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Belyaeva IV, Kosova AN, Vasiliev AG. Tuberculosis and Autoimmunity. PATHOPHYSIOLOGY 2022; 29:298-318. [PMID: 35736650 PMCID: PMC9228380 DOI: 10.3390/pathophysiology29020022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/03/2022] [Accepted: 06/07/2022] [Indexed: 12/17/2022] Open
Abstract
Tuberculosis remains a common and dangerous chronic bacterial infection worldwide. It is long-established that pathogenesis of many autoimmune diseases is mainly promoted by inadequate immune responses to bacterial agents, among them Mycobacterium tuberculosis. Tuberculosis is a multifaceted process having many different outcomes and complications. Autoimmunity is one of the processes characteristic of tuberculosis; the presence of autoantibodies was documented by a large amount of evidence. The role of autoantibodies in pathogenesis of tuberculosis is not quite clear and widely disputed. They are regarded as: (1) a result of imbalanced immune response being reactive in nature, (2) a critical part of TB pathogenicity, (3) a beginning of autoimmune disease, (4) a protective mechanism helping to eliminate microbes and infected cells, and (5) playing dual role, pathogenic and protective. There is no single autoimmunity-mechanism development in tuberculosis; different pathways may be suggested. It may be excessive cell death and insufficient clearance of dead cells, impaired autophagy, enhanced activation of macrophages and dendritic cells, environmental influences such as vitamin D insufficiency, and genetic polymorphism, both of Mycobacterium tuberculosis and host.
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Abstract
Despite decades of research, the induction and maintenance of long-term allograft tolerance without immunosuppression remains an elusive goal in the field of solid organ and cell transplantation. Immunosuppressive medications frequently prevent or minimize acute cellular rejection but have failed to halt antidonor antibody production and chronic organ rejection. Past efforts aimed at promoting lasting allograft tolerance have focused primarily on peripheral T-cell depletion, augmentation of regulatory T cells, or induction via simultaneous hematopoietic stem cell transplantation and facilitation of donor chimerism. So far, none of these methods have led to consistently safe, feasible and long lasting donor organ acceptance. Over the course of the past 4 decades, the study of a unique population of antigen-presenting cells known as dendritic cells has shown promise for breaking new ground in achieving indefinite allograft survival without immunosuppression and its associated adverse effects. In this review, we discuss the discovery and early investigations of dendritic cells and chronicle some of the key studies demonstrating their role in transplantation, particularly in indirect allorecognition, the immunologic pathway thought to drive chronic rejection and perhaps tolerance induction.
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Fuchs EJ, Matzinger P. Does the Danger model shed any light on central tolerance?: A response to Al-Yassin. Scand J Immunol 2018. [PMID: 29542175 DOI: 10.1111/sji.12660] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- E J Fuchs
- Division of Hematologic Malignancies, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA
| | - P Matzinger
- Ghost lab, LIG, NIAID, National Institutes of Health, Bethesda, MD, USA
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Al-Yassin G. Medawar's "actively acquired tolerance" and the Danger model: Setting the record straight. Scand J Immunol 2018; 88:e12652. [PMID: 29476657 DOI: 10.1111/sji.12652] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 02/17/2018] [Indexed: 11/30/2022]
Abstract
I describe here what I believe is a misrepresentation of the classic observations of Billingham, Brent and Medawar on "actively acquired tolerance," by Ridge, Fuchs and Matzinger; I set the record straight by revisiting the original literature and discussing the implications of this misinterpretation.
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Affiliation(s)
- G Al-Yassin
- Department of Microbiology and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
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5
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Dou L, Chen YF, Cowan PJ, Chen XP. Extracellular ATP signaling and clinical relevance. Clin Immunol 2017; 188:67-73. [PMID: 29274390 DOI: 10.1016/j.clim.2017.12.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 12/12/2017] [Accepted: 12/20/2017] [Indexed: 12/20/2022]
Abstract
Since purinergic signaling was discovered in the early 1970s, it has been shown that extracellular nucleotides, and their derivative nucleosides, are released in a regulated or unregulated manner by cells in various challenging settings and then bind defined purinergic receptors to activate intricate signaling networks. Extracellular ATP plays a role based on different P2 receptor subtypes expressed on specific cell types. Sequential hydrolysis of extracellular ATP catalyzed by ectonucleotidases (e.g. CD39, CD73) is the main pathway for the generation of adenosine, which in turn activates P1 receptors. Many studies have demonstrated that extracellular ATP signaling functions as an important dynamic regulatory pathway to coordinate appropriate immune responses in various pathological processes, including intracellular infection, host-tumor interaction, pro-inflammation vascular injury, and transplant immunity. ATP receptors and CD39 also participate in related clinical settings. Here, we review the latest research in to the development of promising clinical treatment strategies.
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Affiliation(s)
- Lei Dou
- Department of Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Department of Gerontology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yi-Fa Chen
- Department of Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Peter J Cowan
- Immunology Research Centre, St Vincent's Hospital, Melbourne, Australia.
| | - Xiao-Ping Chen
- Department of Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Department of Gerontology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Haas J, Schwarz A, Korporal-Kuhnke M, Jarius S, Wildemann B. Myeloid dendritic cells exhibit defects in activation and function in patients with multiple sclerosis. J Neuroimmunol 2016; 301:53-60. [PMID: 27836182 DOI: 10.1016/j.jneuroim.2016.10.007] [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: 09/07/2016] [Revised: 10/23/2016] [Accepted: 10/30/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Regulatory T cells (Tregs) are functionally defective in patients with multiple sclerosis (MS) and this dysfunction is related to an imbalanced composition of naïve and memory Treg subtypes. Several lines of evidence indicate that these abnormalities might result from a premature decline in thymic-dependent Treg neogenesis. Myeloid dendritic cells (mDCs) critically determine Treg differentiation in the thymus, and thymic stromal lymphopoietin receptor (TSLPR) expressed on mDCs is a key component of the signaling pathways involved in this process. TSLPR-expression on mDCs was previously shown to be decreased in MS. We hypothesized that functional alterations in mDCs contribute to aberrant Treg neogenesis and, in turn, to altered Treg homeostasis and function in MS. METHODS We recruited blood samples from 20 MS patients and 20 healthy controls to assess TSLPR expression on mDCs ex vivo by flow cytometry and by activating mDCs induced by recombinant TSLP (rhTSLP) in vitro. As previous studies documented normalization of both function and homeostasis of Tregs under immunomodulatory (IM) therapy with interferon-beta (IFN-beta) and glatiramer acetate (GA), we also tested phenotypes and function of mDCs obtained from IM-treated patients (IFN-beta: n=20, GA: n=20). RESULTS We found that TSLP-induced mDC activation and effector function in vitro was reduced in MS and correlated with TSLPR-expression levels on mDCs. IM treatment prompted upregulation of TSLPR on mDCs and an increase in TSLP-induced activation of mDCs together with a normalization of Treg homeostasis. CONCLUSION The decreased TSLP-induced activation of MS-derived mDCs in vitro, together with the reduced density of TSLPR on the cell surface of mDCs corroborates the hypothesis of mDCs being critically involved in impairing Treg development in MS.
