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Bigley TM, Yang L, Kang LI, Saenz JB, Victorino F, Yokoyama WM. Disruption of thymic central tolerance by infection with murine roseolovirus induces autoimmune gastritis. J Exp Med 2022; 219:213039. [PMID: 35226043 PMCID: PMC8932538 DOI: 10.1084/jem.20211403] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 11/29/2021] [Accepted: 01/24/2022] [Indexed: 12/12/2022] Open
Abstract
Infections with herpesviruses, including human roseoloviruses, have been proposed to cause autoimmune disease, but defining a causal relationship and mechanism has been difficult due to the ubiquitous nature of infection and development of autoimmunity long after acute infection. Murine roseolovirus (MRV) is highly related to human roseoloviruses. Herein we show that neonatal MRV infection induced autoimmune gastritis (AIG) in adult mice in the absence of ongoing infection. MRV-induced AIG was dependent on replication during the neonatal period and was CD4+ T cell and IL-17 dependent. Moreover, neonatal MRV infection was associated with development of a wide array of autoantibodies in adult mice. Finally, neonatal MRV infection reduced medullary thymic epithelial cell numbers, thymic dendritic cell numbers, and thymic expression of AIRE and tissue-restricted antigens, in addition to increasing thymocyte apoptosis at the stage of negative selection. These findings strongly suggest that infection with a roseolovirus early in life results in disruption of central tolerance and development of autoimmune disease.
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Affiliation(s)
- Tarin M. Bigley
- Department of Pediatrics, Division of Rheumatology, Washington University School of Medicine, St. Louis, MO
| | - Liping Yang
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, St. Louis, MO
| | - Liang-I Kang
- Department of Pathology and Immunology, Division of Anatomic and Molecular Pathology, Washington University School of Medicine, St. Louis, MO
| | - Jose B. Saenz
- Department of Medicine, Division of Gastroenterology, Washington University School of Medicine, St. Louis, MO
| | - Francisco Victorino
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, St. Louis, MO
| | - Wayne M. Yokoyama
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, St. Louis, MO
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2
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Tao Z, Jiang Y, Xia S. Regulation of thymic T regulatory cell differentiation by TECs in health and disease. Scand J Immunol 2021; 94:e13094. [PMID: 34780092 DOI: 10.1111/sji.13094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 12/22/2022]
Abstract
The thymus produces self-limiting and self-tolerant T cells through the interaction between thymocytes and thymus epithelial cells (TECs), thereby generating central immune tolerance. The TECs are composed of cortical and medullary thymic epithelial cells, which regulate the positive and negative selection of T cells, respectively. During the process of negative selection, thymocytes with self-reactive ability are deleted or differentiated into regulatory T cells (Tregs). Tregs are a subset of suppressor T cells that are important for maintaining immune homeostasis. The differentiation and development of Tregs depend on the development of TECs and other underlying molecular mechanisms. Tregs regulated by thymic epithelial cells are closely related to human health and are significant in autoimmune diseases, thymoma and pregnancy. In this review, we summarize the current molecular and transcriptional regulatory mechanisms by which TECs affect the development and function of thymic Tregs. We also review the pathophysiological models of thymic epithelial cells regulating thymic Tregs in human diseases and specific physiological conditions.
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Affiliation(s)
- Zehua Tao
- Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Yalan Jiang
- Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Sheng Xia
- Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, China
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3
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Mannie MD, DeOca KB, Bastian AG, Moorman CD. Tolerogenic vaccines: Targeting the antigenic and cytokine niches of FOXP3 + regulatory T cells. Cell Immunol 2020; 355:104173. [PMID: 32712270 PMCID: PMC7444458 DOI: 10.1016/j.cellimm.2020.104173] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/06/2020] [Accepted: 07/10/2020] [Indexed: 02/06/2023]
Abstract
FOXP3+ regulatory T cells (Tregs) constitute a critical barrier that enforces tolerance to both the self-peptidome and the extended-self peptidome to ensure tissue-specific resistance to autoimmune, allergic, and other inflammatory disorders. Here, we review intuitive models regarding how T cell antigen receptor (TCR) specificity and antigen recognition efficiency shape the Treg and conventional T cell (Tcon) repertoires to adaptively regulate T cell maintenance, tissue-residency, phenotypic stability, and immune function in peripheral tissues. Three zones of TCR recognition efficiency are considered, including Tcon recognition of specific low-efficiency self MHC-ligands, Treg recognition of intermediate-efficiency agonistic self MHC-ligands, and Tcon recognition of cross-reactive high-efficiency agonistic foreign MHC-ligands. These respective zones of TCR recognition efficiency are key to understanding how tissue-resident immune networks integrate the antigenic complexity of local environments to provide adaptive decisions setting the balance of suppressive and immunogenic responses. Importantly, deficiencies in the Treg repertoire appear to be an important cause of chronic inflammatory disease. Deficiencies may include global deficiencies in Treg numbers or function, subtle 'holes in the Treg repertoire' in tissue-resident Treg populations, or simply Treg insufficiencies that are unable to counter an overwhelming molecular mimicry stimulus. Tolerogenic vaccination and Treg-based immunotherapy are two therapeutic modalities meant to restore dominance of Treg networks to reverse chronic inflammatory disease. Studies of these therapeutic modalities in a preclinical setting have provided insight into the Treg niche, including the concept that intermediate-efficiency TCR signaling, high IFN-β concentrations, and low IL-2 concentrations favor Treg responses and active dominant mechanisms of immune tolerance. Overall, the purpose here is to assimilate new and established concepts regarding how cognate TCR specificity of the Treg repertoire and the contingent cytokine networks provide a foundation for understanding Treg suppressive strategy.
