initially at the same rate, but only the mice lacking iNKT cells were able to reject the lymphoma. This effect was due to the enhanced activity of tumor-specific CD8(+ T cells in the absence of iNKT cells, and could be partially reversed by reconstitution of iNKT cells in Jalpha 18(-/- mice. Treatment of tumor-bearing WT mice with alpha -galactosyl ceramide, an activating ligand for iNKT cells, reduced the number of tumor-specific CD8(+ T cells. In contrast, lymphoma growth in CD1d1(-/- mice that lack both iNKT and type II NKT cells was similar to that in WT mice, suggesting that type II NKT cells are required for full activation of the anti-tumor immune response. This study reveals a tumor-promoting role for iNKT cells and suggests their capacity to inhibit the CD8(+ T cell response to B cell lymphoma by opposing the effects of type II NKT cells.

Bcl-xL regulates CD1d-mediated antigen presentation to NKT cells by altering CD1d trafficking through the endocytic pathway.

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Subrahmanyam, Priyanka B; Carey, Gregory B; Webb, Tonya J

2014-09-01

NKT cells are a unique subset of T cells that recognize glycolipid Ags presented in the context of CD1d molecules. NKT cells mount strong antitumor responses and are a major focus in developing effective cancer immunotherapy. It is known that CD1d molecules are constantly internalized from the cell surface, recycled through the endocytic compartments, and re-expressed on the cell surface. However, little is known about the regulation of CD1d-mediated Ag processing and presentation in B cell lymphoma. Prosurvival factors of the Bcl-2 family, such as Bcl-xL, are often upregulated in B cell lymphomas and are intimately linked to sphingolipid metabolism, as well as the endocytic compartments. We hypothesized that Bcl-xL can regulate CD1d-mediated Ag presentation to NKT cells. We found that overexpression or induction of Bcl-xL led to increased Ag presentation to NKT cells. Conversely, the inhibition or knockdown of Bcl-xL led to decreased NKT cell activation. Furthermore, knockdown of Bcl-xL resulted in the loss of CD1d trafficking to lysosome-associated membrane protein 1(+) compartments. Rab7, a late endosomal protein, was upregulated and CD1d molecules accumulated in the Rab7(+) late endosomal compartment. These results demonstrate that Bcl-xL regulates CD1d-mediated Ag processing and presentation to NKT cells by altering the late endosomal compartment and changing the intracellular localization of CD1d. Copyright © 2014 by The American Association of Immunologists, Inc.

Migration and chemokine receptor pattern of colitis-preventing DX5+NKT cells.

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Hornung, Matthias; Werner, Jens M; Farkas, Stefan; Schlitt, Hans J; Geissler, Edward K

2011-11-01

DX5(+)NKT cells are a subpopulation of NKT cells expressing both T cell receptor and NK cell markers that show an immune-regulating function. Transferred DX5(+)NKT cells from immune competent Balb/c mice can prevent or reduce induced colitis in severe combined immunodeficient (SCID) mice. Here, we investigated the in vivo migration of DX5(+)NKT cells and their corresponding chemokine receptor patterns. DX5(+)NKT cells were isolated from spleens of Balb/c mice and transferred into Balb/c SCID mice. After 2 and 8 days, in vivo migration was examined using in vivo microscopy. In addition, the chemokine receptor pattern was analyzed with fluorescence-activated cell sorting (FACS) and the migration assay was performed. Our results show that labeled DX5(+)NKT cells were primarily detectable in mesenteric lymph nodes and spleen after transfer. After 8 days, DX5(+)NKT cells were observed in the colonic tissues, especially the appendix. FACS analysis of chemokine receptors in DX5(+)NKT cells revealed expression of CCR3, CCR6, CCR9, CXCR3, CXCR4, and CXCR6, but no CCR5, CXCR5, or the lymphoid homing receptor CCR7. Stimulation upregulated especially CCR7 expression, and chemokine receptor patterns were different between splenic and liver DX5(+)NKT cells. These data indicate that colitis-preventing DX5(+)NKT cells need to traffic through lymphoid organs to execute their immunological function at the site of inflammation. Furthermore, DX5(+)NKT cells express a specific chemokine receptor pattern with an upregulation of the lymphoid homing receptor CCR7 after activation.

iNKT cells require TSC1 for terminal maturation and effector lineage fate decisions

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Wu, Jinhong; Yang, Jialong; Yang, Kai; Wang, Hongxia; Gorentla, Balachandra; Shin, Jinwook; Qiu, Yurong; Que, Loretta G.; Foster, W. Michael; Xia, Zhenwei; Chi, Hongbo; Zhong, Xiao-Ping

2014-01-01

Terminal maturation of invariant NKT (iNKT) cells from stage 2 (CD44+NK1.1–) to stage 3 (CD44+NK1.1+) is accompanied by a functional acquisition of a predominant IFN-γ–producing (iNKT-1) phenotype; however, some cells develop into IL-17–producing iNKT (iNKT-17) cells. iNKT-17 cells are rare and restricted to a CD44+NK1.1– lineage. It is unclear how iNKT terminal maturation is regulated and what factors mediate the predominance of iNKT-1 compared with iNKT-17. The tumor suppressor tuberous scl...

Distinct requirements for activation of NKT and NK cells during viral infection.

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Tyznik, Aaron J; Verma, Shilpi; Wang, Qiao; Kronenberg, Mitchell; Benedict, Chris A

2014-04-15

NK cells are key regulators of innate defense against mouse CMV (MCMV). Like NK cells, NKT cells also produce high levels of IFN-γ rapidly after MCMV infection. However, whether similar mechanisms govern activation of these two cell types, as well as the significance of NKT cells for host resistance, remain unknown. In this article, we show that, although both NKT and NK cells are activated via cytokines, their particular cytokine requirements differ significantly in vitro and in vivo. IL-12 is required for NKT cell activation in vitro but is not sufficient, whereas NK cells have the capacity to be activated more promiscuously in response to individual cytokines from innate cells. In line with these results, GM-CSF-derived dendritic cells activated only NK cells upon MCMV infection, consistent with their virtual lack of IL-12 production, whereas Flt3 ligand-derived dendritic cells produced IL-12 and activated both NK and NKT cells. In vivo, NKT cell activation was abolished in IL-12(-/-) mice infected with MCMV, whereas NK cells were still activated. In turn, splenic NK cell activation was more IL-18 dependent. The differential requirements for IL-12 and IL-18 correlated with the levels of cytokine receptor expression by NK and NKT cells. Finally, mice lacking NKT cells showed reduced control of MCMV, and depleting NK cells further enhanced viral replication. Taken together, our results show that NKT and NK cells have differing requirements for cytokine-mediated activation, and both can contribute nonredundantly to MCMV defense, revealing that these two innate lymphocyte subsets function together to fine-tune antiviral responses.

[Regulatory role of NKT cells in the prevention of type 1 diabetes].

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Ghazarian, Liana; Simoni, Yannick; Pingris, Karine; Beaudoin, Lucie; Lehuen, Agnès

2013-01-01

Type 1 diabetes is an autoimmune disease resulting from the destruction of pancreatic β cells by the immune system. NKT cells are innate-like T cells that can exert potent immuno-regulatory functions. The regulatory role of NKT cells was initially proposed after the observed decreased frequency of this subset in mouse models of type 1 diabetes, as well as in patients developing various autoimmune pathologies. Increasing NKT cell frequency and function prevent the development of type 1 diabetes in mouse models. Several mechanisms including IL-4 and IL-10 production by NKT cells and the accumulation of tolerogenic dendritic cells are critical for the dampening of pathogenic anti-islet T cell responses by NKT cells. Importantly, these cells can at the same time prevent diabetes and promote efficient immune responses against infectious agents. These results strengthen the potential role of NKT cells as a key target for the development of therapeutic strategies against type 1 diabetes. © 2013 médecine/sciences – Inserm.

NKT cell activation by Leishmania mexicana LPG: Description of a novel pathway.

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Zamora-Chimal, Jaime; Fernández-Figueroa, Edith A; Ruiz-Remigio, Adriana; Wilkins-Rodríguez, Arturo A; Delgado-Domínguez, José; Salaiza-Suazo, Norma; Gutiérrez-Kobeh, Laila; Becker, Ingeborg

2017-02-01

NKT cells have been associated with protection against Leishmania donovani, yet their role in infections with Leishmania mexicana has not been addressed, nor has the activation pathway been defined after stimulation with Leishmania mexicana lipophosphoglycan (LPG). We analyzed the activation of NKT cells and their cytokine production in response to Leishmania mexicana LPG. Additionally we compared NKT-cell numbers and cytokine profile in lymph nodes of skin lesions induced by Leishmania mexicana in BALB/c and C57BL/6 mice. We show that LPG activates NKT cells primarily through the indirect pathway, initiating with TLR2 stimulation of dendritic cells (DC), thereby enhancing TLR2, MHC II, and CD86 expressions and IL-12p70 production. This leads to IFN-γ production by NKT cells. C57BL/6 mice showed enhanced DC activation, which correlated with augmented IFN-γ production by NKT cells. Additionally, infected C57BL/6 mice showed elevated percentages of NKT cells with higher IFN-γ and IL-4 production in lymph nodes. We conclude that the response of NKT cells towards Leishmania mexicana LPG initiates with the indirect activation, after binding of LPG to TLR2 in DC. This indirect activation pathway enables NKT cells to produce IFN-γ during the innate phase of Leishmania infection, the magnitude of which differs between mouse strains. Copyright © 2016 The Authors. Published by Elsevier GmbH.. All rights reserved.

Invariant NKT cells regulate experimental autoimmune uveitis through inhibition of Th17 differentiation.

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Oh, Keunhee; Byoun, Ok-Jin; Ham, Don-Il; Kim, Yon Su; Lee, Dong-Sup

2011-02-01

Although NKT cells have been implicated in diverse immunomodulatory responses, the effector mechanisms underlying the NKT cell-mediated regulation of pathogenic T helper cells are not well understood. Here, we show that invariant NKT cells inhibited the differentiation of CD4(+) T cells into Th17 cells both in vitro and in vivo. The number of IL-17-producing CD4(+) T cells was reduced following co-culture with purified NK1.1(+) TCR(+) cells from WT, but not from CD1d(-/-) or Jα18(-/-) , mice. Co-cultured NKT cells from either cytokine-deficient (IL-4(-/-) , IL-10(-/-) , or IFN-γ(-/-) ) or WT mice efficiently inhibited Th17 differentiation. The contact-dependent mechanisms of NKT cell-mediated regulation of Th17 differentiation were confirmed using transwell co-culture experiments. On the contrary, the suppression of Th1 differentiation was dependent on IL-4 derived from the NKT cells. The in vivo regulatory capacity of NKT cells on Th17 cells was confirmed using an experimental autoimmune uveitis model induced with human IRBP(1-20) (IRBP, interphotoreceptor retinoid-binding protein) peptide. NKT cell-deficient mice (CD1d(-/-) or Jα18(-/-) ) demonstrated an increased disease severity, which was reversed by the transfer of WT or cytokine-deficient (IL-4(-/-) , IL-10(-/-) , or IFN-γ(-/-) ) NKT cells. Our results indicate that invariant NKT cells inhibited autoimmune uveitis predominantly through the cytokine-independent inhibition of Th17 differentiation. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Type II NKT-TFH cells against Gaucher lipids regulate B-cell immunity and inflammation.

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Nair, Shiny; Boddupalli, Chandra Sekhar; Verma, Rakesh; Liu, Jun; Yang, Ruhua; Pastores, Gregory M; Mistry, Pramod K; Dhodapkar, Madhav V

2015-02-19

Chronic inflammation including B-cell activation is commonly observed in both inherited (Gaucher disease [GD]) and acquired disorders of lipid metabolism. However, the cellular mechanisms underlying B-cell activation in these settings remain to be elucidated. Here, we report that β-glucosylceramide 22:0 (βGL1-22) and glucosylsphingosine (LGL1), 2 major sphingolipids accumulated in GD, can be recognized by a distinct subset of CD1d-restricted human and murine type II natural killer T (NKT) cells. Human βGL1-22- and LGL1-reactive CD1d tetramer-positive T cells have a distinct T-cell receptor usage and genomic and cytokine profiles compared with the classical type I NKT cells. In contrast to type I NKT cells, βGL1-22- and LGL1-specific NKT cells constitutively express T-follicular helper (TFH) phenotype. Injection of these lipids leads to an increase in respective lipid-specific type II NKT cells in vivo and downstream induction of germinal center B cells, hypergammaglobulinemia, and production of antilipid antibodies. Human βGL1-22- and LGL1-specific NKT cells can provide efficient cognate help to B cells in vitro. Frequency of LGL1-specific T cells in GD mouse models and patients correlates with disease activity and therapeutic response. Our studies identify a novel type II NKT-mediated pathway for glucosphingolipid-mediated dysregulation of humoral immunity and increased risk of B-cell malignancy observed in metabolic lipid disorders. © 2015 by The American Society of Hematology.

Programmed death-1 receptor suppresses γ-IFN producing NKT cells in human tuberculosis.

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Singh, Amar; Dey, Aparajit Ballav; Mohan, Anant; Mitra, Dipendra Kumar

2014-05-01

IFN-γ biased Th1 effector immune response is crucial for containment of Mycobacterium tuberculosis infection. Various T cell subsets with regulatory function dictate the generation of Th1 like cells. NKT cells are a specialized T cell subset known to be activated early in immune response and control T cell response via release of immunoregulatory cytokines like IFN-γ, IL-4 and IL-10. M. tuberculosis, with abundance of its cell wall lipids may potently activate NKT cells resulting in cytokine production and PD-1 expression. In this study, among 49 treatment naive active pulmonary tuberculosis patients, we found a higher percentage of PD1(+) NKT cells correlating with sputum bacillary load. Furthermore, blocking PD-1 increased the number of IFN-γ producing NKT cells by inhibiting their apoptosis. Moreover, peripheral frequency of NKT cells declined with therapy suggesting their role in host T cell response. In this study, we concluded that PD-1 preferentially induces apoptosis of IFN-γ producing NKT cells while sparing NKT cells that produce IL-4. Such a polarized NKT cell function may impose a Th2 bias on the ensuing effector T cell response leading to inefficient clearance of M. tuberculosis. Inhibiting PD-1 may therefore alter the T cell response in favor of the host by rescuing type 1 NKT cells from apoptosis and boosting Th1 effector T cell functions against M. tuberculosis. Copyright © 2014 Elsevier Ltd. All rights reserved.

The effect of radiotherapy on NKT cells in patients with advanced head and neck cancer.

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Kobayashi, Kouichi; Tanaka, Yuriko; Horiguchi, Shigetoshi; Yamamoto, Shouji; Toshinori, Nakayama; Sugimoto, Akira; Okamoto, Yoshitaka

2010-10-01

Cancer immunotherapy with NKT cells is a potential new treatment strategy for advanced head and neck cancer. NKT cell therapy is promising due to its unique anti-tumor activity and higher degree of safety compared to current therapies. Radiotherapy is indispensable as a standard treatment for advanced head and neck cancer. To elucidate the possibility of using NKT cells as an adjuvant immunotherapy with radiotherapy, we examined the effect of radiotherapy on NKT cells in patients with head and neck cancer. The number, IFN-gamma production and proliferation capacity of NKT cells were analyzed before and after 50 Gy radiation therapy in 12 patients with stage IV head and neck squamous cell carcinoma. The cytotoxic activity of NKT cells was examined in vitro. The number of NKT cells in the blood varied widely between patients. After radiation therapy, the population of CD3 T cells decreased significantly, while the NKT cell population remained stable. The number of NKT cells was the same after radiation therapy as before. IFN-gamma production from NKT cells collected just after radiotherapy was impaired after stimulation with exogenous ligand, but the proliferative responses of these NKT cells was enhanced in comparison to those collected before radiation therapy. Furthermore, the proliferated NKT cells displayed a significant level of anti-tumor activity. NKT cells are relatively resistant to radiation and might therefore be suitable for adjuvant immunotherapy to eradicate remnant cancer cells in patients who have undergone radiation therapy.

Crosstalk between type II NKT cells and T cells leads to spontaneous chronic inflammatory liver disease.

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Weng, Xiufang; He, Ying; Visvabharathy, Lavanya; Liao, Chia-Min; Tan, Xiaosheng; Balakumar, Arjun; Wang, Chyung-Ru

2017-10-01

Natural killer T (NKT) cells are CD1d-restricted innate-like T cells that modulate innate and adaptive immune responses. Unlike the well-characterized invariant/type I NKT cells, type II NKT cells with a diverse T cell receptor repertoire are poorly understood. This study defines the pathogenic role of type II NKT cells in the etiology of chronic liver inflammation. Transgenic mice with the Lck promoter directing CD1d overexpression on T cells in Jα18 wild-type (Lck-CD1dTgJα18 + ; type I NKT cell sufficient) and Jα18-deficient (Lck-CD1dTgJα18 o , type I NKT cell deficient) mice were analyzed for liver pathology and crosstalk between type II NKT cells and conventional T cells. CD1d expression on T cells in peripheral blood samples and liver sections from autoimmune hepatitis patients and healthy individuals were also examined. Lck-CD1dTgJα18 o and Lck-CD1dTgJα18 + mice developed similar degrees of liver pathology resembling chronic autoimmune hepatitis in humans. Increased CD1d expression on T cells promoted the activation of type II NKT cells and other T cells. This resulted in T h 1-skewing and impaired T h 2 cytokine production in type II NKT cells. Dysfunction of type II NKT cells was accompanied by conventional T cell activation and pro-inflammatory cytokine production, leading to a hepatic T/B lymphocyte infiltration, elevated autoantibodies and hepatic injury in Lck-CD1dTg mice. A similar mechanism could be extended to humans as CD1d expression is upregulated on activated human T cells and increased presence of CD1d-expressing T cells was observed in autoimmune hepatitis patients. Our data reveals enhanced crosstalk between type II NKT cells and conventional T cells, leading to a T h 1-skewed inflammatory milieu, and consequently, to the development of chronic autoimmune liver disease. Lay summary: CD1d overexpression on T cells enhances crosstalk between type II NKT cells and T cells, resulting in their aberrant activation and leading to the

Reactive Oxygen Species Regulate the Inflammatory Function of NKT Cells through Promyelocytic Leukemia Zinc Finger.

