201
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DR3 signaling modulates the function of Foxp3+ regulatory T cells and the severity of acute graft-versus-host disease. Blood 2016; 128:2846-2858. [PMID: 27760760 DOI: 10.1182/blood-2016-06-723783] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 09/29/2016] [Indexed: 12/20/2022] Open
Abstract
CD4+Foxp3+ regulatory T cells (Treg) are a subpopulation of T cells, which regulate the immune system and enhance immune tolerance after transplantation. Donor-derived Treg prevent the development of lethal acute graft-versus-host disease (GVHD) in murine models of allogeneic hematopoietic stem cell transplantation. We recently demonstrated that a single treatment of the agonistic antibody to DR3 (death receptor 3, αDR3) to donor mice resulted in the expansion of donor-derived Treg and prevented acute GVHD, although the precise role of DR3 signaling in GVHD has not been elucidated. In this study, we comprehensively analyzed the immunophenotype of Treg after DR3 signal activation, demonstrating that DR3-activated Treg (DR3-Treg) had an activated/mature phenotype. Furthermore, the CD25+Foxp3+ subpopulation in DR3-Treg showed stronger suppressive effects in vivo. Prophylactic treatment of αDR3 to recipient mice expanded recipient-derived Treg and reduced the severity of GVHD, whereas DR3 activation in mice with ongoing GVHD further promoted donor T-cell activation/proliferation. These data suggest that the function of DR3 signaling was highly dependent on the activation status of the T cells. In conclusion, our data demonstrated that DR3 signaling affects the function of Treg and T-cell activation after alloantigen exposure in a time-dependent manner. These observations provide important information for future clinical testing using human DR3 signal modulation and highlight the critical effect of the state of T-cell activation on clinical outcomes after activation of DR3.
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202
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Abstract
OBJECTIVES Classically, immune thrombocytopenia (ITP) was thought to be caused by the destruction and insufficient production of platelets, as mediated by autoantibodies. More recently other immune mechanisms that contribute to the disease have been discovered. This review attempts to address the main unresolved questions in ITP. METHODS We review the most current knowledge of the pathophysiology of ITP. Immunological effects of available therapies are also described. DISCUSSION The trigger may be a loss of tolerance due to molecular mimicry with cross-reaction of antibodies arising from infectious agents or drugs, genetic factors, and/or platelet Toll receptors. This loss of tolerance activates autoreactive effector B and T lymphocytes, which in turn initiates platelet destruction, mediated by cytotoxic T lymphocytes and the release of pro-inflammatory cytokines (IL-2/IL-17) by T helper (Th) cells (Th1/Th17). Th2 (anti-inflammatory) and regulatory B (Breg) and Treg cells are also inhibited (with decrease in IL-10/TGF-β), which leads to the disease becoming chronic. Some isotypes of autoantibodies may increase the bleeding risk. Corticosteroids, rituximab, and thrombopoietin receptor agonists (A-TPOs) all increase levels of Tregs and TGF-β. The A-TPOs also increase Breg levels, which could explain why complete remission has been seen in some cases. CONCLUSION A better understanding of the immunomodulatory effects of each ITP therapy is needed to best manage the disease.
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Affiliation(s)
- María Perera
- a Haematology Service , University Hospital Doctor Negrín , Las Palmas de Gran Canaria, Spain
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203
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Furusawa C, Yamaguchi T. Robust and Accurate Discrimination of Self/Non-Self Antigen Presentations by Regulatory T Cell Suppression. PLoS One 2016; 11:e0163134. [PMID: 27668873 PMCID: PMC5036821 DOI: 10.1371/journal.pone.0163134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Accepted: 09/02/2016] [Indexed: 12/22/2022] Open
Abstract
The immune response by T cells usually discriminates self and non-self antigens, even though the negative selection of self-reactive T cells is imperfect and a certain fraction of T cells can respond to self-antigens. In this study, we construct a simple mathematical model of T cell populations to analyze how such self/non-self discrimination is possible. The results demonstrate that the control of the immune response by regulatory T cells enables a robust and accurate discrimination of self and non-self antigens, even when there is a significant overlap between the affinity distribution of T cells to self and non-self antigens. Here, the number of regulatory T cells in the system acts as a global variable controlling the T cell population dynamics. The present study provides a basis for the development of a quantitative theory for self and non-self discrimination in the immune system and a possible strategy for its experimental verification.
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Affiliation(s)
- Chikara Furusawa
- Quantitative Biology Center, RIKEN, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- * E-mail:
| | - Tomoyuki Yamaguchi
- Immunology Frontier Research Center (WPI-IFReC), Osaka University, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan
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204
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Safa K, Chandran S, Wojciechowski D. Pharmacologic targeting of regulatory T cells for solid organ transplantation: current and future prospects. Drugs 2016; 75:1843-52. [PMID: 26493288 DOI: 10.1007/s40265-015-0487-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The last three decades have witnessed significant advances in the development of immunosuppressive medications used in kidney transplantation leading to a remarkable gain in short-term graft function and outcomes. Despite these major breakthroughs, improvements in long-term outcomes lag behind due to a stalemate between drug-related nephrotoxicity and chronic rejection typically due to donor-specific antibodies. Regulatory T cells (Tregs) have been shown to modulate the alloimmune response and can exert suppressive activity preventing allograft rejection in kidney transplantation. Currently available immunosuppressive agents impact Tregs in the alloimmune milieu with some of these interactions being deleterious to the allograft while others may be beneficial. Variable effects are seen with common antibody induction agents such that basiliximab, an IL-2 receptor blocker, decreases Tregs while lymphocyte depleting agents such as antithymocyte globulin increase Tregs. Calcineurin inhibitors, a mainstay of maintenance immunosuppression since the mid-1980s, seem to suppress Tregs while mammalian targets of rapamycin (less commonly used in maintenance regimens) expand Tregs. The purpose of this review is to provide an overview of Treg biology in transplantation, identify in more detail the interactions between commonly used immunosuppressive agents and Tregs in kidney transplantation and lastly describe future directions in the use of Tregs themselves as therapy for tolerance induction.
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Affiliation(s)
- Kassem Safa
- Division of Nephrology and Transplant Center, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Boston, MA, USA
| | - Sindhu Chandran
- Division of Nephrology, Department of Medicine, University of California San Francisco Medical center, San Francisco, CA, USA
| | - David Wojciechowski
- Division of Nephrology and Transplant Center, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Boston, MA, USA.
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205
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Abstract
The immune system has evolved to defend the organism against an almost infinite number of pathogens in a locally confined and antigen-specific manner while at the same time preserving tolerance to harmless antigens and self. Regulatory T (Treg) cells essentially contribute to an immunoregulatory network preventing excessive immune responses and immunopathology. There is emerging evidence that Treg cells not only operate in secondary lymphoid tissue but also regulate immune responses directly at the site of inflammation. Hence, the classification of Treg cells might need to be further extended by Treg cell subsets that are functionally and phenotypically polarized by their residency. In this review, we discuss recent findings on these tissue-resident Treg cell subsets and how these cells may operate in a tissue- and context-dependent manner.
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206
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Microbiota, regulatory T cell subsets, and allergic disorders. ACTA ACUST UNITED AC 2016; 25:114-123. [PMID: 27656354 PMCID: PMC5016534 DOI: 10.1007/s40629-016-0118-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 01/26/2016] [Indexed: 02/07/2023]
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207
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Ohnmacht C. Microbiota, regulatory T cell subsets, and allergic disorders. ALLERGO JOURNAL 2016. [DOI: 10.1007/s15007-016-1137-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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208
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Akiyama N, Takizawa N, Miyauchi M, Yanai H, Tateishi R, Shinzawa M, Yoshinaga R, Kurihara M, Demizu Y, Yasuda H, Yagi S, Wu G, Matsumoto M, Sakamoto R, Yoshida N, Penninger JM, Kobayashi Y, Inoue JI, Akiyama T. Identification of embryonic precursor cells that differentiate into thymic epithelial cells expressing autoimmune regulator. J Exp Med 2016; 213:1441-58. [PMID: 27401343 PMCID: PMC4986530 DOI: 10.1084/jem.20151780] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 05/25/2016] [Indexed: 01/21/2023] Open
Abstract
Medullary thymic epithelial cells (mTECs) expressing autoimmune regulator (Aire) are critical for preventing the onset of autoimmunity. However, the differentiation program of Aire-expressing mTECs (Aire(+) mTECs) is unclear. Here, we describe novel embryonic precursors of Aire(+) mTECs. We found the candidate precursors of Aire(+) mTECs (pMECs) by monitoring the expression of receptor activator of nuclear factor-κB (RANK), which is required for Aire(+) mTEC differentiation. pMECs unexpectedly expressed cortical TEC molecules in addition to the mTEC markers UEA-1 ligand and RANK and differentiated into mTECs in reaggregation thymic organ culture. Introduction of pMECs in the embryonic thymus permitted long-term maintenance of Aire(+) mTECs and efficiently suppressed the onset of autoimmunity induced by Aire(+) mTEC deficiency. Mechanistically, pMECs differentiated into Aire(+) mTECs by tumor necrosis factor receptor-associated factor 6-dependent RANK signaling. Moreover, nonclassical nuclear factor-κB activation triggered by RANK and lymphotoxin-β receptor signaling promoted pMEC induction from progenitors exhibiting lower RANK expression and higher CD24 expression. Thus, our findings identified two novel stages in the differentiation program of Aire(+) mTECs.