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Affiliation(s)
- Mark D Mannie
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, United States.
| | - Kayla B DeOca
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, United States
| | - Alexander G Bastian
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, United States
| | - Cody D Moorman
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, United States
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4
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Abstract
Foxp3-expressing CD4+ regulatory T (Treg) cells play key roles in the prevention of autoimmunity and the maintenance of immune homeostasis and represent a major barrier to the induction of robust antitumor immune responses. Thus, a clear understanding of the mechanisms coordinating Treg cell differentiation is crucial for understanding numerous facets of health and disease and for developing approaches to modulate Treg cells for clinical benefit. Here, we discuss current knowledge of the signals that coordinate Treg cell development, the antigen-presenting cell types that direct Treg cell selection, and the nature of endogenous Treg cell ligands, focusing on evidence from studies in mice. We also highlight recent advances in this area and identify key unanswered questions.
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Affiliation(s)
- Peter A Savage
- Department of Pathology, University of Chicago, Chicago, Illinois 60637, USA; , ,
| | - David E J Klawon
- Department of Pathology, University of Chicago, Chicago, Illinois 60637, USA; , ,
| | - Christine H Miller
- Department of Pathology, University of Chicago, Chicago, Illinois 60637, USA; , ,
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5
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Łyszkiewicz M, Winter SJ, Witzlau K, Föhse L, Brownlie R, Puchałka J, Verheyden NA, Kunze-Schumacher H, Imelmann E, Blume J, Raha S, Sekiya T, Yoshimura A, Frueh JT, Ullrich E, Huehn J, Weiss S, Gutierrez MG, Prinz I, Zamoyska R, Ziętara N, Krueger A. miR-181a/b-1 controls thymic selection of Treg cells and tunes their suppressive capacity. PLoS Biol 2019; 17:e2006716. [PMID: 30856173 PMCID: PMC6428341 DOI: 10.1371/journal.pbio.2006716] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 03/21/2019] [Accepted: 02/27/2019] [Indexed: 12/13/2022] Open
Abstract
The interdependence of selective cues during development of regulatory T cells (Treg cells) in the thymus and their suppressive function remains incompletely understood. Here, we analyzed this interdependence by taking advantage of highly dynamic changes in expression of microRNA 181 family members miR-181a-1 and miR-181b-1 (miR-181a/b-1) during late T-cell development with very high levels of expression during thymocyte selection, followed by massive down-regulation in the periphery. Loss of miR-181a/b-1 resulted in inefficient de novo generation of Treg cells in the thymus but simultaneously permitted homeostatic expansion in the periphery in the absence of competition. Modulation of T-cell receptor (TCR) signal strength in vivo indicated that miR-181a/b-1 controlled Treg-cell formation via establishing adequate signaling thresholds. Unexpectedly, miR-181a/b-1-deficient Treg cells displayed elevated suppressive capacity in vivo, in line with elevated levels of cytotoxic T-lymphocyte-associated 4 (CTLA-4) protein, but not mRNA, in thymic and peripheral Treg cells. Therefore, we propose that intrathymic miR-181a/b-1 controls development of Treg cells and imposes a developmental legacy on their peripheral function.
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MESH Headings
- Animals
- Flow Cytometry
- Mice
- Mice, Knockout
- MicroRNAs/genetics
- MicroRNAs/metabolism
- Microscopy, Confocal
- Nuclear Receptor Subfamily 4, Group A, Member 1/genetics
- Nuclear Receptor Subfamily 4, Group A, Member 1/metabolism
- Nuclear Receptor Subfamily 4, Group A, Member 2/genetics
- Nuclear Receptor Subfamily 4, Group A, Member 2/metabolism
- T-Lymphocytes, Regulatory/metabolism
- Thymocytes/metabolism
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Affiliation(s)
- Marcin Łyszkiewicz
- Institute of Immunology, Hannover Medical School, Hannover, Germany
- Institute for Immunology, Ludwig-Maximilians University, Planegg-Martiensried, Germany
| | - Samantha J. Winter
- Institute for Molecular Medicine, Goethe University Frankfurt am Main, Frankfurt, Germany
| | - Katrin Witzlau
- Institute of Immunology, Hannover Medical School, Hannover, Germany
| | - Lisa Föhse
- Institute of Immunology, Hannover Medical School, Hannover, Germany
| | - Rebecca Brownlie
- Institute for Immunology and Infection Research, The University of Edinburgh, Edinburgh, United Kingdom
| | - Jacek Puchałka
- Department of Pediatrics, Dr. von Hauner Kinderspital, Ludwig-Maximilians University, Munich, Germany
| | - Nikita A. Verheyden
- Institute for Molecular Medicine, Goethe University Frankfurt am Main, Frankfurt, Germany
| | - Heike Kunze-Schumacher
- Institute for Molecular Medicine, Goethe University Frankfurt am Main, Frankfurt, Germany
| | - Esther Imelmann
- Institute for Molecular Medicine, Goethe University Frankfurt am Main, Frankfurt, Germany
| | - Jonas Blume
- Institute of Immunology, Hannover Medical School, Hannover, Germany
| | - Solaiman Raha
- Institute of Immunology, Hannover Medical School, Hannover, Germany
| | - Takashi Sekiya
- Department of Microbiology and Immunology, Keio University School of Medicine, Tokyo, Japan
| | - Akihiko Yoshimura
- Department of Microbiology and Immunology, Keio University School of Medicine, Tokyo, Japan
| | - Jochen T. Frueh
- Experimental Immunology, Department for Children and Adolescents Medicine, Hospital of the Goethe University Frankfurt, Frankfurt, Germany
- LOEWE Center for Cell and Gene Therapy, Goethe University, Frankfurt, Germany
| | - Evelyn Ullrich
- Experimental Immunology, Department for Children and Adolescents Medicine, Hospital of the Goethe University Frankfurt, Frankfurt, Germany
- LOEWE Center for Cell and Gene Therapy, Goethe University, Frankfurt, Germany
| | - Jochen Huehn
- Department of Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Siegfried Weiss