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Kim, Yeung-Hyen; Kumar, Ajay; Chang, Cheong-Hee; Pyaram, Kalyani

2017-11-15

Reactive oxygen species (ROS) are byproducts of aerobic metabolism and contribute to both physiological and pathological conditions as second messengers. ROS are essential for activation of T cells, but how ROS influence NKT cells is unknown. In the present study, we investigated the role of ROS in NKT cell function. We found that NKT cells, but not CD4 or CD8 T cells, have dramatically high ROS in the spleen and liver of mice but not in the thymus or adipose tissues. Accordingly, ROS-high NKT cells exhibited increased susceptibility and apoptotic cell death with oxidative stress. High ROS in the peripheral NKT cells were primarily produced by NADPH oxidases and not mitochondria. We observed that sorted ROS-high NKT cells were enriched in NKT1 and NKT17 cells, whereas NKT2 cells were dominant in ROS-low cells. Furthermore, treatment of NKT cells with antioxidants led to reduced frequencies of IFN-γ- and IL-17-expressing cells, indicating that ROS play a role in regulating the inflammatory function of NKT cells. The transcription factor promyelocytic leukemia zinc finger (PLZF) seemed to control the ROS levels. NKT cells from adipose tissues that do not express PLZF and those from PLZF haplodeficient mice have low ROS. Conversely, ROS were highly elevated in CD4 T cells from mice ectopically expressing PLZF. Thus, our findings demonstrate that PLZF controls ROS levels, which in turn governs the inflammatory function of NKT cells. Copyright © 2017 by The American Association of Immunologists, Inc.

Inhibitory function of NKT cells during early induction phase of nickel allergy.

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Okuno, Hironori; Satoh, Masashi; Takeuchi, Emiko; Eshima, Koji; Terashima, Masazumi; Komotori, Jun; Habu, Sonoko; Tamauchi, Hidekazu; Iwabuchi, Kazuya

2016-07-01

Until now, metal allergies have been regarded as a Th1-type immune response.　However, because the contribution of a Th2-type immune response has been suggested by clinical findings, we previously examined the Th2-type immune response during the development of metal allergies using a GATA-3 transgenic (GATA-3 Tg) mouse model. As a result, a Th2-type immunization reaction was suggested to be involved in the early phase of metal allergies. Recently, the involvement of NKT cells in metal allergies has been suggested. We examined this possibility using the activation of NKT cells and an NKT cell-deficient mouse model to determine the contribution of NKT cells to nickel allergy in the present study. In NKT cell-deficient mice, ear swelling was remarkably increased, compared with that in control mice. Also, in mice that had been treated with α-galactosylceramide (α-GalCer) to activate NKT cells, the ear swelling response was remarkably inhibited, compared with that in untreated mice. These facts show that NKT cells are involved in the inhibition of nickel allergy-induced ear swelling responses. Copyright © 2016 Elsevier GmbH. All rights reserved.

NF-κB Protects NKT Cells from Tumor Necrosis Factor Receptor 1-induced Death.

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Kumar, Amrendra; Gordy, Laura E; Bezbradica, Jelena S; Stanic, Aleksandar K; Hill, Timothy M; Boothby, Mark R; Van Kaer, Luc; Joyce, Sebastian

2017-11-15

Semi-invariant natural killer T (NKT) cells are innate-like lymphocytes with immunoregulatory properties. NKT cell survival during development requires signal processing by activated RelA/NF-κB. Nonetheless, the upstream signal(s) integrated by NF-κB in developing NKT cells remains incompletely defined. We show that the introgression of Bcl-x L -coding Bcl2l1 transgene into NF-κB signalling-deficient IκBΔN transgenic mouse rescues NKT cell development and differentiation in this mouse model. We reasoned that NF-κB activation was protecting developing NKT cells from death signals emanating either from high affinity agonist recognition by the T cell receptor (TCR) or from a death receptor, such as tumor necrosis factor receptor 1 (TNFR1) or Fas. Surprisingly, the single and combined deficiency in PKC-θ or CARMA-1-the two signal transducers at the NKT TCR proximal signalling node-only partially recapitulated the NKT cell deficiency observed in IκBΔN tg mouse. Accordingly, introgression of the Bcl2l1 transgene into PKC-θ null mouse failed to rescue NKT cell development. Instead, TNFR1-deficiency, but not the Fas-deficiency, rescued NKT cell development in IκBΔN tg mice. Consistent with this finding, treatment of thymocytes with an antagonist of the inhibitor of κB kinase -which blocks downstream NF-κB activation- sensitized NKT cells to TNF-α-induced cell death in vitro. Hence, we conclude that signal integration by NF-κB protects developing NKT cells from death signals emanating from TNFR1, but not from the NKT TCR or Fas.

Gal-3 regulates the capacity of dendritic cells to promote NKT-cell-induced liver injury.

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Volarevic, Vladislav; Markovic, Bojana Simovic; Bojic, Sanja; Stojanovic, Maja; Nilsson, Ulf; Leffler, Hakon; Besra, Gurdyal S; Arsenijevic, Nebojsa; Paunovic, Verica; Trajkovic, Vladimir; Lukic, Miodrag L

2015-02-01

Galectin-3 (Gal-3), an endogenous lectin, exhibits pro- and anti-inflammatory effects in various disease conditions. In order to explore the role of Gal-3 in NKT-cell-dependent pathology, we induced hepatitis in C57BL/6 WT and Gal-3-deficient mice by using specific ligand for NKT cells: α-galactosylceramide, glycolipid Ag presented by CD1d. The injection of α-galactosylceramide significantly enhanced expression of Gal-3 in liver NKT and dendritic cells (DCs). Genetic deletion or selective inhibition of Gal-3 (induced by Gal-3-inhibitor TD139) abrogated the susceptibility to NKT-cell-dependent hepatitis. Blood levels of pro-inflammatory cytokines (TNF-α, IFN-γ, IL-12) and their production by liver DCs and NKT cells were also downregulated. Genetic deletion or selective inhibition of Gal-3 alleviated influx of inflammatory CD11c(+) CD11b(+) DCs in the liver and favored tolerogenic phenotype and IL-10 production of liver NKT and DCs. Deletion of Gal-3 attenuated the capacity of DCs to support liver damage in the passive transfer experiments and to produce pro-inflammatory cytokines in vitro. Gal-3-deficient DCs failed to optimally stimulate production of pro-inflammatory cytokines in NKT cells, in vitro and in vivo. In conclusion, Gal-3 regulates the capacity of DCs to support NKT-cell-mediated liver injury, playing an important pro-inflammatory role in acute liver injury. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Percentages of NKT cells in the tissues of patients with non-small cell lung cancer who underwent surgical treatment.

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Pyszniak, Maria; Rybojad, Paweł; Pogoda, Katarzyna; Jabłonka, Andrzej; Bojarska-Junak, Agnieszka; Tabarkiewicz, Jacek

2014-03-01

Natural killer T (NKT) cells are involved in the antitumor response by direct cytotoxicity and indirectly through activation of effector cells. Recent studies have shown a relationship between the number and function of NKT cells and clinical outcomes. NKT cells seem to represent a promising tool for immunotherapy of cancer. The aim of the study was to evaluate the distribution of NKT cells in peripheral blood, lymph nodes and tumor tissue of non-small cell lung cancer (NSCLC) patients, as well as development of the most efficient set of cytokines stimulating differentiation of NKT cells. We evaluated the percentage of iNKT+CD3+ cells in the tissues collected from patients with NSCLC. For the generation of NKT cells, we cultured cells isolated from the blood of 20 healthy donors and from the tissues of 4 NSCLC patients. Cells were stimulated with α-GalCer in combinations with cytokines. We noted significant differences in the percentages of NKT cells in the patients' tissues. The highest percentage of these cells was observed in the tumor tissue and the lowest in the lymph nodes. In vitro, in healthy donors all α-GalCer-cytokine combinations were effective in stimulation of NKT cells' proliferation. NKT cells' proliferation was the most efficiently stimulated by α-GalCer+IL-2+IL-7 and α-GalCer+IL-2+IFN-γ. Our results suggest that in the course of NSCLC, NKT cells migrate to the primary tumor and accumulate therein. All tested combinations of α-GalCer and cytokines were capable of generation of NKT cells in vitro.

Lysophosphatidic acid generation by pulmonary NKT cell ENPP-2/autotaxin exacerbates hyperoxic lung injury.

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Nowak-Machen, Martina; Lange, Martin; Exley, Mark; Wu, Sherry; Usheva, Anny; Robson, Simon C

2015-12-01

Hyperoxia is still broadly used in clinical practice in order to assure organ oxygenation in critically ill patients, albeit known toxic effects. In this present study, we hypothesize that lysophosphatidic acid (LPA) mediates NKT cell activation in a mouse model of hyperoxic lung injury. In vitro, pulmonary NKT cells were exposed to hyperoxia for 72 h, and the induction of the ectonucleotide pyrophosphatase/phosphodiesterase 2 (ENPP-2) was examined and production of lysophosphatidic acid (LPA) was measured. In vivo, animals were exposed to 100 % oxygen for 72 h and lungs and serum were harvested. Pulmonary NKT cells were then incubated with the LPA antagonist Brp-LPA. Animals received BrP-LPA prior to oxygen exposure. Autotaxin (ATX, ENPP-2) was significantly up-regulated on pulmonary NKT cells after hyperoxia (p NKT cells. LPA levels were significantly reduced by incubating NKT cells with LPA-BrP during oxygen exposure (p NKT cell numbers in vivo. BrP-LPA injection significantly improved survival as well as significantly decreased lung injury and lowered pulmonary NKT cell numbers. We conclude that NKT cell-induced hyperoxic lung injury is mediated by pro-inflammatory LPA generation, at least in part, secondary to ENPP-2 up-regulation on pulmonary NKT cells. Being a potent LPA antagonist, BrP-LPA prevents hyperoxia-induced lung injury in vitro and in vivo.

NKT Cells in the Induced Sputum of Severe Asthmatics

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Agnes Hamzaoui

2006-01-01

of the sputum and monoclonal antibodies to CD3, CD4, CD8, CD56, CD25, and TCRγδ. The number of NKT (CD3+CD56+ cells was significantly higher in the sputum of severe asthmatics compared with mild asthmatic and healthy control groups (P<.05. CD8+CD56+ cells were the predominant subtype of the increased NKT cells in severe asthmatics. CD3+CD56+Vα24+, TCRγδ+ CD56+, and CD4+CD25+ T cells were significantly increased in severe asthmatic patients. These results suggest that the immunopathogenesis of severe asthmatics vary between severe and mild asthmatics, and that CD8+CD56+ NKT cells may play an important role in the immunopathogenesis of severe asthma.

iNKT Cell Emigration out of the Lung Vasculature Requires Neutrophils and Monocyte-Derived Dendritic Cells in Inflammation

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Ajitha Thanabalasuriar

2016-09-01

Full Text Available iNKT cells are a subset of innate T cells that recognize glycolipids presented on CD1d molecules and protect against bacterial infections, including S. pneumoniae. Using lung intravital imaging, we examined the behavior and mechanism of pulmonary iNKT cell activation in response to the specific iNKT cell ligand α-galactosylceramide or S. pneumoniae infection. In untreated mice, the major fraction of iNKT cells resided in the vasculature, but a small critical population resided in the extravascular space in proximity to monocyte-derived DCs. Administration of either α-GalCer or S. pneumoniae induced CD1d-dependent rapid recruitment of neutrophils out of the vasculature. The neutrophils guided iNKT cells from the lung vasculature via CCL17. Depletion of monocyte-derived DCs abrogated both the neutrophil and subsequent iNKT cell extravasation. Moreover, impairing iNKT cell recruitment by blocking CCL17 increased susceptibility to S. pneumoniae infection, suggesting a critical role for the influx of iNKT cells in host defense.

Histone demethylases UTX and JMJD3 are required for NKT cell development in mice.

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Northrup, Daniel; Yagi, Ryoji; Cui, Kairong; Proctor, William R; Wang, Chaochen; Placek, Katarzyna; Pohl, Lance R; Wang, Rongfu; Ge, Kai; Zhu, Jinfang; Zhao, Keji

2017-01-01

Natural killer (NK)T cells and conventional T cells share phenotypic characteristic however they differ in transcription factor requirements and functional properties. The role of histone modifying enzymes in conventional T cell development has been extensively studied, little is known about the function of enzymes regulating histone methylation in NKT cells. We show that conditional deletion of histone demethylases UTX and JMJD3 by CD4-Cre leads to near complete loss of liver NKT cells, while conventional T cells are less affected. Loss of NKT cells is cell intrinsic and not due to an insufficient selection environment. The absence of NKT cells in UTX/JMJD3-deficient mice protects mice from concanavalin A-induced liver injury, a model of NKT-mediated hepatitis. GO-analysis of RNA-seq data indicates that cell cycle genes are downregulated in UTX/JMJD3-deleted NKT progenitors, and suggest that failed expansion may account for some of the cellular deficiency. The phenotype appears to be demethylase-dependent, because UTY, a homolog of UTX that lacks catalytic function, is not sufficient to restore their development and removal of H3K27me3 by deletion of EZH2 partially rescues the defect. NKT cell development and gene expression is sensitive to proper regulation of H3K27 methylation. The H3K27me3 demethylase enzymes, in particular UTX, promote NKT cell development, and are required for effective NKT function.

The Function of CD3+CD56+ NKT-Like Cells in HIV-Infected Individuals

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Yongjun Jiang

2014-01-01

Full Text Available CD3+CD56+ NKT-like cells are one of the critical effectors in the immune response to viral infection and tumors, but the functional features of NKT-like cells in HIV infection have been rarely reported. In this study, we observed and described the state of NKT-like cell functions in primary HIV-infected individuals (PHIs, chronic HIV-infected individuals (CHIs, long-term nonprogressors (LTNPs, and HIV-negative controls (NCs. The results showed that the percentage of IFN-γ+CD3+CD56+ NKT-like cells was notably higher in LTNPs compared with CHIs, and the proportion of CD3+CD56+ NKT-like cells with dual function (IFN-γ+CD107a+ NKT-like cells in LTNPs was also much higher than in CHIs. Additionally, the percentages of IFN-γ+CD107a+ NKT-like cells negatively correlated with viral load. Taken together, our data demonstrated that good functions of CD3+CD56+ NKT-like cells in LTNPs likely occurred as a protective mechanism that slows down HIV disease progression.

The function of CD3+CD56+ NKT-like cells in HIV-infected individuals.

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Jiang, Yongjun; Cui, Xiaojian; Cui, Chen; Zhang, Jian; Zhou, Fangyuan; Zhang, Zining; Fu, Yajing; Xu, Junjie; Chu, Zhenxing; Liu, Jing; Han, Xiaoxu; Liao, Christina; Wang, Yanan; Cao, Yaming; Shang, Hong

2014-01-01

CD3(+)CD56(+) NKT-like cells are one of the critical effectors in the immune response to viral infection and tumors, but the functional features of NKT-like cells in HIV infection have been rarely reported. In this study, we observed and described the state of NKT-like cell functions in primary HIV-infected individuals (PHIs), chronic HIV-infected individuals (CHIs), long-term nonprogressors (LTNPs), and HIV-negative controls (NCs). The results showed that the percentage of IFN-γ(+)CD3(+)CD56(+) NKT-like cells was notably higher in LTNPs compared with CHIs, and the proportion of CD3(+)CD56(+) NKT-like cells with dual function (IFN-γ(+)CD107a(+) NKT-like cells) in LTNPs was also much higher than in CHIs. Additionally, the percentages of IFN-γ(+)CD107a(+) NKT-like cells negatively correlated with viral load. Taken together, our data demonstrated that good functions of CD3(+)CD56(+) NKT-like cells in LTNPs likely occurred as a protective mechanism that slows down HIV disease progression.

Type II NKT Cells and Their Emerging Role in Health and Disease.

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Dhodapkar, Madhav V; Kumar, Vipin

2017-02-01

NKT cells recognize lipid Ags presented by a class I MHC-like molecule CD1d, a member of the CD1 family. Although most initial studies on NKT cells focused on a subset with semi-invariant TCR termed invariant NKT cells, the majority of CD1d-restricted lipid-reactive human T cells express diverse TCRs and are termed type II NKT cells. These cells constitute a distinct population of circulating and tissue-resident effector T cells with immune-regulatory properties. They react to a growing list of self- as well as non-self-lipid ligands, and share some properties with both invariant NKT and conventional T cells. An emerging body of evidence points to their role in the regulation of immunity to pathogens/tumors and in autoimmune/metabolic disorders. An improved understanding of the biology of these cells and the ability to manipulate their function may be of therapeutic benefit in diverse disease conditions. Copyright © 2017 by The American Association of Immunologists, Inc.

Enhancement of Mucosal Immunogenicity of Viral Vectored Vaccines by the NKT Cell Agonist Alpha-Galactosylceramide as Adjuvant

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Shailbala Singh

2014-10-01

Full Text Available Gene-based vaccination strategies, specifically viral vectors encoding vaccine immunogens are effective at priming strong immune responses. Mucosal routes offer practical advantages for vaccination by ease of needle-free administration, and immunogen delivery at readily accessible oral/nasal sites to efficiently induce immunity at distant gut and genital tissues. However, since mucosal tissues are inherently tolerant for induction of immune responses, incorporation of adjuvants for optimal mucosal vaccination strategies is important. We report here the effectiveness of alpha-galactosylceramide (α-GalCer, a synthetic glycolipid agonist of natural killer T (NKT cells, as an adjuvant for enhancing immunogenicity of vaccine antigens delivered using viral vectors by mucosal routes in murine and nonhuman primate models. Significant improvement in adaptive immune responses in systemic and mucosal tissues was observed by including α-GalCer adjuvant for intranasal immunization of mice with vesicular stomatitis virus vector encoding the model antigen ovalbumin and adenoviral vectors expressing HIV env and Gag antigens. Activation of NKT cells in systemic and mucosal tissues along with significant increases in adaptive immune responses were observed in rhesus macaques immunized by intranasal and sublingual routes with protein or adenovirus vectored antigens when combined with α-GalCer adjuvant. These results support the utility of α-GalCer adjuvant for enhancing immunogenicity of mucosal vaccines delivered using viral vectors.

