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Xing Q, Chang D, Xie S, Zhao X, Zhang H, Wang X, Bai X, Dong C. BCL6 is required for the thymic development of TCRαβ +CD8αα + intraepithelial lymphocyte lineage. Sci Immunol 2024; 9:eadk4348. [PMID: 38335269 DOI: 10.1126/sciimmunol.adk4348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 12/13/2023] [Indexed: 02/12/2024]
Abstract
TCRαβ+CD8αα+ intraepithelial lymphocytes (CD8αα+ αβ IELs) are a specialized subset of T cells in the gut epithelium that develop from thymic agonist selected IEL precursors (IELps). The molecular mechanisms underlying the selection and differentiation of this T cell type in the thymus are largely unknown. Here, we found that Bcl6 deficiency in αβ T cells resulted in the near absence of CD8αα+ αβ IELs. BCL6 was expressed by approximately 50% of CD8αα+ αβ IELs and by the majority of thymic PD1+ IELps after agonist selection. Bcl6 deficiency blocked early IELp generation in the thymus, and its expression in IELps was induced by thymic TCR signaling in an ERK-dependent manner. As a result of Bcl6 deficiency, the precursors of IELps among CD4+CD8+ double-positive thymocytes exhibited increased apoptosis during agonist selection and impaired IELp differentiation and maturation. Together, our results elucidate BCL6 as a crucial transcription factor during the thymic development of CD8αα+ αβ IELs.
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Affiliation(s)
- Qi Xing
- Shanghai Immune Therapy Institute, New Cornerstone Science Laboratory, Shanghai Jiao Tong University School of Medicine-affiliated Renji Hospital, Shanghai 200127, China
- Institute for Immunology and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Dehui Chang
- Institute for Immunology and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Shiyuan Xie
- Institute for Advanced Interdisciplinary Studies and Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, Peking University, Beijing 100084, China
| | - Xiaohong Zhao
- Institute for Immunology and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Hao Zhang
- Institute for Immunology and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Xiaohu Wang
- Institute for Immunology and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Xue Bai
- Institute for Immunology and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Chen Dong
- Shanghai Immune Therapy Institute, New Cornerstone Science Laboratory, Shanghai Jiao Tong University School of Medicine-affiliated Renji Hospital, Shanghai 200127, China
- Research Unit of Immune Regulation and Immune Diseases of Chinese Academy of Medical Sciences, Shanghai Jiao Tong University School of Medicine-Affiliated Renji Hospital, Shanghai 200127, China
- Westlake University School of Medicine-affiliated Hangzhou First Hospital, Hangzhou 310024, China
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2
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Saleki K, Alijanizadeh P, Javanmehr N, Rezaei N. The role of Toll-like receptors in neuropsychiatric disorders: Immunopathology, treatment, and management. Med Res Rev 2024; 44:1267-1325. [PMID: 38226452 DOI: 10.1002/med.22012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 10/20/2023] [Accepted: 12/20/2023] [Indexed: 01/17/2024]
Abstract
Neuropsychiatric disorders denote a broad range of illnesses involving neurology and psychiatry. These disorders include depressive disorders, anxiety, schizophrenia, bipolar disorder, attention deficit hyperactivity disorder, autism spectrum disorders, headaches, and epilepsy. In addition to their main neuropathology that lies in the central nervous system (CNS), lately, studies have highlighted the role of immunity and neuroinflammation in neuropsychiatric disorders. Toll-like receptors (TLRs) are innate receptors that act as a bridge between the innate and adaptive immune systems via adaptor proteins (e.g., MYD88) and downstream elements; TLRs are classified into 13 families that are involved in normal function and illnesses of the CNS. TLRs expression affects the course of neuropsychiatric disorders, and is influenced during their pharmacotherapy; For example, the expression of multiple TLRs is normalized during the major depressive disorder pharmacotherapy. Here, the role of TLRs in neuroimmunology, treatment, and management of neuropsychiatric disorders is discussed. We recommend longitudinal studies to comparatively assess the cell-type-specific expression of TLRs during treatment, illness progression, and remission. Also, further research should explore molecular insights into TLRs regulation and related pathways.
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Affiliation(s)
- Kiarash Saleki
- Student Research Committee, Babol University of Medical Sciences, Babol, Iran
- USERN Office, Babol University of Medical Sciences, Babol, Iran
- Department of e-Learning, Virtual School of Medical Education and Management, Shahid Beheshti University of Medical Sciences (SBMU), Tehran, Iran
| | - Parsa Alijanizadeh
- Student Research Committee, Babol University of Medical Sciences, Babol, Iran
- USERN Office, Babol University of Medical Sciences, Babol, Iran
| | - Nima Javanmehr
- Student Research Committee, Babol University of Medical Sciences, Babol, Iran
- USERN Office, Babol University of Medical Sciences, Babol, Iran
| | - Nima Rezaei
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
- Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Tehran, Iran
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3
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Tai X, Indart A, Rojano M, Guo J, Apenes N, Kadakia T, Craveiro M, Alag A, Etzensperger R, Badr ME, Zhang F, Zhang Z, Mu J, Guinter T, Crossman A, Granger L, Sharrow S, Zhou X, Singer A. How autoreactive thymocytes differentiate into regulatory versus effector CD4 + T cells after avoiding clonal deletion. Nat Immunol 2023; 24:637-651. [PMID: 36959291 PMCID: PMC10063450 DOI: 10.1038/s41590-023-01469-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 02/14/2023] [Indexed: 03/25/2023]
Abstract
Thymocytes bearing autoreactive T cell receptors (TCRs) are agonist-signaled by TCR/co-stimulatory molecules to either undergo clonal deletion or to differentiate into specialized regulatory T (Treg) or effector T (Teff) CD4+ cells. How these different fates are achieved during development remains poorly understood. We now document that deletion and differentiation are agonist-signaled at different times during thymic selection and that Treg and Teff cells both arise after clonal deletion as alternative lineage fates of agonist-signaled CD4+CD25+ precursors. Disruption of agonist signaling induces CD4+CD25+ precursors to initiate Foxp3 expression and become Treg cells, whereas persistent agonist signaling induces CD4+CD25+ precursors to become IL-2+ Teff cells. Notably, we discovered that transforming growth factor-β induces Foxp3 expression and promotes Treg cell development by disrupting weaker agonist signals and that Foxp3 expression is not induced by IL-2 except under non-physiological in vivo conditions. Thus, TCR signaling disruption versus persistence is a general mechanism of lineage fate determination in the thymus that directs development of agonist-signaled autoreactive thymocytes.
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Affiliation(s)
- Xuguang Tai
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Alyssa Indart
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Mirelle Rojano
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jie Guo
- Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Nicolai Apenes
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Tejas Kadakia
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Marco Craveiro
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Amala Alag
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ruth Etzensperger
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Mohamed Elsherif Badr
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Flora Zhang
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Zhongmei Zhang
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jie Mu
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Terry Guinter
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Assiatu Crossman
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Larry Granger
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Susan Sharrow
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Xuyu Zhou
- Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Alfred Singer
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
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4
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Ohigashi I, Takahama Y. Thymoproteasome optimizes positive selection of CD8 + T cells without contribution of negative selection. Adv Immunol 2021; 149:1-23. [PMID: 33993918 DOI: 10.1016/bs.ai.2021.03.001] [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] [Indexed: 01/03/2023]
Abstract
Functionally competent and self-tolerant T cell repertoire is shaped through positive and negative selection in the cortical and medullary microenvironments of the thymus. The thymoproteasome specifically expressed in the cortical thymic epithelium is essential for the optimal generation of CD8+ T cells. Although how the thymoproteasome governs the generation of CD8+ T cells is not fully understood, accumulating evidence suggests that the thymoproteasome optimizes CD8+ T cell production through the processing of self-peptides associated with MHC class I molecules expressed by cortical thymic epithelial cells. In this review, we describe recent advances in the mechanism of thymoproteasome-dependent generation of CD8+ T cells, focusing on the process of cortical positive selection independent of apoptosis-mediated negative selection.
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Affiliation(s)
- Izumi Ohigashi
- Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima, Japan
| | - Yousuke Takahama
- Thymus Biology Section, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States.
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5
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Lee ST, Georgiev H, Breed ER, Ruscher R, Hogquist KA. MHC Class I on murine hematopoietic APC selects Type A IEL precursors in the thymus. Eur J Immunol 2021; 51:1080-1088. [PMID: 33521937 PMCID: PMC9846822 DOI: 10.1002/eji.202048996] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/06/2020] [Accepted: 01/29/2021] [Indexed: 01/21/2023]
Abstract
TCRαβ+ CD8α+ CD8β- intestinal intraepithelial lymphocytes (CD8αα IEL) are gut T cells that maintain barrier surface homeostasis. Most CD8αα IEL are derived from thymic precursors (IELp) through a mechanism referred to as clonal diversion. In this model, self-reactive thymocytes undergo deletion in the presence of CD28 costimulation, but in its absence undergo diversion to the IEL fate. While previous reports showed that IELp were largely β2m dependent, the APC that drive the development of these cells are poorly defined. We found that both CD80 and CD86 restrain IELp development, and conventional DCs play a prominent role. We sought to define a CD80/86 negative, MHCI positive APC that supports the development to the IEL lineage. Chimera studies showed that MHCI needs to be expressed on hematopoietic APC for selection. As thymic hematopoietic APC are heterogeneous in their expression of MHCI and costimulatory molecules, we identified four thymic APC types that were CD80/86neg/low and MHCI+ . However, selective depletion of β2m in individual APC suggested functional redundancy. Thus, while hematopoietic APC play a critical role in clonal diversion, no single APC subset is specialized to promote the CD8αα IEL fate.