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Affiliation(s)
- Jürgen Haas
- Department of Neurology, University Hospital of Heidelberg, Germany
| | | | | | - Sven Jarius
- Department of Neurology, University Hospital of Heidelberg, Germany
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Scalea JR, Hickman JB, Moore DJ, Brayman KL. An overview of the necessary thymic contributions to tolerance in transplantation. Clin Immunol 2016; 173:S1521-6616(16)30382-5. [PMID: 27989896 DOI: 10.1016/j.clim.2016.10.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 10/04/2016] [Accepted: 10/22/2016] [Indexed: 02/08/2023]
Abstract
The thymus is important for the development of the immune system. However, aging leads to predictable involution of the thymus and immunodeficiency. These immunodeficiencies may be rectified with thymic rejuvenation. Atrophy of the thymus is governed by a complex interplay of molecular, cytokine and hormonal factors. Herein we review the interaction of these factors across age and how they may be targeted for thymic rejuvenation. We further discuss the growing pre-clinical evidence defining the necessary and sufficient contributions of the thymus to successful tolerance induction in transplantation.
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Affiliation(s)
- Joseph R Scalea
- Division of Transplantation, Department of Surgery, University of Maryland, United States.
| | - John B Hickman
- School of Medicine, University of Virginia, United States
| | - Daniel J Moore
- Division of Endocrinology, Department of Pediatrics, Department of Pathology, Microbiology and Immunology, Vanderbilt University, United States
| | - Kenneth L Brayman
- School of Medicine, University of Virginia, United States; Division of Transplantation, Department of Surgery, University of Virginia, United States
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8
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Baroja-Mazo A, Revilla-Nuin B, Parrilla P, Martínez-Alarcón L, Ramírez P, Pons JA. Tolerance in liver transplantation: Biomarkers and clinical relevance. World J Gastroenterol 2016; 22:7676-91. [PMID: 27678350 PMCID: PMC5016367 DOI: 10.3748/wjg.v22.i34.7676] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 07/04/2016] [Accepted: 08/05/2016] [Indexed: 02/06/2023] Open
Abstract
Transplantation is the optimal treatment for end-stage organ failure, and modern immunosuppression has allowed important progress in short-term outcomes. However, immunosuppression poorly influences chronic rejection and elicits chronic toxicity in current clinical practice. Thus, a major goal in transplantation is to understand and induce tolerance. It is well established that human regulatory T cells expressing the transcription factor FoxP3 play important roles in the maintenance of immunological self-tolerance and immune homeostasis. The major regulatory T cell subsets and mechanisms of expansion that are critical for induction and long-term maintenance of graft tolerance and survival are being actively investigated. Likewise, other immune cells, such as dendritic cells, monocyte/macrophages or natural killer cells, have been described as part of the process known as "operational tolerance". However, translation of these results towards clinical practice needs solid tools to identify accurately and reliably patients who are going to be tolerant. In this way, a plethora of genetic and cellular biomarkers is raising and being validated worldwide in large multi-center clinical trials. Few of the studies performed so far have provided a detailed analysis of the impact of immunosuppression withdrawal on pre-existing complications derived from the long-term administration of immunosuppressive drugs and the side effects associated with them. The future of liver transplantation is aimed to develop new therapies which increase the actual low tolerant vs non-tolerant recipients ratio.
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Bretscher PA. The activation and inactivation of mature CD4 T cells: a case for peripheral self-nonself discrimination. Scand J Immunol 2014; 79:348-60. [PMID: 24684567 PMCID: PMC4282366 DOI: 10.1111/sji.12173] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 03/24/2014] [Indexed: 01/09/2023]
Abstract
The establishment of central tolerance to most self-antigens results in a repertoire of mature peripheral lymphocytes specific for foreign and peripheral self-antigens. The framework that single, mature lymphocytes are inactivated by antigen, whereas their activation requires lymphocyte cooperation, accounts for diverse observations and incorporates a mechanism of peripheral tolerance. This framework accounts for the generalizations that the sustained activation by antigen of most B cells and CD8 T cells requires CD4 T helper cells; in the absence of CD4 T cells, antigen can inactivate these B cells and CD8 T cells. In this sense, CD4 T cells are the guardians of the fate of most B cells and CD8 T cells when they encounter antigen. I argue here that the single-lymphocyte/multiple-lymphocyte framework for the inactivation/activation of lymphocytes also applies to CD4 T cells. I consider within this framework a model for the activation/inactivation of CD4 T cells that is consistent with the large majority of contemporary observations, including significant clinical observations. I outline the grounds why I feel this model is more plausible than the contemporary and predominant pathogen-associated molecular pattern (PAMP) and Danger Models for CD4 T cell activation. These models are based upon what I consider the radical premise that self–nonself discrimination does not exist at the level of mature CD4 T cells. I explain why I feel this feature renders the PAMP and Danger Models somewhat implausible. The model I propose, in contrast, is conservative in that it embodies such a process of self–nonself discrimination.
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Affiliation(s)
- P A Bretscher
- University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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Al-Adra DP, Anderson CC. Mixed chimerism and split tolerance: mechanisms and clinical correlations. CHIMERISM 2013; 2:89-101. [PMID: 22509425 DOI: 10.4161/chim.2.4.19017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Establishing hematopoietic mixed chimerism can lead to donor-specific tolerance to transplanted organs and may eliminate the need for long-term immunosuppressive therapy, while also preventing chronic rejection. In this review, we discuss central and peripheral mechanisms of chimerism induced tolerance. However, even in the long-lasting presence of a donor organ or donor hematopoietic cells, some allogeneic tissues from the same donor can be rejected; a phenomenon known as split tolerance. With the current goal of creating mixed chimeras using clinically feasible amounts of donor bone marrow and with minimal conditioning, split tolerance may become more prevalent and its mechanisms need to be explored. Some predisposing factors that may increase the likelihood of split tolerance are immunogenicity of the graft, certain donor-recipient combinations, prior sensitization, location and type of graft and minimal conditioning chimerism induction protocols. Additionally, split tolerance may occur due to a differential susceptibility of various types of tissues to rejection. The mechanisms involved in a tissue's differential susceptibility to rejection include the presence of polymorphic tissue-specific antigens and variable sensitivity to indirect pathway effector mechanisms. Finally, we review the clinical attempts at allograft tolerance through the induction of chimerism; studies that are revealing the complex relationship between chimerism and tolerance. This relationship often displays split tolerance, and further research into its mechanisms is warranted.
