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Evans L, Barral P. CD1 molecules: Beyond antigen presentation. Mol Immunol 2024; 170:1-8. [PMID: 38579449 PMCID: PMC11481681 DOI: 10.1016/j.molimm.2024.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 03/18/2024] [Accepted: 03/29/2024] [Indexed: 04/07/2024]
Abstract
CD1 molecules are well known for their role in binding and presenting lipid antigens to mediate the activation of CD1-restricted T cells. However, much less appreciated is the fact that CD1 molecules can have additional "unconventional" roles which impact the activation and functions of CD1-expressing cells, ultimately controlling tissue homeostasis as well as the progression of inflammatory and infectious diseases. Some of these roles are mediated by so-called reverse signalling, by which crosslinking of CD1 molecules at the cell surface initiates intracellular signalling. On the other hand, CD1 molecules can also control metabolic and inflammatory pathways in CD1-expressing cells through cell-intrinsic mechanisms independent of CD1 ligation. Here, we review the evidence for "unconventional" functions of CD1 molecules and the outcomes of such roles for health and disease.
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Affiliation(s)
- Lauren Evans
- The Peter Gorer Department of Immunobiology. King's College London, London, UK; The Francis Crick Institute, London, UK
| | - Patricia Barral
- The Peter Gorer Department of Immunobiology. King's College London, London, UK; The Francis Crick Institute, London, UK.
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2
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Lin Q, Kuypers M, Philpott DJ, Mallevaey T. The dialogue between unconventional T cells and the microbiota. Mucosal Immunol 2020; 13:867-876. [PMID: 32704035 DOI: 10.1038/s41385-020-0326-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 06/19/2020] [Accepted: 06/19/2020] [Indexed: 02/04/2023]
Abstract
The mammalian immune system is equipped with unconventional T cells that respond to microbial molecules such as glycolipids and small-molecule metabolites, which are invisible to conventional CD4 and CD8 T cells. Unconventional T cells include invariant natural killer T (iNKT) cells and mucosa-associated invariant T (MAIT) cells, which are involved in a wide range of infectious and non-infectious diseases, such as cancer and autoimmunity. In addition, their high conservation across mammals, their restriction by non-polymorphic antigen-presenting molecules, and their immediate and robust responses make these 'innate' T cells appealing targets for the development of one-size-fits-all immunotherapies. In this review, we discuss how iNKT and MAIT cells directly and indirectly detect the presence of and respond to pathogenic and commensal microbes. We also explore the current understanding of the bidirectional relationship between the microbiota and innate T cells, and how this crosstalk shapes the immune response in disease.
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Affiliation(s)
- Qiaochu Lin
- Department of Immunology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Meggie Kuypers
- Department of Immunology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Dana J Philpott
- Department of Immunology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Thierry Mallevaey
- Department of Immunology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada. .,Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON, M5S 3G9, Canada.
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3
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Tripathi P, Sedimbi SK, Singh AK, Löfbom L, Issazadeh-Navikas S, Weiss S, Förster I, Karlsson MCI, Yrlid U, Kadri N, Cardell SL. Innate and adaptive stimulation of murine diverse NKT cells result in distinct cellular responses. Eur J Immunol 2018; 49:443-453. [PMID: 30427069 PMCID: PMC6587840 DOI: 10.1002/eji.201847647] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 10/24/2018] [Accepted: 11/12/2018] [Indexed: 02/06/2023]
Abstract
Natural killer T (NKT) cells recognize glycolipids presented on CD1d. They share features of adaptive T lymphocytes and innate NK cells, and mediate immunoregulatory functions via rapid production of cytokines. Invariant (iNKT) and diverse (dNKT) NKT cell subsets are defined by their TCR. The immunological role of dNKT cells, that do not express the invariant TCRα‐chain used by iNKT cells, is less well explored than that of iNKT cells. Here, we investigated signals driving Toll‐like receptor (TLR) ligand activation of TCR‐transgenic murine dNKT cells. IFN‐γ production by dNKT cells required dendritic cells (DC), cell‐to‐cell contact and presence of TLR ligands. TLR‐stimulated DC activated dNKT cells to secrete IFN‐γ in a CD1d‐, CD80/86‐ and type I IFN‐independent manner. In contrast, a requirement for IL‐12p40, and a TLR ligand‐selective dependence on IL‐18 or IL‐15 was observed. TLR ligand/DC stimulation provoked early secretion of pro‐inflammatory cytokines by both CD62L+ and CD62L− dNKT cells. However, proliferation was limited. In contrast, TCR/co‐receptor‐mediated activation resulted in proliferation and delayed production of a broader cytokine spectrum preferentially in CD62L− dNKT cells. Thus, innate (TLR ligand/DC) and adaptive (TCR/co‐receptor) stimulation of dNKT cells resulted in distinct cellular responses that may contribute differently to the formation of immune memory.
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Affiliation(s)
- Prabhanshu Tripathi
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Saikiran K Sedimbi
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.,Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Avadhesh Kumar Singh
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Linda Löfbom
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Shohreh Issazadeh-Navikas
- Neuroinflammation Unit, Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, Copenhagen Biocentre, University of Copenhagen, Copenhagen, Denmark
| | - Siegfried Weiss
- Institute of Immunology, Medical School Hannover, Hannover, Germany
| | - Irmgard Förster
- Immunology and Environment, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Mikael C I Karlsson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Ulf Yrlid
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Nadir Kadri
- Center of Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institute, Stockholm, Sweden
| | - Susanna L Cardell
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
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4
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Rao P, Wen X, Lo JH, Kim S, Li X, Chen S, Feng X, Akbari O, Yuan W. Herpes Simplex Virus 1 Specifically Targets Human CD1d Antigen Presentation To Enhance Its Pathogenicity. J Virol 2018; 92:e01490-18. [PMID: 30185591 PMCID: PMC6206489 DOI: 10.1128/jvi.01490-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 08/29/2018] [Indexed: 12/19/2022] Open
Abstract
Herpes simplex virus 1 (HSV-1) is one of the most prevalent herpesviruses in humans and represents a constant health threat to aged and immunocompromised populations. How HSV-1 interacts with the host immune system to efficiently establish infection and latency is only partially known. CD1d-restricted NKT cells are a critical arm of the host innate immune system and play potent roles in anti-infection and antitumor immune responses. We discovered previously that upon infection, HSV-1 rapidly and efficiently downregulates CD1d expression on the cell surface and suppresses the function of NKT cells. Furthermore, we identified the viral serine/threonine protein kinase US3 as a major viral factor downregulating CD1d during infection. Interestingly, neither HSV-1 nor its US3 protein efficiently inhibits mouse CD1d expression, suggesting that HSV-1 has coevolved with the human immune system to specifically suppress human CD1d (hCD1d) and NKT cell function for its pathogenesis. This is consistent with the fact that wild-type mice are mostly resistant to HSV-1 infection. On the other hand, in vivo infection of CD1d-humanized mice (hCD1d knock-in mice) showed that HSV-1 can indeed evade hCD1d function and establish infection in these mice. We also report here that US3-deficient viruses cannot efficiently infect hCD1d knock-in mice but infect mice lacking all NKT cells at a higher efficiency. Together, these studies supported HSV-1 evasion of human CD1d and NKT cell function as an important pathogenic factor for the virus. Our results also validated the potent roles of NKT cells in antiherpesvirus immune responses and pointed to the potential of NKT cell ligands as adjuvants for future vaccine development.IMPORTANCE Herpes simplex virus 1 (HSV-1) is among the most common human pathogens. Little is known regarding the exact mechanism by which this virus evades the human immune system, particularly the innate immune system. We reported previously that HSV-1 employs its protein kinase US3 to modulate the expression of the key antigen-presenting molecule, CD1d, so as to evade the antiviral function of NKT cells. Here we demonstrated that the virus has coevolved with the human CD1d and NKT cell system and that NKT cells indeed play potent roles in anti-HSV immune responses. These studies point to the great potential of exploring NKT cell ligands as adjuvants for HSV vaccines.