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Affiliation(s)
| | | | | | - Roland Ruscher
- Corresponding authors: Kristin Hogquist, , Roland Ruscher,
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7
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Du X, Tang F, Liu M, Su J, Zhang Y, Wu W, Devenport M, Lazarski CA, Zhang P, Wang X, Ye P, Wang C, Hwang E, Zhu T, Xu T, Zheng P, Liu Y. A reappraisal of CTLA-4 checkpoint blockade in cancer immunotherapy. Cell Res 2018; 28:416-432. [PMID: 29472691 PMCID: PMC5939050 DOI: 10.1038/s41422-018-0011-0] [Citation(s) in RCA: 164] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 12/11/2017] [Accepted: 12/20/2017] [Indexed: 12/13/2022] Open
Abstract
It is assumed that anti-CTLA-4 antibodies cause tumor rejection by blocking negative signaling from B7-CTLA-4 interactions. Surprisingly, at concentrations considerably higher than plasma levels achieved by clinically effective dosing, the anti-CTLA-4 antibody Ipilimumab blocks neither B7 trans-endocytosis by CTLA-4 nor CTLA-4 binding to immobilized or cell-associated B7. Consequently, Ipilimumab does not increase B7 on dendritic cells (DCs) from either CTLA4 gene humanized (Ctla4h/h) or human CD34+ stem cell-reconstituted NSG™ mice. In Ctla4h/m mice expressing both human and mouse CTLA4 genes, anti-CTLA-4 antibodies that bind to human but not mouse CTLA-4 efficiently induce Treg depletion and Fc receptor-dependent tumor rejection. The blocking antibody L3D10 is comparable to the non-blocking Ipilimumab in causing tumor rejection. Remarkably, L3D10 progenies that lose blocking activity during humanization remain fully competent in inducing Treg depletion and tumor rejection. Anti-B7 antibodies that effectively block CD4 T cell activation and de novo CD8 T cell priming in lymphoid organs do not negatively affect the immunotherapeutic effect of Ipilimumab. Thus, clinically effective anti-CTLA-4 mAb causes tumor rejection by mechanisms that are independent of checkpoint blockade but dependent on the host Fc receptor. Our data call for a reappraisal of the CTLA-4 checkpoint blockade hypothesis and provide new insights for the next generation of safe and effective anti-CTLA-4 mAbs.
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Affiliation(s)
- Xuexiang Du
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Health System, Washington, DC, 20010, USA
| | - Fei Tang
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Health System, Washington, DC, 20010, USA
| | - Mingyue Liu
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Health System, Washington, DC, 20010, USA
| | - Juanjuan Su
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Health System, Washington, DC, 20010, USA
| | - Yan Zhang
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Health System, Washington, DC, 20010, USA
| | - Wei Wu
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Health System, Washington, DC, 20010, USA
| | | | - Christopher A Lazarski
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Health System, Washington, DC, 20010, USA
| | - Peng Zhang
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Health System, Washington, DC, 20010, USA
| | - Xu Wang
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Health System, Washington, DC, 20010, USA
| | - Peiying Ye
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Health System, Washington, DC, 20010, USA
| | | | - Eugene Hwang
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Health System, Washington, DC, 20010, USA
| | - Tinghui Zhu
- Alphamab, Inc., Suzhou, Jiangsu, 215125, China
| | - Ting Xu
- Alphamab, Inc., Suzhou, Jiangsu, 215125, China
| | - Pan Zheng
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Health System, Washington, DC, 20010, USA. .,OncoImmune, Inc., Rockville, MD, 20852, USA.
| | - Yang Liu
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Health System, Washington, DC, 20010, USA.,OncoImmune, Inc., Rockville, MD, 20852, USA
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8
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Uri A, Werner S, Lühder F, Hünig T, Kerkau T, Beyersdorf N. Protection of Mice from Acute Graft-versus-Host Disease Requires CD28 Co-stimulation on Donor CD4 + Foxp3 + Regulatory T Cells. Front Immunol 2017; 8:721. [PMID: 28690612 PMCID: PMC5481316 DOI: 10.3389/fimmu.2017.00721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 06/06/2017] [Indexed: 12/20/2022] Open
Abstract
Acute graft-versus-host disease (aGvHD) is a major cause of morbidity and mortality after allogeneic hematopoietic stem cell plus T cell transplantation (allo-HSCT). In this study, we investigated the requirement for CD28 co-stimulation of donor CD4+ conventional (CD4+CD25-Foxp3-, Tconv) and regulatory (CD4+CD25+Foxp3+, Treg) T cells in aGvHD using tamoxifen-inducible CD28 knockout (iCD28KO) or wild-type (wt) littermates as donors of CD4+ Tconv and Treg. In the highly inflammatory C57BL/6 into BALB/c allo-HSCT transplantation model, CD28 depletion on donor CD4+ Tconv reduced clinical signs of aGvHD, but did not significantly prolong survival of the recipient mice. Selective depletion of CD28 on donor Treg did not abrogate protection of recipient mice from aGvHD until about day 20 after allo-HSCT. Later, however, the pool of CD28-depleted Treg drastically declined as compared to wt Treg. Consequently, only wt, but not CD28-deficient, Treg were able to continuously suppress aGvHD and induce long-term survival of the recipient mice. To our knowledge, this is the first study that specifically evaluates the impact of CD28 expression on donor Treg in aGvHD. Moreover, the delayed kinetics of aGvHD lethality after transplantation of iCD28KO Treg provides a novel animal model for similar disease courses found in patients after allo-HSCT.
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Affiliation(s)
- Anna Uri
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Sandra Werner
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Fred Lühder
- Institute for Multiple Sclerosis Research and Neuroimmunology, University Medical Centre Göttingen, Göttingen, Germany
| | - Thomas Hünig
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Thomas Kerkau
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Niklas Beyersdorf
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
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Ishikura S, Ogawa M, Doi K, Matsuzaki H, Iwaihara Y, Tanaka Y, Tsunoda T, Hideshima H, Okamura T, Shirasawa S. Zfat-deficient CD4⁺ CD8⁺ double-positive thymocytes are susceptible to apoptosis with deregulated activation of p38 and JNK. J Cell Biochem 2016; 116:149-57. [PMID: 25169027 DOI: 10.1002/jcb.24954] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 08/22/2014] [Indexed: 11/08/2022]
Abstract
Zfat, which is a nuclear protein harboring an AT-hook domain and 18-repeats of C2H2 zinc-finger motif, is highly expressed in immune-related tissues, including the thymus and spleen. T cell specific deletion of the Zfat gene by crossing Zfat(f/f) mice with LckCre mice yields a significant reduction in the number of CD4(+) CD8(+) double-positive (DP) thymocytes. However, physiological role for Zfat in T cell development in the thymus remains unknown. Here, we found that Zfat-deficient DP thymocytes in Zfat(f/f)-LckCre mice were susceptible to apoptosis both at an unstimulated state and in response to T cell receptor (TCR)-stimulation. The phosphorylation levels of p38 and JNK were elevated in Zfat-deficient thymocytes at an unstimulated state with an enhanced phosphorylation of ATF2 and with an over-expression of Gadd45α⋅ On the other hand, the activation of JNK in the Zfat-deficient thymocytes, but not p38, was strengthened and prolonged in response to TCR-stimulation. All these results demonstrate that Zfat critically participates in the development of DP thymocytes through regulating the activities of p38 and JNK.
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Affiliation(s)
- Shuhei Ishikura
- Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan; Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka, Japan
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10
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Paterson AM, Lovitch SB, Sage PT, Juneja VR, Lee Y, Trombley JD, Arancibia-Cárcamo CV, Sobel RA, Rudensky AY, Kuchroo VK, Freeman GJ, Sharpe AH. Deletion of CTLA-4 on regulatory T cells during adulthood leads to resistance to autoimmunity. ACTA ACUST UNITED AC 2015; 212:1603-21. [PMID: 26371185 PMCID: PMC4577848 DOI: 10.1084/jem.20141030] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 08/11/2015] [Indexed: 12/31/2022]
Abstract
Paterson et al. demonstrate that, in contrast to CTLA-4 germline knockout mice, conditional deletion on T reg cells during adulthood confers protection from EAE and does not increase resistance to tumors. Cytotoxic T lymphocyte antigen-4 (CTLA-4) is an essential negative regulator of T cell responses. Germline Ctla4 deficiency is lethal, making investigation of the function of CTLA-4 on mature T cells challenging. To elucidate the function of CTLA-4 on mature T cells, we have conditionally ablated Ctla4 in adult mice. We show that, in contrast to germline knockout mice, deletion of Ctla4 during adulthood does not precipitate systemic autoimmunity, but surprisingly confers protection from experimental autoimmune encephalomyelitis (EAE) and does not lead to increased resistance to MC38 tumors. Deletion of Ctla4 during adulthood was accompanied by activation and expansion of both conventional CD4+Foxp3− (T conv) and regulatory Foxp3+ (T reg cells) T cell subsets; however, deletion of CTLA-4 on T reg cells was necessary and sufficient for protection from EAE. CTLA-4 deleted T reg cells remained functionally suppressive. Deletion of Ctla4 on T reg cells alone or on all adult T cells led to major changes in the Ctla4 sufficient T conv cell compartment, including up-regulation of immunoinhibitory molecules IL-10, LAG-3 and PD-1, thereby providing a compensatory immunosuppressive mechanism. Collectively, our findings point to a profound role for CTLA-4 on T reg cells in limiting their peripheral expansion and activation, thereby regulating the phenotype and function of T conv cells.
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Affiliation(s)
- Alison M Paterson
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115 Evergrande Center for Immunological Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115
| | - Scott B Lovitch
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115 Evergrande Center for Immunological Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115 Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115
| | - Peter T Sage
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115 Evergrande Center for Immunological Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115
| | - Vikram R Juneja
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115 Evergrande Center for Immunological Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115
| | - Youjin Lee
- Evergrande Center for Immunological Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115
| | - Justin D Trombley
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115 Evergrande Center for Immunological Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115
| | - Carolina V Arancibia-Cárcamo
- Translational Gastroenterology Unit, Nuffield Department of Clinical Medicine, Experimental Medicine Division, University of Oxford, Oxford OX3 9DU, England, UK
| | - Raymond A Sobel
- Department of Pathology, Stanford University, Stanford, CA 94304
| | - Alexander Y Rudensky
- Howard Hughes Medical Institute and Immunology Program, Sloan-Kettering Institute for Cancer Research; Ludwig Center at Memorial Sloan-Kettering Cancer Center, New York, NY 10065
| | - Vijay K Kuchroo
- Evergrande Center for Immunological Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115
| | - Gordon J Freeman
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115
| | - Arlene H Sharpe
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115 Evergrande Center for Immunological Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115
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11
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Williams JA, Tai X, Hodes RJ. CD28-CD80/86 and CD40-CD40L Interactions Promote Thymic Tolerance by Regulating Medullary Epithelial Cell and Thymocyte Development. Crit Rev Immunol 2015; 35:59-76. [PMID: 25746048 DOI: 10.1615/critrevimmunol.2015012501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Development and central tolerance of T lymphocytes in the thymus requires both TCR signals and collaboration with signals generated through costimulatory molecule interactions. In this review, we discuss the importance of CD28-CD80/86 and CD40-CD40L costimulatory interactions in promoting normal thymic development. This discussion includes roles in the generation of a normal thymic medulla, in the development of specific T-cells subsets, including iNKT and T regulatory cells, and in the generation of a tolerant mature T-cell repertoire. We discuss recent contributions to the understanding of CD28-CD80/86 and CD40-CD40L costimulatory interactions in thymic development, and we highlight the ways in which the many important roles mediated by these interactions collaborate to promote normal thymic development.