- Institute of Immunology, Hannover Medical School, Hannover, Germany
| | | | - Immo Prinz
- Institute of Immunology, Hannover Medical School, Hannover, Germany
| | - Rose Zamoyska
- Institute for Immunology and Infection Research, The University of Edinburgh, Edinburgh, United Kingdom
| | - Natalia Ziętara
- Institute of Immunology, Hannover Medical School, Hannover, Germany
- Institute for Immunology, Ludwig-Maximilians University, Planegg-Martiensried, Germany
| | - Andreas Krueger
- Institute of Immunology, Hannover Medical School, Hannover, Germany
- Institute for Molecular Medicine, Goethe University Frankfurt am Main, Frankfurt, Germany
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6
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Apert C, Romagnoli P, van Meerwijk JPM. IL-2 and IL-15 dependent thymic development of Foxp3-expressing regulatory T lymphocytes. Protein Cell 2018; 9:322-332. [PMID: 28540653 PMCID: PMC5876181 DOI: 10.1007/s13238-017-0425-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 05/04/2017] [Indexed: 12/15/2022] Open
Abstract
Immunosuppressive regulatory T lymphocytes (Treg) expressing the transcription factor Foxp3 play a vital role in the maintenance of tolerance of the immune-system to self and innocuous non-self. Most Treg that are critical for the maintenance of tolerance to self, develop as an independent T-cell lineage from common T cell precursors in the thymus. In this organ, their differentiation requires signals from the T cell receptor for antigen, from co-stimulatory molecules, as well as from cytokine-receptors. Here we focus on the cytokines implicated in thymic development of Treg, with a particular emphasis on the roles of interleukin-2 (IL-2) and IL-15. The more recently appreciated involvement of TGF-β in thymic Treg development is also briefly discussed. Finally, we discuss how cytokine-dependence of Treg development allows for temporal, quantitative, and potentially qualitative modulation of this process.
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Affiliation(s)
- Cécile Apert
- CPTP, Université de Toulouse, CNRS, Inserm, UPS, Toulouse, France
| | - Paola Romagnoli
- CPTP, Université de Toulouse, CNRS, Inserm, UPS, Toulouse, France.
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7
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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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8
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Liu YM, Luo J, Bennett C. Adaptive immunity: Based on the dual recognition responses of αβT cells. SELF NONSELF 2014; 1:62-66. [PMID: 21559178 DOI: 10.4161/self.1.1.10441] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 10/22/2009] [Accepted: 10/27/2009] [Indexed: 11/19/2022]
Abstract
It is proposed that the recently reported second recognition mode of αβT cells allows an explanation of the evolutionary origin of adaptive immunity. The dual modes provide the mechanism of development/differentiation of αβT cells under the control of immune response (Ir) genes by which a given T-cell can distinguish one kind of MHC molecule (as 'self' phase, learned from its positive selection) from others (as 'nonself' phase) involved in antigen recognition. It is thus possible to re-explain the 'self'/'nonself' concept based on 'homotype (phase)'/'heterotype (phase)' recognition at the level of a single clone of T cells. Hence adaptive immunity is explained here as being derived from functions that ensure synchronous ontogeny and prevent the paradoxical (or retrograde) development of vertebrates.
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Affiliation(s)
- Yan-Ming Liu
- Tianjin University of Traditional Chinese Medicine; Tianjin, China
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9
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Walters SN, Webster KE, Daley S, Grey ST. A Role for Intrathymic B Cells in the Generation of Natural Regulatory T Cells. THE JOURNAL OF IMMUNOLOGY 2014; 193:170-6. [DOI: 10.4049/jimmunol.1302519] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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10
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Yamada T, Nanashima N, Akita M, Shimizu T, Miura T, Yamana D, Sawano T, Sakurai T, Tsuchida S. Lectin-like receptor Ly49s3 on dendritic cells contributes to the differentiation of regulatory T cells in the rat thymus. THE JOURNAL OF IMMUNOLOGY 2013; 191:3799-809. [PMID: 23997226 DOI: 10.4049/jimmunol.1203511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Naturally occurring regulatory T cells (nTregs), important for immune regulation and the maintenance of self-tolerance, develop in the thymus. The Hirosaki hairless rat (HHR), derived from the Sprague-Dawley rat (SDR), was shown to have decreased peripheral lymphocyte number, small thymus, and leukocyte infiltration in its dermis. In the HHR thymus, the medulla was underdeveloped and nTreg number was decreased. Array comparative genome hybridization revealed the deletion of an NK cell lectin-like receptor gene, Ly49s3, detecting MHC class I molecules on target cells, in the chromosome 4q42 region in HHRs. The gene was expressed in thymic conventional dendritic cells (cDCs) in SDRs, but not in HHRs. When CD4-single-positive or CD4(+)CD8(-)CD25(-) thymocytes were cultured with thymic cDCs, the expression of nTreg marker genes was lower when these cells were from HHRs than from SDRs, suggesting that HHR cDCs are deficient in the ability to induce and maintain nTreg differentiation. Expression of the genes was recovered when Ly49s3 was expressed on HHR thymic cDCs. Expression levels of MHC class II genes, presumably from cDCs, were parallel to those of nTreg marker genes in mixed-cell cultures. However, in the presence of an anti-MHC class I Ab, blocking interaction between Ly49s3 and MHC class I molecules, the expression of the former genes was upregulated, whereas the latter was downregulated. These results suggest that Ly49s3 contributes to nTreg regulation along with MHC class II molecules, whose effects alone are insufficient, and loss of Ly49s3 from thymic cDCs is the reason for the nTreg deficiency in HHRs.