Critical role for CD1d-restricted invariant NKT cells in stimulating intrahepatic CD8 T-cell responses to liver antigen

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Sprengers, Dave; Sillé, Fenna C. M.; Derkow, Katja; Besra, Gurdyal S.; Janssen, Harry L. A.; Schott, Eckart; Boes, Marianne

2008-01-01

V alpha14 invariant natural killer T cells (iNKT) are localized in peripheral tissues such as the liver rather than lymphoid tissues. Therefore, their role in modulating the stimulation of conventional, major histocompatibility complex (MHC)-restricted T-cell responses has remained ambiguous. We

The Tec kinase ITK regulates thymic expansion, emigration, and maturation of γδ NKT cells.

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Yin, Catherine C; Cho, Ok Hyun; Sylvia, Katelyn E; Narayan, Kavitha; Prince, Amanda L; Evans, John W; Kang, Joonsoo; Berg, Leslie J

2013-03-15

The Tec family tyrosine kinase, Itk, regulates signaling downstream of the TCR. The absence of Itk in CD4(+) T cells results in impaired Th2 responses along with defects in maturation, cytokine production, and survival of iNKT cells. Paradoxically, Itk(-/-) mice have spontaneously elevated serum IgE levels, resulting from an expansion of the Vγ1.1(+)Vδ6.3(+) subset of γδ T cells, known as γδ NKT cells. Comparisons between γδ NKT cells and αβ iNKT cells showed convergence in the pattern of cell surface marker expression, cytokine profiles, and gene expression, suggesting that these two subsets of NKT cells undergo similar differentiation programs. Hepatic γδ NKT cells have an invariant TCR and are derived predominantly from fetal progenitors that expand in the thymus during the first weeks of life. The adult thymus contains these invariant γδ NKT cells plus a heterogeneous population of Vγ1.1(+)Vδ6.3(+) T cells with diverse CDR3 sequences. This latter population, normally excluded from the liver, escapes the thymus and homes to the liver when Itk is absent. In addition, Itk(-/-) γδ NKT cells persistently express high levels of Zbtb16 (PLZF) and Il4, genes that are normally downregulated in the most mature subsets of NKT cells. These data indicate that Itk signaling is required to prevent the expansion of γδ NKT cells in the adult thymus, to block their emigration, and to promote terminal NKT cell maturation.

Rapamycin protects kidney against ischemia reperfusion injury through recruitment of NKT cells.

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Zhang, Chao; Zheng, Long; Li, Long; Wang, Lingyan; Li, Liping; Huang, Shang; Gu, Chenli; Zhang, Lexi; Yang, Cheng; Zhu, Tongyu; Rong, Ruiming

2014-08-19

NKT cells play a protective role in ischemia reperfusion (IR) injury, of which the trafficking in the body and recruitment in injured organs can be influenced by immunosuppressive therapy. Therefore, we investigated the effects of rapamycin on kidneys exposed to IR injury in early stage and on trafficking of NKT cells in a murine model. Balb/c mice were subjected to kidney 30 min ischemia followed by 24 h reperfusion. Rapamycin (2.5 ml/kg) was administered by gavage daily, starting 1 day before the operation. Renal function and histological changes were assessed. The proportion of NKT cells in peripheral blood, spleen and kidney was detected by flow cytometry. The chemokines and corresponding receptor involved in NKT cell trafficking were determined by RT-PCR and flow cytometry respectively. Rapamycin significantly improved renal function and ameliorated histological injury. In rapamycin-treated group, the proportion of NKT cells in spleen was significantly decreased but increased in peripheral blood and kidney. In addition, the CXCR3+ NKT cell in the kidney increased remarkably in the rapamycin-treated group. The chemokines, CXCL9 and CXCL10, as the ligands of CXCR3, were also increased in the rapamycin-treated kidney. Rapamycin may recruit NKT cells from spleen to the IR-induced kidney to ameliorate renal IR injury in the early stage.

Differential Recognition of CD1d-[alpha]-Galactosyl Ceramide by the V[beta]8.2 and V[beta]7 Semi-invariant NKT T Cell Receptors

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Pellicci, Daniel G.; Patel, Onisha; Kjer-Nielsen, Lars; Pang, Siew Siew; Sullivan, Lucy C.; Kyparissoudis, Konstantinos; Brooks, Andrew G.; Reid, Hugh H.; Gras, Stephanie; Lucet, Isabelle S.; Koh, Ruide; Smyth, Mark J.; Mallevaey, Thierry; Matsuda, Jennifer L.; Gapin, Laurent; McCluskey, James; Godfrey, Dale I.; Rossjohn, Jamie; PMCI-A; Monash; UCHSC; Melbourne

2009-09-02

The semi-invariant natural killer T cell receptor (NKT TCR) recognizes CD1d-lipid antigens. Although the TCR{alpha} chain is typically invariant, the {beta} chain expression is more diverse, where three V{beta} chains are commonly expressed in mice. We report the structures of V{alpha}14-V{beta}8.2 and V{alpha}14-V{beta}7 NKT TCRs in complex with CD1d-{alpha}-galactosylceramide ({alpha}-GalCer) and the 2.5 {angstrom} structure of the human NKT TCR-CD1d-{alpha}-GalCer complex. Both V{beta}8.2 and V{beta}7 NKT TCRs and the human NKT TCR ligated CD1d-{alpha}-GalCer in a similar manner, highlighting the evolutionarily conserved interaction. However, differences within the V{beta} domains of the V{beta}8.2 and V{beta}7 NKT TCR-CD1d complexes resulted in altered TCR{beta}-CD1d-mediated contacts and modulated recognition mediated by the invariant {alpha} chain. Mutagenesis studies revealed the differing contributions of V{beta}8.2 and V{beta}7 residues within the CDR2{beta} loop in mediating contacts with CD1d. Collectively we provide a structural basis for the differential NKT TCR V{beta} usage in NKT cells.

The adaptor molecule SAP plays essential roles during invariant NKT cell cytotoxicity and lytic synapse formation.

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Das, Rupali; Bassiri, Hamid; Guan, Peng; Wiener, Susan; Banerjee, Pinaki P; Zhong, Ming-Chao; Veillette, André; Orange, Jordan S; Nichols, Kim E

2013-04-25

The adaptor molecule signaling lymphocytic activation molecule-associated protein (SAP) plays critical roles during invariant natural killer T (iNKT) cell ontogeny. As a result, SAP-deficient humans and mice lack iNKT cells. The strict developmental requirement for SAP has made it difficult to discern its possible involvement in mature iNKT cell functions. By using temporal Cre recombinase-mediated gene deletion to ablate SAP expression after completion of iNKT cell development, we demonstrate that SAP is essential for T-cell receptor (TCR)-induced iNKT cell cytotoxicity against T-cell and B-cell leukemia targets in vitro and iNKT-cell-mediated control of T-cell leukemia growth in vivo. These findings are not restricted to the murine system: silencing RNA-mediated suppression of SAP expression in human iNKT cells also significantly impairs TCR-induced cytolysis. Mechanistic studies reveal that iNKT cell killing requires the tyrosine kinase Fyn, a known SAP-binding protein. Furthermore, SAP expression is required within iNKT cells to facilitate their interaction with T-cell targets and induce reorientation of the microtubule-organizing center to the immunologic synapse (IS). Collectively, these studies highlight a novel and essential role for SAP during iNKT cell cytotoxicity and formation of a functional IS.

CD28 controls the development of innate-like CD8+ T cells by promoting the functional maturation of NKT cells.

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Yousefi, Mitra; Duplay, Pascale

2013-11-01

NK T cells(NKT cells) share functional characteristics and homing properties that are distinct from conventional T cells. In this study, we investigated the contribution of CD28 in the functional development of γδ NKT and αβ NKT cells in mice. We show that CD28 promotes the thymic maturation of promyelocytic leukemia zinc finger(+) IL-4(+) NKT cells and upregulation of LFA-1 expression on NKT cells. We demonstrate that the developmental defect of γδ NKT cells in CD28-deficient mice is cell autonomous. Moreover, we show in both wild-type C57BL/6 mice and in downstream of tyrosine kinase-1 transgenic mice, a mouse model with increased numbers of γδ NKT cells, that CD28-mediated regulation of thymic IL-4(+) NKT cells promotes the differentiation of eomesodermin(+) CD44(high) innate-like CD8(+) T cells. These findings reveal a previously unappreciated mechanism by which CD28 controls NKT-cell homeostasis and the size of the innate-like CD8(+) T-cell pool. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Amelioration of NK cell function driven by Vα24+ invariant NKT cell activation in multiple myeloma.

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Iyoda, Tomonori; Yamasaki, Satoru; Hidaka, Michihiro; Kawano, Fumio; Abe, Yu; Suzuki, Kenshi; Kadowaki, Norimitsu; Shimizu, Kanako; Fujii, Shin-Ichiro

2018-02-01

NK cells represent a first line of immune defense, but are progressively dysregulated in multiple myeloma (MM) patients. To restore and facilitate their antitumor effect, NK cells are required in sufficient quantities and must be stimulated. We initially assessed the proportions of NKT and NK cells in 34 MM patients. The frequencies of both in PBMC populations correlated with those in BMMNCs irrespective of low BMMNC numbers. We then assessed the adjunctive effect of stimulating NKT cells with CD1d and α-GalCer complexes on the NK cells. The expression of NKG2D on CD56 dim CD16 + NK cells and DNAM-1 on CD56 bright CD16 - NK cells increased after NKT cell activation. Apparently, NK cell-mediated anti-tumor effects were dependent on NKG2D and DNAM-1 ligands on myeloma cells. Thus, NK cell function in patients could be ameliorated, beyond the effect of immunosuppression, by NKT cell activation. This NKT-driven NK cell therapy could represent a potential new treatment modality. Copyright © 2017 Elsevier Inc. All rights reserved.

Immunometabolic Activation of Invariant Natural Killer T Cells

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Francesca A. Ververs

2018-05-01

Full Text Available Invariant natural killer T (iNKT cells are lipid-reactive T cells with profound immunomodulatory potential. They are unique in their restriction to lipid antigens presented in CD1d molecules, which underlies their role in lipid-driven disorders such as obesity and atherosclerosis. In this review, we discuss the contribution of iNKT cell activation to immunometabolic disease, metabolic programming of lipid antigen presentation, and immunometabolic activation of iNKT cells. First, we outline the role of iNKT cells in immunometabolic disease. Second, we discuss the effects of cellular metabolism on lipid antigen processing and presentation to iNKT cells. The synthesis and processing of glycolipids and other potential endogenous lipid antigens depends on metabolic demand and may steer iNKT cells toward adopting a Th1 or Th2 signature. Third, external signals such as toll-like receptor ligands, adipokines, and cytokines modulate antigen presentation and subsequent iNKT cell responses. Finally, we will discuss the relevance of metabolic programming of iNKT cells in human disease, focusing on their role in disorders such as obesity and atherosclerosis. The critical response to metabolic changes places iNKT cells at the helm of immunometabolic disease.

CD205-TLR9-IL-12 axis contributes to CpG-induced oversensitive liver injury in HBsAg transgenic mice by promoting the interaction of NKT cells with Kupffer cells.

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Hou, Xin; Hao, Xiaolei; Zheng, Meijuan; Xu, Congfei; Wang, Jun; Zhou, Rongbin; Tian, Zhigang

2017-08-01

Gut-derived bacterial products contribute to liver inflammation and injury during chronic hepatitis B virus infection; however, the underlying mechanisms remain obscure. In this study, hepatitis B surface antigen transgenic (HBs-Tg) mice and their wild-type (WT) control C57BL/6 mice were injected with CpG-oligodeoxynucleotides (ODNs) to mimic the translocation of gut microbial products into the systemic circulation. We found that, compared with the WT mice, the HBs-Tg mice were oversensitive to CpG-ODN-induced liver injury, which was dependent on natural killer T (NKT) cells. CpG-ODN injection enhanced the expression of Fas ligand (FasL) on NKT cells. In addition, hepatocytes from the HBs-Tg mice expressed higher levels of Fas than did those from the WT mice, which was further augmented by CpG-ODN. Interaction of Fas and FasL was involved in the cytotoxicity of NKT cells against hepatocytes in the HBs-Tg mice. Moreover, Kupffer cells in the HBs-Tg mice expressed higher levels of CD205 and produced greater amounts of interleukin (IL)-12 than did those in the WT mice. Finally, the depletion of Kupffer cells, neutralization of IL-12 or specific silencing of CD205 on Kupffer cells significantly inhibited CpG-ODN-induced liver injury and NKT activation in the HBs-Tg mice. Our data suggest that CD205-expressing Kupffer cells respond to CpG-ODNs and subsequently release IL-12 to promote NKT cell activation. Activated NKT cells induce liver damage through the Fas signaling pathway in HBs-Tg mice.

The transcription factor Th-POK negatively regulates Th17 differentiation in Vα14i NKT cells

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Engel, Isaac; Zhao, Meng; Kappes, Dietmar; Taniuchi, Ichiro

2012-01-01

The majority of mouse Vα14 invariant natural killer T (Vα14i NKT) cells produce several cytokines, including IFNγ and IL-4, very rapidly after activation. A subset of these cells, known as NKT17 cells, however, differentiates in the thymus to preferentially produce IL-17. Here, we show that the transcription factor—known as T helper, Poxviruses, and Zinc-finger and Krüppel family, (Th-POK)—represses the formation of NKT17 cells. Vα14i NKT cells from Th-POK–mutant helper deficient (hd/hd) mice have increased transcripts of genes normally expressed by Th17 and NKT17 cells, and even heterozygosity for this mutation leads to dramatically increased numbers of Vα14i NKT cells that are poised to express IL-17, especially in the thymus and lymph nodes. In addition, using gene reporter mice, we demonstrate that NKT17 cells from wild-type mice express lower amounts of Th-POK than the majority population of Vα14i NKT cells. We also show that retroviral transduction of Th-POK represses the expression of the Th17 master regulator RORγT in Vα14i NKT-cell lines. Our data suggest that NKT17-cell differentiation is intrinsically regulated by Th-POK activity, with only low levels of Th-POK permissive for the differentiation of NKT17 cells. PMID:23034280

IL-21 Modulates Activation of NKT Cells in Patients with Stage IV Malignant Melanoma.

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Coquet, Jonathan M; Skak, Kresten; Davis, Ian D; Smyth, Mark J; Godfrey, Dale I

2013-10-01

Interleukin-21 (IL-21) is a common γ-chain cytokine produced by T helper and natural killer T (NKT) cells. It has been shown to regulate the response of various lymphocyte subsets including NK, NKT, T and B cells. Owing to its potent anti-tumor function in preclinical studies and its ability to induce cytotoxicity and interferon-γ (IFN-γ) production in NK and CD8 T cells, recombinant IL-21 (rIL-21) was fast-tracked into early-phase clinical trials of patients with various malignancies. In a phase 2a trial of patients with metastatic melanoma, we analyzed the frequency and function of NKT cells in patients receiving rIL-21. NKT cells were present at a low frequency, but their levels were relatively stable in patients administered rIL-21. Unlike our observations in NK and CD8 T cells, rIL-21 appeared to reduce IFN-γ and TNF production by NKT cells, whereas it enhanced IL-4 production. It also modulated the expression of cell surface markers, specifically on CD4(-) NKT cells. In addition, an increase in CD3(+)CD56(+) NKT-like cells was observed over the course of rIL-21 administration. These results highlight that IL-21 is a potent regulator of NKT cell function in vivo.

Commensal microbiota and NKT cells in the control of inflammatory diseases at mucosal surfaces.

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Zeissig, Sebastian; Blumberg, Richard S

2013-12-01

Natural Killer T (NKT) cells are a phenotypically and functionally diverse subset of T cells, which recognizes self- and microbial lipids in the context of the atypical MHC class I molecule CD1d. NKT cells exhibit potent effector functions and play critical roles in antimicrobial defense, cancer immunosurveillance and the modulation of immune-mediated disorders. Recent evidence has revealed extensive cross-regulation between the mucosal microbiota and CD1d as well as NKT cells. Microbial exposure at mucosal surfaces, particularly during early postnatal development, regulates NKT cell trafficking and function in the intestine and the lung and determines the susceptibility to NKT cell-mediated inflammatory disorders. Conversely, CD1d controls the composition of the intestinal microbiota; perhaps through the regulation of Paneth cell function. Here, we provide an overview of recent findings on the crosstalk between the microbiota and NKT cells and discuss the implication for mucosal homeostasis and its dysregulation in inflammatory disorders. Copyright © 2013 Elsevier Ltd. All rights reserved.

The interaction between regulatory T cells and NKT cells in the liver: a CD1d bridge links innate and adaptive immunity.

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Hua, Jing; Liang, Shuwen; Ma, Xiong; Webb, Tonya J; Potter, James P; Li, Zhiping

2011-01-01

Regulatory T cells (Tregs) and natural killer T (NKT) cells are two distinct lymphocyte subsets that independently regulate hepatic adaptive and innate immunity, respectively. In the current study, we examine the interaction between Tregs and NKT cells to understand the mechanisms of cross immune regulation by these cells. The frequency and function of Tregs were evaluated in wild type and NKT cell deficient (CD1dko) mice. In vitro lymphocyte proliferation and apoptosis assays were performed with NKT cells co-cultured with Tregs. The ability of Tregs to inhibit NKT cells in vivo was examined by adoptive transfer of Tregs in a model of NKT cell mediated hepatitis. CD1dko mice have a significant reduction in hepatic Tregs. Although, the Tregs from CD1dko mice remain functional and can suppress conventional T cells, their ability to suppress activation induced NKT cell proliferation and to promote NKT cell apoptosis is greatly diminished. These effects are CD1d dependent and require cell to cell contact. Adoptive transfer of Tregs inhibits NKT cell-mediated liver injury. NKT cells promote Tregs, and Tregs inhibit NKT cells in a CD1d dependent manner requiring cell to cell contact. These cross-talk immune regulations provide a linkage between innate and adaptive immunity.

The preventive role of type 2 NKT cells in the development of type 1 diabetes.