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Affiliation(s)
- Joy A Williams
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Xuguang Tai
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Richard J Hodes
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
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12
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Melichar HJ, Ross JO, Taylor KT, Robey EA. Stable interactions and sustained TCR signaling characterize thymocyte-thymocyte interactions that support negative selection. THE JOURNAL OF IMMUNOLOGY 2014; 194:1057-1061. [PMID: 25520400 DOI: 10.4049/jimmunol.1400169] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Negative selection is one of the primary mechanisms that render T cells tolerant to self. Thymic dendritic cells play an important role in negative selection, in line with their ability to induce migratory arrest and sustained TCR signals. Thymocytes themselves display self-peptide/MHC class I complexes, and although there is evidence that they can support clonal deletion, it is not clear whether they do so directly via stable cell-cell contacts and sustained TCR signals. In this study, we show that murine thymocytes can support surprisingly efficient negative selection of Ag-specific thymocytes. Furthermore, we observe that agonist-dependent thymocyte-thymocyte interactions occurred as stable, motile conjugates led by the peptide-presenting thymocyte and in which the trailing peptide-specific thymocyte exhibited persistent elevations in intracellular calcium concentration. These data confirm that self-Ag presentation by thymocytes is an additional mechanism to ensure T cell tolerance and further strengthen the correlation between stable cellular contacts, sustained TCR signals, and efficient negative selection.
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Affiliation(s)
- Heather J Melichar
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Jenny O Ross
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Kayleigh T Taylor
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Ellen A Robey
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
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Tinsley KW, Hong C, Luckey MA, Park JY, Kim GY, Yoon HW, Keller HR, Sacks AJ, Feigenbaum L, Park JH. Ikaros is required to survive positive selection and to maintain clonal diversity during T-cell development in the thymus. Blood 2013; 122:2358-68. [PMID: 23908463 PMCID: PMC3790506 DOI: 10.1182/blood-2012-12-472076] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 07/07/2013] [Indexed: 01/12/2023] Open
Abstract
The zinc-finger protein Ikaros is a key player in T-cell development and a potent tumor suppressor in thymocytes. To understand the molecular basis of its function, we disabled Ikaros activity in vivo using a dominant negative Ikaros transgene (DN-IkTg). In DN-IkTg mice, T-cell development was severely suppressed, and positively selected thymocytes clonally expanded, resulting in a small thymus with a heavily skewed T-cell receptor (TCR) repertoire. Notably, DN-IkTg induced vigorous proliferation concomitant to downregulation of antiapoptotic factor expression such as Bcl2. Ikaros activity was required during positive selection, and specifically at the CD4(+)CD8(lo) intermediate stage of thymocyte differentiation, where it prevented persistent TCR signals from inducing aberrant proliferation and expansion. In particular, DN-IkTg induced the accumulation of CD4 single-positive (SP) thymocytes with a developmentally transitional phenotype, and it imposed a developmental arrest accompanied by massive apoptosis. Thus, we identified an in vivo requirement for Ikaros function, which is to suppress the proliferative potential of persistent TCR signals and to promote the survival and differentiation of positively selected thymocytes.
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Affiliation(s)
- Kevin W Tinsley
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD; and
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CTLA-4 controls the thymic development of both conventional and regulatory T cells through modulation of the TCR repertoire. Proc Natl Acad Sci U S A 2012; 110:E221-30. [PMID: 23267099 DOI: 10.1073/pnas.1208573110] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4; CD152) is of pivotal importance for self-tolerance, with deficiency or unfavorable polymorphisms leading to autoimmune disease. Tolerance to self-antigens is achieved through thymic deletion of highly autoreactive conventional T (Tconv) cells and generation of FoxP3(+) regulatory T (Treg) cells. The main costimulatory molecule, CD28, augments the negative selection of Tconv cells and promotes the generation of FoxP3(+) Treg cells. The role of its antagonistic homolog CTLA-4, however, remains a topic of debate. To address this topic, we investigated the thymic development of T cells in the presence and absence of CTLA-4 in a T-cell receptor (TCR) transgenic mouse model specific for the myelin basic protein peptide Ac1-9. We reveal that CTLA-4 is expressed in the corticomedullary region of the thymus. Its absence alters the response of CD4(+)CD8(-) thymocytes to self-antigen recognition, which affects the quantity of the Treg cells generated and broadens the repertoire of peripheral Tconv cells. T-cell repertoire alteration after deletion of CTLA-4 results from changes in TCR Vα and Jα segment selection as well as CDR3α composition in Tconv and Treg cells. CTLA-4, therefore, regulates the early development of self-reactive T cells in the thymus and plays a key role in central tolerance.
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Rybakin V, Gascoigne NRJ. Negative selection assay based on stimulation of T cell receptor transgenic thymocytes with peptide-MHC tetramers. PLoS One 2012; 7:e43191. [PMID: 22900100 PMCID: PMC3416795 DOI: 10.1371/journal.pone.0043191] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 07/20/2012] [Indexed: 02/04/2023] Open
Abstract
Thymocyte negative selection is a requirement for the development of self tolerance. Although it is possible to assay the induction of cell death in thymocytes in vitro using antibody cross-linking, this stimulus is much stronger than the normal range of T cell receptor ligands that could be encountered during normal development. Signaling in thymocytes is finely balanced between positive and negative selection stimuli, where a negative selecting ligand can be only marginally higher affinity than a positive selecting ligand. We have therefore developed an assay for the induction of negative selection that can distinguish such cases, and that is amenable to high-throughput analysis. The assay is based on the induction of activated caspase 3 in thymocytes expressing a defined T cell receptor, after stimulation with MHC-peptide tetramers in vitro for 24 hours or less.
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Affiliation(s)
- Vasily Rybakin
- Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail: (VR); (NRJG)
| | - Nicholas R. J. Gascoigne
- Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail: (VR); (NRJG)
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Cocco E, Meloni A, Murru MR, Corongiu D, Tranquilli S, Fadda E, Murru R, Schirru L, Secci MA, Costa G, Asunis I, Cuccu S, Fenu G, Lorefice L, Carboni N, Mura G, Rosatelli MC, Marrosu MG. Vitamin D responsive elements within the HLA-DRB1 promoter region in Sardinian multiple sclerosis associated alleles. PLoS One 2012; 7:e41678. [PMID: 22848563 PMCID: PMC3404969 DOI: 10.1371/journal.pone.0041678] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 06/24/2012] [Indexed: 12/22/2022] Open
Abstract
Vitamin D response elements (VDREs) have been found in the promoter region of the MS-associated allele HLA-DRB1*15:01, suggesting that with low vitamin D availability VDREs are incapable of inducing *15:01 expression allowing in early life autoreactive T-cells to escape central thymic deletion. The Italian island of Sardinia exhibits a very high frequency of MS and high solar radiation exposure. We test the contribution of VDREs analysing the promoter region of the MS-associated DRB1 *04:05, *03:01, *13:01 and *15:01 and non-MS-associated *16:01, *01, *11, *07:01 alleles in a cohort of Sardinians (44 MS patients and 112 healthy subjects). Sequencing of the DRB1 promoter region revealed a homozygous canonical VDRE in all *15:01, *16:01, *11 and in 45/73 *03:01 and in heterozygous state in 28/73 *03:01 and all *01 alleles. A new mutated homozygous VDRE was found in all *13:03, *04:05 and *07:01 alleles. Functionality of mutated and canonical VDREs was assessed for its potential to modulate levels of DRB1 gene expression using an in vitro transactivation assay after stimulation with active vitamin D metabolite. Vitamin D failed to increase promoter activity of the *04:05 and *03:01 alleles carrying the new mutated VDRE, while the *16:01 and *03:01 alleles carrying the canonical VDRE sequence showed significantly increased transcriptional activity. The ability of VDR to bind the mutant VDRE in the DRB1 promoter was evaluated by EMSA. Efficient binding of VDR to the VDRE sequence found in the *16:01 and in the *15:01 allele reduced electrophoretic mobility when either an anti-VDR or an anti-RXR monoclonal antibody was added. Conversely, the Sardinian mutated VDRE sample showed very low affinity for the RXR/VDR heterodimer. These data seem to exclude a role of VDREs in the promoter region of the DRB1 gene in susceptibility to MS carried by DRB1* alleles in Sardinian patients.