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Affiliation(s)
- Toshiyuki Yamada
- Department of Biochemistry and Genome Biology, Hirosaki University Graduate School of Medicine, Hirosaki 036-8562, Japan
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11
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Romagnoli P, Dooley J, Enault G, Vicente R, Malissen B, Liston A, van Meerwijk JPM. The Thymic Niche Does Not Limit Development of the Naturally Diverse Population of Mouse Regulatory T Lymphocytes. THE JOURNAL OF IMMUNOLOGY 2012; 189:3831-7. [DOI: 10.4049/jimmunol.1201564] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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12
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Yuan X, Malek TR. Cellular and molecular determinants for the development of natural and induced regulatory T cells. Hum Immunol 2012; 73:773-82. [PMID: 22659217 PMCID: PMC3410644 DOI: 10.1016/j.humimm.2012.05.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 04/10/2012] [Accepted: 05/10/2012] [Indexed: 02/06/2023]
Abstract
Regulation of immune responses to self and foreign antigens is critically dependent on suppressive CD4(+) T cells characterized by expression of Foxp3. The large majority of regulatory T (Treg) cells develop in the thymus as a stable suppressive lineage. However, under the proper physiological conditions, conventional peripheral CD4(+) T lymphocytes also develop into Treg cells, particularly in the gut mucosa and inflammatory tissue sites. This review will focus on our current understanding of the immunological and molecular signals controlling the development of thymic derived natural (n)Treg and peripheral converted induced (i)Treg cells. Given the importance of Foxp3 in the development of these cells, particular attention is placed on how such signals are integrated to induce and maintain the expression of this signature transcriptional regulator of Treg cells.
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Affiliation(s)
- Xiaomei Yuan
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, FL 33136, United States
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13
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Pasquet L, Joffre O, Santolaria T, van Meerwijk JPM. Hematopoietic chimerism and transplantation tolerance: a role for regulatory T cells. Front Immunol 2011; 2:80. [PMID: 22566869 PMCID: PMC3342389 DOI: 10.3389/fimmu.2011.00080] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 12/05/2011] [Indexed: 01/13/2023] Open
Abstract
The immunosuppressive regimens currently used in transplantation to prevent allograft destruction by the host's immune system have deleterious side effects and fail to control chronic rejection processes. Induction of donor-specific non-responsiveness (i.e., immunological tolerance) to transplants would solve these problems and would substantially ameliorate patients' quality of life. It has been proposed that bone marrow or hematopoietic stem-cell transplantation, and resulting (mixed) hematopoietic chimerism, lead to immunological tolerance to organs of the same donor. However, a careful analysis of the literature, performed here, clearly establishes that whereas hematopoietic chimerism substantially prolongs allograft survival, it does not systematically prevent chronic rejection. Moreover, the cytotoxic conditioning regimens used to achieve long-term persistence of chimerism are associated with severe side effects that appear incompatible with a routine use in the clinic. Several laboratories recently embarked on different studies to develop alternative strategies to overcome these issues. We discuss here recent advances obtained by combining regulatory T cell infusion with bone-marrow transplantation. In experimental settings, this attractive approach allows development of genuine immunological tolerance to donor tissues using clinically relevant conditioning regimens.
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Affiliation(s)
- Lise Pasquet
- INSERM U1043Toulouse, France
- CNRS U5282Toulouse, France
- Centre de Physiopathologie de Toulouse Purpan, Université Paul Sabatier, Université de ToulouseToulouse, France
| | - Olivier Joffre
- INSERM U1043Toulouse, France
- CNRS U5282Toulouse, France
- Centre de Physiopathologie de Toulouse Purpan, Université Paul Sabatier, Université de ToulouseToulouse, France
| | - Thibault Santolaria
- INSERM U1043Toulouse, France
- CNRS U5282Toulouse, France
- Centre de Physiopathologie de Toulouse Purpan, Université Paul Sabatier, Université de ToulouseToulouse, France
| | - Joost P. M. van Meerwijk
- INSERM U1043Toulouse, France
- CNRS U5282Toulouse, France
- Centre de Physiopathologie de Toulouse Purpan, Université Paul Sabatier, Université de ToulouseToulouse, France
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14
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Nature and nurture in Foxp3(+) regulatory T cell development, stability, and function. Hum Immunol 2011; 73:232-9. [PMID: 22240298 DOI: 10.1016/j.humimm.2011.12.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 04/18/2011] [Accepted: 12/19/2011] [Indexed: 02/06/2023]
Abstract
Foxp3(+) regulatory T lymphocytes (Treg) are critical homeostatic regulators of immune and inflammatory responses. Their absence leads to fulminant multiorgan autoimmunity. This review explores recent studies that have altered our emerging view of the development, stability, and plasticity of these cells. Treg appear not to be a single entity, but a family of immunomodulatory cell types with shared capabilities. On a first level, Treg may alternatively form in response to developmental cues in the thymus as a distinct lineage of CD4(+) T cells or adaptively, in response to environmental cues received by mature conventional CD4(+) T lymphocytes. These 2 populations bear distinct specificity, stability, and genetic profiles and are differentially used in immune responses. Secondarily, in a manner analogous to the generation of T helper (Th)-1, Th2, and other T cell subsets, Treg may further specialize, adapting to the needs of their immunologic surroundings. Treg therefore comprise developmentally distinct, functionally overlapping cell populations that are uniquely designed to preserve immunologic homeostasis. They combine an impressive degree of both stability and adaptability.