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Sørensen, Jakob Ørskov; Buschard, Karsten; Brogren, Carl-Henrik

2014-03-01

In the last two decades, natural killer T (NKT) cells have emerged as an important factor in preventing type 1 diabetes (T1D) when investigated in the experimental non-obese diabetic (NOD) mouse model. So far, investigations have largely focused on type 1 NKT cells with invariant T-cell receptors, whereas the role of type 2 NKT cells with diverse T-cell receptors is less well understood. However, there have been several findings which indicate that in fact type 2 NKT cells may regulate the progression of type 1 diabetes in NOD mice, including a fraction of these cells which recognize β-cell-enriched sulfatide. Therefore, the focus for this review is to present the current evidence of the effect of type 2 NKT cells on the development of T1D. In general, there is still uncertainty surrounding the mechanism of activation and function of NKT cells. Here, we present two models of the effector mechanisms, respectively, Th1/Th2 polarization and the induction of tolerogenic dendritic cells (DC). In conclusion, this review points to the importance of immunoregulation by type 2 NKT cells in preventing the development of T1D and highlights the induction of tolerogenic DC as a likely mechanism. The possible therapeutic role of type 1 and type 2 NKT cells are evaluated and future experiments concerning type 2 NKT cells and T1D are proposed. © 2013 APMIS. Published by John Wiley & Sons Ltd.

Adipose tissue invariant NKT cells protect against diet-induced obesity and metabolic disorder through regulatory cytokine production.

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Lynch, Lydia

2012-09-21

Invariant natural killer T (iNKT) cells are evolutionarily conserved innate T cells that influence inflammatory responses. We have shown that iNKT cells, previously thought to be rare in humans, were highly enriched in human and murine adipose tissue, and that as adipose tissue expanded in obesity, iNKT cells were depleted, correlating with proinflammatory macrophage infiltration. iNKT cell numbers were restored in mice and humans after weight loss. Mice lacking iNKT cells had enhanced weight gain, larger adipocytes, fatty livers, and insulin resistance on a high-fat diet. Adoptive transfer of iNKT cells into obese mice or in vivo activation of iNKT cells via their lipid ligand, alpha-galactocylceramide, decreased body fat, triglyceride levels, leptin, and fatty liver and improved insulin sensitivity through anti-inflammatory cytokine production by adipose-derived iNKT cells. This finding highlights the potential of iNKT cell-targeted therapies, previously proven to be safe in humans, in the management of obesity and its consequences.

The activation of the adaptive immune system: cross-talk between antigen-presenting cells, T cells and B cells.

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den Haan, Joke M M; Arens, Ramon; van Zelm, Menno C

2014-12-01

The adaptive immune system consists of T and B cells that express clonally distributed antigen receptors. To achieve functional adaptive immune responses, antigen-specific T cell populations are stimulated by professional antigen-presenting cells like dendritic cells (DCs), which provide crucial stimulatory signals for efficient expansion and development of effector functions. Antigen-specific B cells receive costimulatory signals from helper T cells to stimulate affinity maturation and isotype switching. Here we elaborate on the interactions between DCs, T cells and B cells, and on the important signals for efficient induction of adaptive immune responses. Copyright © 2014 Elsevier B.V. All rights reserved.

NK and NKT-Like Cells in Patients with Recurrent Furunculosis.

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Nowicka, Danuta; Grywalska, Ewelina; Fitas, Elżbieta; Mielnik, Michał; Roliński, Jacek

2017-12-13

To analyze changes in the number and percentage of NK and NKT-like cells in relation to other immune cells as well as to examine associations between increased susceptibility to infections and NK and NKT-like status in patients with recurrent furunculosis (RF) and healthy controls. Thirty patients with RF and 20 healthy age- and sex-matched volunteers were recruited. Blood samples were examined. Lymphocyte count and cytometric analyses were conducted. For statistical analysis, the Student's t test, F test, and Brown-Forsythe test were used for comparison between groups of variables. Associations were assessed with Pearson coefficient. Patients with RF had lower lymphocyte count than controls. Additionally, they presented with the following changes in the blood picture: a significant increase in the number of NK cells with a CD3 + CD16 + CD56 + phenotype; a proportional increase in the number and percentage of NKT-like cells with a CD3 + CD16 + CD56 + phenotype; a significant decrease in the number and percentage of T CD3 + cells. The number of NK cells was strongly positively correlated with the number of CD3 cells (r = 0.6162). The number of NKT cells was strongly positively correlated with CD3 cells (r = 0.6885) and CD3CD8 cells (r = 0.5465). Periodic exacerbations in RF are associated with the development of furuncles, which are a result of many already discovered as well as just being examined mechanisms. One of them is a significant increase in the number and most likely activation of NK and NKT-like cells during the formation of the inflammatory process and furuncles.

IL-17-producing NKT cells depend exclusively on IL-7 for homeostasis and survival.

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Webster, K E; Kim, H-O; Kyparissoudis, K; Corpuz, T M; Pinget, G V; Uldrich, A P; Brink, R; Belz, G T; Cho, J-H; Godfrey, D I; Sprent, J

2014-09-01

Natural killer T (NKT) cells are innate-like T cells that rapidly recognize pathogens and produce cytokines that shape the ensuing immune response. IL-17-producing NKT cells are enriched in barrier tissues, such as the lung, skin, and peripheral lymph nodes, and the factors that maintain this population in the periphery have not been elucidated. Here we show that NKT17 cells deviate from other NKT cells in their survival requirements. In contrast to conventional NKT cells that are maintained by IL-15, RORγt(+) NKT cells are IL-15 independent and instead rely completely on IL-7. IL-7 initiates a T-cell receptor-independent (TCR-independent) expansion of NKT17 cells, thus supporting their homeostasis. Without IL-7, survival is dramatically impaired, yet residual cells remain lineage committed with no downregulation of RORγt evident. Their preferential response to IL-7 does not reflect enhanced signaling through STAT proteins, but instead is modulated via the PI3K/AKT/mTOR signaling pathway. The ability to compete for IL-7 is dependent on high-density IL-7 receptor expression, which would promote uptake of low levels of IL-7 produced in the non-lymphoid sites of lung and skin. This dependence on IL-7 is also reported for RORγt(+) innate lymphoid cells and CD4(+) Th17 cells, and suggests common survival requirements for functionally similar cells.

Human invariant NKT cell subsets differentially promote differentiation, antibody production, and T cell stimulation by B cells in vitro.

OpenAIRE

O'REILLY, VINCENT

2013-01-01

PUBLISHED Invariant NK T (iNKT) cells can provide help for B cell activation and Ab production. Because B cells are also capable of cytokine production, Ag presentation, and T cell activation, we hypothesized that iNKT cells will also influence these activities. Furthermore, subsets of iNKT cells based on CD4 and CD8 expression that have distinct functional activities may differentially affect B cell functions. We investigated the effects of coculturing expanded human CD4(+), CD8α(+), and ...

Tolerogenic interactions between CD8+ dendritic cells and NKT cells prevent rejection of bone marrow and organ grafts.

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Hongo, David; Tang, Xiaobin; Zhang, Xiangyue; Engleman, Edgar G; Strober, Samuel

2017-03-23

The combination of total lymphoid irradiation and anti-T-cell antibodies safely induces immune tolerance to combined hematopoietic cell and organ allografts in humans. Our mouse model required host natural killer T (NKT) cells to induce tolerance. Because NKT cells normally depend on signals from CD8 + dendritic cells (DCs) for their activation, we used the mouse model to test the hypothesis that, after lymphoid irradiation, host CD8 + DCs play a requisite role in tolerance induction through interactions with NKT cells. Selective deficiency of either CD8 + DCs or NKT cells abrogated chimerism and organ graft acceptance. After radiation, the CD8 + DCs increased expression of surface molecules required for NKT and apoptotic cell interactions and developed suppressive immune functions, including production of indoleamine 2,3-deoxygenase. Injection of naive mice with apoptotic spleen cells generated by irradiation led to DC changes similar to those induced by lymphoid radiation, suggesting that apoptotic body ingestion by CD8 + DCs initiates tolerance induction. Tolerogenic CD8 + DCs induced the development of tolerogenic NKT cells with a marked T helper 2 cell bias that, in turn, regulated the differentiation of the DCs and suppressed rejection of the transplants. Thus, reciprocal interactions between CD8 + DCs and invariant NKT cells are required for tolerance induction in this system that was translated into a successful clinical protocol. © 2017 by The American Society of Hematology.

Recognition of lysophosphatidylcholine by type II NKT cells and protection from an inflammatory liver disease.

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Maricic, Igor; Girardi, Enrico; Zajonc, Dirk M; Kumar, Vipin

2014-11-01

Lipids presented by the MHC class I-like molecule, CD1d, are recognized by NK T (NKT) cells, which can be broadly categorized into two subsets. The well-characterized type I NKT cells express a semi-invariant TCR and can recognize both α- and β-linked glycolipids, whereas type II NKT cells are less well studied, express a relatively diverse TCR repertoire, and recognize β-linked lipids. Recent structural studies have shown a distinct mode of recognition of a self-glycolipid sulfatide bound to CD1d by a type II NKT TCR. To further characterize Ag recognition by these cells, we have used the structural data and screened other small molecules able to bind to CD1d and activate type II NKT cells. Using plate-bound CD1d and APC-based Ag presentation assay, we found that phospholipids such as lysophosphatidylcholine (LPC) can stimulate the sulfatide-reactive type II NKT hybridoma Hy19.3 in a CD1d-dependent manner. Using plasmon resonance studies, we found that this type II NKT TCR binds with CD1d-bound LPC with micromolar affinities similar to that for sulfatide. Furthermore, LPC-mediated activation of type II NKT cells leads to anergy induction in type I NKT cells and affords protection from Con A-induced hepatitis. These data indicate that, in addition to self-glycolipids, self-lysophospholipids are also recognized by type II NKT cells. Because lysophospholipids are involved during inflammation, our findings have implications for not only understanding activation of type II NKT cells in physiological settings, but also for the development of immune intervention in inflammatory diseases. Copyright © 2014 by The American Association of Immunologists, Inc.

Border Patrol Gone Awry: Lung NKT Cell Activation by Francisella tularensis Exacerbates Tularemia-Like Disease.

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Hill, Timothy M; Gilchuk, Pavlo; Cicek, Basak B; Osina, Maria A; Boyd, Kelli L; Durrant, Douglas M; Metzger, Dennis W; Khanna, Kamal M; Joyce, Sebastian

2015-06-01

The respiratory mucosa is a major site for pathogen invasion and, hence, a site requiring constant immune surveillance. The type I, semi-invariant natural killer T (NKT) cells are enriched within the lung vasculature. Despite optimal positioning, the role of NKT cells in respiratory infectious diseases remains poorly understood. Hence, we assessed their function in a murine model of pulmonary tularemia--because tularemia is a sepsis-like proinflammatory disease and NKT cells are known to control the cellular and humoral responses underlying sepsis. Here we show for the first time that respiratory infection with Francisella tularensis live vaccine strain resulted in rapid accumulation of NKT cells within the lung interstitium. Activated NKT cells produced interferon-γ and promoted both local and systemic proinflammatory responses. Consistent with these results, NKT cell-deficient mice showed reduced inflammatory cytokine and chemokine response yet they survived the infection better than their wild type counterparts. Strikingly, NKT cell-deficient mice had increased lymphocytic infiltration in the lungs that organized into tertiary lymphoid structures resembling induced bronchus-associated lymphoid tissue (iBALT) at the peak of infection. Thus, NKT cell activation by F. tularensis infection hampers iBALT formation and promotes a systemic proinflammatory response, which exacerbates severe pulmonary tularemia-like disease in mice.

NKT Cells in the Induced Sputum of Severe Asthmatics

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2006-01-01

Full Text Available To determine whether there was a specific inflammatory process in severe asthmatics, the phenotypic characteristics of induced sputum immune cells were analysed among patients with severe asthma. Twenty-two induced sputa (10 severe asthmatics were studied. Flow cytometric analysis was performed using immune cells of the sputum and monoclonal antibodies to CD3, CD4, CD8, CD56, CD25, and TCRγδ . The number of NKT (CD3 + CD 56+ cells was significantly higher in the sputum of severe asthmatics compared with mild asthmatic and healthy control groups ( p<.05 . CD8+CD 56+ cells were the predominant subtype of the increased NKT cells in severe asthmatics. CD3 +CD56+Vα24 +, TCRγδ CD56+, and CD4+CD25+ T cells were significantly increased in severe asthmatic patients. These results suggest that the immunopathogenesis of severe asthmatics vary between severe and mild asthmatics, and that CD8+ CD 56+ NKT cells may play an important role in the immunopathogenesis of severe asthma.

Cyclooxygenase-2 Inhibition Enhances Proliferation of NKT Cells Derived from Patients with Laryngeal Cancer.

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Klatka, Janusz; Grywalska, Ewelina; Hymos, Anna; Guz, Małgorzata; Polberg, Krzysztof; Roliński, Jacek; Stepulak, Andrzej

2017-08-01

The aim of this study was to analyze whether inhibition of cyclooxygenase-2 by celecoxib and the subsequent enhancement in the proliferation of natural killer T (NKT) cells could play a role in dendritic cell (DC)-based laryngeal cancer (LC) immunotherapy. Peripheral blood mononuclear cells were obtained from 48 male patients diagnosed with LC and 30 control patients without cancer disease. Neoplastic cell lysate preparations were made from cancer tissues obtained after surgery and used for in vitro DCs generation. NKT cells proliferation assay was performed based on 3 H-thymidine incorporation assay. An increased proliferation of NKT cells was obtained from control patients compared to NKT cells obtained from LC patients regardless of the type of stimulation or treatment. In the patient group diagnosed with LC, COX-2 inhibition resulted in a significantly enhanced proliferation of NKT cells when stimulated with autologous DCs than NKT cells stimulated with DCs without COX-2 inhibition. These correlations were not present in the control group. Higher proliferation rate of NKT cells was also observed in non-metastatic and highly differentiated LC, which was independent of the type of stimulation or treatment. COX-2 inhibition could be regarded as immunotherapy-enhancing tool in patients with LC. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

NKT cell self-reactivity: evolutionary master key of immune homeostasis?

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Issazadeh-Navikas, Shohreh

2012-04-01

Complex immune responses have evolved to protect multicellular organisms against the invasion of pathogens. This has exerted strong developmental pressure for specialized functions that can also limit damage to self-tissue. Two arms of immunity, the innate and adaptive immune systems, have evolved for quick, non-specific immune responses to pathogens and more efficient, long-lasting ones upon specific recognition of recurrent pathogens. Specialized cells have arisen as the sentinels of these functions, including macrophages, natural killer (NK), and T and B-lymphocytes. Interestingly, a population of immune cells that can exert both of these complex functions, NKT cells, not only share common functions but also exhibit shared cell surface markers of cells of both arms of the immune system. These features, in combination with sophisticated maintenance of immune homeostasis, will be discussed. The recent finding of self-peptide reactivity of NKT cells in the context of CD1d, with capacity to regulate multiple autoimmune and inflammatory conditions, motivates the current proposal that self-reactive NKT cells might be the ancestral link between present NK and T cells. Their parallel selection through evolution by higher vertebrates could be related to their central function as master regulators of immune homeostasis that in part is shared with regulatory T cells. Hypothetical views on how self-reactive NKT cells secure such a central role will also be proposed.

[Phenotypic and functional features of NK and NKT cells in chronic hepatitis B].

Science.gov (United States)

Wu, Shaofei; Li, Man; Sun, Xuehua; Zhou, Zhenhua; Zhu, Xiaojun; Zhang, Xin; Gao, Yueqiu

2015-06-01

To detect the ratio of natural killer (NK)/natural killer T (NKT) cells in peripheral blood, the levels of NKG2D/NKG2A, interferon γ (IFN-γ) and tumor necrosis factor α (TNF-α) in patients with chronic hepatitis B (CHB). Peripheral blood mononuclear cells (PBMCs) were harvested from CHB patients. The ratio of NK/NKT cells in PBMCs and the levels of NKG2D and NKG2A were detected by flow cytometry. The expressions of intracellular IFN-γ and TNF-α were analyzed by flow cytometry after the treatment with phorbol 12-myristate 13-acetate (PMA), brefeldin A (BFA) or ionomycin in vitro. The comparison between two groups was performed by independent sample t-test. The relationship of each index to hepatitis B virus load and serum alanine aminotransferase was analyzed by Pearson correlation analysis. Compared with healthy controls, CHB patients presented with significantly decreased peripheral blood NK/NKT cell ratio and significantly elevated proportions of NKG2A+ NK and NKG2A+NKT cells, and after the treatment with PMA/BFA/ionomycin, IFN-γ+ NK and IFN-γ+ NKT cells were significantly reduced in CHB patients. NK and NKT cells showed a reduced ratio, disordered receptor expressions and decreased cytokine secretion capacity in CHB patients.

Changes in NK and NKT cells in mesenteric lymph nodes after a Schistosoma japonicum infection.

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Luo, Xueping; Xie, Hongyan; Chen, Dianhui; Yu, Xiuxue; Wu, Fan; Li, Lu; Wu, Changyou; Huang, Jun

2014-03-01

The mesenteric lymph node (MLN) is the main draining lymph node in mouse enterocoelia, which contains many types of immune cells. Among these cells, natural killer (NK) and natural killer T (NKT) cells belong to innate lymphoid cells (ILCs), which have potent activities for controlling a variety of pathogenic infections. In this study, C57BL/6 mice were infected with Schistosoma japonicum for 5-7 weeks. Lymphocytes were isolated from the MLN to detect changes in the phenotype and function of NK and NKT cells using a fluorescence activating cell sorter (FACS). These results demonstrated that a S. japonicum infection could significantly increase the percentage of NK cells in the mouse MLN, (P cell number of both NK and NKT cells. In addition, we found that NK and NKT cells from infected mice expressed higher levels of CD69 compared to normal mice (P NKT cell activation. Moreover, we found that the expression of CD4 was increased in infected MLN NK cells (P NKT cells of infected mice after phorbol 12-myristate 13-acetate (PMA) and ionomycin stimulation (P NKT cells might play roles in modulating the classical T cell response. Finally, our results indicated that the expression of CD94 was decreased in NK cells, suggesting that the downregulation of CD94 expression might served as a mechanism in NK cell activation.