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Affiliation(s)
- Nobuko Akiyama
- Division of Cellular and Molecular Biology, The Institute of Medical Science, The University of Tokyo, Shirokane-dai, Minato-ku, Tokyo 108-8639, Japan
| | - Nobukazu Takizawa
- Division of Cellular and Molecular Biology, The Institute of Medical Science, The University of Tokyo, Shirokane-dai, Minato-ku, Tokyo 108-8639, Japan
| | - Maki Miyauchi
- Division of Cellular and Molecular Biology, The Institute of Medical Science, The University of Tokyo, Shirokane-dai, Minato-ku, Tokyo 108-8639, Japan
| | - Hiromi Yanai
- Division of Cellular and Molecular Biology, The Institute of Medical Science, The University of Tokyo, Shirokane-dai, Minato-ku, Tokyo 108-8639, Japan
| | - Ryosuke Tateishi
- Division of Cellular and Molecular Biology, The Institute of Medical Science, The University of Tokyo, Shirokane-dai, Minato-ku, Tokyo 108-8639, Japan
| | - Miho Shinzawa
- Division of Cellular and Molecular Biology, The Institute of Medical Science, The University of Tokyo, Shirokane-dai, Minato-ku, Tokyo 108-8639, Japan
| | - Riko Yoshinaga
- Division of Cellular and Molecular Biology, The Institute of Medical Science, The University of Tokyo, Shirokane-dai, Minato-ku, Tokyo 108-8639, Japan
| | - Masaaki Kurihara
- Division of Organic Chemistry, National Institute of Health Sciences, Kamiyoga, Setagaya, Tokyo 158-8501, Japan
| | - Yosuke Demizu
- Division of Organic Chemistry, National Institute of Health Sciences, Kamiyoga, Setagaya, Tokyo 158-8501, Japan
| | - Hisataka Yasuda
- Nagahama Institute for Biochemical Science, Oriental Yeast Co., Ltd., 50, Kano-cho, Nagahama, Shiga 526-0804, Japan
| | - Shintaro Yagi
- Laboratory of Cellular Biochemistry, Department of Animal Resource Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Guoying Wu
- Laboratory of Cellular Biochemistry, Department of Animal Resource Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Mitsuru Matsumoto
- Division of Molecular Immunology, Institute for Enzyme Research, Tokushima University, Tokushima 770-8503, Japan
| | - Reiko Sakamoto
- Laboratory of Developmental Genetics, Center for Experimental Medicine and Systems Biology, The Institute of Medical Science, The University of Tokyo, Shirokane-dai, Minato-ku, Tokyo 108-8639, Japan
| | - Nobuaki Yoshida
- Laboratory of Developmental Genetics, Center for Experimental Medicine and Systems Biology, The Institute of Medical Science, The University of Tokyo, Shirokane-dai, Minato-ku, Tokyo 108-8639, Japan
| | - Josef M Penninger
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Yasuhiro Kobayashi
- Institute for Oral Science, Matsumoto Dental University, Hiro-oka, Shiojiri-shi, Nagano 399-0781, Japan
| | - Jun-Ichiro Inoue
- Division of Cellular and Molecular Biology, The Institute of Medical Science, The University of Tokyo, Shirokane-dai, Minato-ku, Tokyo 108-8639, Japan
| | - Taishin Akiyama
- Division of Cellular and Molecular Biology, The Institute of Medical Science, The University of Tokyo, Shirokane-dai, Minato-ku, Tokyo 108-8639, Japan
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209
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Abstract
Regulatory T (Treg) cells that express the transcription factor forkhead box protein P3 (FOXP3) play an essential role in enforcing immune tolerance to self tissues, regulating host-commensal flora interaction, and facilitating tissue repair. Their deficiency and/or dysfunction trigger unbridled autoimmunity and inflammation. A growing number of monogenic defects have been recognized that adversely impact Treg cell development, differentiation, and/or function, leading to heritable diseases of immune dysregulation and autoimmunity. In this article, we review recent insights into Treg cell biology and function, with particular attention to lessons learned from newly recognized clinical disorders of Treg cell deficiency.
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Affiliation(s)
- Fayhan J Alroqi
- Division of Immunology, Boston Children's Hospital, Karp Family Building, Room 10-214. 1 Blackfan Street, Boston, MA, 02115, USA
| | - Talal A Chatila
- Division of Immunology, Boston Children's Hospital, Karp Family Building, Room 10-214. 1 Blackfan Street, Boston, MA, 02115, USA. .,Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
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210
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Levin MJ, Weinberg A. Regulatory T Cells in Infections: Getting It Just Right. J Infect Dis 2016; 214:4-5. [PMID: 27117510 DOI: 10.1093/infdis/jiw092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 03/01/2016] [Indexed: 11/12/2022] Open
Affiliation(s)
- Myron J Levin
- Section of Pediatric Infectious Diseases, Department of Pediatrics Department of Medicine
| | - Adriana Weinberg
- Section of Pediatric Infectious Diseases, Department of Pediatrics Department of Medicine Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora
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211
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Oh J, Shin JS. Molecular mechanism and cellular function of MHCII ubiquitination. Immunol Rev 2016; 266:134-44. [PMID: 26085212 DOI: 10.1111/imr.12303] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The major histocompatibility complex class II (MHCII) is ubiquitinated via the evolutionarily conserved lysine in the cytoplasmic tail of the β chain in dendritic cells (DCs) and B cells. The ubiquitination is mediated by the membrane-associated RING-CH1 (MARCH1) ubiquitin ligase although it can be also mediated by the homologous ligase MARCH8 in model cell lines. The ubiquitination promotes MHCII endocytosis and lysosomal sorting that results in a reduction in the level of MHCII at cell surface. Functionally, MHCII ubiquitination serves as a means by which DCs suppress MHCII expression and reduce antigen presentation in response to the immune regulatory cytokine interleukin-10 (IL-10) and regulatory T cells. Recently, additional roles of MHCII ubiquitination have emerged. MHCII ubiquitination promoted DC production of inflammatory cytokines in response to the Toll-like receptor ligands. It also potentiated DC ability to activate antigen-specific naive CD4(+) T cells while limiting the amount of antigens presented at cell surface. Similarly, MHCII ubiquitination promoted DC activation of CD4(+) thymocytes supporting regulatory T-cell development independent of its effect of limiting antigen presentation. Thus, ubiquitination appears to confer MHCII a function independent of presenting antigens by a mechanism yet to be identified.
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Affiliation(s)
- Jaehak Oh
- Department of Microbiology and Immunology, Sandler Asthma Basic Research Center, University of California San Francisco, San Francisco, CA, USA
| | - Jeoung-Sook Shin
- Department of Microbiology and Immunology, Sandler Asthma Basic Research Center, University of California San Francisco, San Francisco, CA, USA
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212
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213
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Hoeppli RE, MacDonald KG, Levings MK, Cook L. How antigen specificity directs regulatory T-cell function: self, foreign and engineered specificity. HLA 2016; 88:3-13. [PMID: 27256587 DOI: 10.1111/tan.12822] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 04/29/2016] [Indexed: 02/06/2023]
Abstract
Regulatory T cells (Tregs) are a suppressive subset of T cells that have important roles in maintaining self-tolerance and preventing immunopathology. The T-cell receptor (TCR) and its antigen specificity play a dominant role in the differentiation of cells to a Treg fate, either in the thymus or in the periphery. This review focuses on the effects of the TCR and its antigen specificity on Treg biology. The role of Tregs with specificity for self-antigen has primarily been studied in the context of autoimmune disease, although recent studies have focused on their role in steady-state conditions. The role of Tregs that are specific for pathogens, dietary antigens and allergens is much less studied, although recent data suggest a significant and previously underappreciated role for Tregs during memory responses to a wide range of foreign antigens. The development of TCR- or chimeric antigen receptor (CAR)-transduced T cells means we are now able to engineer Tregs with disease-relevant antigen specificities, paving the way for ensuring specificity with Treg-based therapies. Understanding the role that antigens play in driving the generation and function of Tregs is critical for defining the pathophysiology of many immune-mediated diseases, and developing new therapeutic interventions.
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Affiliation(s)
- R E Hoeppli
- Department of Surgery, University of British Columbia and Child & Family Research Institute, Vancouver, Canada
| | - K G MacDonald
- Department of Surgery, University of British Columbia and Child & Family Research Institute, Vancouver, Canada
| | - M K Levings
- Department of Surgery, University of British Columbia and Child & Family Research Institute, Vancouver, Canada
| | - L Cook
- Department of Surgery, University of British Columbia and Child & Family Research Institute, Vancouver, Canada
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214
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Zhang J, Bedel R, Krovi SH, Tuttle KD, Zhang B, Gross J, Gapin L, Matsuda JL. Mutation of the Traj18 gene segment using TALENs to generate Natural Killer T cell deficient mice. Sci Rep 2016; 6:27375. [PMID: 27256918 PMCID: PMC4891675 DOI: 10.1038/srep27375] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 05/13/2016] [Indexed: 11/09/2022] Open
Abstract
Invariant Natural Killer T (iNKT) cells are a unique subset of T lymphocytes that have been implicated in both promoting and suppressing a multitude of immune responses. In mice, iNKT cells express T cell antigen receptors (TCRs) comprising a unique TCRα rearrangement between the Trav11 and Traj18 gene segments. When paired with certain Trbv TCRβ chains, these TCRs recognize lipid antigens presented by the major histocompatibility complex (MHC) class I-like molecule, CD1d. Until recently, the sole model of iNKT deficiency targeted the Jα18, which is absolutely required to form the TCR with the appropriate antigenic specificity. However, these mice were demonstrated to have a large reduction in TCR repertoire diversity, which could confound results arising from studies using these mice. Here, we have created a new NKT-deficient mouse strain using transcription activator-like effector nuclease (TALEN) technology to only disrupt the expression of Jα18, leaving the remaining Jα repertoire unperturbed. We confirm that these mice lack iNKT cells and do not respond to lipid antigen stimulation while the development of conventional T cells, regulatory T cells, and type Ib NKT cells is normal. This new mouse strain will serve as a new model of iNKT cell deficiency to facilitate our understanding of iNKT biology.