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Affiliation(s)
- Eleonora Cocco
- Centro Sclerosi Multipla, Dipartimento di Sanità pubblica, Medicina clinica e molecolare, University of Cagliari, Cagliari, Italy
| | - Alessandra Meloni
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche (CNR), Cagliari, Italy
| | - Maria Rita Murru
- Centro Sclerosi Multipla, Dipartimento di Sanità pubblica, Medicina clinica e molecolare, University of Cagliari, Cagliari, Italy
| | - Daniela Corongiu
- Centro Sclerosi Multipla, Dipartimento di Sanità pubblica, Medicina clinica e molecolare, University of Cagliari, Cagliari, Italy
| | - Stefania Tranquilli
- Centro Sclerosi Multipla, Dipartimento di Sanità pubblica, Medicina clinica e molecolare, University of Cagliari, Cagliari, Italy
| | - Elisabetta Fadda
- Centro Sclerosi Multipla, Dipartimento di Sanità pubblica, Medicina clinica e molecolare, University of Cagliari, Cagliari, Italy
| | - Raffaele Murru
- Centro Sclerosi Multipla, Dipartimento di Sanità pubblica, Medicina clinica e molecolare, University of Cagliari, Cagliari, Italy
| | - Lucia Schirru
- Centro Sclerosi Multipla, Dipartimento di Sanità pubblica, Medicina clinica e molecolare, University of Cagliari, Cagliari, Italy
| | - Maria Antonietta Secci
- Centro Sclerosi Multipla, Dipartimento di Sanità pubblica, Medicina clinica e molecolare, University of Cagliari, Cagliari, Italy
| | - Gianna Costa
- Centro Sclerosi Multipla, Dipartimento di Sanità pubblica, Medicina clinica e molecolare, University of Cagliari, Cagliari, Italy
| | - Isadora Asunis
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche (CNR), Cagliari, Italy
| | - Stefania Cuccu
- Centro Sclerosi Multipla, Dipartimento di Sanità pubblica, Medicina clinica e molecolare, University of Cagliari, Cagliari, Italy
| | - Giuseppe Fenu
- Centro Sclerosi Multipla, Dipartimento di Sanità pubblica, Medicina clinica e molecolare, University of Cagliari, Cagliari, Italy
| | - Lorena Lorefice
- Centro Sclerosi Multipla, Dipartimento di Sanità pubblica, Medicina clinica e molecolare, University of Cagliari, Cagliari, Italy
| | - Nicola Carboni
- Centro Sclerosi Multipla, Dipartimento di Sanità pubblica, Medicina clinica e molecolare, University of Cagliari, Cagliari, Italy
| | - Gioia Mura
- Centro di Psichiatria e Psicosomatica Azienda Ospedaliera Universitaria, Cagliari, Italy
| | - Maria Cristina Rosatelli
- Dipartimento di Sanità pubblica, Medicina clinica e molecolare, University of Cagliari, Cagliari, Italy
| | - Maria Giovanna Marrosu
- Centro Sclerosi Multipla, Dipartimento di Sanità pubblica, Medicina clinica e molecolare, University of Cagliari, Cagliari, Italy
- * E-mail:
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Clonal deletion and the fate of autoreactive thymocytes that survive negative selection. Nat Immunol 2012; 13:569-78. [PMID: 22544394 PMCID: PMC3362677 DOI: 10.1038/ni.2292] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/21/2012] [Indexed: 12/11/2022]
Abstract
Clonal deletion of autoreactive thymocytes is important for self-tolerance, but the intra-thymic signals that induce clonal deletion have not been clearly identified. We now report that clonal deletion during negative selection requires CD28 costimulation of autoreactive thymocytes at the CD4+CD8lo intermediate stage of differentiation. Autoreactive thymocytes were prevented from undergoing clonal deletion by either absent CD28 costimulation or transgenic over-expression of the anti-apoptotic factors Bcl-2 or Mcl-1, with surviving thymocytes differentiating into anergic T cell receptor αβ+ double negative thymocytes that preferentially migrated to the intestine where they re-expressed CD8α and were sequestered as CD8αα intraepithelial lymphocytes (IELs). This study identifies CD28 costimulation as the intrathymic signal required for clonal deletion and identifies CD8αα IELs as the developmental fate of autoreactive thymocytes that survive negative selection.
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Abstract
The thymus serves as the central organ of immunologic self-nonself discrimination. Thymocytes undergo both positive and negative selection, resulting in T cells with a broad range of reactivity to foreign antigens but with a lack of reactivity to self-antigens. The thymus is also the source of a subset of regulatory T cells that inhibit autoreactivity of T-cell clones that may escape negative selection. As a result of these functions, the thymus has been shown to be essential for the induction of tolerance in many rodent and large animal models. Proper donor antigen presentation in the thymus after bone marrow, dendritic cell, or solid organ transplantation has been shown to induce tolerance to allografts. The molecular mechanisms of positive and negative selection and regulatory T-cell development must be understood if a tolerance-inducing therapeutic intervention is to be designed effectively. In this brief and selective review, we present some of the known information on T-cell development and on the role of the thymus in experimental models of transplant tolerance. We also cite some clinical attempts to induce tolerance to allografts using pharmacologic or biologic interventions.
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Park HJ, Ban YL, Byun D, Park SH, Jung KC. Interaction between the mouse homologue of CD99 and its ligand PILR as a mechanism of T cell receptor-independent thymocyte apoptosis. Exp Mol Med 2010; 42:353-65. [PMID: 20208422 DOI: 10.3858/emm.2010.42.5.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Here, we show that the interaction between two membrane proteins, the mouse homologue of CD99 (designated D4) and its ligand, paired immunoglobulin-like type 2 receptor (PILR), is one of the major mechanisms of thymocyte apoptosis. Using the polymeric fusion protein of PILR and IgG1 (PILR-Ig), we demonstrated that D4 ligation in the absence of T cell receptor (TCR) engagement leads to the induction of apoptosis, mainly at the double-positive stage of thymocytes. This was further confirmed by a blocking study in which blocking the interaction between D4 and PILR by soluble D4 protein led to reduced apoptosis in the fetal thymic organ culture with wild type and TCRalpha(-/-) mice. Furthermore, the dissection of intracellular signaling pathway demonstrated that D4 cross-linking led to caspase activation without any change in mitochondrial membrane potential. Based on these data, we propose a mechanism for thymocyte depletion in which the interaction between D4 and PILR delivers an active signal.
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Affiliation(s)
- Hyo Jin Park
- Department of Pathology, Seoul National University College of Medicine, Seoul 110-799, Korea
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20
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Ebert PJR, Li QJ, Huppa JB, Davis MM. Functional development of the T cell receptor for antigen. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2010; 92:65-100. [PMID: 20800817 PMCID: PMC4887107 DOI: 10.1016/s1877-1173(10)92004-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
For over three decades now, the T cell receptor (TCR) for antigen has not ceased to challenge the imaginations of cellular and molecular immunologists alike. T cell antigen recognition transcends every aspect of adaptive immunity: it shapes the T cell repertoire in the thymus and directs T cell-mediated effector functions in the periphery, where it is also central to the induction of peripheral tolerance. Yet, despite its central position, there remain many questions unresolved: how can one TCR be specific for one particular peptide-major histocompatibility complex (pMHC) ligand while also binding other pMHC ligands with an immunologically relevant affinity? And how can a T cell's extreme specificity (alterations of single methyl groups in their ligand can abrogate a response) and sensitivity (single agonist ligands on a cell surface are sufficient to trigger a measurable response) emerge from TCR-ligand interactions that are so low in affinity? Solving these questions is intimately tied to a fundamental understanding of molecular recognition dynamics within the many different contexts of various T cell-antigen presenting cell (APC) contacts: from the thymic APCs that shape the TCR repertoire and guide functional differentiation of developing T cells to the peripheral APCs that support homeostasis and provoke antigen responses in naïve, effector, memory, and regulatory T cells. Here, we discuss our recent findings relating to T cell antigen recognition and how this leads to the thymic development of foreign-antigen-responsive alphabetaT cells.
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Affiliation(s)
- Peter J R Ebert
- The Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
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Gatzka M, Newton RH, Walsh CM. Altered thymic selection and increased autoimmunity caused by ectopic expression of DRAK2 during T cell development. THE JOURNAL OF IMMUNOLOGY 2009; 183:285-97. [PMID: 19542440 DOI: 10.4049/jimmunol.0803530] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Negative regulation of TCR signaling is an important mechanism enforcing immunological self-tolerance to prevent inappropriate activation of T cells and thus the development of autoimmune diseases. The lymphoid-restricted serine/threonine kinase death-associated protein-related apoptotic kinase-2 (DRAK2) raises the TCR activation threshold by targeting TCR-induced calcium mobilization in thymocytes and peripheral T cells and regulates positive thymic selection and peripheral T cell activation. Despite a hypersensitivity of peripheral drak2-deficient T cells, drak2-deficient mice are enigmatically resistant to induced autoimmunity in the model experimental autoimmune encephalomyelitis. To further evaluate the differential role of DRAK2 in central vs peripheral tolerance and to assess its impact on the development of autoimmune diseases, we have generated a transgenic (Tg) mouse strain ectopically expressing DRAK2 via the lck proximal promoter (1017-DRAK2 Tg mice). This transgene led to highest expression levels in double-positive thymocytes that are normally devoid of DRAK2. 1017-DRAK2 Tg mice displayed a reduction of single-positive CD4(+) and CD8(+) thymocytes in context with diminished negative selection in male HY TCR x 1017-DRAK2 Tg mice as well as peripheral T cell hypersensitivity, enhanced susceptibility to experimental autoimmune encephalomyelitis, and spontaneous autoimmunity. These findings suggest that alteration in thymocyte signaling thresholds impacts the sensitivity of peripheral T cell pools.
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Affiliation(s)
- Martina Gatzka
- Department of Molecular Biology and Biochemistry/Institute for Immunology, University of California, Irvine, 92697, USA
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22
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Abstract
Discovery of major histocompatability complex (MHC) restriction helped in the understanding of how T-lymphocytes recognize antigens on bacteria, viruses, and tumor cells. It was initially accepted that MHC restriction was a consequence of "adaptive differentiation" in the thymus; during differentiation, the forming repertoire of T-lymphocytes "learned" a low affinity for self MHC molecules via positive selection. This view was later countered by discovery of artifacts in underlying studies and the fact that adaptive differentiation could not explain direct allogeneic and allorestricted recognition phenomena. Data from experiments with TCR transgenic animals, individual MHC/peptide complex expression, and recipients of xenogenic thymus glands yielded evidence of an ability to adapt to microenvironment and a low specificity of positive selection. These facts led to an alternative interpretation of MHC restriction explained, in part, by specificity of a pool of effector cells activated by primary immunization. Details of this phenomenon were defined in studies that noted differential primary structures of peptides that bound various allelic forms of MHC molecules. Here, the T-lymphocyte repertoire formed in the thymus was a result, in part, of random rearrangement of germinal sequences of TCR gene fragments. Such pre-selected repertoires were inherently capable of reacting with different allelic forms of MHC molecules. In contrast, MHC molecules were characterized by significant intraspecies polymorphisms; negative and positive selections were aimed at adaptation of a pre-selected repertoire to a specific microenvironment in an individual. Via elimination of autoreactive clones and sparing of a broad spectrum of specificity to potential pathogens, selection in the thymus could be considered a life-long allogeneic reaction of a pre-selected repertoire to self MHC molecules resulting in tolerance to "self," increased responsiveness to foreign MHC molecules, and cross-reactivity of the mature T-lymphocyte repertoire to individual foreign peptides plus self MHC.
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Affiliation(s)
- Dmitry B Kazansky
- N. N. Blokhin's Cancer Research Center, Carcinogenesis Institute, Moscow, Russia.