Recognition of microbial glycolipids by Natural Killer T cells

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Dirk Michael Zajonc

2015-08-01

Full Text Available T cells can recognize microbial antigens when presented by dedicated antigen-presenting molecules. While peptides are presented by classical members of the Major Histocompatibility (MHC family (MHC I and II, lipids, glycolipids and lipopeptides can be presented by the non-classical MHC member CD1. The best studied subset of lipid-reactive T cells are Type I Natural killer T (iNKT cells that recognize a variety of different antigens when presented by the non-classical MHCI homolog CD1d. iNKT cells have been shown to be important for the protection against various microbial pathogens, including B. burgdorferi the causative agents of Lyme disease and S. pneumoniae, which causes pneumococcal meningitis and community-acquired pneumonia. Both pathogens carry microbial glycolipids that can trigger the T cell antigen receptor (TCR, leading to iNKT cell activation. iNKT cells have an evolutionary conserved TCR alpha chain, yet retain the ability to recognize structurally diverse glycolipids. They do so using a conserved recognition mode, in which the TCR enforces a conserved binding orientation on CD1d. TCR binding is accompanied by structural changes within the TCR binding site of CD1d, as well as the glycolipid antigen itself. In addition to direct recognition of microbial antigens, iNKT cells can also be activated by a combination of cytokines (IL-12/IL-18 and TCR stimulation. Many microbes carry TLR antigens and microbial infections can lead to TLR activation. The subsequent cytokine response in turn lower the threshold of TCR mediated iNKT cell activation, especially when weak microbial or even self-antigens are presented during the cause of the infection. In summary, iNKT cells can be directly activated through TCR triggering of strong antigens, while cytokines produced by the innate immune response may be necessary for TCR triggering and iNKT cell activation in the presence of weak antigens. Here we will review the molecular basis of iNKT cell

NKp46 identifies an NKT cell subset susceptible to leukemic transformation in mouse and human

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Yu, Jianhua; Mitsui, Takeki; Wei, Min; Mao, Hsiaoyin; Butchar, Jonathan P.; Shah, Mithun Vinod; Zhang, Jianying; Mishra, Anjali; Alvarez-Breckenridge, Christopher; Liu, Xingluo; Liu, Shujun; Yokohama, Akihiko; Trotta, Rossana; Marcucci, Guido; Benson, Don M.; Loughran, Thomas P.; Tridandapani, Susheela; Caligiuri, Michael A.

2011-01-01

IL-15 may have a role in the development of T cell large granular lymphocyte (T-LGL) or NKT leukemias. However, the mechanisms of action and the identity of the cell subset that undergoes leukemic transformation remain elusive. Here we show that in both mice and humans, NKp46 expression marks a minute population of WT NKT cells with higher activity and potency to become leukemic. Virtually 100% of T-LGL leukemias in IL-15 transgenic mice expressed NKp46, as did a majority of human T-LGL leukemias. The minute NKp46+ NKT population, but not the NKp46– NKT population, was selectively expanded by overexpression of endogenous IL-15. Importantly, IL-15 transgenic NKp46– NKT cells did not become NKp46+ in vivo, suggesting that NKp46+ T-LGL leukemia cells were the malignant counterpart of the minute WT NKp46+ NKT population. Mechanistically, NKp46+ NKT cells possessed higher responsiveness to IL-15 in vitro and in vivo compared with that of their NKp46– NKT counterparts. Furthermore, interruption of IL-15 signaling using a neutralizing antibody could prevent LGL leukemia in IL-15 transgenic mice. Collectively, our data demonstrate that NKp46 identifies a functionally distinct NKT subset in mice and humans that appears to be directly susceptible to leukemic transformation when IL-15 is overexpressed. Thus, IL-15 signaling and NKp46 may be useful targets in the treatment of patients with T-LGL or NKT leukemia. PMID:21364281

Uhrf1 Controls iNKT Cell Survival and Differentiation through the Akt-mTOR Axis

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Yu Cui

2016-04-01

Full Text Available Uhrf1 (also known as Np95 is a regulator of DNA methylation and histone ubiquitination and plays an important role in embryogenesis and tumorigenesis. Here, we report that Uhrf1 is essential for invariant natural killer T (iNKT cell development. We found that Uhrf1 was significantly upregulated in stage 1 iNKT cells. Targeted disruption of Uhrf1 resulted in stage 1-specific transition defects as observed by not only increased apoptosis, but also aberrant effector differentiation, which eventually led to the impaired generation of iNKT cells in Uhrf1-deficient mice. Notably, Uhrf1 deficiency resulted in attenuated activation of Akt-mTOR signaling in stage 1 iNKT cells and overexpression of active Akt rescued iNKT cell developmental defects. Collectively, our results suggest that Uhrf1 regulation of the Akt-mTOR signaling pathway is required for iNKT cell development.

The cytokine profile of human NKT cells and PBMCs is dependent on donor sex and stimulus.

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Bernin, Hannah; Fehling, Helena; Marggraff, Claudia; Tannich, Egbert; Lotter, Hannelore

2016-08-01

Sex-related variations in natural killer T (NKT) cells may influence immunoregulation and outcome of infectious and autoimmune diseases. We analyzed sex-specific differences in peripheral blood NKTs and peripheral blood mononuclear cells (PBMCs) from men and women and determined the frequencies of NKT cells and their subpopulations [CD4(+); CD8(+); double negative (DN)] and the levels of cytokine production following stimulation with the NKT cell ligands α-Galactosylceramide (αGalCer) and Entamoeba histolytica lipopeptidephosphoglycan (Lotter et al. in PLoS Pathog 5(5):e1000434, 2009). Total and DN NKT cells were more abundant in women than in men. In women, αGalCer induced higher production of intracellular IFNγ, IL-4, IL-17 and TNF by CD4(+) and DN(+)NKT cells. Both ligands induced expression of multiple cytokines in PBMCs and influenced the ratio of NKT cell subpopulations during long-term culture. Although the sex-specific differences in frequencies of NKT cells and their subpopulations were marginal, the significant sex-specific differences in cytokine production might influence disease outcomes.

RASAL3, a novel hematopoietic RasGAP protein, regulates the number and functions of NKT cells.

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Saito, Suguru; Kawamura, Toshihiko; Higuchi, Masaya; Kobayashi, Takahiro; Yoshita-Takahashi, Manami; Yamazaki, Maya; Abe, Manabu; Sakimura, Kenji; Kanda, Yasuhiro; Kawamura, Hiroki; Jiang, Shuying; Naito, Makoto; Yoshizaki, Takumi; Takahashi, Masahiko; Fujii, Masahiro

2015-05-01

Ras GTPase-activating proteins negatively regulate the Ras/Erk signaling pathway, thereby playing crucial roles in the proliferation, function, and development of various types of cells. In this study, we identified a novel Ras GTPase-activating proteins protein, RASAL3, which is predominantly expressed in cells of hematopoietic lineages, including NKT, B, and T cells. We established systemic RASAL3-deficient mice, and the mice exhibited a severe decrease in NKT cells in the liver at 8 weeks of age. The treatment of RASAL3-deficient mice with α-GalCer, a specific agonist for NKT cells, induced liver damage, but the level was less severe than that in RASAL3-competent mice, and the attenuated liver damage was accompanied by a reduced production of interleukin-4 and interferon-γ from NKT cells. RASAL3-deficient NKT cells treated with α-GalCer in vitro presented augmented Erk phosphorylation, suggesting that there is dysregulated Ras signaling in the NKT cells of RASAL3-deficient mice. Taken together, these results suggest that RASAL3 plays an important role in the expansion and functions of NKT cells in the liver by negatively regulating Ras/Erk signaling, and might be a therapeutic target for NKT-associated diseases. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effective antigen presentation to helper T cells by human eosinophils.

Science.gov (United States)

Farhan, Ruhaifah K; Vickers, Mark A; Ghaemmaghami, Amir M; Hall, Andrew M; Barker, Robert N; Walsh, Garry M

2016-12-01

Although eosinophils are inflammatory cells, there is increasing attention on their immunomodulatory roles. For example, murine eosinophils can present antigen to CD4 + T helper (Th) cells, but it remains unclear whether human eosinophils also have this ability. This study determined whether human eosinophils present a range of antigens, including allergens, to activate Th cells, and characterized their expression of MHC class II and co-stimulatory molecules required for effective presentation. Human peripheral blood eosinophils purified from non-allergic donors were pulsed with the antigens house dust mite extract (HDM), Timothy Grass extract (TG) or Mycobacterium tuberculosis purified protein derivative (PPD), before co-culture with autologous CD4 + Th cells. Proliferative and cytokine responses were measured, with eosinophil expression of HLA-DR/DP/DQ and the co-stimulatory molecules CD40, CD80 and CD86 determined by flow cytometry. Eosinophils pulsed with HDM, TG or PPD drove Th cell proliferation, with the response strength dependent on antigen concentration. The cytokine responses varied with donor and antigen, and were not biased towards any particular Th subset, often including combinations of pro- and anti-inflammatory cytokines. Eosinophils up-regulated surface expression of HLA-DR/DP/DQ, CD80, CD86 and CD40 in culture, increases that were sustained over 5 days when incubated with antigens, including HDM, or the major allergens it contains, Der p I or Der p II. Human eosinophils can, therefore, act as effective antigen-presenting cells to stimulate varied Th cell responses against a panel of antigens including HDM, TG or PPD, an ability that may help to determine the development of allergic disease. © 2016 John Wiley & Sons Ltd.

A possible role for NKT-like cells in patients with chronic hepatitis B during telbivudine treatment.

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Diao, Hongyan; He, Jianqin; Zheng, Qishi; Chen, Jianing; Cui, Guangying; Wei, Yingfeng; Ye, Ping; Kohanawa, Masashi; Li, Lanjuan

2014-07-01

Natural killer T-like (NKT-like) cells are a source of different pro-inflammatory cytokines and therefore may be involved in inflammatory processes. However, little is known about NKT-like cells during antiviral therapy. In this study, we observed significantly higher numbers of CD3(+)CD56(+) cells in patients with chronic hepatitis B (CHB) than healthy controls. Importantly, CD3(+)CD56(+) NKT-like cells markedly decreased during telbivudine treatment in patients with CHB, and a positive correlation between NKT-like cell frequency and the serum HBV DNA level was observed during early antiviral therapy. Interestingly, NKT-like cell frequency significantly reduced in well-responders at week 12 of telbivudine therapy compared to baseline, but did not significantly change in non-responders after treatment. Previous studies have shown that interleukin (IL)-17 plays a role in the pathogenesis of CHB. Serum IL-17 levels reduced significantly during early antiviral therapy, however, interferon (IFN)-γ, IL-6 and tumor necrosis factor (TNF)-α levels did not change significantly. A positive correlation was observed between the NKT-like cell frequency and serum IL-17 level in CHB patients, and NKT-like cells isolated from patients with CHB secreted substantial amounts of IL-17 in vitro. These results suggest that the NKT-like cell frequency may be one of useful immunologic marker for evaluating the efficacy of anti-HBV therapy, and that NKT-like cells are also an important source of IL-17 (in addition to conventional T cells) in patients with CHB. Copyright © 2014 Elsevier B.V. All rights reserved.

Lactic acid in tumor microenvironments causes dysfunction of NKT cells by interfering with mTOR signaling.

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Xie, Di; Zhu, Shasha; Bai, Li

2016-12-01

Cellular metabolism has been shown to regulate differentiation and function of immune cells. Tumor associated immune cells undergo phenotypic and functional alterations due to the change of cellular metabolism in tumor microenvironments. NKT cells are good candidates for immunotherapies against tumors and have been used in several clinical trials. However, the influences of tumor microenvironments on NKT cell functions remain unclear. In our studies, lactic acid in tumor microenvironments inhibited IFNγ and IL4 productions from NKT cells, and more profound influence on IFNγ was observed. By adjusting the pH of culture medium we further showed that, dysfunction of NKT cells could simply be induced by low extracellular pH. Moreover, low extracellular pH inhibited NKT cell functions by inhibiting mammalian target of rapamycin (mTOR) signaling and nuclear translocation of promyelocytic leukemia zinc-finger (PLZF). Together, our results suggest that tumor acidic microenvironments could interfere with NKT cell functions through metabolic controls.

Innate invariant NKT cells recognize Mycobacterium tuberculosis-infected macrophages, produce interferon-gamma, and kill intracellular bacteria.

Directory of Open Access Journals (Sweden)

Isabel Sada-Ovalle

2008-12-01

Full Text Available Cellular immunity to Mycobacterium tuberculosis (Mtb requires a coordinated response between the innate and adaptive arms of the immune system, resulting in a type 1 cytokine response, which is associated with control of infection. The contribution of innate lymphocytes to immunity against Mtb remains controversial. We established an in vitro system to study this question. Interferon-gamma is produced when splenocytes from uninfected mice are cultured with Mtb-infected macrophages, and, under these conditions, bacterial replication is suppressed. This innate control of bacterial replication is dependent on CD1d-restricted invariant NKT (iNKT cells, and their activation requires CD1d expression by infected macrophages as well as IL-12 and IL-18. We show that iNKT cells, even in limiting quantities, are sufficient to restrict Mtb replication. To determine whether iNKT cells contribute to host defense against tuberculosis in vivo, we adoptively transferred iNKT cells into mice. Primary splenic iNKT cells obtained from uninfected mice significantly reduce the bacterial burden in the lungs of mice infected with virulent Mtb by the aerosol route. Thus, iNKT cells have a direct bactericidal effect, even in the absence of synthetic ligands such as alpha-galactosylceramide. Our finding that iNKT cells protect mice against aerosol Mtb infection is the first evidence that CD1d-restricted NKT cells mediate protection against Mtb in vivo.

Restored Circulating Invariant NKT Cells Are Associated with Viral Control in Patients with Chronic Hepatitis B

Science.gov (United States)

Jiang, Xiaotao; Zhang, Mingxia; Lai, Qintao; Huang, Xuan; Li, Yongyin; Sun, Jian; Abbott, William G.H.; Ma, Shiwu; Hou, Jinlin

2011-01-01

Invariant NKT (iNKT) cells are involved in the pathogenesis of various infectious diseases. However, their role in hepatitis B virus (HBV) infection is not fully understood, especially in human species. In this study, 35 chronic hepatitis B (CHB) patients, 25 inactive carriers (IC) and 36 healthy controls (HC) were enrolled and the proportions of circulating iNKT cells in fresh isolated peripheral blood mononuclear cells (PBMC) were detected by flow cytometry. A longitudinal analysis was also conducted in 19 CHB patients who received antiviral therapy with telbivudine. Thereafter, the immune functions of iNKT cells were evaluated by cytokine secretion and a two-chamber technique. The median frequency of circulating iNKT cells in CHB patients (0.13%) was lower than that in HC (0.24%, P = 0.01) and IC (0.19%, P = 0.02), and increased significantly during antiviral therapy with telbivudine (P = 0.0176). The expressions of CC chemokine receptor 5 (CCR5) and CCR6 were dramatically higher on iNKT cells (82.83%±9.87%, 67.67%±16.83% respectively) than on conventional T cells (30.5%±5.65%, 14.02%±5.92%, both P<0.001) in CHB patients. Furthermore, iNKT cells could migrate toward the CC chemokine ligand 5. Patients with a high ratio (≥1.0) of CD4−/CD4+ iNKT cells at baseline had a higher rate (58.33%) of HBeAg seroconversion than those with a low ratio (<1.0, 0%, P = 0.0174). In conclusion, there is a low frequency of peripheral iNKT cells in CHB patients, which increases to normal levels with viral control. The ratio of CD4−/CD4+ iNKT cells at baseline may be a useful predictor for HBeAg seroconversion in CHB patients on telbivudine therapy. PMID:22194934

Foxp3 regulates ratio of Treg and NKT cells in a mouse model of asthma.

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Lu, Yanming; Guo, Yinshi; Xu, Linyun; Li, Yaqin; Cao, Lanfang

2015-05-01

Chronic inflammatory disorder of the airways causes asthma. Regulatory T cells (Treg cells) and Natural killer T cells (NKT cells) both play critical roles in the pathogenesis of asthma. Activation of Treg cells requires Foxp3, whereas whether Foxp3 may regulate the ratio of Treg and NKT cells to affect asthma is uncertain. In an ovalbumin (OVA)-induced mouse model of asthma, we either increased Treg cells by lentivirus-mediated forced expression of exogenous Foxp3, or increased NKT cells by stimulation with its activator α-GalCer. We found that the CD4+CD25+ Treg cells increased by forced Foxp3 expression, and decreased by α-GalCer, while the CD3+CD161+ NKT cells decreased by forced Foxp3 expression, and increased by α-GalCer. Moreover, forced Foxp3 expression, but not α-GalCer, significantly alleviated the hallmarks of asthma. Furthermore, forced Foxp3 increased levels of IL_10 and TGFβ1, and α-GalCer increased levels of IL_4 and INFγ in the OVA-treated lung. Taken together, our study suggests that Foxp3 may activate Treg cells and suppress NKT cells in asthma. Treg and NKT cells may antagonize the effects of each other in asthma.

Skewed distribution of circulating activated natural killer T (NKT) cells in patients with common variable immunodeficiency disorders (CVID).

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Carvalho, Karina I; Melo, Karina M; Bruno, Fernanda R; Snyder-Cappione, Jennifer E; Nixon, Douglas F; Costa-Carvalho, Beatriz T; Kallas, Esper G

2010-09-09

Common variable immunodeficiency disorder (CVID) is the commonest cause of primary antibody failure in adults and children, and characterized clinically by recurrent bacterial infections and autoimmune manifestations. Several innate immune defects have been described in CVID, but no study has yet investigated the frequency, phenotype or function of the key regulatory cell population, natural killer T (NKT) cells. We measured the frequencies and subsets of NKT cells in patients with CVID and compared these to healthy controls. Our results show a skewing of NKT cell subsets, with CD4+ NKT cells at higher frequencies, and CD8+ NKT cells at lower frequencies. However, these cells were highly activated and expression CD161. The NKT cells had a higher expression of CCR5 and concomitantly expression of CCR5+CD69+CXCR6 suggesting a compensation of the remaining population of NKT cells for rapid effector action.