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15
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16
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Föhse L, Suffner J, Suhre K, Wahl B, Lindner C, Lee CW, Schmitz S, Haas JD, Lamprecht S, Koenecke C, Bleich A, Hämmerling GJ, Malissen B, Suerbaum S, Förster R, Prinz I. High TCR diversity ensures optimal function and homeostasis of Foxp3+ regulatory T cells. Eur J Immunol 2011; 41:3101-13. [PMID: 21932448 DOI: 10.1002/eji.201141986] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 08/24/2011] [Accepted: 08/31/2011] [Indexed: 01/08/2023]
Abstract
Dominant tolerance to self-antigen requires the presence of sufficient numbers of CD4(+) Foxp3(+) Treg cells with matching antigen specificity. However, the size and role of TCR repertoire diversity for antigen-specific immuno-regulation through Treg cells is not clear. Here, we developed and applied a novel high-throughput (HT) TCR sequencing approach to analyze the TCR repertoire of Treg cells and revealed the importance of high diversity for Treg-cell homeostasis and function. We found that highly polyclonal Treg cells from WT mice vigorously expanded after adoptive transfer into non-lymphopenic TCR-transgenic recipients with low Treg-cell diversity. In that system, we identified specific Treg-cell TCR preferences in distinct anatomic locations such as the mesenteric LN indicating that Treg cells continuously compete for MHC class-II-presented self-, food-, or flora-antigen. Functionally, we showed that high TCR diversity was required for optimal suppressive function of Treg cells in experimental acute graft versus host disease (GvHD). In conclusion, we suggest that efficient immuno-regulation by Treg cells requires high TCR diversity. Thereby, continuous competition of peripheral Treg cells for limited self-antigen shapes an organ-optimized, yet highly diverse, local TCR repertoire.
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Affiliation(s)
- Lisa Föhse
- Institute of Immunology, Hannover Medical School, Hannover, Germany
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17
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Aichinger M, Hinterberger M, Klein L. Probing gene function in thymic epithelial cells. Eur J Cell Biol 2011; 91:24-30. [PMID: 21392839 DOI: 10.1016/j.ejcb.2011.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 01/22/2011] [Indexed: 01/12/2023] Open
Abstract
Thymic epithelial cells (TECs) provide a highly specialized microenvironment for the generation of a functional and self-tolerant T cell repertoire. Much of our current view of TEC biology is derived from gain- or loss-of-function approaches, which have significantly contributed to our understanding of gene function in TEC development and T cell repertoire selection. Here, we will review transgenic and viral strategies that have been used to manipulate gene expression in TECs, highlight some of the shortcomings of particular currently available tools and provide a brief outline of our own attempts to more rapidly and/or more specifically assess gene function in TECs.
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Affiliation(s)
- Martin Aichinger
- Institute for Immunology, Ludwig-Maximilians-Universität, Goethestrasse 31, Munich, Germany
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Abstract
The development of regulatory T (Treg) cells is essential for the maintenance of immune tolerance and homeostasis. Here, we review recent studies that have advanced our understanding of Treg cell differentiation. In the thymus, TCR specificity to self-antigen appears to be a primary determinant for Treg cell lineage commitment, with c-Rel being an important factor that links T cell receptor (TCR) engagement and Foxp3 expression, along with cytokines and costimulatory molecules. It is also clear that postthymic events shape the peripheral Treg cell population. This includes preferential maintenance of Treg cells specific to self-antigens presented in the periphery, as well as the de novo generation of Treg cells from conventional Foxp3(-) T cells. The process of peripheral Treg cell differentiation shares some features with thymic Treg cell development, but there are notable differences. Together, thymic and peripheral Treg cell differentiation appear to generate an "imprint" of both self- and foreign antigens in the peripheral Treg cell population to provide dominant tolerance.
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Affiliation(s)
- Hyang-Mi Lee
- Department of Internal Medicine, Division of Rheumatology, Washington University in St. Louis, St. Louis, Missouri, USA
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Bunting MD, Comerford I, McColl SR. Finding their niche: chemokines directing cell migration in the thymus. Immunol Cell Biol 2010; 89:185-96. [PMID: 21135866 DOI: 10.1038/icb.2010.142] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
T lymphocytes are generated throughout life, arising from bone marrow-derived progenitors that complete an essential developmental process in the thymus. Thymic T cell education leads to the generation of a self-restricted and largely self-tolerant peripheral T-cell pool and is facilitated by interactions with thymic stromal cells residing in distinct supportive niches. The signals governing thymocyte precursor migration into the thymus, directing thymocyte navigation through thymic microenvironments and mature T-cell egress into circulation were, until recently, largely unknown, but presumed to be mediated to a large extent by chemokine signalling. Recent studies have now uncovered various specific functions for members of the chemokine superfamily in the thymus. These studies have not only revealed distinct but also in some cases overlapping roles for several chemokine family members in various thymocyte migration events and have also shown that homing and positioning of other cells in the thymus, such as dendritic cells and natural killer T cells is also chemokine-dependent. Here, we discuss current understanding of the role of chemokines in the thymus and highlight key future avenues for investigation in this field.
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Affiliation(s)
- Mark D Bunting
- Chemokine Biology Laboratory, Discipline of Microbiology and Immunology, The School of Molecular and Biomedical Science, The University of Adelaide, South Australia, Australia
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del Rio R, Sun Y, Alard P, Tung KSK, Teuscher C. H2 control of natural T regulatory cell frequency in the lymph node correlates with susceptibility to day 3 thymectomy-induced autoimmune disease. THE JOURNAL OF IMMUNOLOGY 2010; 186:382-9. [PMID: 21135167 DOI: 10.4049/jimmunol.1002110] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Day 3 thymectomy (D3Tx) results in a loss of peripheral tolerance mediated by natural regulatory T cells (nTregs) and development of autoimmune ovarian dysgenesis (AOD) and autoimmune dacryoadenitis (ADA) in A/J and (C57BL/6J × A/J) F(1) hybrids (B6A), but not in C57BL/6J (B6) mice. Previously, using quantitative trait locus (QTL) linkage analysis, we showed that D3Tx-AOD is controlled by five unlinked QTL (Aod1-Aod5) and H2. In this study, using D3Tx B6-Chr(A/J)/NaJ chromosome (Chr) substitution strains, we confirm that QTL on Chr16 (Aod1a/Aod1b), Chr3 (Aod2), Chr1 (Aod3), Chr2 (Aod4), Chr7 (Aod5), and Chr17 (H2) control D3Tx-AOD susceptibility. In addition, we also present data mapping QTL controlling D3Tx-ADA to Chr17 (Ada1/H2), Chr1 (Ada2), and Chr3 (Ada3). Importantly, B6-ChrX(A/J) mice were as resistant to D3Tx-AOD and D3Tx-ADA as B6 mice, thereby excluding Foxp3 as a susceptibility gene in these models. Moreover, we report quantitative differences in the frequency of nTregs in the lymph nodes (LNs), but not spleen or thymus, of AOD/ADA-resistant B6 and AOD/ADA-susceptible A/J, B6A, and B6-Chr17(A/J) mice. Similar results correlating with experimental allergic encephalomyelitis and orchitis susceptibility were seen with B10.S and SJL/J mice. Using H2-congenic mice, we show that the observed difference in frequency of LN nTregs is controlled by Ada1/H2. These data support the existence of an LN-specific, H2-controlled mechanism regulating the prevalence of nTregs in autoimmune disease susceptibility.