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Affiliation(s)
- Jingjing Zhang
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine and National Jewish Health, Aurora, CO 80206, USA
| | - Romain Bedel
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine and National Jewish Health, Aurora, CO 80206, USA
| | - S Harsha Krovi
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine and National Jewish Health, Aurora, CO 80206, USA
| | - Kathryn D Tuttle
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine and National Jewish Health, Aurora, CO 80206, USA
| | - Bicheng Zhang
- Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA
| | - James Gross
- Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA
| | - Laurent Gapin
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine and National Jewish Health, Aurora, CO 80206, USA.,Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA
| | - Jennifer L Matsuda
- Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA
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215
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Thymic and Postthymic Regulation of Naïve CD4(+) T-Cell Lineage Fates in Humans and Mice Models. Mediators Inflamm 2016; 2016:9523628. [PMID: 27313405 PMCID: PMC4904118 DOI: 10.1155/2016/9523628] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 04/28/2016] [Indexed: 12/14/2022] Open
Abstract
Our understanding of how thymocytes differentiate into many subtypes has been increased progressively in its complexity. At early life, the thymus provides a suitable microenvironment with specific combination of stromal cells, growth factors, cytokines, and chemokines to induce the bone marrow lymphoid progenitor T-cell precursors into single-positive CD4+ and CD8+ T effectors and CD4+CD25+ T-regulatory cells (Tregs). At postthymic compartments, the CD4+ T-cells acquire distinct phenotypes which include the classical T-helper 1 (Th1), T-helper 2 (Th2), T-helper 9 (Th9), T-helper 17 (Th17), follicular helper T-cell (Tfh), and induced T-regulatory cells (iTregs), such as the regulatory type 1 cells (Tr1) and transforming growth factor-β- (TGF-β-) producing CD4+ T-cells (Th3). Tregs represent only a small fraction, 5–10% in mice and 1-2% in humans, of the overall CD4+ T-cells in lymphoid tissues but are essential for immunoregulatory circuits mediating the inhibition and expansion of all lineages of T-cells. In this paper, we first provide an overview of the major cell-intrinsic developmental programs that regulate T-cell lineage fates in thymus and periphery. Next, we introduce the SV40 immortomouse as a relevant mice model for implementation of new approaches to investigate thymus organogenesis, CD4 and CD8 development, and thymus cells tumorogenesis.
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216
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Zhao Y, Nguyen P, Ma J, Wu T, Jones LL, Pei D, Cheng C, Geiger TL. Preferential Use of Public TCR during Autoimmune Encephalomyelitis. THE JOURNAL OF IMMUNOLOGY 2016; 196:4905-14. [PMID: 27183575 DOI: 10.4049/jimmunol.1501029] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 04/04/2016] [Indexed: 12/21/2022]
Abstract
How the TCR repertoire, in concert with risk-associated MHC, imposes susceptibility for autoimmune diseases is incompletely resolved. Due largely to recombinatorial biases, a small fraction of TCRα or β-chains are shared by most individuals, or public. If public TCR chains modulate a TCRαβ heterodimer's likelihood of productively engaging autoantigen, because they are pervasive and often high frequency, they could also broadly influence disease risk and progression. Prior data, using low-resolution techniques, have identified the heavy use of select public TCR in some autoimmune models. In this study, we assess public repertoire representation in mice with experimental autoimmune encephalomyelitis at high resolution. Saturation sequencing was used to identify >18 × 10(6) TCRβ sequences from the CNSs, periphery, and thymi of mice at different stages of autoimmune encephalomyelitis and healthy controls. Analyses indicated the prominent representation of a highly diverse public TCRβ repertoire in the disease response. Preferential formation of public TCR implicated in autoimmunity was identified in preselection thymocytes, and, consistently, public, disease-associated TCRβ were observed to be commonly oligoclonal. Increased TCR sharing and a focusing of the public TCR response was seen with disease progression. Critically, comparisons of peripheral and CNS repertoires and repertoires from preimmune and diseased mice demonstrated that public TCR were preferentially deployed relative to nonshared, or private, sequences. Our findings implicate public TCR in skewing repertoire response during autoimmunity and suggest that subsets of public TCR sequences may serve as disease-specific biomarkers or influence disease susceptibility or progression.
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Affiliation(s)
- Yunqian Zhao
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN 38105; and
| | - Phuong Nguyen
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN 38105; and
| | - Jing Ma
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN 38105; and
| | - Tianhua Wu
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN 38105; and
| | - Lindsay L Jones
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN 38105; and
| | - Deqing Pei
- Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Cheng Cheng
- Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Terrence L Geiger
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN 38105; and
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217
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Perry JSA, Hsieh CS. Development of T-cell tolerance utilizes both cell-autonomous and cooperative presentation of self-antigen. Immunol Rev 2016; 271:141-55. [PMID: 27088912 PMCID: PMC4837647 DOI: 10.1111/imr.12403] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The development of T-cell self-tolerance in the thymus is important for establishing immune homeostasis and preventing autoimmunity. Here, we review the components of T-cell tolerance, which includes T-cell receptor (TCR) self-reactivity, costimulation, cytokines, and antigen presentation by a variety of antigen-presenting cells (APCs) subsets. We discuss the current evidence on the process of regulatory T (Treg) cell and negative selection and the importance of TCR signaling. We then examine recent evidence showing unique roles for bone marrow (BM)-derived APCs and medullary thymic epithelial cells (mTECs) on the conventional and Treg TCR repertoire, as well as emerging data on the role of B cells in tolerance. Finally, we review the accumulating data that suggest that cooperative antigen presentation is a prominent component of T -ell tolerance. With the development of tools to interrogate the function of individual APC subsets in the medulla, we have gained greater understanding of the complex cellular and molecular events that determine T-cell tolerance.
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Affiliation(s)
- Justin S A Perry
- Department of Internal Medicine, Division of Rheumatology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Chyi-Song Hsieh
- Department of Internal Medicine, Division of Rheumatology, Washington University School of Medicine, St. Louis, MO, 63110, USA
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218
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Leventhal DS, Gilmore DC, Berger JM, Nishi S, Lee V, Malchow S, Kline DE, Kline J, Vander Griend DJ, Huang H, Socci ND, Savage PA. Dendritic Cells Coordinate the Development and Homeostasis of Organ-Specific Regulatory T Cells. Immunity 2016; 44:847-59. [PMID: 27037189 PMCID: PMC4842258 DOI: 10.1016/j.immuni.2016.01.025] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 11/27/2015] [Accepted: 01/29/2016] [Indexed: 12/17/2022]
Abstract
Although antigen recognition mediated by the T cell receptor (TCR) influences many facets of Foxp3(+) regulatory T (Treg) cell biology, including development and function, the cell types that present antigen to Treg cells in vivo remain largely undefined. By tracking a clonal population of Aire-dependent, prostate-specific Treg cells in mice, we demonstrated an essential role for dendritic cells (DCs) in regulating organ-specific Treg cell biology. We have shown that the thymic development of prostate-specific Treg cells required antigen presentation by DCs. Moreover, Batf3-dependent CD8α(+) DCs were dispensable for the development of this clonotype and had negligible impact on the polyclonal Treg cell repertoire. In the periphery, CCR7-dependent migratory DCs coordinated the activation of organ-specific Treg cells in the prostate-draining lymph nodes. Our results demonstrate that the development and peripheral regulation of organ-specific Treg cells are dependent on antigen presentation by DCs, implicating DCs as key mediators of organ-specific immune tolerance.
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Affiliation(s)
| | - Dana C Gilmore
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Julian M Berger
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Saki Nishi
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Victoria Lee
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Sven Malchow
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Douglas E Kline
- Department of Medicine, Section of Hematology-Oncology, University of Chicago, IL 60637, USA
| | - Justin Kline
- Department of Medicine, Section of Hematology-Oncology, University of Chicago, IL 60637, USA
| | | | - Haochu Huang
- Department of Medicine, Section of Rheumatology, University of Chicago, IL 60637, USA
| | - Nicholas D Socci
- Bioinformatics Core, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | - Peter A Savage
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA.
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Nuclear transfer nTreg model reveals fate-determining TCR-β and novel peripheral nTreg precursors. Proc Natl Acad Sci U S A 2016; 113:E2316-25. [PMID: 27044095 DOI: 10.1073/pnas.1523664113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
To study the development and function of "natural-arising" T regulatory (nTreg) cells, we developed a novel nTreg model on pure nonobese diabetic background using epigenetic reprogramming via somatic cell nuclear transfer. On RAG1-deficient background, we found that monoclonal FoxP3(+)CD4(+)Treg cells developed in the thymus in the absence of other T cells. Adoptive transfer experiments revealed that the thymic niche is not a limiting factor in nTreg development. In addition, we showed that the T-cell receptor (TCR) β-chain of our nTreg model was not only sufficient to bias T-cell development toward the CD4 lineage, but we also demonstrated that this TCR β-chain was able to provide stronger TCR signals. This TCR-β-driven mechanism would thus unify former per se contradicting hypotheses of TCR-dependent and -independent nTreg development. Strikingly, peripheral FoxP3(-)CD4(+)T cells expressing the same TCR as this somatic cell nuclear transfer nTreg model had a reduced capability to differentiate into Th1 cells but were poised to differentiate better into induced nTreg cells, both in vitro and in vivo, representing a novel peripheral precursor subset of nTreg cells to which we refer to as pre-nTreg cells.
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Abstract
INTRODUCTION Blockade of the immune checkpoint programmed death receptor ligand-1 (PD-L1)/PD-1 pathway has well-established clinical activity across many tumor types. PD-L1 protein expression by immunohistochemistry is emerging as a predictive biomarker of response to these therapies. Here, we examine PD-L1 expression in a thymic epithelial tumor (TET) tissue microarray (TMA). METHODS The TMA contained 69 TETs and 17 thymic controls, with each case represented by triplicate cores. The TMA was stained with rabbit monoclonal antibody (clone 15; Sino Biological, Beijing, China) to human PD-L1. PD-L1 staining was scored based on intensity as follows: 0 = none, 1 = equivocal/uninterpretable, 2 = weak, and 3 = intermediate-strong. Those cases with all cores scoring three in the epithelial component were categorized as PD-L1 high and the remaining as PD-L1 low. RESULTS PD-L1 high scores were more frequent in TETs than in controls (68.1% versus 17.6%; p = 0.0036). PD-L1 scores and histology were significantly correlated, with higher intensity staining in World Health Organization (WHO). B2/B3/C TETs. Only 14.8% of TETs had PD-L1 staining of associated lymphocytes. In an adjusted analysis (age/sex), PD-L1 high TETs had a significantly worse overall survival (hazard ratio: 5.40, 95% confidence interval: 1.13-25.89; p = 0.035) and a trend for worse event-free survival (hazard ratio: 2.94, 95% confidence interval: 0.94-9.24; p = 0.064). CONCLUSIONS PD-L1 expression was present in all cases of TETs within the epithelial component but only in a minority in the lymphocytic component. TETs stained more intensely for PD-L1 than in controls, and PD-L1 high TETs were associated with more aggressive histology and worse prognosis. This study lends rationale to a clinical trial with anti-PD-1/PD-L1 therapy in this rare tumor type.
