101
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Trottein F, Paget C. Natural Killer T Cells and Mucosal-Associated Invariant T Cells in Lung Infections. Front Immunol 2018; 9:1750. [PMID: 30116242 PMCID: PMC6082944 DOI: 10.3389/fimmu.2018.01750] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 07/16/2018] [Indexed: 12/13/2022] Open
Abstract
The immune system has been traditionally divided into two arms called innate and adaptive immunity. Typically, innate immunity refers to rapid defense mechanisms that set in motion within minutes to hours following an insult. Conversely, the adaptive immune response emerges after several days and relies on the innate immune response for its initiation and subsequent outcome. However, the recent discovery of immune cells displaying merged properties indicates that this distinction is not mutually exclusive. These populations that span the innate-adaptive border of immunity comprise, among others, CD1d-restricted natural killer T cells and MR1-restricted mucosal-associated invariant T cells. These cells have the unique ability to swiftly activate in response to non-peptidic antigens through their T cell receptor and/or to activating cytokines in order to modulate many aspects of the immune response. Despite they recirculate all through the body via the bloodstream, these cells mainly establish residency at barrier sites including lungs. Here, we discuss the current knowledge into the biology of these cells during lung (viral and bacterial) infections including activation mechanisms and functions. We also discuss future strategies targeting these cell types to optimize immune responses against respiratory pathogens.
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Affiliation(s)
- François Trottein
- Univ. Lille, U1019 – UMR 8204 – CIIL – Centre d’Infection et d’Immunité de Lille, Lille, France
- Centre National de la Recherche Scientifique, UMR 8204, Lille, France
- Institut National de la Santé et de la Recherche Médicale U1019, Lille, France
- Centre Hospitalier Universitaire de Lille, Lille, France
- Institut Pasteur de Lille, Lille, France
| | - Christophe Paget
- Institut National de la Santé et de la Recherche Médicale U1100, Centre d’Etude des Pathologies Respiratoires (CEPR), Tours, France
- Université de Tours, Tours, France
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102
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Lezmi G, Leite-de-Moraes M. Invariant Natural Killer T and Mucosal-Associated Invariant T Cells in Asthmatic Patients. Front Immunol 2018; 9:1766. [PMID: 30105031 PMCID: PMC6077286 DOI: 10.3389/fimmu.2018.01766] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 07/17/2018] [Indexed: 12/20/2022] Open
Abstract
Recent studies have highlighted the heterogeneity of asthma. Distinct patient phenotypes (symptoms, age at onset, atopy, and lung function) may result from different pathogenic mechanisms, including airway inflammation, remodeling, and immune and metabolic pathways in a specific microbial environment. These features, which define the asthma endotype, may have significant consequences for the development and progression of the disease. Asthma is generally associated with Th2 cells, which produce a panel of cytokines (IL-4, IL-5, IL-13) that act in synergy to drive lung inflammatory responses, mucus secretion, IgE production, and fibrosis, causing the characteristic symptoms of asthma. In addition to conventional CD4+ T lymphocytes, other T-cell types can produce Th2 or Th17 cytokines rapidly. Promising candidate cells for studies of the mechanisms underlying the pathophysiology of asthma are unconventional T lymphocytes, such as invariant natural killer T (iNKT) and mucosal-associated invariant T (MAIT) cells. This review provides an overview of our current understanding of the impact of iNKT and MAIT cells on asthmatic inflammation, focusing particularly on pediatric asthma.
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Affiliation(s)
- Guillaume Lezmi
- AP-HP, Hôpital Necker-Enfants Malades, Service de Pneumologie et d'Allergologie Pédiatriques, Paris, France.,Université Paris Descartes, Paris, France.,Laboratory of Immunoregulation and Immunopathology, INEM (Institut Necker-Enfants Malades), CNRS UMR8253 and INSERM UMR1151, Paris, France
| | - Maria Leite-de-Moraes
- Université Paris Descartes, Paris, France.,Laboratory of Immunoregulation and Immunopathology, INEM (Institut Necker-Enfants Malades), CNRS UMR8253 and INSERM UMR1151, Paris, France
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103
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Schattgen SA, Thomas PG. Bohemian T cell receptors: sketching the repertoires of unconventional lymphocytes. Immunol Rev 2018; 284:79-90. [PMID: 29944761 PMCID: PMC6128411 DOI: 10.1111/imr.12668] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Over the last several decades, novel populations of unconventional T cells have been identified; defined by an invariant (or nearly invariant) T cell receptor (TCR) with a fixed specificity to non-canonical antigens and major histocompatibility (MHC) molecules, they form large, functionally monoclonal populations tasked with surveying for their specific antigens. With residence in both lymphoid and non-lymphoid tissues coupled with their ability to rapidly produce a spectrum of cytokines and effector molecules, the unconventional T cells are poised as some of the first responders to infection/damage and are thought to provide critical coverage before more focused, conventional T cell responses are mobilized. However, new technologies for the measurement and characterization of TCR repertoires have identified an underappreciated amount of TCR diversity in the unconventional T cells. In many cases, the specificities of these diverse TCRs converge on the same or similar antigens as their invariant counterparts, while others have yet to be defined. Here, we will review the current knowledge of the TCR repertoires of unconventional T cells and discuss how repertoires might be used as a framework for their organization, and further our understanding of their role not only during an immune response, but also their contribution in maintaining homeostasis.