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Affiliation(s)
- David P Al-Adra
- Department of Surgery, Alberta Diabetes Institute, University of Alberta, Edmonton, AB Canada
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Capalbo D, Giardino G, Martino LD, Palamaro L, Romano R, Gallo V, Cirillo E, Salerno M, Pignata C. Genetic basis of altered central tolerance and autoimmune diseases: a lesson from AIRE mutations. Int Rev Immunol 2012; 31:344-62. [PMID: 23083345 DOI: 10.3109/08830185.2012.697230] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The thymus is a specialized organ that provides an inductive environment for the development of T cells from multipotent hematopoietic progenitors. Self-nonself discrimination plays a key role in inducing a productive immunity and in preventing autoimmune reactions. Tolerance represents a state of immunologic nonresponsiveness in the presence of a particular antigen. The immune system becomes tolerant to self-antigens through the two main processes, central and peripheral tolerance. Central tolerance takes place within the thymus and represents the mechanism by which T cells binding with high avidity self-antigens, which are potentially autoreactive, are eliminated through so-called negative selection. This process is mostly mediated by medullary thymic epithelia cells (mTECs) and medullary dendritic cells (DCs). A remarkable event in the process is the expression of tissue-specific antigens (TSA) by mTECs driven by the transcription factor autoimmune regulator (AIRE). Mutations in this gene result in autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), a rare autosomal recessive disease (OMIM 240300). Thus far, this syndrome is the paradigm of a genetically determined failure of central tolerance and autoimmunty. Patients with APECED have a variable pattern of autoimmune reactions, involving different endocrine and nonendocrine organs. However, although APECED is a monogenic disorder, it is characterized by a wide variability of the clinical expression, thus implying a further role for disease-modifying genes and environmental factors in the pathogenesis. Studies on this polyreactive autoimmune syndrome contributed enormously to unraveling several issues of the molecular basis of autoimmunity. This review focuses on the developmental, functional, and molecular events governing central tolerance and on the clinical implication of its failure.
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12
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Pasquet L, Joffre O, Santolaria T, van Meerwijk JPM. Hematopoietic chimerism and transplantation tolerance: a role for regulatory T cells. Front Immunol 2011; 2:80. [PMID: 22566869 PMCID: PMC3342389 DOI: 10.3389/fimmu.2011.00080] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 12/05/2011] [Indexed: 01/13/2023] Open
Abstract
The immunosuppressive regimens currently used in transplantation to prevent allograft destruction by the host's immune system have deleterious side effects and fail to control chronic rejection processes. Induction of donor-specific non-responsiveness (i.e., immunological tolerance) to transplants would solve these problems and would substantially ameliorate patients' quality of life. It has been proposed that bone marrow or hematopoietic stem-cell transplantation, and resulting (mixed) hematopoietic chimerism, lead to immunological tolerance to organs of the same donor. However, a careful analysis of the literature, performed here, clearly establishes that whereas hematopoietic chimerism substantially prolongs allograft survival, it does not systematically prevent chronic rejection. Moreover, the cytotoxic conditioning regimens used to achieve long-term persistence of chimerism are associated with severe side effects that appear incompatible with a routine use in the clinic. Several laboratories recently embarked on different studies to develop alternative strategies to overcome these issues. We discuss here recent advances obtained by combining regulatory T cell infusion with bone-marrow transplantation. In experimental settings, this attractive approach allows development of genuine immunological tolerance to donor tissues using clinically relevant conditioning regimens.
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Affiliation(s)
- Lise Pasquet
- INSERM U1043Toulouse, France
- CNRS U5282Toulouse, France
- Centre de Physiopathologie de Toulouse Purpan, Université Paul Sabatier, Université de ToulouseToulouse, France
| | - Olivier Joffre
- INSERM U1043Toulouse, France
- CNRS U5282Toulouse, France
- Centre de Physiopathologie de Toulouse Purpan, Université Paul Sabatier, Université de ToulouseToulouse, France
| | - Thibault Santolaria
- INSERM U1043Toulouse, France
- CNRS U5282Toulouse, France
- Centre de Physiopathologie de Toulouse Purpan, Université Paul Sabatier, Université de ToulouseToulouse, France
| | - Joost P. M. van Meerwijk
- INSERM U1043Toulouse, France
- CNRS U5282Toulouse, France
- Centre de Physiopathologie de Toulouse Purpan, Université Paul Sabatier, Université de ToulouseToulouse, France
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Moon JJ, Dash P, Oguin TH, McClaren JL, Chu HH, Thomas PG, Jenkins MK. Quantitative impact of thymic selection on Foxp3+ and Foxp3- subsets of self-peptide/MHC class II-specific CD4+ T cells. Proc Natl Acad Sci U S A 2011; 108:14602-7. [PMID: 21873213 PMCID: PMC3167500 DOI: 10.1073/pnas.1109806108] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
It is currently thought that T cells with specificity for self-peptide/MHC (pMHC) ligands are deleted during thymic development, thereby preventing autoimmunity. In the case of CD4(+) T cells, what is unclear is the extent to which self-peptide/MHC class II (pMHCII)-specific T cells are deleted or become Foxp3(+) regulatory T cells. We addressed this issue by characterizing a natural polyclonal pMHCII-specific CD4(+) T-cell population in mice that either lacked or expressed the relevant antigen in a ubiquitous pattern. Mice expressing the antigen contained one-third the number of pMHCII-specific T cells as mice lacking the antigen, and the remaining cells exhibited low TCR avidity. In mice lacking the antigen, the pMHCII-specific T-cell population was dominated by phenotypically naive Foxp3(-) cells, but also contained a subset of Foxp3(+) regulatory cells. Both Foxp3(-) and Foxp3(+) pMHCII-specific T-cell numbers were reduced in mice expressing the antigen, but the Foxp3(+) subset was more resistant to changes in number and TCR repertoire. Therefore, thymic selection of self-pMHCII-specific CD4(+) T cells results in incomplete deletion within the normal polyclonal repertoire, especially among regulatory T cells.