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Spitz C, Winkels H, Bürger C, Weber C, Lutgens E, Hansson GK, Gerdes N. Regulatory T cells in atherosclerosis: critical immune regulatory function and therapeutic potential. Cell Mol Life Sci 2016; 73:901-22. [PMID: 26518635 PMCID: PMC11108393 DOI: 10.1007/s00018-015-2080-2] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 09/30/2015] [Accepted: 10/22/2015] [Indexed: 12/14/2022]
Abstract
Atherosclerosis is a chronic inflammatory disease that is mediated by innate and adaptive immune responses. The disease is characterized by sub-endothelial accumulation and modification of lipids in the artery wall triggering an inflammatory reaction which promotes lesion progression and eventual plaque rupture, thrombus formation, and the respective clinical sequelae such as myocardial infarction or stroke. During the past decade, T-cell-mediated immune responses, especially control of pro-inflammatory signals by regulatory T cells (Tregs), have increasingly attracted the interest of experimental and clinical researchers. By suppression of T cell proliferation and secretion of anti-inflammatory cytokines, such as interleukin-10 (IL-10) and transforming growth factor-β, Tregs exert their atheroprotective properties. Atherosclerosis-prone, hyperlipidemic mice harbor systemically less Tregs compared to wild-type mice, suggesting an imbalance of immune cells which affects local and systemic inflammatory and potentially metabolic processes leading to atherogenesis. Restoring or increasing Treg frequency and enhancing their suppressive capacity by various modulations may pose a promising approach for treating inflammatory conditions such as cardiovascular diseases. In this review, we briefly summarize the immunological basics of atherosclerosis and introduce the role and contribution of different subsets of T cells. We then discuss experimental data and current knowledge pertaining to Tregs in atherosclerosis and perspectives on manipulating the adaptive immune system to alleviate atherosclerosis and cardiovascular disease.
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Affiliation(s)
- Charlotte Spitz
- Institute for Cardiovascular Prevention, Ludwig-Maximilians University Munich, Pettenkoferstr. 9, 80336, Munich, Germany
| | - Holger Winkels
- Institute for Cardiovascular Prevention, Ludwig-Maximilians University Munich, Pettenkoferstr. 9, 80336, Munich, Germany
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Christina Bürger
- Institute for Cardiovascular Prevention, Ludwig-Maximilians University Munich, Pettenkoferstr. 9, 80336, Munich, Germany
| | - Christian Weber
- Institute for Cardiovascular Prevention, Ludwig-Maximilians University Munich, Pettenkoferstr. 9, 80336, Munich, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich, Germany
| | - Esther Lutgens
- Institute for Cardiovascular Prevention, Ludwig-Maximilians University Munich, Pettenkoferstr. 9, 80336, Munich, Germany
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Göran K Hansson
- Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
| | - Norbert Gerdes
- Institute for Cardiovascular Prevention, Ludwig-Maximilians University Munich, Pettenkoferstr. 9, 80336, Munich, Germany.
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Lin J, Yang L, Silva HM, Trzeciak A, Choi Y, Schwab SR, Dustin ML, Lafaille JJ. Increased generation of Foxp3(+) regulatory T cells by manipulating antigen presentation in the thymus. Nat Commun 2016; 7:10562. [PMID: 26923114 PMCID: PMC4773449 DOI: 10.1038/ncomms10562] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 12/28/2015] [Indexed: 12/22/2022] Open
Abstract
Regulatory T-cell (Treg) selection in the thymus is essential to prevent autoimmune diseases. Although important rules for Treg selection have been established, there is controversy regarding the degree of self-reactivity displayed by T-cell receptors expressed by Treg cells. In this study we have developed a model of autoimmune skin inflammation, to determine key parameters in the generation of skin-reactive Treg cells in the thymus (tTreg). tTreg development is predominantly AIRE dependent, with an AIRE-independent component. Without the knowledge of antigen recognized by skin-reactive Treg cells, we are able to enhance skin-specific tTreg cell generation using three approaches. First, we increase medullary thymic epithelial cells by using mice lacking osteoprotegerin or by adding TRANCE (RANKL, Tnfsf11). Second, we inject intrathymically peripheral dendritic cells from skin-draining sites. Finally, we inject skin tissue lysates intrathymically. These findings have implications for enhancing the generation of organ-specific Treg cells in autoimmune diseases.
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Affiliation(s)
- Jiqiang Lin
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
- The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York 10016, USA
| | - Lu Yang
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
- The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York 10016, USA
| | - Hernandez Moura Silva
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
| | - Alissa Trzeciak
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
| | - Yongwon Choi
- Department of Pathology and Laboratory Medicine, Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Susan R. Schwab
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
- Department of Pathology, New York University School of Medicine, New York, New York 10016, USA
| | - Michael L. Dustin
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
- Department of Pathology, New York University School of Medicine, New York, New York 10016, USA
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK
| | - Juan J. Lafaille
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
- Department of Pathology, New York University School of Medicine, New York, New York 10016, USA
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Harnessing the plasticity of CD4(+) T cells to treat immune-mediated disease. Nat Rev Immunol 2016; 16:149-63. [PMID: 26875830 DOI: 10.1038/nri.2015.18] [Citation(s) in RCA: 353] [Impact Index Per Article: 44.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
CD4(+) T cells differentiate and acquire distinct functions to combat specific pathogens but can also adapt their functions in response to changing circumstances. Although this phenotypic plasticity can be potentially deleterious, driving immune pathology, it also provides important benefits that have led to its evolutionary preservation. Here, we review CD4(+) T cell plasticity by examining the molecular mechanisms that regulate it - from the extracellular cues that initiate and drive cells towards varying phenotypes, to the cytosolic signalling cascades that decipher these cues and transmit them into the cell and to the nucleus, where these signals imprint specific gene expression programmes. By understanding how this functional flexibility is achieved, we may open doors to new therapeutic approaches that harness this property of T cells.
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225
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Richards DM, Kyewski B, Feuerer M. Re-examining the Nature and Function of Self-Reactive T cells. Trends Immunol 2016; 37:114-125. [PMID: 26795134 PMCID: PMC7611850 DOI: 10.1016/j.it.2015.12.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 12/11/2015] [Accepted: 12/13/2015] [Indexed: 01/08/2023]
Abstract
Recent studies have leveraged MHC tetramer and TCR sequencing approaches towards a more precise characterization of the peripheral T cell repertoire, providing important insight into both the contribution of self-reactive T cells to the overall repertoire and their function. The peripheral T cell repertoire of healthy individuals contains a high frequency of diverse, self-reactive T cells. Furthermore, self-reactive T cells can perform essential beneficial physiological functions. We review these recent findings here, and discuss their implications to the current understanding of peripheral tolerance and the role of self-reactive T cells in autoimmune disease. We outline gaps in understanding, and argue that an important step forward is to revise the definition of self-reactive T cells to incorporate new concepts regarding the nature and physiological functions of different populations of T cells capable of recognizing self-antigens.
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Affiliation(s)
- David M Richards
- Immune Tolerance, Tumor Immunology Program, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; Current address: Immunology Department, Apogenix GmbH, Im Neuenheimer Feld 584, 69120 Heidelberg, Germany
| | - Bruno Kyewski
- Developmental Immunology, Tumor Immunology Program, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Markus Feuerer
- Immune Tolerance, Tumor Immunology Program, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
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226
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Pedros C, Duguet F, Saoudi A, Chabod M. Disrupted regulatory T cell homeostasis in inflammatory bowel diseases. World J Gastroenterol 2016; 22:974-995. [PMID: 26811641 PMCID: PMC4716049 DOI: 10.3748/wjg.v22.i3.974] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 10/02/2015] [Accepted: 11/19/2015] [Indexed: 02/06/2023] Open
Abstract
In the gut, where billions of non-self-antigens from the food and the microbiota are present, the immune response must be tightly regulated to ensure both host protection against pathogenic microorganisms and the absence of immune-related pathologies. It has been well documented that regulatory T cells (Tregs) play a pivotal role in this context. Indeed, Tregs are able to prevent excessive inflammation, which can lead to the rupture of intestinal homeostasis observed in inflammatory bowel diseases (IBDs). Both the worldwide incidence and prevalence of such diseases have increased throughout the latter part of the 20th century. Therefore, it is crucial to understand how Tregs suppress the colitogenic immune cells to establish new treatments for patients suffering from IBDs. In this review, we will first summarize the results obtained in animal model studies that highlight the importance of Tregs in maintaining intestinal homeostasis and describe the specific suppressive mechanisms involved. Next, our current knowledge about Tregs contribution to human IBDs will be reviewed, as well as the current therapeutic perspective on using Tregs for clinical IBD treatment and the challenges that remain to be resolved to ensure both the safety and effectiveness of these therapies in targeting this critical immune-regulatory cell population.