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Affiliation(s)
- Ping Rao
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Xiangshu Wen
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Jae Ho Lo
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Seil Kim
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Xin Li
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Siyang Chen
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Xiaotian Feng
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Omid Akbari
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Weiming Yuan
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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5
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Weng X, He Y, Visvabharathy L, Liao CM, Tan X, Balakumar A, Wang CR. Crosstalk between type II NKT cells and T cells leads to spontaneous chronic inflammatory liver disease. J Hepatol 2017; 67:791-800. [PMID: 28596110 PMCID: PMC5605413 DOI: 10.1016/j.jhep.2017.05.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 04/28/2017] [Accepted: 05/23/2017] [Indexed: 12/11/2022]
Abstract
BACKGROUND & AIM 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. METHODS 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-CD1dTgJα18o, 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. RESULTS Lck-CD1dTgJα18o 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 Th1-skewing and impaired Th2 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. CONCLUSIONS Our data reveals enhanced crosstalk between type II NKT cells and conventional T cells, leading to a Th1-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 development of chronic autoimmune liver disease.
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Affiliation(s)
- Xiufang Weng
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States; Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Ying He
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States
| | - Lavanya Visvabharathy
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States
| | - Chia-Min Liao
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States
| | - Xiaosheng Tan
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Arjun Balakumar
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States
| | - Chyung-Ru Wang
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States.
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Abos Gracia B, López Relaño J, Revilla A, Castro L, Villalba M, Martín Adrados B, Regueiro JR, Fernández-Malavé E, Martínez Naves E, Gómez Del Moral M. Human Invariant Natural Killer T Cells Respond to Antigen-Presenting Cells Exposed to Lipids from Olea europaea Pollen. Int Arch Allergy Immunol 2017; 173:12-22. [PMID: 28486236 DOI: 10.1159/000467394] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 03/01/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND 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). METHODS 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. RESULTS 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. CONCLUSIONS 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.
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Affiliation(s)
- Beatriz Abos Gracia
- Department of Immunology, Faculty of Medicine, and 12 de Octubre Health Research Institute (imas12), Complutense University, Madrid, Spain
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7
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Dasgupta S, Kumar V. Type II NKT cells: a distinct CD1d-restricted immune regulatory NKT cell subset. Immunogenetics 2016; 68:665-76. [PMID: 27405300 PMCID: PMC6334657 DOI: 10.1007/s00251-016-0930-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 06/22/2016] [Indexed: 12/16/2022]
Abstract
Type II natural killer T cells (NKT) are a subset of the innate-like CD1d-restricted lymphocytes that are reactive to lipid antigens. Unlike the type I NKT cells, which express a semi-invariant TCR, type II NKT cells express a broader TCR repertoire. Additionally, other features, such as their predominance over type I cells in humans versus mice, the nature of their ligands, CD1d/lipid/TCR binding, and modulation of immune responses, distinguish type II NKT cells from type I NKT cells. Interestingly, it is the self-lipid-reactivity of type II NKT cells that has helped define their physiological role in health and in disease. The discovery of sulfatide as one of the major antigens for CD1d-restricted type II NKT cells in mice has been instrumental in the characterization of these cells, including the TCR repertoire, the crystal structure of the CD1d/lipid/TCR complex, and their function. Subsequently, several other glycolipids and phospholipids from both endogenous and microbial sources have been shown to activate type II NKT cells. The activation of a specific subset of type II NKT cells following administration with sulfatide or lysophosphatidylcholine (LPC) leads to engagement of a dominant immunoregulatory pathway associated with the inactivation of type I NKT cells, conventional dendritic cells, and inhibition of the proinflammatory Th1/Th17 cells. Thus, type II NKT cells have been shown to be immunosuppressive in autoimmune diseases, inflammatory liver diseases, and in cancer. Knowing their relatively higher prevalence in human than type I NKT cells, understanding their biology is imperative for health and disease.
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Affiliation(s)
- Suryasarathi Dasgupta
- Division of Gastroenterology, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92037, USA
| | - Vipin Kumar
- Division of Gastroenterology, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92037, USA.
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Labrada M, Pablos I, Prete F, Hevia G, Clavell M, Benvenuti F, Fernández LE. Induction of leukocyte infiltration at metastatic site mediates the protective effect of NGcGM3-based vaccine. Hum Vaccin Immunother 2015; 10:2312-20. [PMID: 25424937 DOI: 10.4161/hv.29161] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
While the NGcGM3/VSSP vaccine, a preparation consisting in very small sized proteoliposomes (VSSP) obtained by the incorporation of the NGcGM3 ganglioside into the outer membrane protein (OMP) complex of Neisseria meningitides, is currently studied in late stage clinical trials in breast cancer and melanoma patients, mechanisms involved in the vaccine's antitumor effect are insufficiently understood. Here we have addressed the role of adaptive and innate immune cells in mediating the protective effect of the vaccine. To this aim we selected the 3LL-D122 Lewis lung spontaneous metastasis model. Unexpectedly, inoculation of the vaccine in tumor bearing C57BL/6 mice, either by subcutaneous (sc) or intraperitoneal (ip) routes, induced similar anti-metastatic effect. Regardless the T-independent nature of NGcGM3 ganglioside as antigen, the antimetastatic effect of NGcGM3/VSSP is dependent on CD4(+) T cells. In a further step we found that the vaccine was able to promote the increase, maturation, and cytokine secretion of conventional DCs and the maturation of Bone Marrow-derived plasmacytoid DCs. In line with this result the in vivo IFNα serum level in ip vaccinated mice increased as soon as 2h after treatment. On the other hand the infiltration of NK1.1(+)CD3(-) and NK1.1(+)CD3(+) cells in lungs of vaccinated mice was significantly increased, compared with the presence of these cells in control animal lungs. In the same way NGcGM3/VSSP mobilized acquired immunity effector cells into the lungs of vaccinated tumor bearing mice. Finally and not less noteworthy, leukocyte infiltration in lungs of tumor bearing mice correlates with vaccine induced inhibition of lung metastization.
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Affiliation(s)
- Mayrel Labrada
- a Center of Molecular Immunology (CIM); Immunobiology Division; Atabey; Havana Cuba
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9
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Van Kaer L, Parekh VV, Wu L. The Response of CD1d-Restricted Invariant NKT Cells to Microbial Pathogens and Their Products. Front Immunol 2015; 6:226. [PMID: 26029211 PMCID: PMC4429631 DOI: 10.3389/fimmu.2015.00226] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 04/27/2015] [Indexed: 12/18/2022] Open
Abstract
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.