Pak2 Controls Acquisition of NKT Cell Fate by Regulating Expression of the Transcription Factors PLZF and Egr2

Science.gov (United States)

O’Hagan, Kyle L.; Zhao, Jie; Pryshchep, Olga; Wang, Chyung-Ru

2015-01-01

NKT cells constitute a small population of T cells developed in the thymus that produce large amounts of cytokines and chemokines in response to lipid Ags. Signaling through the Vα14-Jα18 TCR instructs commitment to the NKT cell lineage, but the precise signaling mechanisms that instruct their lineage choice are unclear. In this article, we report that the cytoskeletal remodeling protein, p21-activated kinase 2 (Pak2), was essential for NKT cell development. Loss of Pak2 in T cells reduced stage III NKT cells in the thymus and periphery. Among different NKT cell subsets, Pak2 was necessary for the generation and function of NKT1 and NKT2 cells, but not NKT17 cells. Mechanistically, expression of Egr2 and promyelocytic leukemia zinc finger (PLZF), two key transcription factors for acquiring the NKT cell fate, were markedly diminished in the absence of Pak2. Diminished expression of Egr2 and PLZF were not caused by aberrant TCR signaling, as determined using a Nur77-GFP reporter, but were likely due to impaired induction and maintenance of signaling lymphocyte activation molecule 6 expression, a TCR costimulatory receptor required for NKT cell development. These data suggest that Pak2 controls thymic NKT cell development by providing a signal that links Egr2 to induce PLZF, in part by regulating signaling lymphocyte activation molecule 6 expression. PMID:26519537

Components of Streptococcus pneumoniae suppress allergic airways disease and NKT cells by inducing regulatory T cells.

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Thorburn, Alison N; Foster, Paul S; Gibson, Peter G; Hansbro, Philip M

2012-05-01

Asthma is an allergic airways disease (AAD) caused by dysregulated immune responses and characterized by eosinophilic inflammation, mucus hypersecretion, and airway hyperresponsiveness (AHR). NKT cells have been shown to contribute to AHR in some mouse models. Conversely, regulatory T cells (Tregs) control aberrant immune responses and maintain homeostasis. Recent evidence suggests that Streptococcus pneumoniae induces Tregs that have potential to be harnessed therapeutically for asthma. In this study, mouse models of AAD were used to identify the S. pneumoniae components that have suppressive properties, and the mechanisms underlying suppression were investigated. We tested the suppressive capacity of type-3-polysaccharide (T3P), isolated cell walls, pneumolysoid (Ply) and CpG. When coadministered, T3P + Ply suppressed the development of: eosinophilic inflammation, Th2 cytokine release, mucus hypersecretion, and AHR. Importantly, T3P + Ply also attenuated features of AAD when administered during established disease. We show that NKT cells contributed to the development of AAD and also were suppressed by T3P + Ply treatment. Furthermore, adoptive transfer of NKT cells induced AHR, which also could be reversed by T3P + Ply. T3P + Ply-induced Tregs were essential for the suppression of NKT cells and AAD, which was demonstrated by Treg depletion. Collectively, our results show that the S. pneumoniae components T3P + Ply suppress AAD through the induction of Tregs that blocked the activity of NKT cells. These data suggest that S. pneumoniae components may have potential as a therapeutic strategy for the suppression of allergic asthma through the induction of Tregs and suppression of NKT cells.

Differential inhibitory and activating NK cell receptor levels and NK/NKT-like cell functionality in chronic and recovered stages of chikungunya.

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Thanapati, Subrat; Ganu, Mohini A; Tripathy, Anuradha S

2017-01-01

The role of natural killer (NK; CD3-CD56+)/NKT (CD3+CD56+)-like cells in chikungunya virus (CHIKV) disease progression/recovery remains unclear. Here, we investigated the expression profiles and function of NK and NKT-like cells from 35 chronic chikungunya patients, 30 recovered individuals, and 69 controls. Percentage of NKT-like cells was low in chronic chikungunya patients. NKp30+, CD244+, DNAM-1+, and NKG2D+ NK cell percentages were also lower (MFI and/or percentage), while those of CD94+ and NKG2A+ NKT-like cells were higher (MFI and/or percentage) in chronic patients than in recovered subjects. IFN-γ and TNF-α expression on NKT-like cells was high in the chronic patients, while only IFN-γ expression on NK cells was high in the recovered individuals. Furthermore, percentage of perforin+NK cells was low in the chronic patients. Lower cytotoxic activity was observed in the chronic patients than in the controls. CD107a expression on NK and NKT-like cells post anti-CD94/anti-NKG2A blocking was comparable among the patients and controls. Upregulated inhibitory and downregulated activating NK receptor expressions on NK/NKT-like cells, lower perforin+ and CD107a+NK cells are likely responsible for inhibiting the NK and NKT-like cell function in the chronic stage of chikungunya. Therefore, deregulation of NKR expression might underlie CHIKV-induced chronicity.

Pak2 Controls Acquisition of NKT Cell Fate by Regulating Expression of the Transcription Factors PLZF and Egr2.

Science.gov (United States)

O'Hagan, Kyle L; Zhao, Jie; Pryshchep, Olga; Wang, Chyung-Ru; Phee, Hyewon

2015-12-01

NKT cells constitute a small population of T cells developed in the thymus that produce large amounts of cytokines and chemokines in response to lipid Ags. Signaling through the Vα14-Jα18 TCR instructs commitment to the NKT cell lineage, but the precise signaling mechanisms that instruct their lineage choice are unclear. In this article, we report that the cytoskeletal remodeling protein, p21-activated kinase 2 (Pak2), was essential for NKT cell development. Loss of Pak2 in T cells reduced stage III NKT cells in the thymus and periphery. Among different NKT cell subsets, Pak2 was necessary for the generation and function of NKT1 and NKT2 cells, but not NKT17 cells. Mechanistically, expression of Egr2 and promyelocytic leukemia zinc finger (PLZF), two key transcription factors for acquiring the NKT cell fate, were markedly diminished in the absence of Pak2. Diminished expression of Egr2 and PLZF were not caused by aberrant TCR signaling, as determined using a Nur77-GFP reporter, but were likely due to impaired induction and maintenance of signaling lymphocyte activation molecule 6 expression, a TCR costimulatory receptor required for NKT cell development. These data suggest that Pak2 controls thymic NKT cell development by providing a signal that links Egr2 to induce PLZF, in part by regulating signaling lymphocyte activation molecule 6 expression. Copyright © 2015 by The American Association of Immunologists, Inc.

The adaptor protein SAP regulates type II NKT-cell development, cytokine production, and cytotoxicity against lymphoma.

Science.gov (United States)

Weng, Xiufang; Liao, Chia-Min; Bagchi, Sreya; Cardell, Susanna L; Stein, Paul L; Wang, Chyung-Ru

2014-12-01

CD1d-restricted NKT cells represent a unique lineage of immunoregulatory T cells that are divided into two groups, type I and type II, based on their TCR usage. Because there are no specific tools to identify type II NKT cells, little is known about their developmental requirements and functional regulation. In our previous study, we showed that signaling lymphocytic activation molecule associated protein (SAP) is essential for the development of type II NKT cells. Here, using a type II NKT-cell TCR transgenic mouse model, we demonstrated that CD1d-expressing hematopoietic cells, but not thymic epithelial cells, meditate efficient selection of type II NKT cells. Furthermore, we showed that SAP regulates type II NKT-cell development by controlling early growth response 2 protein and promyelocytic leukemia zinc finger expression. SAP-deficient 24αβ transgenic T cells (24αβ T cells) exhibited an immature phenotype with reduced Th2 cytokine-producing capacity and diminished cytotoxicity to CD1d-expressing lymphoma cells. The impaired IL-4 production by SAP-deficient 24αβ T cells was associated with reduced IFN regulatory factor 4 and GATA-3 induction following TCR stimulation. Collectively, these data suggest that SAP is critical for regulating type II NKT cell responses. Aberrant responses of these T cells may contribute to the immune dysregulation observed in X-linked lymphoproliferative disease caused by mutations in SAP. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

NKT cell self-reactivity: evolutionary master key of immune homeostasis?

DEFF Research Database (Denmark)

Navikas, Shohreh

2011-01-01

Complex immune responses have evolved to protect multicellular organisms against the invasion of pathogens. This has exerted strong developmental pressure for specialized functions that can also limit damage to self-tissue. Two arms of immunity, the innate and adaptive immune system, have evolved...... through evolution by higher vertebrates could be related to their central function as master regulators of immune homeostasis that in part is shared with regulatory T cells. Hypothetical views on how self-reactive NKT cells secure such a central role will also be proposed.......Complex immune responses have evolved to protect multicellular organisms against the invasion of pathogens. This has exerted strong developmental pressure for specialized functions that can also limit damage to self-tissue. Two arms of immunity, the innate and adaptive immune system, have evolved....... The recent finding of self-peptide reactivity of NKT cells in the context of CD1d, with capacity to regulate multiple autoimmune and inflammatory conditions, motivates the current proposal that self-reactive NKT cells might be the ancestral link between present NK and T cells. Their parallel selection...

NKT cells mediate the recruitment of neutrophils by stimulating epithelial chemokine secretion during colitis.

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Huang, Enyu; Liu, Ronghua; Lu, Zhou; Liu, Jiajing; Liu, Xiaoming; Zhang, Dan; Chu, Yiwei

2016-05-27

Ulcerative colitis (UC) is a kind of inflammatory bowel diseases characterized by chronic inflammation and ulcer in colon, and UC patients have increased risk of getting colorectal cancer. NKT cells are cells that express both NK cell markers and semi-invariant CD1d-restricted TCRs, can regulate immune responses via secreting a variety of cytokines upon activation. In our research, we found that the NKT cell-deficient CD1d(-/-) mice had relieved colitis in the DSS-induced colitis model. Further investigations revealed that the colon of CD1d(-/-) mice expressed less neutrophil-attracting chemokine CXCL 1, 2 and 3, and had decreased neutrophil infiltration. Infiltrated neutrophils also produced less reactive oxygen species (ROS) and TNF-α, indicating they may cause less epithelial damage. In addition, colitis-associated colorectal cancer was also relieved in CD1d(-/-) mice. During colitis, NKT cells strongly expressed TNF-α, which could stimulate CXCL 1, 2, 3 expressions by the epithelium. In conclusion, NKT cells can regulate colitis via the NKT cell-epithelium-neutrophil axis. Targeting this mechanism may help to improve the therapy of UC and prevent colitis-associated colorectal cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

Reconfiguration of NKT Cell Subset Compartment Is Associated with Plaque Development in Patients with Carotid Artery Stenosis.

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Cai, Lun; Yu, Lei; Liu, Sa; Li, Tongxun; Zhang, Xiaoping; Cui, Wei; Du, Jie; Zhang, Qinyi

2017-02-01

Accumulating evidence shows that immune cells play an important role in carotid atherosclerotic plaque development. In this study, we assessed the association of 6 different natural killer T (NKT) cell subsets, based on CD57 and CD8 expression, with risk for development of carotid atherosclerotic plaque (CAP). Molecular expression by peripheral NKT cells was evaluated in 13 patients with high-risk CAP and control without carotid stenosis (n = 18). High-risk CAP patients, compared with healthy subjects, had less percentage of CD57+CD8- NKT cell subsets (8.64 ± 10.15 versus 19.62 ± 10.8 %; P = 0.01) and CD57+CD8int NKT cell subsets (4.32 ± 3.04 versus 11.87 ± 8.56 %; P = 0.002), with a corresponding increase in the CD57-CD8high NKT cell subsets (33.22 ± 11.87 versus 18.66 ± 13.68 %; P = 0.007). Intracellular cytokine staining showed that CD8+ NKT cell subset was the main cytokine-producing NKT cell. Cytokine production in plasma was measured with Bio-Plex assay. The expression levels of pro-inflammatory mediators (IFN-γ, IL-17, IP-10) were significantly higher in CAP patients as compared to that from controls. These data provide evidence that NKT cell subset compartment reconfiguration in patients with carotid stenosis seems to be associated with the occurrence of carotid atherosclerotic plaque and suggest that both pathogenic and protective NKT cell subsets exist.

Dendritic cells and anergic type I NKT cells play a crucial role in sulfatide-mediated immune regulation in experimental autoimmune encephalomyelitis.

Science.gov (United States)

Maricic, Igor; Halder, Ramesh; Bischof, Felix; Kumar, Vipin

2014-08-01

CD1d-restricted NKT cells can be divided into two groups: type I NKT cells use a semi-invariant TCR, whereas type II express a relatively diverse set of TCRs. A major subset of type II NKT cells recognizes myelin-derived sulfatides and is selectively enriched in the CNS tissue during experimental autoimmune encephalomyelitis (EAE). We have shown that activation of sulfatide-reactive type II NKT cells by sulfatide prevents induction of EAE. In this article, we have addressed the mechanism of regulation, as well as whether a single immunodominant form of synthetic sulfatide can treat ongoing chronic and relapsing EAE in SJL/J mice. We have shown that the activation of sulfatide-reactive type II NKT cells leads to a significant reduction in the frequency and effector function of myelin proteolipid proteins 139-151/I-A(s)-tetramer(+) cells in lymphoid and CNS tissues. In addition, type I NKT cells and dendritic cells (DCs) in the periphery, as well as CNS-resident microglia, are inactivated after sulfatide administration, and mice deficient in type I NKT cells are not protected from disease. Moreover, tolerized DCs from sulfatide-treated animals can adoptively transfer protection into naive mice. Treatment of SJL/J mice with a synthetic cis-tetracosenoyl sulfatide, but not α-galactosylceramide, reverses ongoing chronic and relapsing EAE. Our data highlight a novel immune-regulatory pathway involving NKT subset interactions leading to inactivation of type I NKT cells, DCs, and microglial cells in suppression of autoimmunity. Because CD1 molecules are nonpolymorphic, the sulfatide-mediated immune-regulatory pathway can be targeted for development of non-HLA-dependent therapeutic approaches to T cell-mediated autoimmune diseases. Copyright © 2014 by The American Association of Immunologists, Inc.

Altered phenotypic and functional characteristics of CD3+CD56+ NKT-like cells in human gastric cancer.

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Peng, Liu-Sheng; Mao, Fang-Yuan; Zhao, Yong-Liang; Wang, Ting-Ting; Chen, Na; Zhang, Jin-Yu; Cheng, Ping; Li, Wen-Hua; Lv, Yi-Pin; Teng, Yong-Sheng; Guo, Gang; Luo, Ping; Chen, Weisan; Zou, Quan-Ming; Zhuang, Yuan

2016-08-23

CD3+CD56+ natural killer T (NKT)-like cells are a group of CD3+ T cells sharing characteristics of NK and T cells and constitute a major component of host anti-tumor immune response in human cancer. However, the nature, function and clinical relevance of CD3+CD56+ NKT-like cells in human gastric cancer (GC) remain unclear. In this study, we showed that the frequencies of CD3+CD56+NKT-like cells in GC tumors were significantly decreased and low levels of tumor-infiltrating CD3+CD56+ NKT-like cells were positively correlated with poor survival and disease progression. Most CD3+CD56+NKT-like cells in GC tumors were CD45RA-CD27+/- central/effector-memory cells with decreased activity and lower expression levels of CD69, NKG2D and DNAM-1 than those in non-tumor tissues. We further observed that tumor-infiltrating CD3+CD56+ NKT-like cells had impaired effector function as shown by decreased IFN-γ, TNF-α, granzyme B and Ki-67 expression. Moreover, in vitro studies showed that soluble factors released from GC tumors could induce the functional impairment of CD3+CD56+ NKT-like cells. Collectively, our data indicate that decreased tumor-infiltrating CD3+CD56+ NKT-like cells with impaired effector function are associated with tumor progression and poor survival of GC patients, which may contribute to immune escape of GC.

The Adaptor Protein SAP Regulates Type II NKT Cell Development, Cytokine Production and Cytotoxicity Against Lymphoma1

Science.gov (United States)

Weng, Xiufang; Liao, Chia-Min; Bagchi, Sreya; Cardell, Susanna L.; Stein, Paul L.; Wang, Chyung-Ru

2014-01-01

CD1d-restricted NKT cells represent a unique lineage of immunoregulatory T cells that are divided into two groups, type I and type II, based on their TCR usage. Because there are no specific tools to identify type II NKT cells, little is known about their developmental requirements and functional regulation. In our previous study, we showed that signaling lymphocytic activation molecule-associated protein (SAP) is essential for the development of type II NKT cells. Here, using a type II NKT cell TCR transgenic mouse model (24αβTg), we demonstrated that CD1d-expressing hematopoietic cells but not thymic epithelial cells meditate efficient selection of type II NKT cells. Further, we showed that SAP regulates type II NKT cell development by controlling Egr2 and PLZF expression. SAP-deficient 24αβ transgenic T cells (24αβ T cells) exhibited an immature phenotype with reduced Th2 cytokine-producing capacity and diminished cytotoxicity to CD1d-expressing lymphoma cells. The impaired IL-4 production by SAP-deficient 24αβ T cells was associated with reduced IRF4 and GATA-3 induction following TCR stimulation. Collectively, these data suggest that SAP is critical for regulating type II NKT cell responses. Aberrant responses of these T cells may contribute to the immune dysregulation observed in X-linked lymphoproliferative disease caused by mutations in SAP. PMID:25236978

Type I NKT-cell-mediated TNF-α is a positive regulator of NLRP3 inflammasome priming.

Science.gov (United States)

Chow, Melvyn T; Duret, Helene; Andrews, Daniel M; Faveeuw, Christelle; Möller, Andreas; Smyth, Mark J; Paget, Christophe

2014-07-01

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. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Human Invariant Natural Killer T Cells Respond to Antigen-Presenting Cells Exposed to Lipids from Olea europaea Pollen.