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227
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Mahr B, Unger L, Hock K, Pilat N, Baranyi U, Schwarz C, Maschke S, Farkas AM, Wekerle T. IL-2/α-IL-2 Complex Treatment Cannot Be Substituted for the Adoptive Transfer of Regulatory T cells to Promote Bone Marrow Engraftment. PLoS One 2016; 11:e0146245. [PMID: 26731275 PMCID: PMC4701413 DOI: 10.1371/journal.pone.0146245] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 12/15/2015] [Indexed: 12/16/2022] Open
Abstract
Cell therapy with recipient Tregs achieves engraftment of allogeneic bone marrow (BM) without the need for cytoreductive conditioning (i.e., without irradiation or cytotoxic drugs). Thereby mixed chimerism and transplantation tolerance are established in recipients conditioned solely with costimulation blockade and rapamycin. However, clinical translation would be substantially facilitated if Treg-stimulating pharmaceutical agents could be used instead of individualized cell therapy. Recently, it was shown that interleukin-2 (IL-2) complexed with a monoclonal antibody (mAb) (clone JES6-1A12) against IL-2 (IL-2 complexes) potently expands and activates Tregs in vivo. Therefore, we investigated whether IL-2 complexes can replace Treg therapy in a costimulation blockade-based and irradiation-free BM transplantation (BMT) model. Unexpectedly, the administration of IL-2 complexes at the time of BMT (instead of Tregs) failed to induce BM engraftment in non-irradiated recipients (0/6 with IL-2 complexes vs. 3/4 with Tregs, p<0.05). Adding IL-2 complexes to an otherwise effective regimen involving recipient irradiation (1Gy) but no Treg transfer indeed actively triggered donor BM rejection at higher doses (0/8 with IL-2 complexes vs. 9/11 without, p<0.01) and had no detectable effect at two lower doses (3/5 vs. 9/11, p>0.05). CD8 T cells and NK cells of IL-2 complex-treated naïve mice showed an enhanced proliferative response towards donor antigens in vitro despite the marked expansion of Tregs. However, IL-2 complexes also expanded conventional CD4 T cells, CD8 T cells, NK cells, NKT cells and notably even B cells, albeit to a lesser extent. Notably, IL-2 complex expanded Tregs featured less potent suppressive functions than in vitro activated Tregs in terms of T cell suppression in vitro and BM engraftment in vivo. In conclusion, these data suggest that IL-2 complexes are less effective than recipient Tregs in promoting BM engraftment and in contrast actually trigger BM rejection, as their effect is not sufficiently restricted to Tregs but rather extends to several other lymphocyte populations.
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Affiliation(s)
- Benedikt Mahr
- Section of Transplantation Immunology, Department of Surgery, Medical University of Vienna, Währinger Gürtel 18–20, 1090, Vienna, Austria
| | - Lukas Unger
- Section of Transplantation Immunology, Department of Surgery, Medical University of Vienna, Währinger Gürtel 18–20, 1090, Vienna, Austria
| | - Karin Hock
- Section of Transplantation Immunology, Department of Surgery, Medical University of Vienna, Währinger Gürtel 18–20, 1090, Vienna, Austria
| | - Nina Pilat
- Section of Transplantation Immunology, Department of Surgery, Medical University of Vienna, Währinger Gürtel 18–20, 1090, Vienna, Austria
| | - Ulrike Baranyi
- Section of Transplantation Immunology, Department of Surgery, Medical University of Vienna, Währinger Gürtel 18–20, 1090, Vienna, Austria
| | - Christoph Schwarz
- Section of Transplantation Immunology, Department of Surgery, Medical University of Vienna, Währinger Gürtel 18–20, 1090, Vienna, Austria
| | - Svenja Maschke
- Section of Transplantation Immunology, Department of Surgery, Medical University of Vienna, Währinger Gürtel 18–20, 1090, Vienna, Austria
| | - Andreas Michael Farkas
- Section of Transplantation Immunology, Department of Surgery, Medical University of Vienna, Währinger Gürtel 18–20, 1090, Vienna, Austria
| | - Thomas Wekerle
- Section of Transplantation Immunology, Department of Surgery, Medical University of Vienna, Währinger Gürtel 18–20, 1090, Vienna, Austria
- * E-mail:
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228
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Dijke IE, Hoeppli RE, Ellis T, Pearcey J, Huang Q, McMurchy AN, Boer K, Peeters AMA, Aubert G, Larsen I, Ross DB, Rebeyka I, Campbell A, Baan CC, Levings MK, West LJ. Discarded Human Thymus Is a Novel Source of Stable and Long-Lived Therapeutic Regulatory T Cells. Am J Transplant 2016; 16:58-71. [PMID: 26414799 DOI: 10.1111/ajt.13456] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Revised: 06/19/2015] [Accepted: 07/14/2015] [Indexed: 01/25/2023]
Abstract
Regulatory T cell (Treg)-based therapy is a promising approach to treat many immune-mediated disorders such as autoimmune diseases, organ transplant rejection, and graft-versus-host disease (GVHD). Challenges to successful clinical implementation of adoptive Treg therapy include difficulties isolating homogeneous cell populations and developing expansion protocols that result in adequate numbers of cells that remain stable, even under inflammatory conditions. We investigated the potential of discarded human thymuses, routinely removed during pediatric cardiac surgery, to be used as a novel source of therapeutic Tregs. Here, we show that large numbers of FOXP3(+) Tregs can be isolated and expanded from a single thymus. Expanded thymic Tregs had stable FOXP3 expression and long telomeres, and suppressed proliferation and cytokine production of activated allogeneic T cells in vitro. Moreover, expanded thymic Tregs delayed development of xenogeneic GVHD in vivo more effectively than expanded Tregs isolated based on CD25 expression from peripheral blood. Importantly, in contrast to expanded blood Tregs, expanded thymic Tregs remained stable under inflammatory conditions. Our results demonstrate that discarded pediatric thymuses are an excellent source of therapeutic Tregs, having the potential to overcome limitations currently hindering the use of Tregs derived from peripheral or cord blood.
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Affiliation(s)
- I E Dijke
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada.,Alberta Transplant Institute, University of Alberta, Edmonton, AB, Canada
| | - R E Hoeppli
- Department of Surgery, University of British Columbia, Vancouver, BC, Canada
| | - T Ellis
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada.,Alberta Transplant Institute, University of Alberta, Edmonton, AB, Canada
| | - J Pearcey
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada.,Alberta Transplant Institute, University of Alberta, Edmonton, AB, Canada
| | - Q Huang
- Department of Surgery, University of British Columbia, Vancouver, BC, Canada
| | - A N McMurchy
- Department of Surgery, University of British Columbia, Vancouver, BC, Canada
| | - K Boer
- Department of Internal Medicine, Erasmus MC Medical Center, Rotterdam, the Netherlands
| | - A M A Peeters
- Department of Internal Medicine, Erasmus MC Medical Center, Rotterdam, the Netherlands
| | - G Aubert
- Terry Fox Laboratory, British Columbia Cancer Research Centre, Vancouver, BC, Canada
| | - I Larsen
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada.,Alberta Transplant Institute, University of Alberta, Edmonton, AB, Canada
| | - D B Ross
- Alberta Transplant Institute, University of Alberta, Edmonton, AB, Canada.,Department of Surgery, University of Alberta, Edmonton, AB, Canada
| | - I Rebeyka
- Alberta Transplant Institute, University of Alberta, Edmonton, AB, Canada.,Department of Surgery, University of Alberta, Edmonton, AB, Canada
| | - A Campbell
- Department of Surgery, University of British Columbia, Vancouver, BC, Canada
| | - C C Baan
- Department of Internal Medicine, Erasmus MC Medical Center, Rotterdam, the Netherlands
| | - M K Levings
- Department of Surgery, University of British Columbia, Vancouver, BC, Canada
| | - L J West
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada.,Alberta Transplant Institute, University of Alberta, Edmonton, AB, Canada.,Department of Surgery, University of Alberta, Edmonton, AB, Canada
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Hu B, Simon-Keller K, Küffer S, Ströbel P, Braun T, Marx A, Porubsky S. Myf5 and Myogenin in the development of thymic myoid cells - Implications for a murine in vivo model of myasthenia gravis. Exp Neurol 2015; 277:76-85. [PMID: 26708556 DOI: 10.1016/j.expneurol.2015.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Revised: 11/24/2015] [Accepted: 12/15/2015] [Indexed: 01/24/2023]
Abstract
Myasthenia gravis (MG) is caused by autoantibodies against the neuromuscular junction of striated muscle. Most MG patients have autoreactive T- and B-cells directed to the acetylcholine receptor (AChR). To achieve immunologic tolerance, developing thymocytes are normally eliminated after recognition of self-antigen-derived peptides. Presentation of muscle-specific antigens is likely achieved through two pathways: on medullary thymic epithelial cells and on medullary dendritic cells cross-presenting peptides derived from a unique population of thymic myoid cells (TMC). Decades ago, it has been hypothesized that TMC play a key role in the induction of immunological tolerance towards skeletal muscle antigens. However, an experimental model to address this postulate has not been available. To generate such a model, we tested the hypothesis that the development of TMC depends on myogenic regulatory factors. To this end, we utilized Myf5-deficient mice, which lack the first wave of muscle cells but form normal skeletal muscles later during development, and Myogenin-deficient mice, which fail to form differentiated myofibers. We demonstrate for the first time that Myf5- and Myogenin-deficient mice showed a partial or complete, respectively, loss of TMC in an otherwise regularly structured thymus. To overcome early postnatal lethality of muscle-deficient, Myogenin-knockout mice we transplanted Myogenin-deficient fetal thymuses into Foxn1(nu/nu) mice that lack their own thymus anlage. We found that the transplants are functional but lack TMC. In combination with established immunization strategies (utilizing AChR or Titin), this model should enable us in the future testing the hypothesis that TMC play an indispensable role in the development of central tolerance towards striated muscle antigens.
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Affiliation(s)
- Bo Hu
- Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - Katja Simon-Keller
- Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - Stefan Küffer
- Institute of Pathology, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Philipp Ströbel
- Institute of Pathology, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Thomas Braun
- Cardiac Development and Remodelling, Max Planck Institute for Heart and Lung Research, Ludwigstrasse 43, 61231 Bad Nauheim, Germany
| | - Alexander Marx
- Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - Stefan Porubsky
- Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
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230
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Mosaad YM. Clinical Role of Human Leukocyte Antigen in Health and Disease. Scand J Immunol 2015; 82:283-306. [PMID: 26099424 DOI: 10.1111/sji.12329] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/02/2015] [Accepted: 06/12/2015] [Indexed: 12/19/2022]
Abstract
Most of the genes in the major histocompatibility complex (MHC) region express high polymorphism that is fundamental for their function. The most important function of human leukocyte antigen (HLA) molecule is in the induction, regulation of immune responses and the selection of the T cell repertoire. A clinician's attention is normally drawn to a system only when it malfunctions. The HLA system is no exception in this regard, but in contrast to other systems, it also arouses interest when it functions well - too well, in fact. Population studies carried out over the last several decades have identified a long list of human diseases that are significantly more common among individuals that carry particular HLA alleles including inflammatory, autoimmune and malignant disorders. HLA-disease association is the name of this phenomenon, and the mechanism underlying is still a subject of hot debate. Social behaviours are affected by HLA genes and preference for HLA disparate mates may provide 'good genes' for an individual's offspring. Also, certain HLA genes may be associated with shorter life and others with longer lifespan, but the effects depend both on the genetic background and on the environmental conditions. The following is a general overview of the important functional aspects of HLA in health and diseases.