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Affiliation(s)
- James J Moon
- Department of Microbiology and Center for Immunology, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
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Ezzelarab M, Thomson AW. Tolerogenic dendritic cells and their role in transplantation. Semin Immunol 2011; 23:252-63. [PMID: 21741270 DOI: 10.1016/j.smim.2011.06.007] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 06/10/2011] [Indexed: 01/09/2023]
Abstract
The pursuit of clinical transplant tolerance has led to enhanced understanding of mechanisms underlying immune regulation, including the characterization of immune regulatory cells, in particular antigen-presenting cells (APC) and regulatory T cells (Treg), that may play key roles in promoting operational tolerance. Dendritic cells (DC) are highly efficient APC that have been studied extensively in rodents and humans, and more recently in non-human primates. Owing to their ability to regulate both innate and adaptive immune responses, DC are considered to play crucial roles in directing the alloimmune response towards transplant tolerance or rejection. Mechanisms via which they can promote central and peripheral tolerance include clonal deletion, the induction of Treg, and inhibition of memory T cell responses. These properties have led to the use of tolerogenic DC as a therapeutic strategy to promote organ transplant tolerance. In rodents, infusion of donor- or recipient-derived tolerogenic DC can extensively prolong donor-specific allograft survival, in association with regulation of the host T cell response. In clinical transplantation, progress has been made in monitoring DC in relation to graft outcome, including studies in operational liver transplant tolerance. Although clinical trials involving immunotherapeutic DC for patients with cancer are ongoing, implementation of human DC therapy in clinical transplantation will require assessment of various critical issues. These include cell isolation and purification techniques, source, route and timing of administration, and combination immunosuppressive therapy. With ongoing non-human primate studies focused on DC therapy, these logistics can be investigated seeking the optimal approaches. The scientific rationale for implementation of tolerogenic DC therapy to promote clinical transplant tolerance is strong. Evaluation of technical and therapeutic logistic issues is an important next step prior to the application of tolerogenic DC in clinical organ transplantation.
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Affiliation(s)
- Mohamed Ezzelarab
- Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh School of Medicine, 200 Lothrop Street, BST W1540, Pittsburgh, PA 15261, USA
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15
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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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Abstract
Systemic lupus erythematosus (SLE) persists as a chronic inflammatory autoimmune disease and is characterized by the production of autoantibodies and immune complexes that affect multiple organs. The underlying mechanism that triggers and sustains disease are complex and involve certain susceptibility genes and environmental factors. There have been several immune mediators linked to SLE including cytokines and chemokines that have been reviewed elsewhere [ 1-3 ]. A number of articles have reviewed the role of B cells and T cells in SLE [ 4-10 ]. Here, we focus on the role of dendritic cells (DC) and innate immune factors that may regulate autoreactive B cells.
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Affiliation(s)
- Heather M Seitz
- Johnson County Community College, Science Division, Overland Park, Kansas, USA
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17
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Thymic selection and lineage commitment of CD4(+)Foxp3(+) regulatory T lymphocytes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2010; 92:251-77. [PMID: 20800824 DOI: 10.1016/s1877-1173(10)92010-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Regulatory T lymphocytes play a central role in the control of a variety of immune-responses. Their absence in humans and in experimental animal models leads to severe autoimmune and inflammatory disorders. Consistent with their major role in prevention of autoimmune pathology, their repertoire is enriched in autospecific cells. Probably the majority of regulatory T cells develop in the thymus. How T cell-precursors choose between the conventional versus regulatory T cell lineages remains an unanswered question. More is known about selection of regulatory T cell precursors. Positive selection of these cells is favored by high affinity interactions with MHC class II/peptide ligands expressed by thymic epithelial or dendritic cells. They are also known to be relatively resistant to negative selection. These two parameters allow for the generation of the autoreactive regulatory T cell repertoire, and clearly distinguish selection-criteria of conventional versus regulatory T cell-precursors. It will now be important to elucidate the molecular mechanisms involved in the intrathymic choice of the regulatory T cell-lineage.
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Nobrega C, Roque S, Nunes-Alves C, Coelho A, Medeiros I, Castro AG, Appelberg R, Correia-Neves M. Dissemination of mycobacteria to the thymus renders newly generated T cells tolerant to the invading pathogen. THE JOURNAL OF IMMUNOLOGY 2009; 184:351-8. [PMID: 19949112 DOI: 10.4049/jimmunol.0902152] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The ability of the thymus to generate a population of T cells that is, for the most part, self-restricted and self-tolerant depends to a great extent on the Ags encountered during differentiation. We recently showed that mycobacteria disseminate to the thymus, which raised the questions of how mycobacteria within the thymus influence T cell differentiation and whether such an effect impacts host-pathogen interactions. Athymic nude mice were reconstituted with thymic grafts from Mycobacterium avium-infected or control noninfected donors. T cells generated from thymi of infected donors seemed generally normal, because they retained the ability to reconstitute the periphery and to respond to unspecific stimuli in vitro as well as to antigenic stimulation with third-party Ags, such as OVA, upon in vivo immunization. However, these cells were unable to mount a protective immune response against a challenge with M. avium. The observation that thymic infection interferes with T cell differentiation, generating T cells that are tolerant to pathogen-specific Ags, is of relevance to understand the immune response during chronic persistent infections. In addition, it has potential implications for the repertoire of T cells generated in patients with a mycobacterial infection recovering from severe lymphopenia, such as patients coinfected with HIV and receiving antiretroviral therapy.
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Affiliation(s)
- Claudia Nobrega
- Life and Health Sciences Research Institute, School of Health Sciences, University of Minho, Braga, Portugal
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Baba T, Nakamoto Y, Mukaida N. Crucial contribution of thymic Sirp alpha+ conventional dendritic cells to central tolerance against blood-borne antigens in a CCR2-dependent manner. THE JOURNAL OF IMMUNOLOGY 2009; 183:3053-63. [PMID: 19675159 DOI: 10.4049/jimmunol.0900438] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Thymic dendritic cells (DCs) as well as thymic epithelial cells are presumed to be major sentinels in central tolerance by inducing the apoptosis of autoreactive T progenitor cells. The thymic DC population is composed of heterogeneous subsets including CD11c(+)B220(+) plasmacytoid DCs, CD11c(+)B220(-)CD8alpha(+) signal regulatory protein alpha (Sirpalpha)(-) and CD11c(+)B220(-)CD8alpha(-)Sirpalpha(+) conventional DCs (cDCs). However, the distinctive role of each DC subset remains undefined. We show herein that Sirpalpha(+) cDCs, a minor subpopulation, was disseminated in the thymic cortical area with some of them uniquely localized inside perivascular regions and nearby small vessels in the thymus. The Sirpalpha(+) but not Sirpalpha(-) cDC subset can selectively capture blood-circulating Ags. Moreover, in CCR2-deficient mice, the thymic Sirpalpha(+) cDC subset, but not other thymic cell components, was moderately decreased especially in the perivascular regions. Concomitantly, these mice exhibited a modest impairment in intrathymic negative selection against blood-borne Ags, with the reduced capacity to uptake blood-borne Ags. Given their intrathymic cortical localization, CD11c(+)B220(-)CD8alpha(-)Sirpalpha(+) cDCs can have a unique role in the development of central tolerance against circulating peripheral Ags, at least partially in a CCR2-dependent manner.