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Bour-Jordan H, Bluestone JA. Regulating the regulators: costimulatory signals control the homeostasis and function of regulatory T cells. Immunol Rev 2009; 229:41-66. [PMID: 19426214 PMCID: PMC2714548 DOI: 10.1111/j.1600-065x.2009.00775.x] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
SUMMARY Costimulation is a concept that goes back to the early 1980s when Lafferty and others hypothesized that cell surface and soluble molecules must exist that are essential for initiating immune responses subsequent to antigen exposure. The explosion in this field of research ensued as over a dozen molecules have been identified to function as second signals following T-cell receptor engagement. By 1994, it seemed clear that the most prominent costimulatory pathway CD28 and functionally related costimulatory molecules, such as CD154, were the major drivers of a positive immune response. Then the immunology world turned upside down. CD28 knockout mice, which were, in most cases, immunodeficient, led to increased autoimmunity when bred into the non-obese diabetic background. Another CD28 family member, cytotoxic T-lymphocyte-associated protein 4, which was presumed to be a costimulatory molecule on activated T cells, turned out to be critical in downregulating immunity. These results, coupled with the vast suppressor cell literature which had been largely rebuked, suggested that the immune system was not poised for response but controlled in such a way that regulation was dominant. Over the last decade, we have learned that these costimulatory molecules play a key role in the now classical CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) that provide critical control of unwanted autoimmune responses. In this review, we discuss the connections between costimulation and Tregs that have changed the costimulation paradigm.
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Affiliation(s)
- Hélène Bour-Jordan
- UCSF Diabetes Center, University of California at San Francisco, San Francisco, CA USA
| | - Jeffrey A. Bluestone
- UCSF Diabetes Center, University of California at San Francisco, San Francisco, CA USA
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Fang L, Zhang X, Miao J, Zhao F, Yang K, Zhuang R, Bujard H, Wei Y, Yang A, Chen L, Jin B. Expression of CD226 Antagonizes Apoptotic Cell Death in Murine Thymocytes. THE JOURNAL OF IMMUNOLOGY 2009; 182:5453-60. [DOI: 10.4049/jimmunol.0803090] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Abstract
Immune self tolerance involves the deletion in the thymus of developing T cells that have the ability to recognize self-antigens, but by which cells? New evidence argues that cortical epithelial cells can induce deletion of self-reactive T cells.
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Wakimoto T, Tomisaka R, Nishikawa Y, Sato H, Yoshino T, Takahashi K. Identification and characterization of human thymic cortical dendritic macrophages that may act as professional scavengers of apoptotic thymocytes. Immunobiology 2008; 213:837-47. [PMID: 18926298 DOI: 10.1016/j.imbio.2008.07.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Accepted: 07/23/2008] [Indexed: 11/29/2022]
Abstract
We identify and characterize a special type of macrophage in the human thymic cortex that may act as professional scavengers of apoptotic thymocytes. These are large cells with clear cytoplasm, evenly distributed exclusively in the thymic cortex, and usually contain degraded nuclei in their cytoplasm. They are distinct from ordinary macrophages (OM) in the thymic cortex in expressing fascin, an actin-bundling protein specific for dendritic cells (DC), and in lacking lysozyme (LZM) and CD68. They are also different from DC in lacking major histocompatibility complex (MHC)-class II molecules. To distinguish them from OM and DC, we called them thymic cortical dendritic macrophages (TCDM). Both TCDM and OM are positive for DC-SIGN (CD209) and HAM56, whereas fascin(hi) MHC-class II(hi) medullary DC (mDC) are negative for these antigens. TCDM exhibit either dendritic or plump feature depending on cases examined. Plump TCDM usually contain several degraded nuclei, while dendritic TCDM contain one or two. These degraded nuclei are positive for active caspase-3 (aCasp-3), indicating that they are apoptotic thymocytes. In contrast to TCDM, LZM(hi) CD68(hi) OM are smaller round cells, distributed unevenly throughout the thymus, and do not contain apoptotic thymocytes at all. TCDM tend to adhere to capillaries with their dendrites or they make extensive contacts covering a large portion of the capillaries. Electron microscopic analysis confirmed the extensive contact between TCDM and capillaries and indicated that TCDM possess extremely electron-lucent, abundant cytoplasm with numerous tubulovesicular structures and secondary lysosomes. The finding of numerous condensed nuclei in most of the TCDM indicates that these cells represent a special type of fixed macrophages in the human thymic cortex, and that they play a central role in the clearance of apoptotic thymocytes.
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Affiliation(s)
- Taku Wakimoto
- Faculty of Health Science, Postgraduate School of Okayama University, Shikata-cho 2-5-1, Okayama-city 700-8558, Japan
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Gong Y, Zhang R, Zhang J, Xu L, Zhang F, Xu W, Wang Y, Chu Y, Xiong S. Alpha-dystroglycan is involved in positive selection of thymocytes by participating in immunological synapse formation. FASEB J 2008; 22:1426-39. [PMID: 18171694 DOI: 10.1096/fj.07-9264com] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Alpha-dystroglycan has been proved to be involved in lymphocyte activation by participating in immunological synapse (IS) formation. Considering the existence of IS formation in thymic development, we questioned whether alpha-dystroglycan was expressed in thymus and influenced thymic development. In this study, we demonstrated that alpha-dystroglycan was expressed on fetal thymocytes, especially on double-positive (DP, CD4(+)CD8(+)) cells. Blocking alpha-dystroglycan by treatment of fetal thymus organ culture (FTOC) with anti-alpha-dystroglycan antibody IIH6C4 decreased the number of DP cells compared with nontreated or isotype antibody controls. Down-regulation of alpha-dystroglycan by retroviruses carrying antisense cDNA of dystroglycan in reaggregate thymus organ culture (RTOC) further confirmed these results. Enhanced apoptosis of DP cells was observed after blocking alpha-dystroglycan. Interestingly, we found that blocking alpha-dystroglycan reduced IS formation between DP cells and thymic epithelial cells. Furthermore, blocking alpha-dystroglycan up-regulated CD95/CD95L expression and reduced Bcl-2 expression on DP cells in the developing thymus. Finally, the increase in the apoptosis of DP cells was associated with a consequent decrease in the positive selection, as indicated by the reduction of both ERK phosphorylation in DP cells and single-positive (SP, CD4(+) or CD8(+)) cell outcome. Altogether, these results indicated that alpha-dystroglycan was involved in positive selection of thymocytes by participating in the IS formation.
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Affiliation(s)
- Yanping Gong
- Department of Immunology, Shanghai Medical College of Fudan University, 138 Yixueyuan Rd., Shanghai 200032, China
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Sasaki E, Yatabe Y, Hashimoto M, Yamashita Y, Hasegawa Y, Kojima H, Nagasawa T, Mori N. Development-dependent expression of cyclin D3 in precursor T-cell lymphoblastic leukemia/lymphoma. Pathol Int 2007; 57:53-9. [PMID: 17300668 DOI: 10.1111/j.1440-1827.2006.02058.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In contrast to the clear oncogenic role of cyclins D1 and D2, cyclin D3 is suggested to have a role in the initiation and/or maintenance of differentiation in a lineage-associated manner in addition to its basic role in proliferation. Recently, it has been reported that in cyclin D3-deficient mice, normal expansion of T lymphocytes is impaired because of maturation arrest at the double-negative thymocyte stage, suggesting a crucial role for cyclin D3 in early T-cell development. Therefore, cyclin D3 expression was examined in 36 human precursor T-lymphoblastic leukemia/lymphomas (T-LBLL), a neoplastic counterpart of T cells at the early developmental stages of differentiation. Using a standard panel of differentiation markers, all T-LBLL were categorized into four stages according to differentiation: progenitor, double-negative, double-positive, and single-positive stages. Cyclin D3 expression was initiated at the boundary between double-negative and double-positive stages, and was sustained in the single-positive stage. T-cell receptor was expressed simultaneously with cyclin D3, whereas CD79a expression was specific in the double-negative stage, and thus it was inversely correlated with that of cyclin D3. Taken together with the crucial and non-redundant role in T-cell development in mice, this molecule is suggested to play an important role in human T-cell development.
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MESH Headings
- CD79 Antigens/genetics
- CD79 Antigens/metabolism
- Cell Differentiation
- Cell Proliferation
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Child
- Child, Preschool
- Cyclin D3
- Cyclins/genetics
- Cyclins/metabolism
- Disease Progression
- Gene Expression Regulation, Neoplastic
- Humans
- Infant
- Leukemia, Lymphoid/metabolism
- Leukemia, Lymphoid/pathology
- Male
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/metabolism
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathology
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/metabolism
- Thymus Gland/cytology
- Thymus Gland/metabolism
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Affiliation(s)
- Eiichi Sasaki
- Department of Pathology and Molecular Diagnostics, Aichi Cancer Center Hospital, Nagoya, Japan
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30
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Petrie HT, Zúñiga-Pflücker JC. Zoned out: functional mapping of stromal signaling microenvironments in the thymus. Annu Rev Immunol 2007; 25:649-79. [PMID: 17291187 DOI: 10.1146/annurev.immunol.23.021704.115715] [Citation(s) in RCA: 339] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
All hematopoietic cells, including T lymphocytes, originate from stem cells that reside in the bone marrow. Most hematopoietic lineages also mature in the bone marrow, but in this respect, T lymphocytes differ. Under normal circumstances, most T lymphocytes are produced in the thymus from marrow-derived progenitors that circulate in the blood. Cells that home to the thymus from the marrow possess the potential to generate multiple T and non-T lineages. However, there is little evidence to suggest that, once inside the thymus, they give rise to anything other than T cells. Thus, signals unique to the thymic microenvironment compel multipotent progenitors to commit to the T lineage, at the expense of other potential lineages. Summarizing what is known about the signals the thymus delivers to uncommitted progenitors, or to immature T-committed progenitors, to produce functional T cells is the focus of this review.
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Affiliation(s)
- Howard T Petrie
- Scripps Florida Research Institute, Jupiter, Florida 33458, USA.
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31
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Pasare C, Medzhitov R. Toll-like receptors: linking innate and adaptive immunity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 560:11-8. [PMID: 15932016 DOI: 10.1007/0-387-24180-9_2] [Citation(s) in RCA: 361] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Work in recent years has shown an essential role for Toll-like receptors (TLRs) in the activation of innate and adaptive immunity in vertebrate animals. These germ-line encoded receptors, expressed on a diverse variety of cells and tissues, recognize conserved molecular products derived from various classes of pathogens, including Gram-positive and -negative bacteria, DNA and RNA viruses, fungi and protozoa. Ligand recognition induces a conserved host defense program, which includes production of inflammatory cytokines, upregulation of costimulatory molecules, and induction of antimicrobial defenses. Importantly, activation of dendritic cells by TLR ligands is necessary for their maturation and consequent ability to initiate adaptive immune responses. How responses are tailored by individual TLRs to contain specific classes of pathogens is not yet clear.