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Affiliation(s)
| | - Paul G Thomas
- St. Jude Children's Research Hospital, Memphis, TN, USA
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104
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Garner LC, Klenerman P, Provine NM. Insights Into Mucosal-Associated Invariant T Cell Biology From Studies of Invariant Natural Killer T Cells. Front Immunol 2018; 9:1478. [PMID: 30013556 PMCID: PMC6036249 DOI: 10.3389/fimmu.2018.01478] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 06/14/2018] [Indexed: 12/24/2022] Open
Abstract
Mucosal-associated invariant T (MAIT) cells and invariant natural killer T (iNKT) cells are innate-like T cells that function at the interface between innate and adaptive immunity. They express semi-invariant T cell receptors (TCRs) and recognize unconventional non-peptide ligands bound to the MHC Class I-like molecules MR1 and CD1d, respectively. MAIT cells and iNKT cells exhibit an effector-memory phenotype and are enriched within the liver and at mucosal sites. In humans, MAIT cell frequencies dwarf those of iNKT cells, while in laboratory mouse strains the opposite is true. Upon activation via TCR- or cytokine-dependent pathways, MAIT cells and iNKT cells rapidly produce cytokines and show direct cytotoxic activity. Consequently, they are essential for effective immunity, and alterations in their frequency and function are associated with numerous infectious, inflammatory, and malignant diseases. Due to their abundance in mice and the earlier development of reagents, iNKT cells have been more extensively studied than MAIT cells. This has led to the routine use of iNKT cells as a reference population for the study of MAIT cells, and such an approach has proven very fruitful. However, MAIT cells and iNKT cells show important phenotypic, functional, and developmental differences that are often overlooked. With the recent availability of new tools, most importantly MR1 tetramers, it is now possible to directly study MAIT cells to understand their biology. Therefore, it is timely to compare the phenotype, development, and function of MAIT cells and iNKT cells. In this review, we highlight key areas where MAIT cells show similarity or difference to iNKT cells. In addition, we discuss important avenues for future research within the MAIT cell field, especially where comparison to iNKT cells has proven less informative.
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Affiliation(s)
- Lucy C. Garner
- Translational Gastroenterology Unit, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Paul Klenerman
- Translational Gastroenterology Unit, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
| | - Nicholas M. Provine
- Translational Gastroenterology Unit, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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105
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Kjer-Nielsen L, Corbett AJ, Chen Z, Liu L, Mak JY, Godfrey DI, Rossjohn J, Fairlie DP, McCluskey J, Eckle SB. An overview on the identification of MAIT cell antigens. Immunol Cell Biol 2018; 96:573-587. [PMID: 29656544 DOI: 10.1111/imcb.12057] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/05/2018] [Accepted: 04/05/2018] [Indexed: 12/11/2022]
Abstract
Mucosal associated invariant T (MAIT) cells are restricted by the monomorphic MHC class I-like molecule, MHC-related protein-1 (MR1). Until 2012, the origin of the MAIT cell antigens (Ags) was unknown, although it was established that MAIT cells could be activated by a broad range of bacteria and yeasts, possibly suggesting a conserved Ag. Using a combination of protein chemistry, mass spectrometry, cellular biology, structural biology and small molecule chemistry, we discovered MR1 ligands derived from folic acid (vitamin B9) and from an intermediate in the microbial biosynthesis of riboflavin (vitamin B2). While the folate derivative 6-formylpterin generally inhibited MAIT cell activation, two riboflavin pathway derivatives, 5-(2-oxopropylideneamino)-6-D-ribitylaminouracil and 5-(2-oxoethylideneamino)-6-D-ribitylaminouracil, were potent MAIT cell agonists. Other intermediates and derivatives of riboflavin synthesis displayed weak or no MAIT cell activation. Collectively, these studies revealed that in addition to peptide and lipid-based Ags, small molecule natural product metabolites are also ligands that can activate T cells expressing αβ T-cell receptors, and here we recount this discovery.
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Affiliation(s)
- Lars Kjer-Nielsen
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - Alexandra J Corbett
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - Zhenjun Chen
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - Ligong Liu
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Jeffrey Yw Mak
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Dale I Godfrey
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, The University of Melbourne, Melbourne, VIC, 3000, Australia
| | - Jamie Rossjohn
- Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.,Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, VIC, 3800, Australia.,Institute of Infection and Immunity, Cardiff University School of Medicine, Cardiff, CF14 4XN, UK
| | - David P Fairlie
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - James McCluskey
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - Sidonia Bg Eckle
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
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106
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Koay HF, Godfrey DI, Pellicci DG. Development of mucosal-associated invariant T cells. Immunol Cell Biol 2018; 96:598-606. [PMID: 29569752 PMCID: PMC6446805 DOI: 10.1111/imcb.12039] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 03/13/2018] [Accepted: 03/13/2018] [Indexed: 01/17/2023]
Abstract
Mucosal‐associated invariant T (MAIT) cells develop in the thymus and migrate into the periphery to become the largest antigen‐specific αβ T‐cell population in the human immune system. However, the frequency of MAIT cells varies widely between human individuals, and the basis for this is unclear. While MAIT cells are highly conserved through evolution and are phenotypically similar between humans and mice, they represent a much smaller proportion of total T cells in mice. In this review, we discuss how MAIT cells transition through a three‐stage development pathway in both mouse and human thymus, and continue to mature and expand after they leave the thymus. Moreover, we will explore and speculate on how specific factors regulate different stages of this process.
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Affiliation(s)
- Hui-Fern Koay
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia
| | - Dale I Godfrey
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia
| | - Daniel G Pellicci
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia
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