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Affiliation(s)
- Tomohisa Baba
- Division of Molecular Bioregulation, Cancer Research Institute, Kanazawa University, Kanazawa, Ishikawa, Japan
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20
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Abstract
Surfactant protein A (SP-A) is a lung collectin with diverse immunoregulatory activities. SP-A regulates the innate host defense by enhancing phagocytosis of pathogens and modulating the production of nitric oxide and cytokines by immune cells. Additionally, SP-A also modulates the phenotypic and functional properties of the cells of adaptive immune response such as dendritic cells (DCs) and lymphocytes. Bone marrow-derived DCs generated in the presence of SP-A fail to increase lipopolysaccharide-induced upregulation of major histocompatibility complex (MHC) class II and CD86 costimulatory molecule on DCs surface and behaves like "tolerogenic DCs". SP-A may also induce tolerance by suppressing the proliferation of activated T lymphocytes. Thus, based on immunoregulatory properties of SP-A, it may be employed as a therapeutic agent for the treatment of autoimmune disease and organ transplantation.
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Affiliation(s)
- Shabbir Hussain
- Autoimmunity/Diabetes Group, Robarts Research Institute, 107 SDRI. 1400 Western Road, London, ON, Canada.
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Chu HH, Moon JJ, Takada K, Pepper M, Molitor JA, Schacker TW, Hogquist KA, Jameson SC, Jenkins MK. Positive selection optimizes the number and function of MHCII-restricted CD4+ T cell clones in the naive polyclonal repertoire. Proc Natl Acad Sci U S A 2009; 106:11241-5. [PMID: 19541603 PMCID: PMC2708705 DOI: 10.1073/pnas.0902015106] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Indexed: 02/02/2023] Open
Abstract
T cell receptors (TCRs) on T lymphocytes in an individual bind foreign peptides bound to major histocompatibility complex (MHC) molecules expressed in that individual (designated MHC(A)). Results from radiation bone marrow chimeras and TCR transgenic mice indicate that this complex form of antigen recognition is the result of positive selection of clones with low affinity for self peptide:MHC(A) complexes during development. Here we used a sensitive peptide:MHC tetramer enrichment method to quantify the role of positive selection in the generation of the preimmune polyclonal T cell repertoire in normal individuals. We made the surprising observation that mouse and human naive T cells capable of binding to foreign peptide:MHC(A) were present at the same frequency in hosts that expressed MHC(A) or a different MHC isoform (MHC(B)). However, most of the clones in MHC(B) hosts also recognized self peptide:MHC(A) complexes. When these "alloreactive" T cells were removed from the MHC(B) repertoire via negative selection in an MHC(A) host, the number of foreign peptide:MHC(A)-binding T cells was reduced to one fifth and many of the remaining cells did not respond to the peptide. Therefore, although positive selection on MHC(A) was not required to produce foreign peptide:MHC(A)-binding clones, it had a large effect on selecting responsive clones.
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Affiliation(s)
| | | | | | | | - Jerry A. Molitor
- Medicine, Center for Immunology, University of Minnesota Medical School, Minneapolis, MN 55455
| | - Timothy W. Schacker
- Medicine, Center for Immunology, University of Minnesota Medical School, Minneapolis, MN 55455
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22
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Oluwole SF, Oluwole OO, Adeyeri AO, DePaz HA. New strategies in immune tolerance induction. Cell Biochem Biophys 2009; 40:27-48. [PMID: 15289641 DOI: 10.1385/cbb:40:3:27] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Induction of tolerance in clinical organ transplantation that will obviate the use of chronic immunosuppression and preserve host immune response to other antigens remains the goal of transplant research. The thymus plays a critical role in the ability of the immune system to discriminate between self- and nonself-antigens or harmful and harmless alloantigens. We now know that multiple factors determine how the immune system responds to a self-antigen or foreign antigen. These determinants include developmental stage of the host, stage of T-cell maturity, site of antigen encounter, type and maturity of antigen-presenting cells, and presence and type of costimulatory molecules. Our understanding of the mechanisms of T-cell interactions with peptide/ major histocompatibility complex in peripheral lymphoid organs has led to experiments that translate into peripheral T-cell tolerance. The induction of high-avidity peripheral alloreactive T cells in the early phase of organ transplantation makes it difficult to achieve long-term alloantigen-specific tolerance without the use of transient perioperative immunosuppression. Therefore, protocols that induce robust tolerance in rodent and nonhuman primate models involve the use of donor antigen combined with a short course of perioperative immunosuppression. These studies suggest that the underlying mechanisms of peripheral tolerance include deletion, anergy, immune deviation, and regulatory T cells. This review focuses on recent advances in tolerance induction in experimental animal models and discusses their relevance to the development of protocols for the induction and maintenance of clinical transplant tolerance.
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Affiliation(s)
- Soji F Oluwole
- Department of Surgery, Columbia University, College of Physicians and Surgeons, New York, NY, USA.
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23
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Ohnmacht C, Pullner A, King SBS, Drexler I, Meier S, Brocker T, Voehringer D. Constitutive ablation of dendritic cells breaks self-tolerance of CD4 T cells and results in spontaneous fatal autoimmunity. ACTA ACUST UNITED AC 2009; 206:549-59. [PMID: 19237601 PMCID: PMC2699126 DOI: 10.1084/jem.20082394] [Citation(s) in RCA: 439] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Lack of immunological tolerance against self-antigens results in autoimmune disorders. During onset of autoimmunity, dendritic cells (DCs) are thought to be critical for priming of self-reactive T cells that have escaped tolerance induction. However, because DCs can also induce T cell tolerance, it remains unclear whether DCs are required under steady-state conditions to prevent autoimmunity. To address this question, we crossed CD11c-Cre mice with mice that express diphtheria toxin A (DTA) under the control of a loxP-flanked neomycin resistance (neoR) cassette from the ROSA26 locus. Cre-mediated removal of the neoR cassette leads to DTA expression and constitutive loss of conventional DCs, plasmacytoid DCs, and Langerhans cells. These DC-depleted (ΔDC) mice showed increased frequencies of CD4 single-positive thymocytes and infiltration of CD4 T cells into peripheral tissues. They developed spontaneous autoimmunity characterized by reduced body weight, splenomegaly, autoantibody formation, neutrophilia, high numbers of Th1 and Th17 cells, and inflammatory bowel disease. Pathology could be induced by reconstitution of wild-type (WT) mice with bone marrow (BM) from ΔDC mice, whereas mixed BM chimeras that received BM from ΔDC and WT mice remained healthy. This demonstrates that DCs play an essential role to protect against fatal autoimmunity under steady-state conditions.