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Affiliation(s)
- Y M Mosaad
- Clinical Immunology Unit, Clinical Pathology Department & Mansoura Research Center for Cord Stem Cell (MARC_CSC), Mansoura Faculty of Medicine, Mansoura University, Mansoura, Egypt
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231
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Hahn SA, Bellinghausen I, Trinschek B, Becker C. Translating Treg Therapy in Humanized Mice. Front Immunol 2015; 6:623. [PMID: 26697017 PMCID: PMC4677486 DOI: 10.3389/fimmu.2015.00623] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 11/30/2015] [Indexed: 12/30/2022] Open
Abstract
Regulatory T cells (Treg) control immune cell function as well as non-immunological processes. Their far-reaching regulatory activities suggest their functional manipulation as a means to sustainably and causally intervene with the course of diseases. Preclinical tools and strategies are however needed to further test and develop interventional strategies outside the human body. “Humanized” mouse models consisting of mice engrafted with human immune cells and tissues provide new tools to analyze human Treg ontogeny, immunobiology, and therapy. Here, we summarize the current state of humanized mouse models as a means to study human Treg function at the molecular level and to design strategies to harness these cells for therapeutic purposes.
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Affiliation(s)
- Susanne A Hahn
- Department of Dermatology, University Medical Center, Johannes Gutenberg-University , Mainz , Germany
| | - Iris Bellinghausen
- Department of Dermatology, University Medical Center, Johannes Gutenberg-University , Mainz , Germany
| | - Bettina Trinschek
- Department of Dermatology, University Medical Center, Johannes Gutenberg-University , Mainz , Germany
| | - Christian Becker
- Department of Dermatology, University Medical Center, Johannes Gutenberg-University , Mainz , Germany
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232
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Differential effect of DJ-1/PARK7 on development of natural and induced regulatory T cells. Sci Rep 2015; 5:17723. [PMID: 26634899 PMCID: PMC4669505 DOI: 10.1038/srep17723] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 11/04/2015] [Indexed: 12/19/2022] Open
Abstract
Regulatory T cells (Tregs) are essential for maintaining an effective immune tolerance and a homeostatic balance of various other immune cells. To manipulate the immune response during infections and autoimmune disorders, it is essential to know which genes or key molecules are involved in the development of Tregs. Transcription factor Foxp3 is required for the development of Tregs and governs most of the suppressive functions of these cells. Inhibited PI3K/AKT/mTOR signalling is critical for Foxp3 stability. Previous studies have suggested that DJ-1 or PARK7 protein is a positive regulator of the PI3K/AKT/mTOR pathway by negatively regulating the activity of PTEN. Thus, we hypothesised that a lack of DJ-1 could promote the development of Tregs. As a result, loss of DJ-1 decreased the total CD4(+) T cell numbers but increased the fraction of thymic and peripheral nTregs. In contrast, Foxp3 generation was not augmented following differentiation of DJ-1-deficient naïve CD4(+) T cells. DJ-1-deficient-iTregs were imperfect in replication, proliferation and more prone to cell death. Furthermore, DJ-1 deficient iTregs were less sensitive to pSmad2 and pStat5 signalling but had activated AKT/mTOR signalling. These observations reveal an unexpected differential role of DJ-1 in the development of nTregs and iTregs.
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233
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Rae W, Gao Y, Bunyan D, Holden S, Gilmour K, Patel S, Wellesley D, Williams A. A novel FOXP3 mutation causing fetal akinesia and recurrent male miscarriages. Clin Immunol 2015; 161:284-5. [DOI: 10.1016/j.clim.2015.09.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 09/12/2015] [Indexed: 11/16/2022]
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234
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Legoux FP, Lim JB, Cauley AW, Dikiy S, Ertelt J, Mariani TJ, Sparwasser T, Way SS, Moon JJ. CD4+ T Cell Tolerance to Tissue-Restricted Self Antigens Is Mediated by Antigen-Specific Regulatory T Cells Rather Than Deletion. Immunity 2015; 43:896-908. [PMID: 26572061 DOI: 10.1016/j.immuni.2015.10.011] [Citation(s) in RCA: 174] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 08/02/2015] [Accepted: 08/21/2015] [Indexed: 01/14/2023]
Abstract
Deletion of self-antigen-specific T cells during thymic development provides protection from autoimmunity. However, it is unclear how efficiently this occurs for tissue-restricted self antigens, or how immune tolerance is maintained for self-antigen-specific T cells that routinely escape deletion. Here we show that endogenous CD4+ T cells with specificity for a set of tissue-restricted self antigens were not deleted at all. For pancreatic self antigen, this resulted in an absence of steady-state tolerance, while for the lung and intestine, tolerance was maintained by the enhanced presence of thymically-derived antigen-specific Foxp3+ regulatory T (Treg) cells. Unlike deletional tolerance, Treg cell-mediated tolerance was broken by successive antigen challenges. These findings reveal that for some tissue-restricted self antigens, tolerance relies entirely on nondeletional mechanisms that are less durable than T cell deletion. This might explain why autoimmunity is often tissue-specific, and it offers a rationale for cancer vaccine strategies targeting tissue-restricted tumor antigens.
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Affiliation(s)
- Francois P Legoux
- Center for Immunology and Inflammatory Diseases, and Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital; and Harvard Medical School, Charlestown, MA 02129, USA
| | - Jong-Baeck Lim
- Center for Immunology and Inflammatory Diseases, and Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital; and Harvard Medical School, Charlestown, MA 02129, USA
| | - Andrew W Cauley
- Center for Immunology and Inflammatory Diseases, and Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital; and Harvard Medical School, Charlestown, MA 02129, USA
| | - Stanislav Dikiy
- Howard Hughes Medical Institute, Ludwig Center, and Immunology Program; Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - James Ertelt
- Division of Infectious Diseases and Perinatal Institute; Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Thomas J Mariani
- Division of Neonatology and Pediatric Molecular and Personalized Medicine Program; University of Rochester, Rochester, NY 14642, USA
| | - Tim Sparwasser
- TWINCORE - Centre for Experimental and Clinical Infection Research, 30625 Hannover, Germany
| | - Sing Sing Way
- Division of Infectious Diseases and Perinatal Institute; Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - James J Moon
- Center for Immunology and Inflammatory Diseases, and Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital; and Harvard Medical School, Charlestown, MA 02129, USA.
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235
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Talaber G, Jondal M, Okret S. Local glucocorticoid production in the thymus. Steroids 2015; 103:58-63. [PMID: 26102271 DOI: 10.1016/j.steroids.2015.06.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 06/09/2015] [Accepted: 06/15/2015] [Indexed: 12/29/2022]
Abstract
Besides generating immunocompetent T lymphocytes, the thymus is an established site of de novo extra-adrenal glucocorticoid (GC) production. Among the compartments of the thymus, both stromal thymic epithelial cells (TECs) and thymocytes secrete biologically active GCs. Locally produced GCs secreted by the various thymic cellular compartments have been suggested to have different impact on thymic homeostasis. TEC-derived GCs may regulate thymocyte differentiation whereas thymocyte-derived GCs might regulate age-dependent involution. However the full biological significance of thymic-derived GCs is still not fully understood. In this review, we summarize and describe recent advances in the understanding of local GC production in the thymus and immunoregulatory steroid production by peripheral T cells and highlight the possible role of local GCs for thymus function.
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Affiliation(s)
- Gergely Talaber
- Department of Biosciences and Nutrition, Karolinska Institutet, NOVUM, Huddinge, Sweden.
| | - Mikael Jondal
- Department of Microbiology, Tumor and Cell Biology, Karolinska Insitutet, Stockholm, Sweden
| | - Sam Okret
- Department of Biosciences and Nutrition, Karolinska Institutet, NOVUM, Huddinge, Sweden
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236
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Rothenberg EV, Ungerbäck J, Champhekar A. Forging T-Lymphocyte Identity: Intersecting Networks of Transcriptional Control. Adv Immunol 2015; 129:109-74. [PMID: 26791859 DOI: 10.1016/bs.ai.2015.09.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
T-lymphocyte development branches off from other lymphoid developmental programs through its requirement for sustained environmental signals through the Notch pathway. In the thymus, Notch signaling induces a succession of T-lineage regulatory factors that collectively create the T-cell identity through distinct steps. This process involves both the staged activation of T-cell identity genes and the staged repression of progenitor-cell-inherited regulatory genes once their roles in self-renewal and population expansion are no longer needed. With the recent characterization of innate lymphoid cells (ILCs) that share transcriptional regulation programs extensively with T-cell subsets, T-cell identity can increasingly be seen as defined in modular terms, as the processes selecting and actuating effector function are potentially detachable from the processes generating and selecting clonally unique T-cell receptor structures. The developmental pathways of different classes of T cells and ILCs are distinguished by the numbers of prerequisites of gene rearrangement, selection, and antigen contact before the cells gain access to nearly common regulatory mechanisms for choosing effector function. Here, the major classes of transcription factors that interact with Notch signals during T-lineage specification are discussed in terms of their roles in these programs, the evidence for their spectra of target genes at different stages, and their cross-regulatory and cooperative actions with each other. Specific topics include Notch modulation of PU.1 and GATA-3, PU.1-Notch competition, the relationship between PU.1 and GATA-3, and the roles of E proteins, Bcl11b, and GATA-3 in guiding acquisition of T-cell identity while avoiding redirection to an ILC fate.