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Affiliation(s)
- Roxana del Rio
- Department of Medicine, University of Vermont, Burlington, VT 05405, USA
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Abstract
Natural regulatory T cells (nTregs) are defined by their inherent ability to establish and maintain peripheral self-tolerance. In recent years, the development of nTregs has come under close examination with the advent of Forkhead Box P3 protein (FOXP3)-green fluorescent protein reporter mice that pinpointed the initiation of FOXP3 expression within the thymus. The mechanism and pathway of nTreg development has only recently been studied in detail and to a large degree remains unclear. In this review, we will discuss our current understanding of nTreg lineage choice and development from a cellular and intracellular standpoint.
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Affiliation(s)
- Matthew L Bettini
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105-3678, USA
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Atibalentja DF, Byersdorfer CA, Unanue ER. Thymus-blood protein interactions are highly effective in negative selection and regulatory T cell induction. THE JOURNAL OF IMMUNOLOGY 2010; 183:7909-18. [PMID: 19933868 DOI: 10.4049/jimmunol.0902632] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Using hen egg-white lysozyme, the effect of blood proteins on CD4 thymic cells was examined. A small fraction of i.v. injected hen egg-white lysozyme rapidly entered the thymus into the medulla. There it was captured and presented by dendritic cells (DCs) to thymocytes from two TCR transgenic mice, one directed to a dominant peptide and a second to a poorly displayed peptide, both presented by MHC class II molecules I-A(k). Presentation by DC led to negative selection and induction of regulatory T cells, independent of epithelial cells. Presentation took place at very low levels, less than 100 peptide-MHC complexes per DC. Such low levels could induce negative selection, but even lower levels could induce regulatory T cells. The anatomy of the thymus-blood barrier, the highly efficient presentation by DC, together with the high sensitivity of thymic T cells to peptide-MHC complexes, results in blood protein Ags having a profound effect on thymic T cells.
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Affiliation(s)
- Danielle F Atibalentja
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA
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Nunes‐Cabaço H, Ribot JC, Caramalho Í, Serra‐Caetano A, Silva‐Santos B, Sousa AE. Foxp3 induction in human and murine thymus precedes the CD4
+
CD8
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stage but requires early T‐cell receptor expression. Immunol Cell Biol 2010; 88:523-8. [DOI: 10.1038/icb.2010.4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Helena Nunes‐Cabaço
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa Lisboa Portugal
| | - Julie C Ribot
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa Lisboa Portugal
- Instituto Gulbenkian de Ciência Oeiras Portugal
| | - Íris Caramalho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa Lisboa Portugal
| | - Ana Serra‐Caetano
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa Lisboa Portugal
| | - Bruno Silva‐Santos
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa Lisboa Portugal
- Instituto Gulbenkian de Ciência Oeiras Portugal
| | - Ana E Sousa
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa Lisboa Portugal
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Thymic selection and lineage commitment of CD4(+)Foxp3(+) regulatory T lymphocytes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2010; 92:251-77. [PMID: 20800824 DOI: 10.1016/s1877-1173(10)92010-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Regulatory T lymphocytes play a central role in the control of a variety of immune-responses. Their absence in humans and in experimental animal models leads to severe autoimmune and inflammatory disorders. Consistent with their major role in prevention of autoimmune pathology, their repertoire is enriched in autospecific cells. Probably the majority of regulatory T cells develop in the thymus. How T cell-precursors choose between the conventional versus regulatory T cell lineages remains an unanswered question. More is known about selection of regulatory T cell precursors. Positive selection of these cells is favored by high affinity interactions with MHC class II/peptide ligands expressed by thymic epithelial or dendritic cells. They are also known to be relatively resistant to negative selection. These two parameters allow for the generation of the autoreactive regulatory T cell repertoire, and clearly distinguish selection-criteria of conventional versus regulatory T cell-precursors. It will now be important to elucidate the molecular mechanisms involved in the intrathymic choice of the regulatory T cell-lineage.
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Lee HM, Hsieh CS. Rare development of Foxp3+ thymocytes in the CD4+CD8+ subset. THE JOURNAL OF IMMUNOLOGY 2009; 183:2261-6. [PMID: 19620303 DOI: 10.4049/jimmunol.0901304] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The CD4(+)CD8(+) (double positive, DP) stage of thymic development is thought to be the earliest period that generates natural Foxp3(+) regulatory T (Treg) cells important for the prevention of autoimmunity. However, we found that most Foxp3(+) DP cells identified by routine flow cytometry represent doublets comprised of Foxp3(-) DP and Foxp3(+) CD4(+)CD8(-) (CD4SP) cells. This was determined using analysis of flow cytometric height and width parameters, postsort contaminants, and thymocyte mixing studies. Temporal analysis of Treg cell development arising from bone marrow precursors in neonatal bone marrow chimeras suggested that Foxp3(+) DP cells are not a major percentage of Foxp3(+) thymocytes, and it supported the notion that most Treg cell development occurred at the immature HSA(high) CD4SP stage. Thus, these data demonstrate that the frequency of Foxp3(+) cells generated at the DP stage is much smaller than previously recognized, suggesting that additional thymocyte maturation may be required to facilitate efficient induction of Foxp3.