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Affiliation(s)
- Caspar Ohnmacht
- Institute for Immunology, Department of Medicine, University of Munich, 80336 Munich, Germany
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Layton DS, Bean AG, Dodge NM, Strom ADG, Sandrin MS, Ierino FL. Differential cytokine expression and regulation of human anti-pig xenogeneic responses by modified porcine dendritic cells. Xenotransplantation 2009; 15:257-67. [PMID: 18957048 DOI: 10.1111/j.1399-3089.2008.00477.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Porcine dendritic cells (DC) are likely to be pivotal cells in the initiation of stimulatory and potential tolerogenic responses to xenoantigens, however, there are limited studies characterizing these antigen presenting cells. METHODS Porcine PBMC (CD172a(+)) were cultured with GM-CSF and IL-4 and phenotype and functional capabilities assessed. Lipopolysaccharide (LPS), IL-10, and IL-3 were added to the GM-CSF/IL-4 DC cultures to determine phenotypic and functional changes. Quantitative real-time polymerase chain reaction (PCR) for key cytokines was performed and the modified porcine DC were further assessed by primary mixed lymphocyte reaction to determine the effect of LPS, IL-10, and IL-3 on stimulatory capability. RESULTS Porcine PBMC (CD172(+)) cultured with GM-CSF and IL-4 produced cells with DC morphology, which were major histocompatability complex (MHC) class II(+), CD14(-/lo), and CD1a(lo). Addition of IL-10 or IL-3 to GM-CSF/IL-4 DC cultures produced cells with lower levels of MHC class II and higher levels of antigen uptake consistent with less mature DC. Quantitative real-time PCR of DC showed the addition of IL-10 induced an increase in IL-10 mRNA, no detectable IL-12, and reduced IL-6 mRNA. The addition of IL-3 to DC cultures decreased IL-12, IL-6 and tumor necrosis factor (TNF), with no change in IL-10 mRNA. GM-CSF/IL-4 DC induced strong human lymphocyte proliferation, compared with significantly reduced stimulatory capacity induced by IL-10 and IL-3 treated DC cultures. CONCLUSIONS The profound effect on differential DC cytokine profile and reduced human anti-pig responses has important therapeutic implications in xenotransplantation. The mechanism of altered regulation warrants further investigation.
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Abstract
Mutations in the transcriptional regulator, Aire, cause APECED, a polyglandular autoimmune disease with monogenic transmission. Animal models of APECED have revealed that Aire plays an important role in T cell tolerance induction in the thymus, mainly by promoting ectopic expression of a large repertoire of transcripts encoding proteins normally restricted to differentiated organs residing in the periphery. The absence of Aire results in impaired clonal deletion of self-reactive thymocytes, which escape into the periphery and attack a variety of organs. In addition, Aire is a proapoptotic factor, expressed at the final maturation stage of thymic medullary epithelial cells, a function that may promote cross-presentation of the antigens encoded by Aire-induced transcripts in these cells. Transcriptional regulation by Aire is unusual in being very broad, context-dependent, probabilistic, and noisy. Structure/function analyses and identification of its interaction partners suggest that Aire may impact transcription at several levels, including nucleosome displacement during elongation and transcript splicing or other aspects of maturation.
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Affiliation(s)
- Diane Mathis
- Section on Immunology and Immunogenetics, Joslin Diabetes Center; Department of Medicine, Brigham and Women's Hospital; Harvard Medical School; and the Harvard Stem Cell Institute, Boston, Massachusetts 02215, USA.
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26
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Abstract
Dendritic cells (DCs) are professional antigen-presenting cells that have the ability to sense infection and tissue stress, sample and present antigen to T lymphocytes, and instruct the initiation of different forms of immunity and tolerance. The functional versatility of DCs depends on their remarkable ability to translate collectively the information from the invading microbes, as well as their resident tissue microenvironments. Recent progress in understanding Toll-like receptor (TLR) biology has illuminated the mechanisms by which DCs link innate and adaptive antimicrobial immune responses. However, how tissue microenvironments shape the function of DCs has remained elusive. Recent studies of TSLP (thymic stromal lymphopoietin), an epithelial cell-derived cytokine that strongly activates DCs, provide strong evidence at a molecular level that epithelial cells/tissue microenvironments directly communicate with DCs, the professional antigen-presenting cells of the immune system. We review recent progress on how TSLP expressed within thymus and peripheral lymphoid and nonlymphoid tissues regulates DC-mediated central tolerance, peripheral T cell homeostasis, and inflammatory Th2 responses.
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Affiliation(s)
- Yong-Jun Liu
- Department of Immunology, Center for Cancer Immunology Research, The University of Texas, M. D. Anderson Cancer Center, Houston, Texas, USA
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27
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Goldberg GL, Alpdogan O, Muriglan SJ, Hammett MV, Milton MK, Eng JM, Hubbard VM, Kochman A, Willis LM, Greenberg AS, Tjoe KH, Sutherland JS, Chidgey A, van den Brink MRM, Boyd RL. Enhanced immune reconstitution by sex steroid ablation following allogeneic hemopoietic stem cell transplantation. THE JOURNAL OF IMMUNOLOGY 2007; 178:7473-84. [PMID: 17513799 DOI: 10.4049/jimmunol.178.11.7473] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Delayed immune reconstitution in adult recipients of allogeneic hemopoietic stem cell transplantations (HSCT) is related to age-induced thymic atrophy. Overcoming this paucity of T cell function is a major goal of clinical research but in the context of allogeneic transplants, any strategy must not exacerbate graft-vs-host disease (GVHD) yet ideally retain graft-vs-tumor (GVT) effects. We have shown sex steroid ablation reverses thymic atrophy and enhances T cell recovery in aged animals and in congenic bone marrow (BM) transplant but the latter does not have the complications of allogeneic T cell reactivity. We have examined whether sex steroid ablation promoted hemopoietic and T cell recovery following allogeneic HSCT and whether this benefit was negated by enhanced GVHD. BM and thymic cell numbers were significantly increased at 14 and 28 days after HSCT in castrated mice compared with sham-castrated controls. In the thymus, the numbers of donor-derived thymocytes and dendritic cells were significantly increased after HSCT and castration; donor-derived BM precursors and developing B cells were also significantly increased. Importantly, despite restoring T cell function, sex steroid inhibition did not exacerbate the development of GVHD or ameliorate GVT activity. Finally, IL-7 treatment in combination with castration had an additive effect on thymic cellularity following HSCT. These results indicate that sex steroid ablation can profoundly enhance thymic and hemopoietic recovery following allogeneic HSCT without increasing GVHD and maintaining GVT.
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Affiliation(s)
- Gabrielle L Goldberg
- Department of Pathology and Immunology, Central and Eastern Clinical School, Monash University, Melbourne, Australia.