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Affiliation(s)
- Ellen V Rothenberg
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, California, USA.
| | - Jonas Ungerbäck
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, California, USA; Department of Clinical and Experimental Medicine, Experimental Hematopoiesis Unit, Faculty of Health Sciences, Linköping University, Linköping, Sweden
| | - Ameya Champhekar
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, California, USA
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237
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Differences in Expression Level of Helios and Neuropilin-1 Do Not Distinguish Thymus-Derived from Extrathymically-Induced CD4+Foxp3+ Regulatory T Cells. PLoS One 2015; 10:e0141161. [PMID: 26495986 PMCID: PMC4619666 DOI: 10.1371/journal.pone.0141161] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 10/05/2015] [Indexed: 12/15/2022] Open
Abstract
Helios transcription factor and semaphorin receptor Nrp-1 were originally described as constitutively expressed at high levels on CD4+Foxp3+ T regulatory cells of intrathymic origin (tTregs). On the other hand, CD4+Foxp3+ Tregs generated in the periphery (pTregs) or induced ex vivo (iTregs) were reported to express low levels of Helios and Nrp-1. Soon afterwards the reliability of Nrp-1 and Helios as markers discriminating between tTregs and pTregs was questioned and until now no consensus has been reached. Here, we used several genetically modified mouse strains that favor pTregs or tTregs formation and analyzed the TCR repertoire of these cells. We found that Tregs with variable levels of Nrp-1 and Helios were abundant in mice with compromised ability to support natural differentiation of tTregs or pTregs. We also report that TCR repertoires of Treg clones expressing high or low levels of Nrp-1 or Helios are similar and more alike repertoire of CD4+Foxp3+ than repertoire of CD4+Foxp3- thymocytes. These results show that high vs. low expression of Nrp-1 or Helios does not unequivocally identify Treg clones of thymic or peripheral origin.
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238
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Osorio F, Fuentes C, López MN, Salazar-Onfray F, González FE. Role of Dendritic Cells in the Induction of Lymphocyte Tolerance. Front Immunol 2015; 6:535. [PMID: 26539197 PMCID: PMC4611163 DOI: 10.3389/fimmu.2015.00535] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/02/2015] [Indexed: 01/07/2023] Open
Abstract
The ability of dendritic cells (DCs) to trigger tolerance or immunity is dictated by the context in which an antigen is encountered. A large body of evidence indicates that antigen presentation by steady-state DCs induces peripheral tolerance through mechanisms such as the secretion of soluble factors, the clonal deletion of autoreactive T cells, and feedback control of regulatory T cells. Moreover, recent understandings on the function of DC lineages and the advent of murine models of DC depletion have highlighted the contribution of DCs to lymphocyte tolerance. Importantly, these findings are now being applied to human research in the contexts of autoimmune diseases, allergies, and transplant rejection. Indeed, DC-based immunotherapy research has made important progress in the area of human health, particularly in regards to cancer. A better understanding of several DC-related aspects including the features of DC lineages, milieu composition, specific expression of surface molecules, the control of signaling responses, and the identification of competent stimuli able to trigger and sustain a tolerogenic outcome will contribute to the success of DC-based immunotherapy in the area of lymphocyte tolerance. This review will discuss the latest advances in the biology of DC subtypes related to the induction of regulatory T cells, in addition to presenting current ex vivo protocols for tolerogenic DC production. Particular attention will be given to the molecules and signals relevant for achieving an adequate tolerogenic response for the treatment of human pathologies.
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Affiliation(s)
- Fabiola Osorio
- Millennium Institute on Immunology and Immunotherapy, Faculty of Medicine, University of Chile , Santiago , Chile ; Disciplinary Program of Immunology, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile , Santiago , Chile
| | - Camila Fuentes
- Millennium Institute on Immunology and Immunotherapy, Faculty of Medicine, University of Chile , Santiago , Chile ; Disciplinary Program of Immunology, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile , Santiago , Chile
| | - Mercedes N López
- Millennium Institute on Immunology and Immunotherapy, Faculty of Medicine, University of Chile , Santiago , Chile ; Disciplinary Program of Immunology, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile , Santiago , Chile ; Cell Therapy Laboratory, Blood Bank Service, University of Chile Clinical Hospital , Santiago , Chile
| | - Flavio Salazar-Onfray
- Millennium Institute on Immunology and Immunotherapy, Faculty of Medicine, University of Chile , Santiago , Chile ; Disciplinary Program of Immunology, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile , Santiago , Chile
| | - Fermín E González
- Millennium Institute on Immunology and Immunotherapy, Faculty of Medicine, University of Chile , Santiago , Chile ; Laboratory of Experimental Immunology and Cancer, Faculty of Dentistry, University of Chile , Santiago , Chile
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239
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van Nieuwenhuijze A, Liston A. The Molecular Control of Regulatory T Cell Induction. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 136:69-97. [PMID: 26615093 DOI: 10.1016/bs.pmbts.2015.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Regulatory T cells (Tregs) are characterized by the expression of the master transcription factor forkhead box P3 (Foxp3). Although Foxp3 expression is widely used as a marker of the Treg lineage, recent data show that the Treg fate is determined by a multifactorial signaling pathway, involving cytokines, nuclear factors, and epigenetic modifications. Foxp3 expression and the Treg phenotype can be acquired by T cells in the periphery, illustrating that the Treg fate is not necessarily conferred during thymic development. The two main Treg populations in vivo, thymic Tregs and peripheral Tregs, differ in the pathways followed for their maturation. This chapter discusses the molecular control of Treg induction, in the thymus as well as the periphery.
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Affiliation(s)
- Annemarie van Nieuwenhuijze
- Translational Immunology Laboratory, VIB, Leuven, Belgium; Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium.
| | - Adrian Liston
- Translational Immunology Laboratory, VIB, Leuven, Belgium; Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
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240
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Krishnamurthy B, Chee J, Jhala G, Trivedi P, Catterall T, Selck C, Gurzov EN, Brodnicki TC, Graham KL, Wali JA, Zhan Y, Gray D, Strasser A, Allison J, Thomas HE, Kay TWH. BIM Deficiency Protects NOD Mice From Diabetes by Diverting Thymocytes to Regulatory T Cells. Diabetes 2015; 64:3229-38. [PMID: 25948683 DOI: 10.2337/db14-1851] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 04/15/2015] [Indexed: 11/13/2022]
Abstract
Because regulatory T-cell (Treg) development can be induced by the same agonist self-antigens that induce negative selection, perturbation of apoptosis will affect both negative selection and Treg development. But how the processes of thymocyte deletion versus Treg differentiation bifurcate and their relative importance for tolerance have not been studied in spontaneous organ-specific autoimmune disease. We addressed these questions by removing a critical mediator of thymocyte deletion, BIM, in the NOD mouse model of autoimmune diabetes. Despite substantial defects in the deletion of autoreactive thymocytes, BIM-deficient NOD (NODBim(-/-)) mice developed less insulitis and were protected from diabetes. BIM deficiency did not impair effector T-cell function; however, NODBim(-/-) mice had increased numbers of Tregs, including those specific for proinsulin, in the thymus and peripheral lymphoid tissues. Increased levels of Nur77, CD5, GITR, and phosphorylated IκB-α in thymocytes from NODBim(-/-) mice suggest that autoreactive cells receiving strong T-cell receptor signals that would normally delete them escape apoptosis and are diverted into the Treg pathway. Paradoxically, in the NOD model, reduced thymic deletion ameliorates autoimmune diabetes by increasing Tregs. Thus, modulating apoptosis may be one of the ways to increase antigen-specific Tregs and prevent autoimmune disease.
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Affiliation(s)
- Balasubramanian Krishnamurthy
- St. Vincent's Institute, Fitzroy, Australia Department of Medicine, The University of Melbourne, St. Vincent's Hospital, Fitzroy, Australia
| | | | | | | | | | | | | | | | | | | | - Yifan Zhan
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Daniel Gray
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Andreas Strasser
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | | | - Helen E Thomas
- St. Vincent's Institute, Fitzroy, Australia Department of Medicine, The University of Melbourne, St. Vincent's Hospital, Fitzroy, Australia
| | - Thomas W H Kay
- St. Vincent's Institute, Fitzroy, Australia Department of Medicine, The University of Melbourne, St. Vincent's Hospital, Fitzroy, Australia
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241
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Barra MM, Richards DM, Hansson J, Hofer AC, Delacher M, Hettinger J, Krijgsveld J, Feuerer M. Transcription Factor 7 Limits Regulatory T Cell Generation in the Thymus. THE JOURNAL OF IMMUNOLOGY 2015; 195:3058-70. [DOI: 10.4049/jimmunol.1500821] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 07/23/2015] [Indexed: 02/06/2023]
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242
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Pasztoi M, Pezoldt J, Huehn J. Microenvironment Matters: Unique Conditions Within Gut-Draining Lymph Nodes Favor Efficient De Novo Induction of Regulatory T Cells. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 136:35-56. [PMID: 26615091 DOI: 10.1016/bs.pmbts.2015.07.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The gastrointestinal tract constitutes the largest surface of the body and thus has developed multitude mechanisms to either prevent pathogen entry or to efficiently eliminate invading pathogens. At the same time, the gastrointestinal system has to avoid unwanted immune responses against self and harmless nonself antigens, such as nutrients and commensal microbiota. Therefore, it is somewhat not unexpected that the gastrointestinal mucosa serves as the largest repository of immune cells throughout the body, harboring both potent pro- as well as anti-inflammatory properties. One additional key element of this regulatory machinery is created by trillions of symbiotic commensal bacteria in the gut. The microbiota not only simply contribute to the breakdown of nutrients, but are essential in limiting the expansion of pathogens, directing the development of the intestinal immune system, and establishing mucosal tolerance by fostering the induction of regulatory T cells (Tregs). In this review, we will discuss our current understanding about the microenvironmental factors fostering the de novo generation of Tregs within the gastrointestinal immune system, focusing on unique properties of antigen-presenting cells, tolerogenic cytokines, commensal-derived metabolites and the contribution of lymph node stromal cells.
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Affiliation(s)
- Maria Pasztoi
- Department of Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Joern Pezoldt
- Department of Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Jochen Huehn
- Department of Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany.
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243
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244
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Caramalho Í, Nunes-Cabaço H, Foxall RB, Sousa AE. Regulatory T-Cell Development in the Human Thymus. Front Immunol 2015; 6:395. [PMID: 26284077 PMCID: PMC4522873 DOI: 10.3389/fimmu.2015.00395] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 07/19/2015] [Indexed: 12/23/2022] Open
Abstract
The thymus generates a lineage-committed subset of regulatory T-cells (Tregs), best identified by the expression of the transcription factor FOXP3. The development of thymus-derived Tregs is known to require high-avidity interaction with MHC-self peptides leading to the generation of self-reactive Tregs fundamental for the maintenance of self-tolerance. Notwithstanding their crucial role in the control of immune responses, human thymic Treg differentiation remains poorly understood. In this mini-review, we will focus on the developmental stages at which Treg lineage commitment occurs, and their spatial localization in the human thymus, reviewing the molecular requirements, including T-cell receptor and cytokine signaling, as well as the cellular interactions involved. An overview of the impact of described thymic defects on the Treg compartment will be provided, illustrating the importance of these in vivo models to investigate human Treg development.