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Affiliation(s)
- Chandrashekhar Pasare
- Howard Hughes Medical Institute, Section of Immunobiology, 300 Cedar Street, TAC S660, Yale University School of Medicine, New Haven, CT 06510, USA
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32
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Thomas M, Calamito M, Srivastava B, Maillard I, Pear WS, Allman D. Notch activity synergizes with B-cell-receptor and CD40 signaling to enhance B-cell activation. Blood 2006; 109:3342-50. [PMID: 17179224 DOI: 10.1182/blood-2006-09-046698] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
How diverse environmental cues are integrated to regulate B-cell activation and development remains poorly understood. Here we show that Notch activity synergizes with B-cell receptor (BCR) and/or CD40 signaling to enhance several aspects of B-cell activation and function. We find that costimulation of follicular B cells with the Notch ligand Delta-like-1 leads to significant increases in BCR- and CD40-mediated proliferation and enhances production of IgG1(+) cells in vitro and in vivo. We further find that coengagement of Notch and the BCR results in increased activation of the MAPK pathway, and MAPK and Notch inhibitors prevent B-cell activation events mediated by coengagement of Notch and the BCR. These data suggest that the BCR and CD40 signaling pathways collaborate with the Notch pathway to optimize B-cell activation.
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Affiliation(s)
- Matthew Thomas
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, 36th and Hamilton Walk, Philadelphia, PA 19104, USA
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33
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Engelhardt JJ, Sullivan TJ, Allison JP. CTLA-4 overexpression inhibits T cell responses through a CD28-B7-dependent mechanism. THE JOURNAL OF IMMUNOLOGY 2006; 177:1052-61. [PMID: 16818761 DOI: 10.4049/jimmunol.177.2.1052] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
CTLA-4 has been shown to be an important negative regulator of T cell activation. To better understand its inhibitory action, we constructed CTLA-4 transgenic mice that display constitutive cell surface expression of CTLA-4 on CD4 and CD8 T cells. In both in vivo and in vitro T cell responses, CTLA-4 overexpression inhibits T cell activation. This inhibition is dependent on B7 and CD28, suggesting that overexpressed CTLA-4 inhibits responses by competing with CD28 for B7 binding or by interfering with CD28 signaling. In addition, expression of the transgene decreases the number of CD25+Foxp3+ T cells in these mice, but does not affect their suppressive ability. Our data confirm the activity of CTLA-4 as a negative regulator of T cell activation and that its action may be by multiple mechanisms.
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MESH Headings
- Animals
- Antigens, CD
- Antigens, Differentiation/biosynthesis
- Antigens, Differentiation/genetics
- Antigens, Differentiation/physiology
- B7-1 Antigen/metabolism
- B7-1 Antigen/physiology
- Binding, Competitive/genetics
- Binding, Competitive/immunology
- CD28 Antigens/metabolism
- CD28 Antigens/physiology
- CTLA-4 Antigen
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cells, Cultured
- Down-Regulation/genetics
- Down-Regulation/immunology
- Encephalomyelitis, Autoimmune, Experimental/genetics
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Encephalomyelitis, Autoimmune, Experimental/prevention & control
- Epitopes, T-Lymphocyte/genetics
- Epitopes, T-Lymphocyte/immunology
- Humans
- Lymph Nodes/cytology
- Lymph Nodes/immunology
- Lymph Nodes/metabolism
- Lymphocyte Activation/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Mice, Knockout
- Mice, Transgenic
- Resting Phase, Cell Cycle/genetics
- Resting Phase, Cell Cycle/immunology
- Signal Transduction/genetics
- Signal Transduction/immunology
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
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Affiliation(s)
- John J Engelhardt
- Division of Immunology, Howard Hughes Medical Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
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34
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Freywald A, Sharfe N, Miller CD, Rashotte C, Roifman CM. EphA Receptors Inhibit Anti-CD3-Induced Apoptosis in Thymocytes. THE JOURNAL OF IMMUNOLOGY 2006; 176:4066-74. [PMID: 16547242 DOI: 10.4049/jimmunol.176.7.4066] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The EphA receptor tyrosine kinases interact with membrane-bound ligands of the ephrin-A subfamily. Interaction induces EphA receptor oligomerization, tyrosine phosphorylation, and, as a result, EphA receptor signaling. EphA receptors have been shown to regulate cell survival, migration, and cell-cell and cell-matrix interactions. However, their functions in lymphoid cells are only beginning to be described. We show in this study that functional EphA receptors are expressed by murine thymocytes, including CD4(+)CD8(+), CD4(+)CD8(-), and CD4(-)CD8(+) subpopulations. We demonstrate that activation of EphA receptors by the ephrin-A1 ligand inhibits the anti-CD3-induced apoptosis of CD4(+)CD8(+) double-positive thymocytes. Furthermore, ephrin-A1 costimulation suppresses up-regulation of both the IL-2R alpha-chain (CD25) and early activation Ag CD69 and can block IL-2 production by CD4(+) single-positive cells. In agreement, EphA receptor activation in thymocytes also inhibits TCR-induced activation of the Ras-MAPK pathway. Our findings suggest that EphA receptor activation is antithetical to TCR signaling in thymocytes, and that the level of engagement by ephrin-A proteins on thymic APCs regulates thymocyte selection.
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MESH Headings
- Animals
- Antibodies/immunology
- Antigens, CD/metabolism
- Antigens, Differentiation, T-Lymphocyte/metabolism
- Apoptosis/drug effects
- Apoptosis/immunology
- CD3 Complex/immunology
- Cells, Cultured
- Ephrin-A1/pharmacology
- Female
- Gene Expression Regulation
- Interleukin-2/metabolism
- Lectins, C-Type
- MAP Kinase Signaling System
- Mice
- Mice, Inbred BALB C
- Mitogen-Activated Protein Kinases/metabolism
- Receptors, Antigen, T-Cell/metabolism
- Receptors, Eph Family/immunology
- Receptors, Eph Family/metabolism
- Receptors, Interleukin-2/metabolism
- Thymus Gland/cytology
- Thymus Gland/drug effects
- Thymus Gland/immunology
- Thymus Gland/metabolism
- ras Proteins/metabolism
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Affiliation(s)
- Andrew Freywald
- Department of Chemistry and Biochemistry, University of Regina, Saskatchewan, Canada
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35
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Thien CBF, Blystad FD, Zhan Y, Lew AM, Voigt V, Andoniou CE, Langdon WY. Loss of c-Cbl RING finger function results in high-intensity TCR signaling and thymic deletion. EMBO J 2005; 24:3807-19. [PMID: 16211006 PMCID: PMC1276723 DOI: 10.1038/sj.emboj.7600841] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Accepted: 09/19/2005] [Indexed: 01/15/2023] Open
Abstract
Signaling from the T-cell receptor (TCR) in thymocytes is negatively regulated by the RING finger-type ubiquitin ligase c-Cbl. To further investigate this regulation, we generated mice with a loss-of-function mutation in the c-Cbl RING finger domain. These mice exhibit complete thymic deletion by young adulthood, which is not caused by a developmental block, lack of progenitors or peripheral T-cell activation. Rather, this phenotype correlates with greatly increased expression of the CD5 and CD69 activation markers and increased sensitivity to anti-CD3-induced cell death. Thymic loss contrasts the normal fate of the c-Cbl-/- thymus, even though thymocytes from both mutant mice show equivalent enhancement in proximal TCR signaling, Erk activation and calcium mobilization. Remarkably, only the RING finger mutant thymocytes show prominent TCR-directed activation of Akt. We show that the mutant c-Cbl protein itself is essential for activating this pathway by recruiting the p85 regulatory subunit of PI 3-kinase. This study provides a unique model for analyzing high-intensity TCR signals that cause thymocyte deletion and highlights multiple roles of c-Cbl in regulating this process.
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MESH Headings
- Amino Acid Substitution
- Animals
- Antigens, CD/analysis
- Antigens, Differentiation, T-Lymphocyte/analysis
- Apoptosis
- CD3 Complex/analysis
- CD5 Antigens/analysis
- Extracellular Signal-Regulated MAP Kinases/analysis
- Lectins, C-Type
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/analysis
- Mice
- Mice, Transgenic
- Mutation
- Phosphatidylinositol 3-Kinases/metabolism
- Protein Structure, Tertiary
- Proto-Oncogene Proteins c-cbl/chemistry
- Proto-Oncogene Proteins c-cbl/genetics
- Proto-Oncogene Proteins c-cbl/physiology
- Receptors, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell/physiology
- Signal Transduction
- Thymus Gland/immunology
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Affiliation(s)
- Christine B F Thien
- School of Surgery and Pathology, University of Western Australia, Crawley, Australia
| | - Frøydis D Blystad
- School of Surgery and Pathology, University of Western Australia, Crawley, Australia
| | - Yifan Zhan
- The Walter and Eliza Hall Institute of Medical Research, Royal Parade, Melbourne, Australia
| | - Andrew M Lew
- The Walter and Eliza Hall Institute of Medical Research, Royal Parade, Melbourne, Australia
| | - Valentina Voigt
- Centre for Experimental Immunology, The Lions Eye Institute, Nedlands, Australia
| | | | - Wallace Y Langdon
- School of Surgery and Pathology, University of Western Australia, Crawley, Australia
- School of Surgery and Pathology, University of Western Australia, Crawley, WA 6009, Australia. Tel.: +61 8 9346 2939; Fax: +61 8 9346 2891; E-mail:
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36
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Rubin RL, Hermanson TM. Plasticity in the positive selection of T cells: affinity of the selecting antigen and IL-7 affect T cell responsiveness. Int Immunol 2005; 17:959-71. [PMID: 15994177 DOI: 10.1093/intimm/dxh277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The current study examines how responsiveness of T cells is affected by the avidity of the peptide/MHC engaged during positive selection of their thymocyte precursors. We used a thymus reaggregate culture system in which CD4(+)CD8(+) thymocytes from AND TCR transgenic mice were induced to undergo positive selection by pigeon cytochrome c (PCC) peptide or its analogs presented by I-E(k) class II MHC on a thymic epithelial cell line. When low-affinity peptide analogs drove positive selection, up to 100 microM was needed to produce >50% CD4(+) T cells, and these cells were highly responsive to PCC. In contrast, <0.2 microM high-affinity peptides was required to achieve similar selection efficiency, but the resultant cells failed to respond to PCC. However, these cells were not dead based on dye exclusion and capacity to respond to phorbal ester and to agonist if IL-2 was also present, supporting the view that non-responsiveness of cells selected on high-affinity peptides is a form of central T cell tolerance distinct from deletion. Cells selected on intermediate-affinity peptides showed variable responsiveness which was suppressed 5- to 10-fold by addition during reaggregate culture of antibody to the IL-7R. Similarly, supplementary IL-7 in the reaggregate culture produced CD4(+) T cells that were promiscuously responsive. Overall, this study demonstrates that the responsiveness of T cells is not rigidly controlled and that the presence of IL-7 during T cell development has the potential to negate central T cell tolerance and produce autoreactive T cells.