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Liu YJ, Soumelis V, Watanabe N, Ito T, Wang YH, Malefyt RDW, Omori M, Zhou B, Ziegler SF. TSLP: an epithelial cell cytokine that regulates T cell differentiation by conditioning dendritic cell maturation. Annu Rev Immunol 2007; 25:193-219. [PMID: 17129180 DOI: 10.1146/annurev.immunol.25.022106.141718] [Citation(s) in RCA: 466] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dendritic cells (DCs) are professional antigen-presenting cells that have the ability to sense infection and tissue stress, sample and present antigen to T lymphocytes, and induce different forms of immunity and tolerance. The functional versatility of DCs depends on their remarkable ability to translate collectively the information from both the invading microbes and their resident tissue microenvironments and then make an appropriate immune response. Recent progress in understanding TLR biology has illuminated the mechanisms by which DCs link innate and adaptive antimicrobial immune responses. However, how tissue microenvironments shape the function of DCs has remained elusive. Recent studies of TSLP (thymic stromal lymphopoietin), an epithelial cell-derived cytokine that strongly activates DCs, provide evidence at a molecular level that epithelial cells/tissue microenvironments directly communicate with DCs. We review recent progress on how TSLP expressed within thymus and peripheral lymphoid and nonlymphoid tissues regulates DC-mediated central tolerance, peripheral T cell homeostasis, and inflammatory Th2 responses.
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Affiliation(s)
- Yong-Jun Liu
- Department of Immunology, Center of Cancer Immunology Research, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA.
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29
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Prechtel AT, Steinkasserer A. CD83: an update on functions and prospects of the maturation marker of dendritic cells. Arch Dermatol Res 2007; 299:59-69. [PMID: 17334966 DOI: 10.1007/s00403-007-0743-z] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Accepted: 02/12/2007] [Indexed: 12/12/2022]
Abstract
CD83 is one of the most characteristic cell surface markers for fully matured dendritic cells (DCs). In their function as antigen presenting cells they induce T-cell mediated immune responses. In this review we provide an overview on well described and proposed functions of this molecule as well as on very recent insights and new hypothesis. Already the CD83 messenger RNA processing differs remarkably from the processing of other cellular mRNAs: instead of the usual TAP mRNA export pathway, the CD83 mRNA is exported by the specific CRM1-mediated pathway, utilized only by a minority of cellular mRNAs. On the protein level, two different isoforms of CD83 exist: a membrane-bound and a soluble form. The isoforms are generated by different subsets of cells, including DCs, T-cells and B-cells, and also differ in their biological function. While the membrane-bound CD83 is of immune stimulatory capacity, activates T-cells and is important for the generation of thymocytes, the soluble CD83 has the opposite effect and has an immune inhibitory capacity. Due to its immune inhibitory function, CD83 has great potential for treatment of autoimmune diseases, for organ transplantations, and for immunotherapy, just to name a few examples. Moreover, some viruses prevent recognition by the host's immune system by specifically targeting CD83 surface expression.
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Affiliation(s)
- Alexander T Prechtel
- Department of Dermatology, University Hospital Erlangen, Hartmannstrasse 14, 91052, Erlangen, Germany.
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Howard CJ, Charleston B, Stephens SA, Sopp P, Hope JC. The role of dendritic cells in shaping the immune response. Anim Health Res Rev 2007; 5:191-5. [PMID: 15984324 DOI: 10.1079/ahr200468] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AbstractDendritic cells are central to the initiation of primary immune responses. They are the only antigen-presenting cell capable of stimulating naive T cells, and hence they are pivotal in the generation of adaptive immunity. Dendritic cells also interact with and influence the response of cells of the innate immune system. The manner in which dendritic cells influence the responses in cells of both the innate and adaptive immune systems has consequences for the bias of the adaptive response that mediates immunity to infection after vaccination or infection. It also provides an opportunity to intervene and to influence the response, allowing ways of developing appropriate vaccination strategies. Mouse and human studies have identified myeloid, lymphoid and plasmacytoid dendritic cells. Studies in domesticated animals with agents of specific infectious diseases have confirmed the applicability of certain of the generic models developed from mice or from in vitro studies on human cells. In vivo and ex vivo studies in cattle have demonstrated the existence of a number of subpopulations of myeloid dendritic cells. These cells differ in their ability to stimulate T cells and in the cytokines that they produce, observations clearly having important implications for the bias of the T-cell response. Dendritic cells also interact with the innate immune system, inducing responses that potentially bias the subsequent adaptive response.
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Affiliation(s)
- C J Howard
- Institute for Animal Health, Compton, Newbury, Berkshire RG20 7NN, UK.
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31
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Charalambous A, Oks M, Nchinda G, Yamazaki S, Steinman RM. Dendritic cell targeting of survivin protein in a xenogeneic form elicits strong CD4+ T cell immunity to mouse survivin. THE JOURNAL OF IMMUNOLOGY 2007; 177:8410-21. [PMID: 17142738 DOI: 10.4049/jimmunol.177.12.8410] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
To determine whether strong CD4+ T cell immunity could be induced to a nonmutated self protein that is important for tumorigenesis, we selectively targeted the xenogeneic form of survivin, a survival protein overexpressed in tumors, to maturing dendritic cells in lymphoid tissues. Dendritic cell targeting via the DEC205 receptor in the presence of anti-CD40 and poly(I:C) as maturation stimuli, induced strong human and mouse survivin-specific CD4+ T cell responses, as determined by IFN-gamma, TNF-alpha, and IL-2 production, as well as the development of lytic MHC class II-restricted T cells and memory. Immunity was enhanced further by depletion of CD25+foxp3+ cells before vaccination. anti-DEC205-human survivin was superior in inducing CD4+ T cell responses relative to other approaches involving survivin plasmid DNA or survivin peptides with adjuvants. However, we were unable to induce CD8+ T cell immunity to survivin by two doses of DEC205-targeted survivin or the other strategies. Therefore, significant CD4+ T cell immunity to a self protein that is overexpressed in most human cancers can be induced by DEC205 targeting of the Ag in its xenogeneic form to maturing DCs.
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Affiliation(s)
- Anna Charalambous
- Laboratory of Cellular Physiology and Immunology, Chris Browne Center for Immunology and Immune Diseases, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
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Bonasio R, Scimone ML, Schaerli P, Grabie N, Lichtman AH, von Andrian UH. Clonal deletion of thymocytes by circulating dendritic cells homing to the thymus. Nat Immunol 2006; 7:1092-100. [PMID: 16951687 DOI: 10.1038/ni1385] [Citation(s) in RCA: 311] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Accepted: 08/01/2006] [Indexed: 11/08/2022]
Abstract
Dendritic cell (DC) presentation of self antigen to thymocytes is essential to the establishment of central tolerance. We show here that circulating DCs were recruited to the thymic medulla through a three-step adhesion cascade involving P-selectin, interactions of the integrin VLA-4 with its ligand VCAM-1, and pertussis toxin-sensitive chemoattractant signaling. Ovalbumin-specific OT-II thymocytes were selectively deleted after intravenous injection of antigen-loaded exogenous DCs. We documented migration of endogenous DCs to the thymus in parabiotic mice and after painting mouse skin with fluorescein isothiocyanate. Antibody to VLA-4 blocked the accumulation of peripheral tissue-derived DCs in the thymus and also inhibited the deletion of OT-II thymocytes in mice expressing membrane-bound ovalbumin in cardiac myocytes. These findings identify a migratory route by which peripheral DCs may contribute to central tolerance.