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Affiliation(s)
- Hyang Mi Lee
- Department of Internal Medicine, Division of Rheumatology, Washington University, St Louis, MO 63110, USA
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Regulatory T cell differentiation of thymocytes does not require a dedicated antigen-presenting cell but is under T cell-intrinsic developmental control. Proc Natl Acad Sci U S A 2009; 106:10278-83. [PMID: 19515822 DOI: 10.1073/pnas.0901877106] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The majority of regulatory T cells (T(regs)) are believed to be of thymic origin. It has been hypothesized that this may result from unique intrathymic environmental cues, possibly requiring a dedicated antigen-presenting cell (APC). However, T cell-intrinsic developmental regulation of the susceptibility to T(reg) differentiation remains a mutually non-exclusive scenario. We found that upon exposure of monoclonal T cells of sequential developmental stages to a thymic microenvironment expressing cognate antigen, the efficiency of T(reg) induction inversely correlated with progressive maturation. This inclination of immature thymocytes toward T(reg) differentiation was even seen in an APC-free in vitro system, providing only TCR stimulation and IL-2. In support of quantitative but not qualitative features of external cues being critical, thymic epithelial cells as well as different thymic dendritic cell (DC)-subtypes efficiently induced T(reg) development of immature thymocytes, albeit at strikingly different optimal doses of cognate antigen. We propose that the intrinsically high predisposition of immature thymocytes to T(reg) development may contribute to the predominantly thymic origin of the T(reg) repertoire. The underlying instructive stimulus, however, does not require unique features of a dedicated APC and can be delivered by hematopoietic as well as epithelial thymic stromal cells.
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Abstract
A pool of immature T cells with a seemingly unrestricted repertoire of antigen specificities is generated life-long in the thymus. Amongst these cells are, however, thymocytes that express a strongly self-reactive antigen receptor and hence hold the potential to trigger autoimmunity. To prevent such an outcome, the thymus employs several independent but functionally related strategies that act in parallel to enforce self-tolerance. The deletion of strongly self-reactive thymocytes and the generation of regulatory T cells constitute the two most efficient mechanisms to induce and maintain immunological tolerance. Thymic epithelial cells of the medulla express for this purpose tissue-restricted self-antigens. This review will focus on the cellular and molecular mechanisms operative in the thymus to shape a repertoire of mature T cells tolerant to self-antigens.
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Affiliation(s)
- G A Holländer
- Department of Clinical-Biological Sciences, Laboratory of Pediatric Immunology, Center for Biomedicine, University of Basel and The University Children's Hospital, Switzerland.
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Ohnmacht C, Pullner A, King SBS, Drexler I, Meier S, Brocker T, Voehringer D. Constitutive ablation of dendritic cells breaks self-tolerance of CD4 T cells and results in spontaneous fatal autoimmunity. ACTA ACUST UNITED AC 2009; 206:549-59. [PMID: 19237601 PMCID: PMC2699126 DOI: 10.1084/jem.20082394] [Citation(s) in RCA: 439] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Lack of immunological tolerance against self-antigens results in autoimmune disorders. During onset of autoimmunity, dendritic cells (DCs) are thought to be critical for priming of self-reactive T cells that have escaped tolerance induction. However, because DCs can also induce T cell tolerance, it remains unclear whether DCs are required under steady-state conditions to prevent autoimmunity. To address this question, we crossed CD11c-Cre mice with mice that express diphtheria toxin A (DTA) under the control of a loxP-flanked neomycin resistance (neoR) cassette from the ROSA26 locus. Cre-mediated removal of the neoR cassette leads to DTA expression and constitutive loss of conventional DCs, plasmacytoid DCs, and Langerhans cells. These DC-depleted (ΔDC) mice showed increased frequencies of CD4 single-positive thymocytes and infiltration of CD4 T cells into peripheral tissues. They developed spontaneous autoimmunity characterized by reduced body weight, splenomegaly, autoantibody formation, neutrophilia, high numbers of Th1 and Th17 cells, and inflammatory bowel disease. Pathology could be induced by reconstitution of wild-type (WT) mice with bone marrow (BM) from ΔDC mice, whereas mixed BM chimeras that received BM from ΔDC and WT mice remained healthy. This demonstrates that DCs play an essential role to protect against fatal autoimmunity under steady-state conditions.
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Affiliation(s)
- Caspar Ohnmacht
- Institute for Immunology, Department of Medicine, University of Munich, 80336 Munich, Germany
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Abstract
The CD4(+) CD25(+) regulatory population of T cells (Treg cells), which expresses the forkhead family transcription factor (Foxp3), is the key component of the peripheral tolerance mechanism that protects us from a variety of autoimmune diseases. Experimental evidence shows that Treg cells recognize a wide range of antigenic specificities with increased reactivity to self antigens, although the affinity of these interactions remains to be further defined. The Treg repertoire is highly diverse with a distinct set of T-cell receptors (TCRs), and yet is overlapping to some extent with the repertoire of conventional T cells (Tconv cells). The majority of Treg cells are generated in the thymus. However, the role of the TCR specificity in directing thymic precursors to become Treg or Tconv cells remains unclear. On the one hand, the higher self reactivity of Treg cells and utilization of different TCRs in Treg and Tconv repertoires suggest that in TCR interactions an initial decision is made about the 'suitability' of a developing thymocyte to become a Treg cell. On the other hand, as Treg cells can recognize a wide range of foreign antigens, have a diverse TCR repertoire, and show some degree of overlap with Tconv cells, the signals through the TCR may be complementary to the TCR-independent process that generates precursors of Treg cells. In this review, we discuss how different features of the Treg repertoire influence our understanding of Treg specificities and the role of self reactivity in the generation of this population.
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Affiliation(s)
- Rafal Pacholczyk
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta, 30912-2400, USA.