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Affiliation(s)
- Robert L Rubin
- Department of Molecular Genetics and Microbiology, MSC08 4660, 1 University of New Mexico Medical School, Albuquerque, NM 87131, USA.
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37
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Vacchio MS, Williams JA, Hodes RJ. A novel role for CD28 in thymic selection: elimination of CD28/B7 interactions increases positive selection. Eur J Immunol 2005; 35:418-27. [PMID: 15657954 DOI: 10.1002/eji.200424918] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
While the importance of the CD28/B7 costimulation pathway is well established for mature T cells, the role of CD28 in thymocyte selection is less well defined. The role of CD28 in both negative and positive selection was assessed using H-Y-specific TCR-transgenic (Tg) RAG-2-deficient (H-Yrag) mice. Negative selection in male H-Yrag mice was not affected by deficiency in CD28 or B7. Surprisingly, absence of CD28 or B7 in H-Yrag females resulted in increased numbers of CD8 single-positive (SP) thymocytes. The CD8 SP thymocytes found in these females were mature and functionally competent. Furthermore, double-positive (DP) thymocytes from CD28-knockout (CD28KO) or B7.1/B7.2 double-KO (B7DKO) females had higher levels of both CD5 and TCR than those from WT females, consistent with a stronger selecting signal. CD28KO H-Yrag fetal thymic organ cultures also had elevated numbers of thymic CD8 SP cells, reflecting increased thymic differentiation and not recirculation of peripheral T cells. Finally, increased selection of mature CD4 and CD8 SP T cells was observed in non-TCR-Tg CD28KO and B7DKO mice, indicating that this function of CD28-B7 interaction is not unique to a TCR-Tg model. Together these findings demonstrate a novel negative regulatory role for CD28 in inhibiting differentiation of SP thymocytes, probably through inhibition of thymic selection.
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Affiliation(s)
- Melanie S Vacchio
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, USA.
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38
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Tai X, Cowan M, Feigenbaum L, Singer A. CD28 costimulation of developing thymocytes induces Foxp3 expression and regulatory T cell differentiation independently of interleukin 2. Nat Immunol 2005; 6:152-62. [PMID: 15640801 DOI: 10.1038/ni1160] [Citation(s) in RCA: 457] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2004] [Accepted: 12/16/2004] [Indexed: 01/25/2023]
Abstract
Efficient generation of regulatory T cells (T(reg) cells) in the thymus requires CD28 costimulation, but it is not known why. Here, molecular mapping of CD28 costimulation showed that T(reg) cell generation requires a motif that binds the tyrosine kinase Lck, precisely the same motif that is required for CD28 costimulation of interleukin 2 production. Nevertheless, CD28 costimulation provides more than interleukin 2 to developing T(reg) cells, as CD28 costimulation of T cell receptor-signaled double-positive thymocytes induced expression of Foxp3, considered to be the T(reg) 'master gene', as well as GITR and CTLA-4, two proteins expressed on T(reg) cells. Thus, CD28 costimulation directly signals developing thymocytes to express Foxp3 and to initiate the T(reg) cell differentiation program.
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Affiliation(s)
- Xuguang Tai
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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39
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Abstract
Detection of and response to microbial infections by the immune system depends largely on a family of pattern-recognition receptors called Toll-like receptors (TLRs). These receptors recognize conserved molecular products derived from various classes of pathogens, including Gram-positive and -negative bacteria, DNA and RNA viruses, fungi and protozoa. Recognition of ligands by TLRs leads to a series of signaling events resulting in induction of acute responses necessary to kill the pathogen. TLRs are also responsible for the induction of dendritic cell maturation, which is responsible and necessary for initiation of adaptive immune responses. Although TLRs control induction of adaptive immunity, it is not clear at this point how responses are appropriately tailored by individual TLRs to the advantage of the host.
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Affiliation(s)
- Chandrashekhar Pasare
- Section of Immunobiology, Howard Hughes Medical Institute, Yale University School of Medicine, 300 Cedar Street, TAC S660, New Haven, CT 06510, USA.
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40
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Bour-Jordan H, Salomon BL, Thompson HL, Szot GL, Bernhard MR, Bluestone JA. Costimulation controls diabetes by altering the balance of pathogenic and regulatory T cells. J Clin Invest 2004; 114:979-87. [PMID: 15467837 PMCID: PMC518661 DOI: 10.1172/jci20483] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2003] [Accepted: 08/03/2004] [Indexed: 12/23/2022] Open
Abstract
The development of autoimmune diabetes in the nonobese diabetic (NOD) mouse results from a breakdown in tolerance to pancreatic islet antigens. CD28-B7 and CD40 ligand-CD40 (CD40L-CD40) costimulatory pathways affect the development of disease and are promising therapeutic targets. Indeed, it was shown previously that diabetes fails to develop in NOD-B7-2-/- and NOD-CD40L-/- mice. In this study, we examined the relative role of these 2 costimulatory pathways in the balance of autoimmunity versus regulation in NOD mice. We demonstrate that initiation but not effector function of autoreactive T cells was defective in NOD-B7-2-/- mice. Moreover, the residual proliferation of the autoreactive cells was effectively controlled by CD28-dependent CD4+CD25+ regulatory T cells (Treg's), as depletion of Treg's partially restored proliferation of autoreactive T cells and resulted in diabetes in an adoptive-transfer model. Similarly, disruption of the CD28-B7 pathway and subsequent Treg deletion restored autoimmunity in NOD-CD40L-/- mice. These results demonstrate that development of diabetes is dependent on a balance of pathogenic and regulatory T cells that is controlled by costimulatory signals. Thus, elimination of Treg's results in diabetes even in the absence of costimulation, which suggests a need for alternative strategies for immunotherapeutic approaches.
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Affiliation(s)
- Hélène Bour-Jordan
- UCSF Diabetes Center, University of California at San Francisco, San Francisco, California 94143, USA
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41
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Bour-Jordan H, Salomon BL, Thompson HL, Szot GL, Bernhard MR, Bluestone JA. Costimulation controls diabetes by altering the balance of pathogenic and regulatory T cells. J Clin Invest 2004. [DOI: 10.1172/jci200420483] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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42
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Esashi E, Ito H, Ishihara K, Hirano T, Koyasu S, Miyajima A. Development of CD4+Macrophages from Intrathymic T Cell Progenitors Is Induced by Thymic Epithelial Cells. THE JOURNAL OF IMMUNOLOGY 2004; 173:4360-7. [PMID: 15383565 DOI: 10.4049/jimmunol.173.7.4360] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It was recently demonstrated that there are CD4(+) macrophages, which exhibit strong phagocytic activity, in the thymus. They are suggested to play an important role for the elimination of apoptotic thymocytes. However, the origin and nature of CD4(+) macrophages in the thymus remain unexplored. In this study, we describe that the most immature intrathymic progenitors (CD25(-)/CD44(+)/FcR(+)) give rise to CD4(+) macrophages by oncostatin M-responsive thymic epithelial cells (ORTEC) in an IL-7-dependent manner. Neither conditioned medium of ORTEC nor a mixture of cytokines induced CD4(+) macrophages, and oncostatin M receptor was not expressed in thymocytes, suggesting that the development of CD4(+) macrophages from the immature thymocytes requires a direct interaction with ORTEC. These results collectively suggest that the development of CD4(+) macrophages from the intrathymic T cell progenitors is induced by thymic epithelial cells.
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Affiliation(s)
- Eiji Esashi
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo, Japan
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43
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Jung KC, Park WS, Kim HJ, Choi EY, Kook MC, Lee HW, Bae Y. TCR-independent and caspase-independent apoptosis of murine thymocytes by CD24 cross-linking. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2004; 172:795-802. [PMID: 14707049 DOI: 10.4049/jimmunol.172.2.795] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CD24, also referred to as the heat-stable Ag, is a T cell differentiation Ag that is highly expressed on both CD4-CD8- double negative and CD4+CD8+ double positive thymocytes. Here, we report that CD24 ligation by a new anti-CD24 Ab, mT-20, induced the apoptosis of both double negative and double positive thymocytes, as well as the Scid.adh thymic lymphoma cell line, in the absence of TCR/CD3 engagement. CD24-mediated apoptosis of mouse thymocytes and its signaling pathway appeared not to be associated with p53, CD95, TNFR, or caspases. Furthermore, we found that cell death was blocked by the addition of scavengers of reactive oxygen species or by Bcl-2 overexpression, implying the role of CD24 signaling in the mitochondrial regulation. In this study, we suggest that CD24 ligation induced the apoptosis of immature thymocytes independently of both caspase and TCR.
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MESH Headings
- Animals
- Antibodies, Monoclonal/metabolism
- Antigens, CD/immunology
- Antigens, CD/metabolism
- Antigens, CD/physiology
- Apoptosis/genetics
- Apoptosis/immunology
- Apoptosis Inducing Factor
- CD24 Antigen
- Caspases/metabolism
- Caspases/physiology
- Cell Line
- Cell Line, Tumor
- Cells, Cultured
- Down-Regulation/immunology
- Enzyme Activation
- Flavoproteins/metabolism
- Intracellular Membranes/immunology
- Ligands
- Membrane Glycoproteins
- Membrane Potentials/immunology
- Membrane Proteins/metabolism
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Inbred MRL lpr
- Mice, Knockout
- Mice, SCID
- Mitochondria/immunology
- Permeability
- Reactive Oxygen Species/metabolism
- Receptors, Antigen, T-Cell/physiology
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/enzymology
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
- Thymus Gland/cytology
- Thymus Gland/enzymology
- Thymus Gland/immunology
- Thymus Gland/metabolism
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Affiliation(s)
- Kyeong Cheon Jung
- Department of Pathology, Hallym University College of Medicine, Chuncheon, Korea
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Habiro K, Kotani M, Omoto K, Kobayashi S, Tanabe K, Shimmura H, Suzuki K, Hayashi T, Toma H, Abe R. Mechanism of allorecognition and skin graft rejection in CD28 and CD40 ligand double-deficient mice. Transplantation 2003; 76:854-8. [PMID: 14501867 DOI: 10.1097/01.tp.0000084868.09385.83] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND It has been shown that simultaneous blockade of CD28- and CD40-mediated costimulatory signals significantly prolongs allograft survival. Although these results led to an expectation of the establishment of specific immunotolerant therapy for organ transplantation, it became evident that these treatments rarely resulted in indefinite allograft survival. To uncover the mechanisms underlying these costimulation blockade-resistant allograft rejections, we studied the process of allogenic skin graft rejection in CD28 and CD40 ligand (L) double-deficient (double-knockout [dKO]) mice. METHODS Skin grafts from BALB/c or BALB.B mice were transplanted to C57BL/6 background dKO mice. The frequency of CD4+ and CD8+ T cells responding to alloantigens presented by direct or indirect pathways were defined by the use of a cytostaining assay. RESULTS BALB/c skin grafts were rapidly rejected by dKO mice. This CD28 and CD40L independent allograft rejection was inhibited by the depletion of CD8+ T cells. In vitro studies indicated that CD8+ T cells from BALB/c skin-grafted dKO mice responded to donor antigen presented only by the direct pathway. Unlike major histocompatibility complex (MHC)-mismatched donors, allogenic skin grafts from MHC-matched donors were accepted by dKO mice. CONCLUSION In the absence of CD28 and CD40 costimulatory signals, CD8+ T cells recognize MHC antigens by the direct pathway, resulting in the rejection of skin grafts from MHC-mismatched donors. In contrast, MHC-matched and non-MHC-mismatched donor skin grafts indefinitely survive in dKO mice. These results indicated that donor-host MHC matching may still be critical to costimulation blockade therapy for organ transplantation.