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Affiliation(s)
- Luc Van Kaer
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine , Nashville, TN , USA
| | - Vrajesh V Parekh
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine , Nashville, TN , USA
| | - Lan Wu
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine , Nashville, TN , USA
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Abstract
The observation that a subset of cancer patients show evidence for spontaneous CD8+ T cell priming against tumor-associated antigens has generated renewed interest in the innate immune pathways that might serve as a bridge to an adaptive immune response to tumors. Manipulation of this endogenous T cell response with therapeutic intent-for example, using blocking antibodies inhibiting PD-1/PD-L1 (programmed death-1/programmed death ligand 1) interactions-is showing impressive clinical results. As such, understanding the innate immune mechanisms that enable this T cell response has important clinical relevance. Defined innate immune interactions in the cancer context include recognition by innate cell populations (NK cells, NKT cells, and γδ T cells) and also by dendritic cells and macrophages in response to damage-associated molecular patterns (DAMPs). Recent evidence has indicated that the major DAMP driving host antitumor immune responses is tumor-derived DNA, sensed by the stimulator of interferon gene (STING) pathway and driving type I IFN production. A deeper knowledge of the clinically relevant innate immune pathways involved in the recognition of tumors is leading toward new therapeutic strategies for cancer treatment.
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Abstract
Over the past 15 years, investigators have shown that T lymphocytes can recognize not only peptides in the context of MHC class I and class II molecules but also foreign and self-lipids in association with the nonclassical MHC class I-like molecules, CD1 proteins. In this review, we describe the most recent events in the field, with particular emphasis on (a) structural and functional aspects of lipid presentation by CD1 molecules, (b) the development of CD1d-restricted invariant natural killer T (iNKT) cells and transcription factors required for their differentiation, (c) the ability of iNKT cells to modulate innate and adaptive immune responses through their cross talk with lymphoid and myeloid cells, and (d) MR1-restricted and group I (CD1a, CD1b, and CD1c)-restricted T cells.
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Affiliation(s)
- Mariolina Salio
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom;
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12
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Dowds CM, Kornell SC, Blumberg RS, Zeissig S. Lipid antigens in immunity. Biol Chem 2014; 395:61-81. [PMID: 23999493 PMCID: PMC4128234 DOI: 10.1515/hsz-2013-0220] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 08/27/2013] [Indexed: 02/07/2023]
Abstract
Lipids are not only a central part of human metabolism but also play diverse and critical roles in the immune system. As such, they can act as ligands of lipid-activated nuclear receptors, control inflammatory signaling through bioactive lipids such as prostaglandins, leukotrienes, lipoxins, resolvins, and protectins, and modulate immunity as intracellular phospholipid- or sphingolipid-derived signaling mediators. In addition, lipids can serve as antigens and regulate immunity through the activation of lipid-reactive T cells, which is the topic of this review. We will provide an overview of the mechanisms of lipid antigen presentation, the biology of lipid-reactive T cells, and their contribution to immunity.
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Affiliation(s)
- C. Marie Dowds
- Department of Internal Medicine I, University Medical Center
Schleswig-Holstein, Schittenhelmstraße 12, D-24105 Kiel,
Germany
| | - Sabin-Christin Kornell
- Department of Internal Medicine I, University Medical Center
Schleswig-Holstein, Schittenhelmstraße 12, D-24105 Kiel,
Germany
| | - Richard S. Blumberg
- Division of Gastroenterology, Hepatology, and Endoscopy, Brigham
and Women’s Hospital, Harvard Medical School, 75 Francis Street,
Boston, MA 02115, USA
| | - Sebastian Zeissig
- Department of Internal Medicine I, University Medical Center
Schleswig-Holstein, Schittenhelmstraße 12, D-24105 Kiel,
Germany
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13
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Abstract
CD1d-restricted natural killer T (NKT) cells are a distinct subset of T cells that rapidly produce an array of cytokines on activation and play a critical role in regulating various immune responses. NKT cells are classified into 2 groups based on differences in T-cell receptor usage. Type I NKT cells have an invariant T-cell receptor α-chain and are readily detectable by α-galactosylceramide (α-GalCer)-loaded CD1d tetramers. Type II NKT cells have a more diverse T-cell receptor repertoire and cannot be directly identified. Both types of NKT cells and 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, type I NKT cells have been shown to make both protective and pathogenic contributions to disease. In contrast, in patients with ulcerative colitis, and a mouse model in which both CD1d expression and the frequency of type II NKT cells are increased, type II NKT cells seem to promote intestinal inflammation. In this review, we summarize the present knowledge on the antigen recognition, activation, and function of NKT cells with a particular focus on their role in inflammatory bowel disease and discuss factors that may influence the functional outcome of NKT cell responses in intestinal inflammation.
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14
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Huang YK, Zheng Z, Cheng CX, Wang LY, Li YR, Qiu F. The antitumor effect of the toll-like receptor 3 ligand polyinosinic-cytidylic acid as an adjuvant. Cancer Immunol Immunother 2013; 62:237-44. [PMID: 22868899 PMCID: PMC11028857 DOI: 10.1007/s00262-012-1328-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Accepted: 07/24/2012] [Indexed: 01/06/2023]
Abstract
Although polyinosinic-polycytidylic acid (poly(I:C)) has been applied in tumor immunity as a Toll-like receptor 3 (TLR3) ligand, the interaction between poly(I:C) and TLR3 is still unclear, as are the mechanisms underlying the antitumor effect of poly(I:C). Our aim was to investigate the interaction between poly(I:C) and TLR3, as well as the mechanisms underlying the antitumor effect of poly(I:C). NK92 cells were maintained in medium (untreated group), or medium containing E7(44-62) (E7 group) or E7(44-62)+poly(I:C) (poly(I:C)/E7 group), and we measured the expression of TLR3 mRNA, p-p65, and IκB-α protein. The cells were first incubated in medium alone or medium containing TLR3 monoclonal antibody, and then in medium containing poly(I:C)/E7. Finally, we measured the level of interferon-beta (INF-β) in the supernatant and determined the tumor cell-killing effect of the NK92 cells. At 1 h, the expression of TLR3 mRNA in the poly(I:C)/E7 group was markedly higher than that in the untreated and E7 groups (P < 0.05). When compared with the poly(I:C)/E7 group, the expression of IκB-α was dramatically increased in the E7 and untreated groups, and the expression of p-p65 was dramatically decreased in the E7 and untreated groups (all P < 0.05). At 24 h, INF-β content and tumor cell-killing activity in the poly(I:C)/E7 group were markedly higher than those in the untreated group (P < 0.001, <0.05, respectively). Treatment with TLR3 monoclonal antibody significantly inhibited poly(I:C)/E7-induced INF-β secretion and tumor cell-killing activity in NK92 cells (P < 0.001, <0.05, respectively). The interaction between poly(I:C) and TLR3 plays an important role in the antitumor immunity of NK92 cells. In addition, the interaction between poly(I:C) and TLR3 increases INF-β expression, which may be attributed to the activation of NFκB.