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Sharma R, Ju ACY, Kung JT, Fu SM, Ju ST. Rapid and selective expansion of nonclonotypic T cells in regulatory T cell-deficient, foreign antigen-specific TCR-transgenic scurfy mice: antigen-dependent expansion and TCR analysis. THE JOURNAL OF IMMUNOLOGY 2008; 181:6934-41. [PMID: 18981113 DOI: 10.4049/jimmunol.181.10.6934] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Foreign Ag-specific TCR-transgenic (Tg) mice contain a small fraction of T cells bearing the endogenous Vbeta and Valpha chains as well as a population expressing an intermediate level of Tg TCR. Importantly, these minor nonclonotypic populations contain > or = 99% of the CD4(+)Foxp3(+) regulatory T cells (Treg) and, despite low overall Treg expression, peripheral tolerance is maintained. In the OT-II TCR (OVA-specific, Vbeta5(high)Valpha2(high)) Tg scurfy (Sf) mice (OT-II Sf) that lack Treg, nonclonotypic T cells markedly expanded in the periphery but not in the thymus. Expanded T cells expressed memory/effector phenotype and were enriched in blood and inflamed lungs. In contrast, Vbeta5(high)Valpha2(high) clonotypic T cells were not expanded, displayed the naive phenotype, and found mainly in the lymph nodes. Importantly, Vbeta5(neg) T cells were able to transfer multiorgan inflammation in Rag1(-/-) recipients. T cells bearing dual TCR (dual Vbeta or dual Valpha) were demonstrated frequently in the Vbeta5(int) and Valpha2(int) populations. Our study demonstrated that in the absence of Treg, the lack of peripheral expansion of clonotypic T cells is due to the absence of its high-affinity Ag OVA. Thus, the rapid expansion of nonclonotypic T cells in OT-II Sf mice must require Ag (self and foreign) with sufficient affinity. Our study has implications with respect to the roles of Ag and dual TCR in the selection and regulation of Treg and Treg-controlled Ag-dependent T cell expansion in TCR Tg and TCR Tg Sf mice, respectively.
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Affiliation(s)
- Rahul Sharma
- Department of Medicine, Center for Immunity, Inflammation and Regenerative Medicine, University of Virginia, Charlottesville, VA 22908, USA
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Frericks M, Burgoon LD, Zacharewski TR, Esser C. Promoter analysis of TCDD-inducible genes in a thymic epithelial cell line indicates the potential for cell-specific transcription factor crosstalk in the AhR response. Toxicol Appl Pharmacol 2008; 232:268-79. [DOI: 10.1016/j.taap.2008.07.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Revised: 06/20/2008] [Accepted: 07/07/2008] [Indexed: 12/19/2022]
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Abstract
Regulatory Foxp3(+) T cells (T(R)) are indispensable for preventing autoimmune pathology in multiple organs and tissues. During thymic differentiation T cell receptor (TCR)-ligand interactions within a certain increased affinity range, in conjunction with gammac-containing cytokine receptor signals, induce Foxp3 expression and thereby commit developing thymocytes to the T(R) lineage. The contribution of distinct MHC class II-expressing accessory cell types to the differentiation process of Foxp3(+) thymocytes remains controversial, because a unique role in this process has been ascribed to either thymic dendritic cells (tDC) or to medullary thymic epithelial cells (mTEC). Furthermore, it was suggested that the thymic medulla, where the bulk of the negative selection of self-reactive thymocytes takes place, provides a specialized microenvironment supporting T(R) differentiation. Here, we report that the cortex, as defined by cortical thymic epithelial cells (cTEC), is sufficient for supporting T(R) differentiation. MHC class II expression restricted to both cTEC and mTEC or to cTEC alone did not significantly affect the numbers of Foxp3(+) thymocytes. Furthermore, genetic or pharmacologic blockade of thymocyte migration resulted in a prominent accumulation of Foxp3(+) thymocytes in the cortex, demonstrating that secondary signals required for Foxp3 up-regulation exist in the cortex. Our results suggest that mTEC or tDC do not serve as a cell type singularly responsible for T(R) differentiation and that neither the cortex nor the medulla exclusively provides an environment suitable for Foxp3 induction. Instead, multiple accessory cell types probably contribute to the thymic generation of regulatory Foxp3(+) T cells.
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Yu P, Haymaker CL, Divekar RD, Ellis JS, Hardaway J, Jain R, Tartar DM, Hoeman CM, Cascio JA, Ostermeier A, Zaghouani H. Fetal exposure to high-avidity TCR ligand enhances expansion of peripheral T regulatory cells. THE JOURNAL OF IMMUNOLOGY 2008; 181:73-80. [PMID: 18566371 DOI: 10.4049/jimmunol.181.1.73] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Lately, it has become clear that regulatory T cells (Tregs) play a major role in the maintenance of peripheral tolerance and control of autoimmunity. Despite these critical functions, the process underlying the development of Tregs remains largely undefined. Herein, altered peptide ligand (APL) variants derived from the proteolipid protein-1 (PLP1) epitope were expressed on immunoglobulins (Igs) and the resulting Ig-APLs were used to deliver the APLs from mother to fetus through the maternal placenta to influence thymic T cell selection. This delivery system was then adapted to the SJL/J mouse, a strain that expresses only the DM20 form of PLP, which lacks the dominant PLP1 epitope in the thymus during fetal and neonatal development. This model, which restores thymic T cell selection for PLP1, was then used to determine whether affinity plays a role in the development of Tregs. The findings show that fetal exposure to low-affinity peptide ligand was unable to drive development of Tregs while variants with higher affinity to the TCR resulted in significant seeding of the periphery with mature, naive Tregs. Thus, contrary to pathogenic T cells, Tregs require avid TCR-ligand interaction to undergo thymic development and maturation.
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Affiliation(s)
- Ping Yu
- Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine, Columbia, MD 65212, USA
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