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Affiliation(s)
- Katsuyoshi Habiro
- Division of Immunobiology, Research Institute for Biological Sciences, Tokyo University of Science, Noda City, Japan
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45
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Esashi E, Sekiguchi T, Ito H, Koyasu S, Miyajima A. Cutting Edge: A possible role for CD4+ thymic macrophages as professional scavengers of apoptotic thymocytes. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:2773-7. [PMID: 12960296 DOI: 10.4049/jimmunol.171.6.2773] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A vast majority of thymocytes are eliminated during T cell development by apoptosis. However, apoptotic thymocytes are not usually found in the thymus, indicating that apoptotic thymocytes must be eliminated rapidly by scavengers. Although macrophages and dendritic cells are believed to play such role, little is known about scavengers in the thymus. We found that CD4(+)/CD11b(+)/CD11c(-) cells were present in the thymus and that they expressed costimulatory molecules for T cell selection and possessed Ag-presenting activity. Moreover, these CD4(+)/CD11b(+) cells phagocytosed apoptotic thymocytes much more efficiently than thymic CD4(-)/CD11b(+) cells as well as activated peritoneal macrophages. CD4(+)/CD11b(+) cells became larger along with thymus development, while no such change was observed in CD4(-)/CD11b(+) cells. Finally, engulfed nuclei were frequently found in CD4(+)/CD11b(+) cells. These results strongly suggest that thymic CD4(+)/CD11b(+) cells are major scavengers of apoptotic thymocytes.
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Affiliation(s)
- Eiji Esashi
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo, Japan
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46
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Na SY, Patra A, Scheuring Y, Marx A, Tolaini M, Kioussis D, Hemmings BA, Hemmings B, Hünig T, Bommhardt U. Constitutively active protein kinase B enhances Lck and Erk activities and influences thymocyte selection and activation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:1285-96. [PMID: 12874217 DOI: 10.4049/jimmunol.171.3.1285] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Protein kinase B (PKB), a serine threonine kinase is critically involved in cellular proliferation and survival. To characterize its role in T cell development in vivo, we have analyzed transgenic mice that express a membrane-targeted constitutively active version of PKB (myr PKB) in thymocytes and peripheral T cells. We report that myr PKB renders proliferative responses of thymocytes more sensitive to TCR signals by increased and sustained activation of Src kinase Lck and the extracellular signal-regulated kinase/mitogen-activated protein kinase pathway. In addition, the proliferative response of myr PKB T cells is relatively independent of calcium mobilization and calcineurin activity. We also find that myr PKB enhances phosphorylation of glycogen synthase kinase 3, a negative regulator of NFAT and T cell activation, and the recruitment of the adapter protein Cbl-c. Interestingly, we demonstrate that upon TCR/CD3 stimulation of wild-type T cells PKB is translocated into lipid rafts, adding a new role for PKB in TCR-initiated signalosome formation in T cell activation. Localization of transgenic PKB in lipid rafts could contribute to the higher TCR sensitivity of myr PKB thymocytes which is reflected in an increase in positive selection toward the CD4 lineage and variable effects on negative selection depending on the model system analyzed. Thus, our observations clearly indicate a cross-talk between PKB and important signaling molecules downstream of TCR that modulate the thresholds of thymocyte selection and T cell activation.
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Affiliation(s)
- Shin-Young Na
- Institutes of Virology and Immunobiology, University of Würzburg, Würzburg, Germany
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47
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Buhlmann JE, Elkin SK, Sharpe AH. A role for the B7-1/B7-2:CD28/CTLA-4 pathway during negative selection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:5421-8. [PMID: 12759417 DOI: 10.4049/jimmunol.170.11.5421] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Although costimulation plays an important role in activating naive T cells, its role in negative selection is controversial. By following thymocyte deletion induced by endogenous superantigens in mice lacking B7-1 and/or B7-2, we have identified a role for both B7-1 and B7-2 in negative selection. Studies using CD28-deficient and CD28/CTLA-4-double-deficient mice have revealed that either CD28 or another as yet undefined coreceptor can mediate these B7-dependent signals that promote negative selection. Finally, CTLA-4 delivers signals that inhibit selection, suggesting that CTLA-4 and CD28 have opposing functions in thymic development. Combined, the data demonstrate that B7-1/B7-2-dependent signals help shape the T cell repertoire.
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Affiliation(s)
- Janet E Buhlmann
- Department of Pathology, Immunology Research Division, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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48
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Abstract
The CD5 coreceptor is a cysteine-rich scavenger receptor family glycoprotein that is expressed constitutively on all T cells and a subset of B cells (B I a B cells). It is now generally accepted that the biologic role of CD5 is to regulate intracellular strength induced by antigen receptors in both T and B cells. However, at present it is unclear if this coreceptor's effect on antigen receptor signaling is primarily costimulatory or inhibitory since support for both exists. Our studies focus on understanding the physiologic role of CD5 in the context of regulation of antigen receptor activation, B and T cell selection, and generation/maintenance of immune tolerance. In this overview, I discuss studies using experimental models of lymphocyte selection and tolerance showing that CD5 plays a key role in B and T cell selection as well as generation and maintenance of tolerance. I and others, reviewed here, now provide clear evidence that CD5 is a key regulator of immune tolerance and that alterations of its activity can promote development of autoreactivity.
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Affiliation(s)
- Chander Raman
- Department of Medicine, University of Alabama at Birmingham, 35294-0007, USA.
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49
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Wang J, Fu YX. LIGHT (a cellular ligand for herpes virus entry mediator and lymphotoxin receptor)-mediated thymocyte deletion is dependent on the interaction between TCR and MHC/self-peptide. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:3986-93. [PMID: 12682226 DOI: 10.4049/jimmunol.170.8.3986] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Negative selection serves as a major mechanism to maintain self-tolerance. We previously reported that LIGHT (a cellular ligand for herpes virus entry mediator and lymphotoxin receptor), a TNF family member, plays an important role in thymocyte development via promoting apoptosis of double-positive thymocytes. Here, we demonstrated that LIGHT-mediated deletion of thymocyte requires the strong interaction of TCR with MHC/self-peptide. Transgenic mice overexpressing LIGHT in thymocytes were bred with a transgenic mouse line expressing a TCR recognizing the H-Y male Ag in the context of H-2b class I MHC molecules. In male H-Y/LIGHT double-transgenic mice, more efficient negative selection of H-Y T cells occurred, and total thymocyte number was further reduced compared with H-Y/negative littermates. In contrast, the presence of LIGHT transgene had no evident impact on the thymocyte development of female H-Y/LIGHT double-transgenic mice. Taken together, LIGHT plays a role in negative selection of thymocytes via inducing the apoptosis of thymocytes bearing high affinity TCR during negative selection.
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MESH Headings
- Animals
- Apoptosis/genetics
- Apoptosis/immunology
- Autoantigens/biosynthesis
- Autoantigens/genetics
- Autoantigens/metabolism
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Clonal Deletion/immunology
- Epitopes, T-Lymphocyte/metabolism
- Female
- H-Y Antigen/biosynthesis
- H-Y Antigen/genetics
- H-Y Antigen/metabolism
- Ligands
- Lymphotoxin beta Receptor
- Male
- Membrane Proteins/biosynthesis
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Membrane Proteins/physiology
- Mice
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Transgenic
- Receptors, Antigen, T-Cell/metabolism
- Receptors, Tumor Necrosis Factor/metabolism
- Receptors, Tumor Necrosis Factor/physiology
- Receptors, Tumor Necrosis Factor, Member 14
- Receptors, Virus/metabolism
- Sex Characteristics
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
- Thymus Gland/cytology
- Thymus Gland/immunology
- Thymus Gland/metabolism
- Tumor Necrosis Factor Ligand Superfamily Member 14
- Tumor Necrosis Factor-alpha/biosynthesis
- Tumor Necrosis Factor-alpha/genetics
- Tumor Necrosis Factor-alpha/metabolism
- Tumor Necrosis Factor-alpha/physiology
- Up-Regulation/genetics
- Up-Regulation/immunology
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Affiliation(s)
- Jing Wang
- Department of Pathology and Committee on Immunology, University of Chicago, Chicago, IL 60637, USA
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50
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Cho HJ, Edmondson SG, Miller AD, Sellars M, Alexander ST, Somersan S, Punt JA. Cutting edge: identification of the targets of clonal deletion in an unmanipulated thymus. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:10-3. [PMID: 12496375 DOI: 10.4049/jimmunol.170.1.10] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Autoreactive thymocytes can be eliminated by clonal deletion during their development in the thymus. The precise developmental stage(s) at which clonal deletion occurs in a normal thymus has been difficult to assess, in large part because of the absence of a specific marker for TCR-mediated apoptosis. In this report, we reveal that Nur77 expression can be used as a specific marker of clonal deletion in an unmanipulated thymus and directly identify TCRintCD4+CD8+ and semimature CD4+CD8- thymocytes as the principal targets of deletion. These data indicate that clonal deletion normally occurs at a relatively late stage of development, as cells mature from CD4+CD8+ thymocytes to single-positive T cells.
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Affiliation(s)
- Hyung J Cho
- Department of Biology, Haverford College, Haverford, PA 19041, USA
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