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Affiliation(s)
- Yu-Kun Huang
- Department of Infectious Diseases, Xiangya Hospital, Central South University, Changsha, 410078 Hunan Province People’s Republic of China
| | - Zhi Zheng
- Xiangya Third Hospital, Central South University, Changsha, 410013 Hunan Province People’s Republic of China
| | - Chun-Xia Cheng
- Department of Obstetrics and Gynecology, Xiangya Third Hospital, Central South University, Changsha, 410013 Hunan Province People’s Republic of China
| | - Lu-Ying Wang
- Department of Obstetrics and Gynecology, Xiangya Third Hospital, Central South University, Changsha, 410013 Hunan Province People’s Republic of China
| | - Yue-Ran Li
- Department of Obstetrics and Gynecology, Xiangya Third Hospital, Central South University, Changsha, 410013 Hunan Province People’s Republic of China
| | - Fu Qiu
- Department of General Surgery, Xiangya Third Hospital, Central South University, Changsha, 410013 Hunan Province People’s Republic of China
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15
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CD1d and natural killer T cells in immunity to Mycobacterium tuberculosis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 783:199-223. [PMID: 23468111 DOI: 10.1007/978-1-4614-6111-1_11] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The critical role of peptide antigen-specific T cells in controlling mycobacterial infections is well documented in natural resistance and vaccine-induced immunity against Mycobacterium tuberculosis. However, many other populations of leukocytes contribute to innate and adaptive immunity against mycobacteria. Among these, non-conventional T cells recognizing lipid antigens presented by the CD1 antigen presentation system have attracted particular interest. In this chapter, we review the basic immunobiology and potential antimycobacterial properties of a subset of CD1-restricted T cells that have come to be known as Natural Killer T cells. This group of lipid reactive T cells is notable for its high level of conservation between humans and mice, thus enabling a wide range of highly informative studies in mouse models. As reviewed below, NKT cells appear to have subtle but potentially significant activities in the host response to mycobacteria. Importantly, they also provide a framework for investigations into other types of lipid antigen-specific T cells that may be more abundant in larger mammals such as humans.
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16
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Abós-Gracia B, del Moral MG, López-Relaño J, Viana-Huete V, Castro L, Villalba M, Martínez-Naves E. Olea europaea pollen lipids activate invariant natural killer T cells by upregulating CD1d expression on dendritic cells. J Allergy Clin Immunol 2012; 131:1393-9.e5. [PMID: 23265858 DOI: 10.1016/j.jaci.2012.11.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 10/18/2012] [Accepted: 11/08/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND Invariant natural killer T (iNKT) cells recognize lipids presented by CD1d and have been implicated in the pathogenesis of allergic asthma. Recognition of plant pollen lipids by iNKT cells and their role in allergic responses are poorly defined. OBJECTIVE Our goal was to investigate whether iNKT cells can be activated by monocyte-derived dendritic cells (DCs) exposed to lipid antigens from Olea europaea. METHODS DCs generated in vitro were exposed to O europaea pollen grains or lipids isolated from them. Expression of lipid-presenting molecules (CD1), as well as maturation markers (HLA-DR, HLA-I, CD86, and CD80 molecules), on DCs was analyzed. iNKT cell activation after coculture with DCs was evaluated based on expansion, cytokine production, and cytotoxicity tests. RESULTS DCs upregulated CD1d and CD86 expression and downregulated CD1a expression after exposure to a whole extract of olive pollen lipids. CD1d and CD1a were regulated at the transcriptional level in a peroxisome proliferator-activated receptor γ activation-dependent manner. Polar lipids, diacylglycerols, free fatty acids, and triacylglycerols isolated from pollen grains upregulate CD1d. The increase in CD1d expression on the DC cell surface induced by polar lipids was not regulated at the RNA level. iNKT cells efficiently recognize DCs treated with the different lipids isolated from olive pollen grains. CONCLUSIONS Lipids from O europaea pollen upregulate CD1d and CD86 molecules on DCs, which are then able to activate iNKT cells through a CD1d-dependent pathway.
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Affiliation(s)
- Beatriz Abós-Gracia
- Unidad de Inmunología, Facultad de Medicina, Universidad Complutense, Madrid, Spain
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17
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Lawson V. Turned on by danger: activation of CD1d-restricted invariant natural killer T cells. Immunology 2012; 137:20-7. [PMID: 22734667 DOI: 10.1111/j.1365-2567.2012.03612.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
CD1d-restricted invariant natural killer T (iNKT) cells bear characteristics of innate and adaptive lymphocytes, which allow them to bridge the two halves of the immune response and play roles in many disease settings. Recent work has characterized precisely how their activation is initiated and regulated. Novel antigens from important pathogens have been identified, as has an abundant self-antigen, β-glucopyranosylcaramide, capable of mediating an iNKT-cell response. Studies of the iNKT T-cell receptor (TCR)-antigen-CD1d complex show how docking between CD1d-antigen and iNKT TCR is highly conserved, and how small sequence differences in the TCR establish intrinsic variation in iNKT TCR affinity. The sequence of the TCR CDR3β loop determines iNKT TCR affinity for ligand-CD1d, independent of ligand identity. CD1d ligands can promote T helper type 1 (Th1) or Th2 biased cytokine responses, depending on the composition of their lipid tails. Ligands loaded into CD1d on the cell surface promote Th2 responses, whereas ligands with long hydrophobic tails are loaded endosomally and promote Th1 responses. This information is informing the design of synthetic iNKT-cell antigens. The iNKT cells may be activated by exogenous antigen, or by a combination of dendritic cell-derived interleukin-12 and iNKT TCR-self-antigen-CD1d engagement. The iNKT-cell activation is further modulated by recent foreign or self-antigen encounter. Activation of dendritic cells through pattern recognition receptors alters their antigen presentation and cytokine production, strongly influencing iNKT-cell activation. In a range of bacterial infections, dendritic cell-dependent innate activation of iNKT cells through interleukin-12 is the dominant influence on their activity.
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18
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Van Kaer L, Parekh VV, Wu L. Invariant natural killer T cells as sensors and managers of inflammation. Trends Immunol 2012; 34:50-8. [PMID: 23017731 DOI: 10.1016/j.it.2012.08.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 08/28/2012] [Accepted: 08/28/2012] [Indexed: 02/08/2023]
Abstract
Invariant natural killer T (iNKT) cells are a subset of innate-like lymphocytes that recognize glycolipid antigens bound by the major histocompatibility complex (MHC)-class-I-related protein CD1d. iNKT cells are activated early during a variety of infections and inflammatory diseases and contribute to the subsequent development of adaptive immune responses. Consequently, iNKT cells play a critical role in the development and resolution of inflammatory diseases and represent attractive targets for the development of immunotherapies. Recent studies have provided important insight into the mechanisms by which iNKT cells become activated in response to diverse inflammatory stimuli. These new findings should be instrumental to promote the immunomodulatory properties of iNKT cells for treatment of inflammatory diseases.