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Affiliation(s)
- Íris Caramalho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa , Lisbon , Portugal
| | - Helena Nunes-Cabaço
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa , Lisbon , Portugal
| | - Russell B Foxall
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa , Lisbon , Portugal
| | - Ana E Sousa
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa , Lisbon , Portugal
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245
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Ono M, Tanaka RJ. Controversies concerning thymus-derived regulatory T cells: fundamental issues and a new perspective. Immunol Cell Biol 2015. [PMID: 26215792 PMCID: PMC4650266 DOI: 10.1038/icb.2015.65] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Thymus-derived regulatory T cells (Tregs) are considered to be a distinct T-cell lineage that is genetically programmed and specialised for immunosuppression. This perspective is based on the key evidence that CD25+ Tregs emigrate to neonatal spleen a few days later than other T cells and that thymectomy of 3-day-old mice depletes Tregs only, causing autoimmune diseases. Although widely believed, the evidence has never been reproduced as originally reported, and some studies indicate that Tregs exist in neonates. Thus we examine the consequences of the controversial evidence, revisit the fundamental issues of Tregs and thereby reveal the overlooked relationship of T-cell activation and Foxp3-mediated control of the T-cell system. Here we provide a new model of Tregs and Foxp3, a feedback control perspective, which views Tregs as a component of the system that controls T-cell activation, rather than as a distinct genetically programmed lineage. This perspective provides new insights into the roles of self-reactivity, T cell–antigen-presenting cell interaction and T-cell activation in Foxp3-mediated immune regulation.
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Affiliation(s)
- Masahiro Ono
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK.,Immunobiology Section, Institute of Child Health, University College London, London, UK
| | - Reiko J Tanaka
- Department of Bioengineering, Imperial College London, London, UK
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246
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O'Hagan KL, Choi J, Pryshchep O, Chernoff J, Phee H. Pak2 Links TCR Signaling Strength to the Development of Regulatory T Cells and Maintains Peripheral Tolerance. THE JOURNAL OF IMMUNOLOGY 2015; 195:1564-77. [PMID: 26157175 DOI: 10.4049/jimmunol.1500843] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 06/10/2015] [Indexed: 01/01/2023]
Abstract
Although significant effort has been devoted to understanding the thymic development of Foxp3(+) regulatory T cells (Tregs), the precise signaling pathways that govern their lineage commitment still remain enigmatic. Our findings show a novel role for the actin cytoskeletal remodeling protein, p21-activated kinase 2 (Pak2), in Treg development and homeostasis. The absence of Pak2 in T cells resulted in a marked reduction in both thymus- and peripherally derived Tregs, accompanied by the development of spontaneous colitis in Pak2-deficient mice. Additionally, Pak2 was required for the proper differentiation of in vitro-induced Tregs as well as maintenance of Tregs. Interestingly, Pak2 was necessary for generating the high-affinity TCR- and IL-2-mediated signals that are required by developing Tregs for their lineage commitment. These findings provide novel insight into how developing thymocytes translate lineage-specific high-affinity TCR signals to adopt the Treg fate, and they further posit Pak2 as an essential regulator for this process.
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Affiliation(s)
- Kyle Leonard O'Hagan
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611; and
| | - Jinyong Choi
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611; and
| | - Olga Pryshchep
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611; and
| | - Jonathan Chernoff
- Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Hyewon Phee
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611; and
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Lu J, Meng H, Zhang A, Yang J, Zhang X. Phenotype and function of tissue-resident unconventional Foxp3-expressing CD4(+) regulatory T cells. Cell Immunol 2015; 297:53-9. [PMID: 26142700 DOI: 10.1016/j.cellimm.2015.06.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Revised: 06/22/2015] [Accepted: 06/26/2015] [Indexed: 12/25/2022]
Abstract
It is becoming increasingly clear that regulatory T cells (Treg cells) in specific tissues are important parts of immune system. Tissue-resident Treg cells, which are largely Foxp3-expressing CD4(+) Treg cells, are distinct from one another and conventional Treg cells, and have tissue-specific phenotype and function. They have roles in improving insulin sensitivity in adipose tissue, promoting muscle repair, limiting inflammation in intestine, skin and central nervous system. In this Review, we discuss the current understanding of phenotype and function of tissue-resident Treg cells. Understanding phenotypic and functional diversity in different tissues could provide new insight into Treg cells development and investigation.
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Affiliation(s)
- Jingli Lu
- Department of Pharmacy, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, PR China
| | - Haiyang Meng
- Department of Pharmacy, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, PR China
| | - Ailing Zhang
- Department of Pharmacy, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, PR China
| | - Jie Yang
- Department of Pharmacy, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, PR China
| | - Xiaojian Zhang
- Department of Pharmacy, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, PR China.
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248
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Oh J, Shin JS. The Role of Dendritic Cells in Central Tolerance. Immune Netw 2015; 15:111-20. [PMID: 26140042 PMCID: PMC4486773 DOI: 10.4110/in.2015.15.3.111] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/26/2015] [Accepted: 06/02/2015] [Indexed: 12/16/2022] Open
Abstract
Dendritic cells (DCs) play a significant role in establishing self-tolerance through their ability to present self-antigens to developing T cells in the thymus. DCs are predominantly localized in the medullary region of thymus and present a broad range of self-antigens, which include tissue-restricted antigens expressed and transferred from medullary thymic epithelial cells, circulating antigens directly captured by thymic DCs through coticomedullary junction blood vessels, and peripheral tissue antigens captured and transported by peripheral tissue DCs homing to the thymus. When antigen-presenting DCs make a high affinity interaction with antigen-specific thymocytes, this interaction drives the interacting thymocytes to death, a process often referred to as negative selection, which fundamentally blocks the self-reactive thymocytes from differentiating into mature T cells. Alternatively, the interacting thymocytes differentiate into the regulatory T (Treg) cells, a distinct T cell subset with potent immune suppressive activities. The specific mechanisms by which thymic DCs differentiate Treg cells have been proposed by several laboratories. Here, we review the literatures that elucidate the contribution of thymic DCs to negative selection and Treg cell differentiation, and discusses its potential mechanisms and future directions.
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Affiliation(s)
- Jaehak Oh
- Department of Microbiology and Immunology, Sandler Asthma Basic Research Center, University of California San Francisco, San Francisco, CA 94143, USA
| | - Jeoung-Sook Shin
- Department of Microbiology and Immunology, Sandler Asthma Basic Research Center, University of California San Francisco, San Francisco, CA 94143, USA
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249
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Saeki K, Doekes HM, De Boer RJ. Optimal T cell cross-reactivity and the role of regulatory T cells. J Theor Biol 2015; 375:4-12. [PMID: 25446707 DOI: 10.1016/j.jtbi.2014.11.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 11/04/2014] [Accepted: 11/11/2014] [Indexed: 12/01/2022]
Abstract
The T lymphocytes of the adaptive immune system constitute a highly diverse repertoire of clones expressing a unique T cell receptor (TCR). It has been argued that TCRs are cross-reactive, meaning that one receptor can recognize a multitude of epitopes. Cross-reactivity between self and foreign epitopes can potentially lead to autoimmune responses. Regulatory T cells (Tregs) down-regulate immune reactions, and play an important role in the avoidance of autoimmunity. We use a probabilistic modeling approach to investigate how suppression of antigen-presenting dendritic cells (DCs) by Tregs influences the probability of mounting a successful immune response against a pathogen while remaining self-tolerant. For T cell cross-reactivity values close to experimental estimates, we find that the presence of Tregs increases this success probability somewhat. However, the probability of a successful immune response remains relatively low for these cross-reactivity values, and the probability of success is optimized when T cells are more specific and no Tregs are formed. We conclude that DC suppression on its own is insufficient to provide an evolutionary benefit of regulatory T cells. Rejecting one intuitively likely hypothesis for the function of Tregs thus narrows down the search for the mechanisms by which they are suppressing inappropriate immune responses.
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Affiliation(s)
- Koichi Saeki
- Department of Evolutionary Studies of Biosystems, School of Advanced Sciences, The Graduate University for Advanced Studies, Shonan Village, Hayama, Kanagawa 240-0193, Japan
| | - Hilje M Doekes
- Theoretical Biology and Bioinformatics, Department of Biology, Utrecht University, The Netherlands
| | - Rob J De Boer
- Theoretical Biology and Bioinformatics, Department of Biology, Utrecht University, The Netherlands
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250
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Premature expression of Foxp3 in double-negative thymocytes. PLoS One 2015; 10:e0127038. [PMID: 25978037 PMCID: PMC4433242 DOI: 10.1371/journal.pone.0127038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 04/14/2015] [Indexed: 01/09/2023] Open
Abstract
Peripheral immune regulation depends on the generation of thymic-derived regulatory T (tTreg) cells to maintain self-tolerance and to counterbalance overshooting immune responses. The expression of the Treg lineage defining transcription factor Foxp3 in developing tTreg cells depends on TCR signaling during the thymic selection process of these T cells. In this study, we surprisingly identify Foxp3+ immature thymocytes at the double-negative (DN) stage in transcription factor 7 (Tcf7)-deficient mice. These Foxp3+ cells did not express a TCR (β or γδ chains), CD3 or CD5 and therefore these cells were true DN cells. Further investigation of this phenomenon in a transgenic TCR model showed that Foxp3-expressing DN cells could not respond to TCR stimulation in vivo. These data suggest that Foxp3 expression in these DN cells occurred independently of TCR signaling. Interestingly, these Foxp3+ DN cells were located in a transition state between DN1 and DN2 (CD4-CD8-CD3-TCR-CD44highCD25low). Our results indicate that Tcf7 is involved in preventing the premature expression of Foxp3 in DN thymocytes.
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