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Abos Gracia, Beatriz; López Relaño, Juan; Revilla, Ana; Castro, Lourdes; Villalba, Mayte; Martín Adrados, Beatriz; Regueiro, Jose Ramon; Fernández-Malavé, Edgar; Martínez Naves, Eduardo; Gómez Del Moral, Manuel

2017-01-01

Allergic sensitization might be influenced by the lipids present in allergens, which can be recognized by natural killer T (NKT) cells on antigen-presenting cells (APCs). The aim of this study was to analyze the effect of olive pollen lipids in human APCs, including monocytes as well as monocyte-derived macrophages (Mϕ) and dendritic cells (DCs). Lipids were extracted from olive (Olea europaea) pollen grains. Invariant (i)NKT cells, monocytes, Mϕ, and DCs were obtained from buffy coats of healthy blood donors, and their cell phenotype was determined by flow cytometry. iNKT cytotoxicity was measured using a lactate dehydrogenase assay. Gene expression of CD1A and CD1D was performed by RT-PCR, and the production of IL-6, IL-10, IL-12, and TNF-α cytokines by monocytes, Mϕ, and DCs was measured by ELISA. Our results showed that monocytes and monocyte-derived Mϕ treated with olive pollen lipids strongly activate iNKT cells. We observed several phenotypic modifications in the APCs upon exposure to pollen-derived lipids. Both Mϕ and monocytes treated with olive pollen lipids showed an increase in CD1D gene expression, whereas upregulation of cell surface CD1d protein occurred only in Mϕ. Furthermore, DCs differentiated in the presence of human serum enhance their surface CD1d expression when exposed to olive pollen lipids. Finally, olive pollen lipids were able to stimulate the production of IL-6 but downregulated the production of lipopolysaccharide- induced IL-10 by Mϕ. Olive pollen lipids alter the phenotype of monocytes, Mϕ, and DCs, resulting in the activation of NKT cells, which have the potential to influence allergic immune responses. © 2017 S. Karger AG, Basel.

ZBTB7B (Th-POK) regulates the development of IL-17-producing CD1d-restricted mouse NKT cells.

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Enders, Anselm; Stankovic, Sanda; Teh, Charis; Uldrich, Adam P; Yabas, Mehmet; Juelich, Torsten; Altin, John A; Frankenreiter, Sandra; Bergmann, Hannes; Roots, Carla M; Kyparissoudis, Konstantinos; Goodnow, Chris C; Godfrey, Dale I

2012-12-01

CD1d-dependent NKT cells represent a heterogeneous family of effector T cells including CD4(+)CD8(-) and CD4(-)CD8(-) subsets that respond to glycolipid Ags with rapid and potent cytokine production. NKT cell development is regulated by a unique combination of factors, however very little is known about factors that control the development of NKT subsets. In this study, we analyze a novel mouse strain (helpless) with a mis-sense mutation in the BTB-POZ domain of ZBTB7B and demonstrate that this mutation has dramatic, intrinsic effects on development of NKT cell subsets. Although NKT cell numbers are similar in Zbtb7b mutant mice, these cells are hyperproliferative and most lack CD4 and instead express CD8. Moreover, the majority of ZBTB7B mutant NKT cells in the thymus are retinoic acid-related orphan receptor γt positive, and a high frequency produce IL-17 while very few produce IFN-γ or other cytokines, sharply contrasting the profile of normal NKT cells. Mice heterozygous for the helpless mutation also have reduced numbers of CD4(+) NKT cells and increased production of IL-17 without an increase in CD8(+) cells, suggesting that ZBTB7B acts at multiple stages of NKT cell development. These results reveal ZBTB7B as a critical factor genetically predetermining the balance of effector subsets within the NKT cell population.

Leishmania infantum Exoproducts Inhibit Human Invariant NKT Cell Expansion and Activation

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Renata Belo

2017-06-01

Full Text Available Leishmania infantum is one of the major parasite species associated with visceral leishmaniasis, a severe form of the disease that can become lethal if untreated. This obligate intracellular parasite has developed diverse strategies to escape the host immune response, such as exoproducts (Exo carrying a wide range of molecules, including parasite virulence factors, which are potentially implicated in early stages of infection. Herein, we report that L. infantum Exo and its two fractions composed of extracellular vesicles (EVs and vesicle-depleted-exoproducts (VDEs inhibit human peripheral blood invariant natural killer T (iNKT cell expansion in response to their specific ligand, the glycolipid α-GalactosylCeramide (α-GalCer, as well as their capacity to promptly produce IL-4 and IFNγ. Using plate-bound CD1d and α-GalCer, we found that Exo, EV, and VDE fractions reduced iNKT cell activation in a dose-dependent manner, suggesting that they prevented α-GalCer presentation by CD1d molecules. This direct effect on CD1d was confirmed by the observation that CD1d:α-GalCer complex formation was impaired in the presence of Exo, EV, and VDE fractions. Furthermore, lipid extracts from the three compounds mimicked the inhibition of iNKT cell activation. These lipid components of L. infantum exoproducts, including EV and VDE fractions, might compete for CD1-binding sites, thus blocking iNKT cell activation. Overall, our results provide evidence for a novel strategy through which L. infantum can evade immune responses of mammalian host cells by preventing iNKT lymphocytes from recognizing glycolipids in a TCR-dependent manner.

CD4(+) type II NKT cells mediate ICOS and programmed death-1-dependent regulation of type 1 diabetes.

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Kadri, Nadir; Korpos, Eva; Gupta, Shashank; Briet, Claire; Löfbom, Linda; Yagita, Hideo; Lehuen, Agnes; Boitard, Christian; Holmberg, Dan; Sorokin, Lydia; Cardell, Susanna L

2012-04-01

Type 1 diabetes (T1D) is a chronic autoimmune disease that results from T cell-mediated destruction of pancreatic β cells. CD1d-restricted NKT lymphocytes have the ability to regulate immunity, including autoimmunity. We previously demonstrated that CD1d-restricted type II NKT cells, which carry diverse TCRs, prevented T1D in the NOD mouse model for the human disease. In this study, we show that CD4(+) 24αβ type II NKT cells, but not CD4/CD8 double-negative NKT cells, were sufficient to downregulate diabetogenic CD4(+) BDC2.5 NOD T cells in adoptive transfer experiments. CD4(+) 24αβ NKT cells exhibited a memory phenotype including high ICOS expression, increased cytokine production, and limited display of NK cell markers, compared with double-negative 24αβ NKT cells. Blocking of ICOS or the programmed death-1/programmed death ligand 1 pathway was shown to abolish the regulation that occurred in the pancreas draining lymph nodes. To our knowledge, these results provide for the first time cellular and molecular information on how type II CD1d-restricted NKT cells regulate T1D.

NKT cells are important mediators of hepatic ischemia-reperfusion injury.

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Richards, James A; Wigmore, Stephen J; Anderton, Stephen M; Howie, Sarah E M

2017-12-01

IRI results from the interruption then reinstatement of an organ's blood supply, and this poses a significant problem in liver transplantation and resectional surgery. In this paper, we explore the role T cells play in the pathogenesis of this injury. We used an in vivo murine model of warm partial hepatic IRI, genetically-modified mice, in vivo antibody depletion, adoptive cell transfer and flow cytometry to determine which lymphocyte subsets contribute to pathology. Injury was assessed by measuring serum alanine aminotransfersase (ALT) and by histological examination of liver tissue sections. The absence of T cells (CD3εKO) is associated with significant protection from injury (p=0.010). Through a strategy of antibody depletion it appears that NKT cells (p=0.0025), rather than conventional T (CD4+ or CD8+) (p=0.11) cells that are the key mediators of injury. Our results indicate that tissue-resident NKT cells, but not other lymphocyte populations are responsible for the injury in hepatic IRI. Targeting the activation of NKT cells and/or their effector apparatus would be a novel approach in protecting the liver during transplantation and resection surgery; this may allow us to expand our current criteria for surgery. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Bimodal CD40/Fas-Dependent Crosstalk between iNKT Cells and Tumor-Associated Macrophages Impairs Prostate Cancer Progression.

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Cortesi, Filippo; Delfanti, Gloria; Grilli, Andrea; Calcinotto, Arianna; Gorini, Francesca; Pucci, Ferdinando; Lucianò, Roberta; Grioni, Matteo; Recchia, Alessandra; Benigni, Fabio; Briganti, Alberto; Salonia, Andrea; De Palma, Michele; Bicciato, Silvio; Doglioni, Claudio; Bellone, Matteo; Casorati, Giulia; Dellabona, Paolo

2018-03-13

Heterotypic cellular and molecular interactions in the tumor microenvironment (TME) control cancer progression. Here, we show that CD1d-restricted invariant natural killer (iNKT) cells control prostate cancer (PCa) progression by sculpting the TME. In a mouse PCa model, iNKT cells restrained the pro-angiogenic and immunosuppressive capabilities of tumor-infiltrating immune cells by reducing pro-angiogenic TIE2 + , M2-like macrophages (TEMs), and sustaining pro-inflammatory M1-like macrophages. iNKT cells directly contacted macrophages in the PCa stroma, and iNKT cell transfer into tumor-bearing mice abated TEMs, delaying tumor progression. iNKT cells modulated macrophages through the cooperative engagement of CD1d, Fas, and CD40, which promoted selective killing of M2-like and survival of M1-like macrophages. Human PCa aggressiveness associate with reduced intra-tumoral iNKT cells, increased TEMs, and expression of pro-angiogenic genes, underscoring the clinical significance of this crosstalk. Therefore, iNKT cells may control PCa through mechanisms involving differential macrophage modulation, which may be harnessed for therapeutically reprogramming the TME. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Increased Numbers of NK Cells, NKT-Like Cells, and NK Inhibitory Receptors in Peripheral Blood of Patients with Chronic Obstructive Pulmonary Disease

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Ying Tang

2013-01-01

Full Text Available T cells and B cells participate in the pathogenesis of COPD. Currently, NK cells and NKT cells have gained increasing attention. In the present study, 19 COPD patients and 12 healthy nonsmokers (HNS were recruited, and their pulmonary function was assessed. The frequencies of CD3+ T, CD4+ T, CD8+ T, B, NK, and NKT-like cells were determined using flow cytometry. The frequencies of spontaneous and inducible IFN-γ+ or CD107a+ NK and NKT-like cells as well as activating or inhibitory receptors were also detected. The potential association of lymphocyte subsets with disease severity was further analyzed. Significantly decreased numbers of CD3+ and CD4+ T cells, and the CD4+/CD8+ ratio, but increased numbers of CD3−CD56+ NK and CD3+CD56+ NKT-like cells were observed in COPD patients compared to HNS. The frequencies of inducible IFN-γ-secreting NK and NKT-like cells were less in COPD patients. The frequencies of CD158a and CD158b on NK cells and CD158b on NKT-like cells were greater. The frequency of CD158b+ NK cells was negatively correlated with FEV1% prediction and FEV1/FVC. Our data indicate that COPD patients have immune dysfunction, and higher frequencies of inhibitory NK cells and NKT-like cells may participate in the pathogenesis of COPD.

The immunoregulatory role of CD1d-restricted natural killer T cells in disease.

NARCIS (Netherlands)

Vliet, van der HJ; Molling, J.W.; Blomberg - van der Flier, von B.M.E.; Nishi, N.; Kolgen, W; Eertwegh, van den A.J.M.; Pinedo, H.M.; Giaccone, G.; Scheper, R.J.

2004-01-01

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

GM-CSF and IL-4 produced by NKT cells inversely regulate IL-1β production by macrophages.

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Ahn, Sehee; Jeong, Dongjin; Oh, Sae Jin; Ahn, Jiye; Lee, Seung Hyo; Chung, Doo Hyun

2017-02-01

Natural Killer T (NKT) cells are distinct T cell subset that link innate and adaptive immune responses. IL-1β, produced by various immune cells, plays a key role in the regulation of innate immunity in vivo. However, it is unclear whether NKT cells regulate IL-1β production by macrophages. To address this, we co-cultured NKT cells and peritoneal macrophages in the presence of TCR stimulation and inflammasome activators. Among cytokines secreted from NKT cells, GM-CSF enhanced IL-1β production by macrophages via regulating LPS-mediated pro-IL-1β expression and NLRP3-dependent inflammasome activation, whereas IL-4 enhanced M2-differentiation of macrophages and decreased IL-1β production. Together, our findings suggest the NKT cells have double-sided effects on IL-1β-mediated innate immune responses by producing IL-4 and GM-CSF. These findings may be helpful for a comprehensive understanding of NKT cell-mediated regulatory mechanisms of the pro-inflammatory effects of IL-1β in inflammatory diseases in vivo. Copyright © 2017 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.

[IL-2 stimulated responses of CD3(+) CD56(+) NKT cells in pulmonary tuberculosis patients].

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Yao, Chun-Yan; Wang, Zhao-Hua; Jiang, Li-Na; Peng, Mei-Yu; Wang, Jing; Li, Bai-Qing

2010-09-01

To observe the activation and proliferation characteristics of IL-2 stimulated CD3(+);CD56(+); NKT cells in pulmonary tuberculosis (PTB) patients. Peripheral blood mononuclear cells (PBMCs) from PTB patients and normal subjects were stimulated with IL-2 and cultured for different time points. The CD69 expression on and amount of the CD3(+);CD56(+); NKT cells were detected by multi fluorescence staining and flow cytometry at different time of stimulation and culture. There was no significant difference in percentage of NKT cells between PTB patients and normal healthy controls before culture. When IL-2 was used to stimulate for 0 h, 8 h, 16 h, 40 h and 64 h, the expression of CD69 on NKT cells in normal controls and PTB patients increased significantly, but the CD69 expression level of NKT cells in PTB patients was significantly higher than that in normal persons(PNKT cells increased from (3.44+/-1.20)x10(4); to (323.23+/-75.98) x10(4); (PNKT cells increased from (5.57+/-5.16)x10(4); to (1475.05+/-868.98)x10(4); (PNKT cells in PTB patients present with high activation but low proliferation after stimulated by IL-2.

The molecular bases of δ/αβ T cell-mediated antigen recognition.

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Pellicci, Daniel G; Uldrich, Adam P; Le Nours, Jérôme; Ross, Fiona; Chabrol, Eric; Eckle, Sidonia B G; de Boer, Renate; Lim, Ricky T; McPherson, Kirsty; Besra, Gurdyal; Howell, Amy R; Moretta, Lorenzo; McCluskey, James; Heemskerk, Mirjam H M; Gras, Stephanie; Rossjohn, Jamie; Godfrey, Dale I

2014-12-15

αβ and γδ T cells are disparate T cell lineages that can respond to distinct antigens (Ags) via the use of the αβ and γδ T cell Ag receptors (TCRs), respectively. Here we characterize a population of human T cells, which we term δ/αβ T cells, expressing TCRs comprised of a TCR-δ variable gene (Vδ1) fused to joining α and constant α domains, paired with an array of TCR-β chains. We demonstrate that these cells, which represent ∼50% of all Vδ1(+) human T cells, can recognize peptide- and lipid-based Ags presented by human leukocyte antigen (HLA) and CD1d, respectively. Similar to type I natural killer T (NKT) cells, CD1d-lipid Ag-reactive δ/αβ T cells recognized α-galactosylceramide (α-GalCer); however, their fine specificity for other lipid Ags presented by CD1d, such as α-glucosylceramide, was distinct from type I NKT cells. Thus, δ/αβTCRs contribute new patterns of Ag specificity to the human immune system. Furthermore, we provide the molecular bases of how δ/αβTCRs bind to their targets, with the Vδ1-encoded region providing a major contribution to δ/αβTCR binding. Our findings highlight how components from αβ and γδTCR gene loci can recombine to confer Ag specificity, thus expanding our understanding of T cell biology and TCR diversity. © 2014 Pellicci et al.

[Sulfatide-loaded CD1d tetramer to detect typeII NKT cells in mice].

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Zhang, Gu-qin; Nie, Han-xiang; Yang, Jiong; Yu, Hong-ying

2012-07-01

To create a method of detecting typeII natural killer T (NKT) cells of mice. Biotinylated mouse CD1d monomers were mixed with sulfatide at a molar ratio of 1:3 (protein:lipid) and incubated at room temperature overnight, and then 80 μg of streptavidin-PE was added into 200 μg of the CD1d-sulfatide mixture and incubated at room temperature for 4 h to get sulfatide/CD1d tetramer. Flow cytometry was used to detect the percentage of typeII NKT cells in mononuclear cells (MNCs) of lung and spleen of normal mice, as well as the percentage of typeII NKT cells in spleen MNCs of mice after stimulated with sulfatide. In normal mice, the percentage of typeII NKT cells accounted for (0.875±0.096)% and (1.175±0.263)% in MNCs of spleen and lung; the percentage in spleen MNCs after activated with sulfatide was (2.75±0.603)%, which significantly increased as compared with that in normal mice (PNKT cells in mice.

Dissection of SAP-dependent and SAP-independent SLAM family signaling in NKT cell development and humoral immunity

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Cai, Chenxu; Liu, Guangao; Wang, Yuande; Du, Juan; Lin, Xin; Yang, Meixiang

2017-01-01

Signaling lymphocytic activation molecule (SLAM)–associated protein (SAP) mutations in X-linked lymphoproliferative disease (XLP) lead to defective NKT cell development and impaired humoral immunity. Because of the redundancy of SLAM family receptors (SFRs) and the complexity of SAP actions, how SFRs and SAP mediate these processes remains elusive. Here, we examined NKT cell development and humoral immunity in mice completely deficient in SFR. We found that SFR deficiency severely impaired NKT cell development. In contrast to SAP deficiency, SFR deficiency caused no apparent defect in follicular helper T (TFH) cell differentiation. Intriguingly, the deletion of SFRs completely rescued the severe defect in TFH cell generation caused by SAP deficiency, whereas SFR deletion had a minimal effect on the defective NKT cell development in SAP-deficient mice. These findings suggest that SAP-dependent activating SFR signaling is essential for NKT cell selection; however, SFR signaling is inhibitory in SAP-deficient TFH cells. Thus, our current study revises our understanding of the mechanisms underlying T cell defects in patients with XLP. PMID:28049627

Dissection of SAP-dependent and SAP-independent SLAM family signaling in NKT cell development and humoral immunity.

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Chen, Shasha; Cai, Chenxu; Li, Zehua; Liu, Guangao; Wang, Yuande; Blonska, Marzenna; Li, Dan; Du, Juan; Lin, Xin; Yang, Meixiang; Dong, Zhongjun

2017-02-01

Signaling lymphocytic activation molecule (SLAM)-associated protein (SAP) mutations in X-linked lymphoproliferative disease (XLP) lead to defective NKT cell development and impaired humoral immunity. Because of the redundancy of SLAM family receptors (SFRs) and the complexity of SAP actions, how SFRs and SAP mediate these processes remains elusive. Here, we examined NKT cell development and humoral immunity in mice completely deficient in SFR. We found that SFR deficiency severely impaired NKT cell development. In contrast to SAP deficiency, SFR deficiency caused no apparent defect in follicular helper T (T FH ) cell differentiation. Intriguingly, the deletion of SFRs completely rescued the severe defect in T FH cell generation caused by SAP deficiency, whereas SFR deletion had a minimal effect on the defective NKT cell development in SAP-deficient mice. These findings suggest that SAP-dependent activating SFR signaling is essential for NKT cell selection; however, SFR signaling is inhibitory in SAP-deficient T FH cells. Thus, our current study revises our understanding of the mechanisms underlying T cell defects in patients with XLP. © 2017 Chen et al.