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Affiliation(s)
- Luc Van Kaer
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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19
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Liao CM, Zimmer MI, Shanmuganad S, Yu HT, Cardell SL, Wang CR. dysregulation of CD1d-restricted type ii natural killer T cells leads to spontaneous development of colitis in mice. Gastroenterology 2012; 142:326-34.e1-2. [PMID: 22057113 PMCID: PMC3267843 DOI: 10.1053/j.gastro.2011.10.030] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 10/14/2011] [Accepted: 10/17/2011] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS CD1d-restricted natural killer (NK) T cells are a subset of immunoregulatory T cells that comprise type I (express the semi-invariant T-cell receptor [TCR] and can be detected using the α-galactosylceramide/CD1d tetramer) and type II (express diverse TCRs and cannot be directly identified). Studies in mouse models of inflammatory bowel disease revealed a complex role for type I NKT cells in the development of colitis. Type II NKT cells have been associated with intestinal inflammation in patients with ulcerative colitis. METHODS To investigate whether dysregulation of type II NKT cells, caused by increased expression of CD1d, can contribute to colitis, we generated transgenic mice that express high levels of CD1d and a TCR from an autoreactive, type II NKT cell (CD1dTg/24αβTg mice). RESULTS CD1dTg/24αβTg mice had reduced numbers of 24αβ T cells compared with 24αβTg mice, indicating that negative selection increases among type II NKT cells engaged by abundant self-antigen. The residual 24αβ T cells in CD1dTg/24αβTg mice had an altered surface phenotype and acquired a cytokine profile distinct from that of equivalent cells in 24αβTg mice. Interestingly, CD1dTg/24αβTg mice spontaneously developed colitis; adoptive transfer experiments confirmed that type II NKT cells that develop in the context of increased CD1d expression are pathogenic. CONCLUSIONS Aberrant type II NKT cell responses directly contribute to intestinal inflammation in mice, indicating the importance of CD1d expression levels in the development and regulation of type II NKT cells.
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Affiliation(s)
- Chia-Min Liao
- Department of Microbiology and Immunology, Northwestern University, Chicago, IL, USA,Institute of Zoology and Department of Life Science, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Michael I. Zimmer
- Department of Microbiology and Immunology, Northwestern University, Chicago, IL, USA
| | - Sharmila Shanmuganad
- Department of Microbiology and Immunology, Northwestern University, Chicago, IL, USA
| | - Hon-Tsen Yu
- Institute of Zoology and Department of Life Science, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Susanna L. Cardell
- Department of Microbiology and Immunology, University of Gothenburg, Gothenburg, Sweden
| | - Chyung-Ru Wang
- Department of Microbiology and Immunology, Northwestern University, Chicago, IL, USA
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20
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Issazadeh-Navikas S. NKT cell self-reactivity: evolutionary master key of immune homeostasis? J Mol Cell Biol 2011; 4:70-8. [PMID: 22167750 DOI: 10.1093/jmcb/mjr035] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
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.
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Affiliation(s)
- Shohreh Issazadeh-Navikas
- Neuroinflammation Unit, Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen Biocentre, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark.
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21
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Nakajima H, Oka Y, Tsuboi A, Tatsumi N, Yamamoto Y, Fujiki F, Li Z, Murao A, Morimoto S, Hosen N, Shirakata T, Nishida S, Kawase I, Isaka Y, Oji Y, Sugiyama H. Enhanced tumor immunity of WT1 peptide vaccination by interferon-β administration. Vaccine 2011; 30:722-9. [PMID: 22133512 DOI: 10.1016/j.vaccine.2011.11.074] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 11/18/2011] [Accepted: 11/19/2011] [Indexed: 10/14/2022]
Abstract
To induce and activate tumor-associated antigen-specific cytotoxic T lymphocytes (CTLs) for cancer immunity, it is important not only to select potent CTL epitopes but also to combine them with appropriate immunopotentiating agents. Here we investigated whether tumor immunity induced by WT1 peptide vaccination could be enhanced by IFN-β. For the experimental group, C57BL/6 mice were twice pre-treated with WT1 peptide vaccine, implanted with WT1-expressing C1498 cells, and treated four times with WT1 peptide vaccine at one-week intervals. During the vaccination period, IFN-β was injected three times a week. Mice in control groups were treated with WT1 peptide alone, IFN-β alone, or PBS alone. The mice in the experimental group rejected tumor cells and survived significantly longer than mice in the control groups. The overall survival on day 75 was 40% for the mice treated with WT1 peptide+IFN-β, while it was 7, 7, and 0% for those treated with WT1 peptide alone, IFN-β alone or PBS alone, respectively. Induction of WT1-specific CTLs and enhancement of NK activity were detected in splenocytes from mice in the experimental group. Furthermore, administration of IFN-β enhanced expression of MHC class I molecules on the implanted tumor cells. In conclusion, our results showed that co-administration of WT1 peptide+IFN-β enhanced tumor immunity mainly through the induction of WT1-specific CTLs, enhancement of NK activity, and promotion of MHC class I expression on the tumor cells. WT1 peptide vaccination combined with IFN-β administration can thus be expected to enhance the clinical efficacy of WT1 immunotherapy.
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Affiliation(s)
- Hiroko Nakajima
- Department of Cancer Immunology, Osaka University Graduate School of Medicine, Osaka, Japan
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22
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Requirement for invariant chain in macrophages for Mycobacterium tuberculosis replication and CD1d antigen presentation. Infect Immun 2011; 79:3053-63. [PMID: 21576321 DOI: 10.1128/iai.01108-10] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Mycobacterium tuberculosis is an intracellular bacterium that persists in phagosomes of myeloid cells. M. tuberculosis-encoded factors support pathogen survival and reduce fusion of phagosomes with bactericidal lysosomal compartments. It is, however, not entirely understood if host factors that mediate endosomal fusion affect M. tuberculosis intracellular localization and survival. Neither is it known if endosomal fusion influences induction of host immune reactivity by M. tuberculosis-infected cells. Lysosomal degradation of M. tuberculosis appears to be pivotal for making available lipid substrates for assembly into lipid-CD1d complexes to allow activation of CD1d-restricted invariant natural killer T (iNKT) cells. To clarify the role for endosomal fusion in M. tuberculosis survival and induction of host CD1d-mediated immune defense, we focused our studies on the invariant chain (Ii). Ii regulates endosome docking and fusion and thereby controls endosomal transport. Through direct binding, Ii also directs intracellular transport of the class II major histocompatibility complex and CD1d. Our findings demonstrate that upon infection of Ii-knockout (Ii(-/-)) macrophages, M. tuberculosis is initially retained in early endosomal antigen 1-positive lysosomal-associated membrane protein 1-negative phagosomes, which results in slightly impaired pathogen replication. The absence of Ii did not affect the ability of uninfected and infected macrophages to produce nitric oxide, tumor necrosis factor alpha, or interleukin-12. However, induction of cell surface CD1d was impaired in infected Ii(-/-) macrophages, and CD1d-restricted iNKT cells were unable to suppress bacterial replication when they were cocultured with M. tuberculosis-infected Ii(-/-) macrophages. Thus, while the host factor Ii is not essential for the formation of the M. tuberculosis-containing vacuole, its presence is crucial for iNKT cell recognition of infected macrophages.
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23
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Brigl M, Tatituri RVV, Watts GFM, Bhowruth V, Leadbetter EA, Barton N, Cohen NR, Hsu FF, Besra GS, Brenner MB. Innate and cytokine-driven signals, rather than microbial antigens, dominate in natural killer T cell activation during microbial infection. ACTA ACUST UNITED AC 2011; 208:1163-77. [PMID: 21555485 PMCID: PMC3173255 DOI: 10.1084/jem.20102555] [Citation(s) in RCA: 219] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Invariant natural killer T cells (iNKT cells) are critical for host defense against a variety of microbial pathogens. However, the central question of how iNKT cells are activated by microbes has not been fully explained. The example of adaptive MHC-restricted T cells, studies using synthetic pharmacological α-galactosylceramides, and the recent discovery of microbial iNKT cell ligands have all suggested that recognition of foreign lipid antigens is the main driver for iNKT cell activation during infection. However, when we compared the role of microbial antigens versus innate cytokine-driven mechanisms, we found that iNKT cell interferon-γ production after in vitro stimulation or infection with diverse bacteria overwhelmingly depended on toll-like receptor-driven IL-12. Importantly, activation of iNKT cells in vivo during infection with Sphingomonas yanoikuyae or Streptococcus pneumoniae, pathogens which are known to express iNKT cell antigens and which require iNKT cells for effective protection, also predominantly depended on IL-12. Constitutive expression of high levels of IL-12 receptor by iNKT cells enabled instant IL-12-induced STAT4 activation, demonstrating that among T cells, iNKT cells are uniquely equipped for immediate, cytokine-driven activation. These findings reveal that innate and cytokine-driven signals, rather than cognate microbial antigen, dominate in iNKT cell activation during microbial infections.
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Affiliation(s)
- Manfred Brigl
- Department of Pathology, Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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24
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Liu W, Huber SA. Cross-talk between cd1d-restricted nkt cells and γδ cells in t regulatory cell response. Virol J 2011; 8:32. [PMID: 21255407 PMCID: PMC3033358 DOI: 10.1186/1743-422x-8-32] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 01/21/2011] [Indexed: 01/07/2023] Open
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.
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Affiliation(s)
- Wei Liu
- The First Affiliated Hospital of Harbin Medical University, Harbin 150001, PR China
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25
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Wu L, Van Kaer L. Natural killer T cells in health and disease. Front Biosci (Schol Ed) 2011; 3:236-51. [PMID: 21196373 DOI: 10.2741/s148] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Natural killer T (NKT) cells are a subset of T lymphocytes that share surface markers and functional characteristics with both conventional T lymphocytes and natural killer cells. Most NKT cells express a semi-invariant T cell receptor that reacts with glycolipid antigens presented by the major histocompatibility complex class I-related protein CD1d on the surface of antigen-presenting cells. NKT cells become activated during a variety of infections and inflammatory conditions, rapidly producing large amounts of immunomodulatory cytokines. NKT cells can influence the activation state and functional properties of multiple other cell types in the immune system and, thus, modulate immune responses against infectious agents, autoantigens, tumors, tissue grafts and allergens. One attractive aspect of NKT cells is that their immunomodulatory activities can be readily harnessed with cognate glycolipid antigens, such as the marine sponge-derived glycosphingolipid alpha-galactosylceramide. These properties of NKT cells are being exploited for therapeutic intervention to prevent or treat cancer, infections, and autoimmune and inflammatory diseases.
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Affiliation(s)
- Lan Wu
- Department of Microbiology and Immunology, Room A-5301, Medical Center North, 1161 21st Avenue South, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2363, USA
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26
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De Santo C, Arscott R, Booth S, Karydis I, Jones M, Asher R, Salio M, Middleton M, Cerundolo V. Invariant NKT cells modulate the suppressive activity of IL-10-secreting neutrophils differentiated with serum amyloid A. Nat Immunol 2010; 11:1039-46. [PMID: 20890286 PMCID: PMC3001335 DOI: 10.1038/ni.1942] [Citation(s) in RCA: 232] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Accepted: 09/08/2010] [Indexed: 12/15/2022]
Abstract
Neutrophils are the primary effector cells during inflammation, but can also control excessive inflammatory responses by secreting anti-inflammatory cytokines. However, the mechanisms modulating their plasticity remain unclear. We now show that systemic serum amyloid A-1 (SAA-1) controls the plasticity of neutrophil differentiation. SAA-1 not only induced anti-inflammatory IL-10-secreting neutrophils but also promoted invariant NKT (iNKT) cell interaction with these neutrophils, a process that limits their suppressive activity by reducing IL-10 and enhancing IL-12 production. Because SAA-1-producing melanomas promote differentiation of IL-10-secreting neutrophils, harnessing iNKT cells could be useful therapeutically by reducing the frequency of immunosuppressive neutrophils and restoring tumor specific immune responses.
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Affiliation(s)
- Carmela De Santo
- Medical Research Council Human Immunology Unit, Nuffield Department of Medicine, Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
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27
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Van Kaer L, Parekh VV, Wu L. Invariant natural killer T cells: bridging innate and adaptive immunity. Cell Tissue Res 2010; 343:43-55. [PMID: 20734065 DOI: 10.1007/s00441-010-1023-3] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 07/13/2010] [Indexed: 02/08/2023]
Abstract
Cells of the innate immune system interact with pathogens via conserved pattern-recognition receptors, whereas cells of the adaptive immune system recognize pathogens through diverse, antigen-specific receptors that are generated by somatic DNA rearrangement. Invariant natural killer T (iNKT) cells are a subset of lymphocytes that bridge the innate and adaptive immune systems. Although iNKT cells express T cell receptors that are generated by somatic DNA rearrangement, these receptors are semi-invariant and interact with a limited set of lipid and glycolipid antigens, thus resembling the pattern-recognition receptors of the innate immune system. Functionally, iNKT cells most closely resemble cells of the innate immune system, as they rapidly elicit their effector functions following activation, and fail to develop immunological memory. iNKT cells can become activated in response to a variety of stimuli and participate in the regulation of various immune responses. Activated iNKT cells produce several cytokines with the capacity to jump-start and modulate an adaptive immune response. A variety of glycolipid antigens that can differentially elicit distinct effector functions in iNKT cells have been identified. These reagents have been employed to test the hypothesis that iNKT cells can be harnessed for therapeutic purposes in human diseases. Here, we review the innate-like properties and functions of iNKT cells and discuss their interactions with other cell types of the immune system.
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Affiliation(s)
- Luc Van Kaer
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Medical Center North, Room A-5301, 1161 21st Ave. South, Nashville, TN 37232-2363, USA.
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28
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iNKT cell autoreactivity: what is 'self' and how is it recognized? Nat Rev Immunol 2010; 10:272-7. [PMID: 20224567 DOI: 10.1038/nri2743] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Following stimulation through their T cell receptor, invariant natural killer T (iNKT) cells function as innate effector cells by rapidly releasing large amounts of effector cytokines and chemokines and therefore have an important role in modulating the ensuing immune response. iNKT cells recognize, and are activated by, diverse glycolipid antigens, many of which are found in microorganisms. However, iNKT cells also show some reactivity to 'self'. Here, I outline our current understanding of iNKT cell autoreactivity and propose that several self lipids are probably involved in the positive selection and autoreactivity of iNKT cells.