NKT cells act through third party bone marrow-derived cells to suppress NK cell activity in the liver and exacerbate hepatic melanoma metastases.

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Sadegh, Leila; Chen, Peter W; Brown, Joseph R; Han, Zhiqiang; Niederkorn, Jerry Y

2015-09-01

Uveal melanoma (UM) is the most common intraocular tumor in adults and liver metastasis is the leading cause of death in UM patients. We have previously shown that NKT cell-deficient mice develop significantly fewer liver metastases from intraocular melanomas than do wild-type (WT) mice. Here, we examine the interplay between liver NKT cells and NK cells in resistance to liver metastases from intraocular melanomas. NKT cell-deficient CD1d(-/-) mice and WT C57BL/6 mice treated with anti-CD1d antibody developed significantly fewer liver metastases than WT mice following either intraocular or intrasplenic injection of B16LS9 melanoma cells. The increased number of metastases in WT mice was associated with reduced liver NK cytotoxicity and decreased production of IFN-γ. However, liver NK cell-mediated cytotoxic activity was identical in non-tumor bearing NKT cell-deficient mice and WT mice, indicating that liver metastases were crucial for the suppression of liver NK cells. Depressed liver NK cytotoxicity in WT mice was associated with production of IL-10 by bone marrow-derived liver cells that were neither Kupffer cells nor myeloid-derived suppressor cells and by increased IL-10 receptor expression on liver NK cells. IL-10(-/-) mice had significantly fewer liver metastases than WT mice, but were not significantly different from NKT cell-deficient mice. Thus, development of melanoma liver metastases is associated with upregulation of IL-10 in the liver and an elevated expression of IL-10 receptor on liver NK cells. This impairment of liver NK activity is NKT cell-dependent and only occurs in hosts with melanoma liver metastases. © 2015 UICC.

Clinical development of a novel CD1d-binding NKT cell ligand as a vaccine adjuvant

OpenAIRE

Padte, Neal N.; Li, Xiangming; Tsuji, Moriya; Vasan, Sandhya

2010-01-01

Natural killer T (NKT) cells are known to play a role against certain microbial infections, including malaria and HIV, two major global infectious diseases. Strategies that acn harness and amplify the immunotherapeutic potential of NKT cells can serve as powerful tools in the fight against such diseases. 7DW8-5, a novel glycolipid, may be one such tool. The interaction of 7DW8-5 with CD1d molecules induces activation of NKT cells, thereby activating various immune-competent cells including de...

Spontaneous focal activation of invariant natural killer T (iNKT cells in mouse liver and kidney

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Zeng Jia

2010-11-01

Full Text Available Abstract Background Invariant natural killer T (iNKT cells differ from other T cells by their hyperactive effector T-cell status, in addition to the expression of NK lineage receptors and semi-invariant T-cell receptors. It is generally agreed that the immune phenotype of iNKT cells is maintained by repeated activation in peripheral tissues although no explicit evidence for such iNKT cell activity in vivo has so far been reported. Results We used an interferon (IFN-γ-inducible cytoplasmic protein, Irga6, as a histological marker for local IFN-γ production. Irga6 was intensely expressed in small foci of liver parenchymal cells and kidney tubular epithelium. Focal Irga6 expression was unaffected by germ-free status or loss of TLR signalling and was totally dependent on IFN-γ secreted by T cells in the centres of expression foci. These were shown to be iNKT cells by diagnostic T cell receptor usage and their activity was lost in both CD1 d and Jα-deficient mice. Conclusions This is the first report that supplies direct evidence for explicit activation events of NKT cells in vivo and raises issues about the triggering mechanism and consequences for immune functions in liver and kidney.

Altered development of NKT cells, γδ T cells, CD8 T cells and NK cells in a PLZF deficient patient.

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Maggie Eidson

Full Text Available In mice, the transcription factor, PLZF, controls the development of effector functions in invariant NKT cells and a subset of NKT cell-like, γδ T cells. Here, we show that in human lymphocytes, in addition to invariant NKT cells, PLZF was also expressed in a large percentage of CD8+ and CD4+ T cells. Furthermore, PLZF was also found to be expressed in all γδ T cells and in all NK cells. Importantly, we show that in a donor lacking functional PLZF, all of these various lymphocyte populations were altered. Therefore, in contrast to mice, PLZF appears to control the development and/or function of a wide variety of human lymphocytes that represent more than 10% of the total PBMCs. Interestingly, the PLZF-expressing CD8+ T cell population was found to be expanded in the peripheral blood of patients with metastatic melanoma but was greatly diminished in patients with autoimmune disease.

Downregulation of BTLA on NKT Cells Promotes Tumor Immune Control in a Mouse Model of Mammary Carcinoma.

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Sekar, Divya; Govene, Luisa; Del Río, María-Luisa; Sirait-Fischer, Evelyn; Fink, Annika F; Brüne, Bernhard; Rodriguez-Barbosa, José I; Weigert, Andreas

2018-03-07

Natural Killer T cells (NKT cells) are emerging as critical regulators of pro- and anti-tumor immunity, both at baseline and in therapeutic settings. While type I NKT cells can promote anti-tumor immunity, their activity in the tumor microenvironment may be limited by negative regulators such as inhibitory immune checkpoints. We observed dominant expression of B- and T-lymphocyte attenuator (BTLA) on type I NKT cells in polyoma middle T oncogene-driven (PyMT) murine autochthonous mammary tumors. Other immune checkpoint receptors, such as programmed cell death 1 (PD-1) were equally distributed among T cell populations. Interference with BTLA using neutralizing antibodies limited tumor growth and pulmonary metastasis in the PyMT model in a therapeutic setting, correlating with an increase in type I NKT cells and expression of cytotoxic marker genes. While therapeutic application of an anti-PD-1 antibody increased the number of CD8+ cytotoxic T cells and elevated IL-12 expression, tumor control was not established. Expression of ZBTB16, the lineage-determining transcription factor of type I NKT cells, was correlated with a favorable patient prognosis in the METABRIC dataset, and BTLA levels were instrumental to further distinguish prognosis in patents with high ZBTB16 expression. Taken together, these data support a role of BTLA on type I NKT cells in limiting anti-tumor immunity.

Downregulation of BTLA on NKT Cells Promotes Tumor Immune Control in a Mouse Model of Mammary Carcinoma

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Divya Sekar

2018-03-01

Full Text Available Natural Killer T cells (NKT cells are emerging as critical regulators of pro- and anti-tumor immunity, both at baseline and in therapeutic settings. While type I NKT cells can promote anti-tumor immunity, their activity in the tumor microenvironment may be limited by negative regulators such as inhibitory immune checkpoints. We observed dominant expression of B- and T-lymphocyte attenuator (BTLA on type I NKT cells in polyoma middle T oncogene-driven (PyMT murine autochthonous mammary tumors. Other immune checkpoint receptors, such as programmed cell death 1 (PD-1 were equally distributed among T cell populations. Interference with BTLA using neutralizing antibodies limited tumor growth and pulmonary metastasis in the PyMT model in a therapeutic setting, correlating with an increase in type I NKT cells and expression of cytotoxic marker genes. While therapeutic application of an anti-PD-1 antibody increased the number of CD8+ cytotoxic T cells and elevated IL-12 expression, tumor control was not established. Expression of ZBTB16, the lineage-determining transcription factor of type I NKT cells, was correlated with a favorable patient prognosis in the METABRIC dataset, and BTLA levels were instrumental to further distinguish prognosis in patents with high ZBTB16 expression. Taken together, these data support a role of BTLA on type I NKT cells in limiting anti-tumor immunity.

Protective role of NKT cells and macrophage M2-driven phenotype in bleomycin-induced pulmonary fibrosis.

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Grabarz, Felipe; Aguiar, Cristhiane Favero; Correa-Costa, Matheus; Braga, Tárcio Teodoro; Hyane, Meire I; Andrade-Oliveira, Vinícius; Landgraf, Maristella Almeida; Câmara, Niels Olsen Saraiva

2018-04-01

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 -/- ) were subjected to the protocol of bleomycin-induced pulmonary fibrosis with or without treatment with NKT cell agonists α-galactosylceramide and sulfatide. The participation of different cell populations, collagen deposition, and protein levels of different cytokines involved in inflammation and fibrosis was evaluated. The results indicate a benign role of NKT cells in Jα18 -/- mice and in wild-type α-galactosylceramide-sulfatide-treated groups. These animals presented lower levels of collagen deposition, fibrogenic molecules such as TGF-β and vimentin and improved survival rates. In contrast, WT mice developed a Th2-driven response augmenting IL-4, 5, and 13 protein synthesis and increased collagen deposition. Furthermore, the arginase-1 metabolic pathway was downregulated in wild-type NKT-activated and knockout mice indicating lower activity of M2 macrophages in lung tissue. Hence, our data suggest that NKT cells play a protective role in this experimental model by down modulating the Th2 milieu, inhibiting M2 polarization and finally preventing fibrosis.

Different subsets of natural killer T cells may vary in their roles in health and disease

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Kumar, Vipin; Delovitch, Terry L

2014-01-01

Natural killer T cells (NKT) can regulate innate and adaptive immune responses. Type I and type II NKT cell subsets recognize different lipid antigens presented by CD1d, an MHC class-I-like molecule. Most type I NKT cells express a semi-invariant T-cell receptor (TCR), but a major subset of type II NKT cells reactive to a self antigen sulphatide use an oligoclonal TCR. Whereas TCR-α dominates CD1d-lipid recognition by type I NKT cells, TCR-α and TCR-β contribute equally to CD1d-lipid recognition by type II NKT cells. These variable modes of NKT cell recognition of lipid–CD1d complexes activate a host of cytokine-dependent responses that can either exacerbate or protect from disease. Recent studies of chronic inflammatory and autoimmune diseases have led to a hypothesis that: (i) although type I NKT cells can promote pathogenic and regulatory responses, they are more frequently pathogenic, and (ii) type II NKT cells are predominantly inhibitory and protective from such responses and diseases. This review focuses on a further test of this hypothesis by the use of recently developed techniques, intravital imaging and mass cytometry, to analyse the molecular and cellular dynamics of type I and type II NKT cell antigen-presenting cell motility, interaction, activation and immunoregulation that promote immune responses leading to health versus disease outcomes. PMID:24428389

Abnormalities in iNKT cells are associated with impaired ability of monocytes to produce IL-10 and suppress T-cell proliferation in sarcoidosis.

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Crawshaw, Anjali; Kendrick, Yvonne R; McMichael, Andrew J; Ho, Ling-Pei

2014-07-01

Sarcoidosis is a multisystem granulomatous disorder characterized by marked T-cell expansion of T helper 1 (Th1) cells. The cause of T-cell overactivity is unknown. We hypothesized that interleukin-10 (IL-10) production by a yet undefined cell type might be defective, resulting in loss of regulation of T-cell activity. Focusing on IL-10-producing monocytes, we first showed that monocytes isolated from the peripheral blood of corticosteroid-naïve sarcoidosis patients (n = 51) produced less IL-10 compared to controls, and were less able to suppress T-cell proliferation. In addition, monocytic IL-10 production correlated negatively with disease activity score. As invariant natural killer T (iNKT) cells are known to both interact with monocytes and be reduced in sarcoidosis patients, we then asked whether iNKT-specific defects might be responsible for this reduced IL-10 production. We found that greater numbers of circulating iNKT cells was associated with higher IL-10 production. Moreover, iNKT cells enhanced monocytic IL-10 production in vitro. Defective IL-10 production and T-cell suppression by sarcoidosis monocytes could be restored following their coculture with iNKT cells, in a CD1d- and cell contact-dependent process. We suggest that reduced iNKT-cell numbers in sarcoidosis may lead to impaired monocytic IL-10 production and unchecked T-cell expansion in sarcoidosis. These findings provide fresh insight into the mechanism of sarcoidosis disease, and interaction between iNKT cells and monocytes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Maternal low protein diet leads to dysregulation of placental iNKT cells and M1/M2 macrophage ratio, body weight loss in male, neonate Sprague-Dawley rats and increased UCP-1 mediated thermogenesis

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Placental immune cells provide cytokines and growth factors that are necessary for placenta development and function. Invariant natural killer T (iNKT) cells are innate cells specific for glycolipid antigens presented by the CD1d molecule and secrete Th1 cytokines in the placenta, suggesting an imm...

TRAF2 regulates peripheral CD8(+) T-cell and NKT-cell homeostasis by modulating sensitivity to IL-15.

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Villanueva, Jeanette E; Malle, Elisabeth K; Gardam, Sandra; Silveira, Pablo A; Zammit, Nathan W; Walters, Stacey N; Brink, Robert; Grey, Shane T

2015-06-01

In this study, a critical and novel role for TNF receptor (TNFR) associated factor 2 (TRAF2) is elucidated for peripheral CD8(+) T-cell and NKT-cell homeostasis. Mice deficient in TRAF2 only in their T cells (TRAF2TKO) show ∼40% reduction in effector memory and ∼50% reduction in naïve CD8(+) T-cell subsets. IL-15-dependent populations were reduced further, as TRAF2TKO mice displayed a marked ∼70% reduction in central memory CD8(+) CD44(hi) CD122(+) T cells and ∼80% decrease in NKT cells. TRAF2TKO CD8(+) CD44(hi) T cells exhibited impaired dose-dependent proliferation to exogenous IL-15. In contrast, TRAF2TKO CD8(+) T cells proliferated normally to anti-CD3 and TRAF2TKO CD8(+) CD44(hi) T cells exhibited normal proliferation to exogenous IL-2. TRAF2TKO CD8(+) T cells expressed normal levels of IL-15-associated receptors and possessed functional IL-15-mediated STAT5 phosphorylation, however TRAF2 deletion caused increased AKT activation. Loss of CD8(+) CD44(hi) CD122(+) and NKT cells was mechanistically linked to an inability to respond to IL-15. The reduced CD8(+) CD44(hi) CD122(+) T-cell and NKT-cell populations in TRAF2TKO mice were rescued in the presence of high dose IL-15 by IL-15/IL-15Rα complex administration. These studies demonstrate a critical role for TRAF2 in the maintenance of peripheral CD8(+) CD44(hi) CD122(+) T-cell and NKT-cell homeostasis by modulating sensitivity to T-cell intrinsic growth factors such as IL-15. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of age and latent CMV infection on CD8+ CD56+ T cells (NKT-like) frequency and functionality.

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Hassouneh, Fakhri; Campos, Carmen; López-Sejas, Nelson; Alonso, Corona; Tarazona, Raquel; Solana, Rafael; Pera, Alejandra

2016-09-01

Changes in the T cell pool caused by CMV infection have been proposed to contribute to immunosenescence, but it has been postulated that CMV can also have some beneficial effects in young individuals improving the immune response to other pathogens. T cells expressing CD56 (NKT-like cells) are cytotoxic effector cells with a significant role in the immune response against cancer. We have studied how age and latent CMV infection affect the frequency of NKT-like cells (CD8+ CD56+ T cells) and their response to Staphylococcal Enterotoxin B (SEB) in the context of CMV and ageing. NKT-like cell percentage increases with the combination of both CMV and age. The response to SEB and the polyfunctional index of NKT-like cells also increase with age in CMV-seropositive individuals. In young individuals, CMV infection induces a shift on the polyfunctional profile of CD8+ CD56- T cells not observed on the NKT-like cells response. NKT-like cells expressing CD57 are expanded in CMV-seropositive individuals and are more polyfunctional than their CD57-  counterpart. In addition CD57- NKT-like cells are more polyfunctional than CD8+ CD56- CD57- T cells. The results support that the expansion of polyfunctional NKT-cells may have a beneficial effect on the immune response against pathogens. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Increased Intraepithelial Vα24 Invariant NKT Cells in the Celiac Duodenum

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Montalvillo, Enrique; Bernardo, David; Martínez-Abad, Beatriz; Allegretti, Yessica; Fernández-Salazar, Luis; Calvo, Carmen; Chirdo, Fernando G.; Garrote, José A.; Arranz, Eduardo

2015-01-01

Celiac Disease (CD) is an interferon (IFN)γ-mediated duodenal hypersensitivity to wheat gluten occurring in genetically predisposed individuals. Gluten-free diet (GFD) leads to a complete remission of the disease. Vα24-restricted invariant NKT (iNKT) cells are important to maintain immune homeostasis in the gut mucosa because of their unique capacity to rapidly produce large quantities of both T-helper (Th)1 and Th2 cytokines upon stimulation. We studied the presence of these cells in the CD duodenum. Duodenal biopsies were obtained from 45 untreated-CD patients (uCD), 15 Gluten Free Diet-CD patients (GFD-CD), 44 non-inflamed non-CD controls (C-controls) and 15 inflamed non-CD controls (I-controls). Two populations from Spain and Argentina were recruited. Messenger RNA (mRNA) expression of Vα24-Jα18 (invariant TCRα chain of human iNKT cells), IFNγ and intracellular transcription factor Forkhead Box P3 (Foxp3), and flow cytometry intraepithelial lymphocyte (IEL) profile were determined. Both uCD and GFD-CD patients had higher Vα24-Jα18 mRNA levels than non-CD controls (I and C-controls). The expression of Vα24-Jα18 correlated with Marsh score for the severity of mucosal lesion and also with increased mRNA IFNγ levels. uCD and GFD-CD patients had decreased mRNA expression of FoxP3 but increased expression of Vα24-Jα18, which revealed a CD-like molecular profile. Increased numbers of iNKT cells were confirmed by flow cytometry within the intraepithelial lymphocyte compartment of uCD and GFD-CD patients and correlated with Vα24-Jα18 mRNA expression. In conclusion, we have found an increased number of iNKT cells in the duodenum from both uCD and GFD-CD patients, irrespective of the mucosal status. A CD-like molecular profile, defined by an increased mRNA expression of Vα24-Jα18 together with a decreased expression of FoxP3, may represent a pro-inflammatory signature of the CD duodenum. PMID:26529008

NKT sublineage specification and survival requires the ubiquitin-modifying enzyme TNFAIP3/A20.