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29
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Yue SC, Nowak M, Shaulov-Kask A, Wang R, Yue D, Balk SP, Exley MA. Direct CD1d-mediated stimulation of APC IL-12 production and protective immune response to virus infection in vivo. THE JOURNAL OF IMMUNOLOGY 2009; 184:268-76. [PMID: 19949077 DOI: 10.4049/jimmunol.0800924] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
CD1d-restricted NKT cells rapidly stimulate innate and adaptive immunity through production of Th1 and/or Th2 cytokines and induction of CD1d(+) APC maturation. However, therapeutic exploitation of NKT cells has been hampered by their paucity and defects in human disease. NKT cell-APC interactions can be modeled by direct stimulation of human APCs through CD1d in vitro. We have now found that direct ligation with multiple CD1d mAbs also stimulated bioactive IL-12 release from CD1d(+) but not CD1d knockout murine splenocytes in vitro. Moreover, all of the CD1d mAbs tested also induced IL-12 as well as both IFN-gamma and IFN-alpha in vivo from CD1d(+) but not CD1d-deficient recipients. Unlike IFN-gamma, CD1d-induced IFN-alpha was at least partially dependent on invariant NKT cells. Optimal resistance to infection with picornavirus encephalomyocarditis virus is known to require CD1d-dependent APC IL-12-induced IFN-gamma as well as IFN-alpha. CD1d ligation in vivo enhanced systemic IL-12, IFN-gamma, and IFN-alpha and was protective against infection by encephalomyocarditis virus, suggesting an alternative interpretation for previous results involving CD1d "blocking" in other systems. Such protective responses, including elevations in Th1 cytokines, were also seen with CD1d F(ab')(2)s in vivo, whereas an IgM mAb (with presumably minimal tissue penetration) was comparably effective at protection in vivo as well as cytokine induction both in vivo and in vitro. Although presumably acting immediately "downstream," CD1d mAbs were protective later during infection than the invariant NKT cell agonist alpha-galactosylceramide. These data indicate that NKT cells can be bypassed with CD1d-mediated induction of robust Th1 immunity, which may have therapeutic potential both directly and as an adjuvant.
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Affiliation(s)
- Simon C Yue
- Cancer Biology Program, Division of Hematology and Oncology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
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How invariant natural killer T cells respond to infection by recognizing microbial or endogenous lipid antigens. Semin Immunol 2009; 22:79-86. [PMID: 19948416 DOI: 10.1016/j.smim.2009.10.006] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Accepted: 10/26/2009] [Indexed: 12/12/2022]
Abstract
Invariant natural killer T (iNKT) cells have evolved to recognize CD1d-presented lipid antigens and are known to play important roles during infection with bacterial, viral, protozoan, and fungal pathogens. The limited antigen specificity and reactivity to self- and foreign antigens distinguish iNKT cells from MHC-restricted T cells and bear similarity to innate-like lymphocytes, such as NK cells, gammadelta T cells, MZB and B1-B cells. This review summarizes how direct recognition of microbial lipids or synergistic stimulation by self-lipids and pro-inflammatory cytokines results in activation of these innate-like iNKT cell during infection. iNKT cell activation in the absence of foreign antigen recognition is unique for cells bearing TCRs and underscores that not only the function but also the activation mechanism of iNKT cells is innate-like, and distinct from adaptive T cells. The different pathways of activation endow iNKT cells with the ability to respond rapidly to a wide variety of infectious agents and to contribute effectively to the early immune response during infection.
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Abstract
Immune activation is often associated with inflammation, but inflammation's role in the expansion of antigen-specific immune responses remains unclear. This primer focuses on recent findings that show how specific natural killer T cells are activated by inflammatory messengers, thus illuminating the cellular and molecular links between immunity and inflammation.
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Affiliation(s)
- Mariolina Salio
- Nuffield Department of Clinical Medicine, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Vincenzo Cerundolo
- Nuffield Department of Clinical Medicine, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
- * E-mail:
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Choi HJ, Xu H, Geng Y, Colmone A, Cho H, Wang CR. Bacterial infection alters the kinetics and function of iNKT cell responses. J Leukoc Biol 2008; 84:1462-71. [PMID: 18772281 DOI: 10.1189/jlb.0108038] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
CD1d-restricted Valpha14 invariant NKT cells (iNKT) are innate-like, immunoregulatory lymphocytes that play critical roles in autoimmunity, tumor surveillance, and infectious disease. Although iNKT cells are activated during microbial infection, the impacts of infection on the function of iNKT cells have not been fully characterized. Using a Listeria monocytogenes (LM) infection model, we found that iNKT cells failed to expand after infection, resulting in prolonged loss in the spleen, in contrast to the typical expansion and contraction of conventional T cells. iNKT cells from LM-infected mice responded more rapidly to secondary LM infection; however, they became functionally hyporesponsive to antigenic challenge for at least 1 month. This infection-induced hyporesponsiveness was also induced by Mycobacteria infection and was more profound in LM-infected, thymectomized mice, suggesting that infection-primed iNKT cells might have altered functionality. Interestingly, activation with alpha-galactosylceramide-loaded dendritic cells was able to overcome infection-induced hyporesponsiveness of iNKT cells, suggesting a role for extrinsic factors in this functional deficit. Taken together, these findings suggest that infection affects iNKT cell responses quantitatively and qualitatively. As humans are under constant microbial insult, predictions of iNKT cell function based on naïve animal models may not accurately reflect iNKT cell behavior in a clinical setting.
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Affiliation(s)
- Hak-Jong Choi
- Department of Pathology, University of Chicago, Chicago, IL, USA
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Raftery MJ, Winau F, Giese T, Kaufmann SHE, Schaible UE, Schönrich G. Viral danger signals control CD1d de novo synthesis and NKT cell activation. Eur J Immunol 2008; 38:668-79. [PMID: 18253929 DOI: 10.1002/eji.200737233] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The nonpolymorphic CD1 molecules present lipid antigens to T cells. In myeloid DC humans express five different CD1 proteins (CD1a-e; the corresponding CD1 genes are designated CD1A-E). A role for CD1d-restricted NKT cells in the control of virus infections has been delineated from clinical observations, mouse models and viral evasion mechanisms targeting CD1d. How NKT cells are activated by virus infections is unclear. We found that human myeloid DC differentially regulate CD1 antigen presentation in response to viral danger signals. Stimulation with type I IFN, viral TLR ligands or viruses strongly enhanced the number of CD1D transcripts in human myeloid DC but diminished the abundance of CD1A, CD1B and CD1E mRNA. These changes on the transcriptional level were mirrored by altered cellular distribution and increased surface expression of CD1d. As a consequence NKT cells were activated and showed a Th1-like response. Moreover, NKT cell activation in PBMC exposed to viral danger signals was dependent on human plasmacytoid DC which produce large amounts of IFN-alpha. In conclusion, our data indicate that viral danger signals trigger NKT cell activation by enhancing CD1d de novo synthesis through increasing the abundance of CD1D mRNA in human myeloid DC.
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Affiliation(s)
- Martin J Raftery
- Institute of Virology, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Modulation of human natural killer T cell ligands on TLR-mediated antigen-presenting cell activation. Proc Natl Acad Sci U S A 2007; 104:20490-5. [PMID: 18077358 DOI: 10.1073/pnas.0710145104] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Invariant natural killer T (iNKT) cells are a subset of nonconventional T cells recognizing endogenous and/or exogenous glycolipid antigens in the context of CD1d molecules. It remains unclear whether innate stimuli can modify the profile of endogenous lipids recognized by iNKT cells on the surface of antigen-presenting cells (APCs). We report that activation of human APCs by Toll-like receptor ligands (TLR-L) modulates the lipid biosynthetic pathway, resulting in enhanced recognition of CD1d-associated lipids by iNKT cells, as defined by IFN-gamma secretion. APC-derived soluble factors further increase CD1d-restricted iNKT cell activation. Finally, using soluble tetrameric iNKT T cell receptors (TCR) as a staining reagent, we demonstrate specific up-regulation of CD1d-bound ligand(s) on TLR-mediated APC maturation. The ability of innate stimuli to modulate the lipid profile of APCs resulting in iNKT cell activation and APC maturation underscores the role of iNKT cells in assisting priming of antigen-specific immune responses.
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Correale J, Farez M. Monocyte-derived dendritic cells in multiple sclerosis: the effect of bacterial infection. J Neuroimmunol 2007; 190:177-89. [PMID: 17936916 DOI: 10.1016/j.jneuroim.2007.08.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 08/28/2007] [Accepted: 08/29/2007] [Indexed: 11/18/2022]
Abstract
We investigated whether monocyte-derived dendritic cells (MDDCs) generated in vitro from bacteria-infected MS patients modified autoreactive T cells activation patterns. T cell clones (TCCs) stimulated with MDDCs from infected MS patients responded with maximal proliferation, inducing IL-12, IL-17 and IFN-gamma secretion, at concentrations significantly lower than after incubation with MDDCs isolated from uninfected individuals and bacterial meningitis (BM) patients. Moreover, infected MDDCs promoted TCCs survival, and secreted more IL-12, IL-18, and IL-23. Finally, MDDCs from infected MS subjects showed higher expression of myeloid differentiation factor 88 (MyD88), as well as of HLA-DR, CD1a, CD80, CD86, CD273, CD40, CD83 and CCR7 when compared to MDDCs from uninfected MS individuals, and BM patients. Thus, activation of the innate immune system by microbial products in MS patients affects the generation MDDCs and their ability to modify autoreactive T cell activation patterns, which may be linked to MS relapse induction during bacterial infections.
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Affiliation(s)
- Jorge Correale
- Department of Neurology, Raúl Carrea Institute for Neurological Research (FLENI), Montañeses 2325, Buenos Aires, Argentina.
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Paget C, Mallevaey T, Speak AO, Torres D, Fontaine J, Sheehan KCF, Capron M, Ryffel B, Faveeuw C, Leite de Moraes M, Platt F, Trottein F. Activation of invariant NKT cells by toll-like receptor 9-stimulated dendritic cells requires type I interferon and charged glycosphingolipids. Immunity 2007; 27:597-609. [PMID: 17950005 DOI: 10.1016/j.immuni.2007.08.017] [Citation(s) in RCA: 214] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Revised: 07/05/2007] [Accepted: 08/21/2007] [Indexed: 01/18/2023]
Abstract
Invariant natural killer T (iNKT) cells are a subset of innate lymphocytes that recognize lipid antigens in the context of CD1d and mediate potent immune regulatory functions via the rapid production of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4). We investigated whether diverse Toll-like receptor (TLR) signals in myeloid dendritic cells (DCs) could differentially stimulate iNKT cells. Together with the lipopolysaccharide-detecting receptor TLR4, activation of the nucleic acid sensors TLR7 and TLR9 in DCs were particularly potent in stimulating iNKT cells to produce IFN-gamma, but not IL-4. iNKT cell activation in response to TLR9 stimulation required combined synthesis of type I interferon and de novo production of charged beta-linked glycosphingolipid(s) by DCs. In addition, DCs stimulated via TLR9 activated both iNKT cells and NK cells in vivo and protected mice against B16F10-induced melanoma metastases. These data underline the role of TLR9 in iNKT cell activation and might have relevance to infectious diseases and cancer.
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Affiliation(s)
- Christophe Paget
- Institut National de la Recherche Médicale, U547, 59019 Lille, France
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Gigli G, Caielli S, Cutuli D, Falcone M. Innate immunity modulates autoimmunity: type 1 interferon-beta treatment in multiple sclerosis promotes growth and function of regulatory invariant natural killer T cells through dendritic cell maturation. Immunology 2007; 122:409-17. [PMID: 17617156 PMCID: PMC2266024 DOI: 10.1111/j.1365-2567.2007.02655.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Type 1 interferon-beta (T1IFN-beta) is an innate cytokine and the first-choice therapy for multiple sclerosis (MS). It is still unclear how T1IFN-beta, whose main function is to promote innate immunity during infections, plays a beneficial role in autoimmune disease. Here we show that T1IFN-beta promoted the expansion and function of invariant natural killer (iNKT) cells, an innate T-cell subset with strong immune regulatory properties that is able to prevent autoimmune disease in pre-clinical models of MS and type 1 diabetes. Specifically, we observed that T1IFN-beta treatment significantly increased the percentages of Valpha24(+) NKT cells in peripheral blood mononuclear cells of MS patients. Furthermore, iNKT cells of T1IFN-beta-treated individuals showed a dramatically improved secretion of cytokines (interleukins 4 and 5 and interferon-gamma) in response to antigenic stimulation compared to iNKT cells isolated from the same patients before T1IFN-beta treatment. The effect of T1IFN-beta on iNKT cells was mediated through the modulation of myeloid dendritic cells (DCs). In fact, DCs modulated in vivo or in vitro by T1IFN-beta were more efficient antigen-presenting cells for iNKT cells. Such a modulatory effect of T1IFN-beta was associated with up-regulation on DCs of key costimulatory molecules for iNKT (i.e. CD80, CD40 and CD1d). Our data identified the iNKT cell/DC pathway as a new target for the immune regulatory effect of T1IFNs in autoimmune diseases and provide a possible mechanism to explain the clinical efficacy of T1IFN-beta in MS.
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Affiliation(s)
- Gianluigi Gigli
- Immunology of Diabetes Unit, San Raffaele Scientific Institute, Milan, Italy
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Tupin E, Kinjo Y, Kronenberg M. The unique role of natural killer T cells in the response to microorganisms. Nat Rev Microbiol 2007; 5:405-17. [PMID: 17487145 DOI: 10.1038/nrmicro1657] [Citation(s) in RCA: 355] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Natural killer T (NKT) cells combine features of the innate and adaptive immune systems. Recently, it has become evident that these T cells have crucial roles in the response to infectious agents. The antigen receptor expressed by NKT cells directly recognizes unusual glycolipids that are part of the membrane of certain Gram-negative bacteria and spirochetes. Moreover, even in the absence of microbial glycolipid antigens, these T cells respond to innate cytokines produced by dendritic cells that have been activated by microbes. This indirect sensing of infection, by responding to cytokines from activated dendritic cells, allows NKT cells to react to a broad range of infectious agents.
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Affiliation(s)
- Emmanuel Tupin
- Division of Developmental Immunology, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, California 92037, USA
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