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Affiliation(s)
- Roberto Bonasio
- The CBR Institute for Biomedical Research, Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, 02115, USA
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Abstract
Dendritic cells (DCs) are uniquely well equipped antigen (Ag)-presenting cells. Their classic function was thought to be that of potent initiators of innate and adaptive immunity to infectious organisms and other Ags (including transplanted organs). Evidence has emerged, however, that DCs have a central and crucial role in determining the fate of immune responses toward either immunity or tolerance. This dichotomous function of DCs, coupled with their remarkable plasticity, renders them attractive therapeutic targets for immune modulation. In transplantation, much recent work has focused on the ability of DCs to silence immune reactivity in an Ag-specific manner in the hope of preventing rejection and diminishing reliance on potentially harmful immunosuppressive agents. Experimental strategies have included in vivo targeting of DCs, as well as ex vivo generation of regulatory (or tolerogenic) DCs with subsequent reinfusion (i.e. cell therapy). Different approaches to 'program' DC toward tolerogenic properties include genetic (transgene insertion), biologic (differential culture conditions, anti-inflammatory cytokine exposure) and pharmacologic manipulation. Recent data suggest a promising role for pharmacologic treatment as a means of generating potent regulatory DCs and have further stimulated speculation regarding their potential clinical application. Herein, we discuss evidence that the potential of regulatory DC therapy is considerable and that there are compelling reasons to evaluate it in the setting of organ transplantation in the near future.
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Affiliation(s)
- Kenneth R McCurry
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
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34
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Abstract
Dendritic cells (DCs) play a crucial role during the initiation of immune responses against non-self antigens. Following organ transplantation, activated donor- and recipient-derived DCs participate actively in graft rejection by sensitising recipient T cells via the direct or indirect pathways of allorecognition, respectively. There is increasing evidence that immature/semi-mature DCs induce antigen-specific unresponsiveness or tolerance to self antigens, both in central lymphoid tissue and in the periphery, through a variety of mechanisms (deletion, anergy and regulation). In the past few years, DC-based therapy of experimental allograft rejection has focused on ex vivo biological, pharmacological and genetic engineering of DCs to mimic/enhance their natural tolerogenicity. Successful outcomes in rodent models have built the case that DC-based therapy may provide a novel approach to transplant tolerance. Ongoing research into the role that DCs play in the induction of tolerance should allow for its clinical application in the near future.
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Affiliation(s)
- Mahyar Nouri-Shirazi
- Texas A&M University System Health Science Center, Baylor College of Dentistry, Department of Biomedical Sciences, Immunology Laboratory, 3302 Gaston Avenue, Dallas, TX 75246, USA.
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35
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Strutt TM, Uzonna J, McKinstry KK, Bretscher PA. Activation of thymic T cells by MHC alloantigen requires syngeneic, activated CD4+ T cells and B cells as APC. Int Immunol 2006; 18:719-28. [PMID: 16569677 DOI: 10.1093/intimm/dxl009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We examine here the in vitro requirements to activate immunocompetent T cells, present among thymocytes, to give rise to CTL, CD4+ T cells producing IL-2 and CD8+ T cells producing IFN-gamma. These thymocytes are naive in not having received antigen-dependent signals characteristic of the periphery. Their activation, upon stimulation with allogeneic spleen cells depleted of T cells, referred to here as allogeneic antigen-presenting cells (APCs), to produce allo-MHC-specific effector T cells, requires activated (radiation resistant) CD4+ T cells, syngeneic with the responding thymocytes. We refer here to these T cells as 'help'. Furthermore, optimal T cell activation requires an Ig+ B220+ cell in the allogeneic APC population, most probably a B cell. The allogeneic APCs cannot be replaced by conventional bone marrow (BM)-derived dendritic cells (DCs) activated by CD40 ligation or exposure to LPS. The requirements for both help and allogeneic B cells in the activation of thymocytes contrast with the requirements to generate substantial responses from splenic T cell populations. Activated, BM-derived DCs stimulate substantial splenic responses without help. These different requirements for activation could reflect the fact that thymocytes have not received an exit-thymus signal and/or that splenic T cells are heterogeneous, containing naive, memory and partially-activated T cells.
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Affiliation(s)
- Tara M Strutt
- Department of Microbiology and Immunology, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada
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36
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Abstract
The lymph nodes (LNs) harbor a cryptic T-lymphopoietic pathway that is dramatically amplified by oncostatin M (OM). OM-transgenic mice generate massive amounts of T lymphocytes in the absence of Lin(-)c-Kit(hi)IL-7Ralpha- lymphoid progenitors and of reticular epithelial cells. Extrathymic T cells that develop along the OM-dependent LN pathway originate from Lin(-)c-Kit(lo)IL-7Ralpha+ lymphoid progenitors and are different from classic T cells in terms of turnover kinetics and function. Positive selection does not obey the same rules in the thymus and the LNs, where positive selection of developing T cells is supported primarily by epithelial and hematopoietic cells, respectively. Extrathymic T cells undergo enhanced homeostatic proliferation and thereby acquire some properties of memory T cells. Following antigen encounter, extrathymic T-cells initiate proliferation and cytokine secretion more readily than classic T cells, but their accumulation is limited by an exquisite susceptibility to apoptosis. Studies on in vitro and in vivo extrathymic T-cell development have yielded novel insights into the essence of a primary T-lymphoid organ. Furthermore, comparison of the thymic and OM-dependent extrathymic pathways shows how the division of labor between primary and secondary lymphoid organs influences the repertoire and homeostasis of T lymphocytes.
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Affiliation(s)
- Marie-Eve Blais
- Institute of Research in Immunology and Cancer, University of Montreal, Montreal, Quebec, Canada
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Anderson MS, Venanzi ES, Chen Z, Berzins SP, Benoist C, Mathis D. The cellular mechanism of Aire control of T cell tolerance. Immunity 2005; 23:227-39. [PMID: 16111640 DOI: 10.1016/j.immuni.2005.07.005] [Citation(s) in RCA: 446] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Revised: 06/10/2005] [Accepted: 07/13/2005] [Indexed: 01/30/2023]
Abstract
Aire promotes the tolerization of thymocytes by inducing the expression of a battery of peripheral-tissue antigens in thymic medullary epithelial cells. We demonstrate that the cellular mechanism by which Aire exerts its tolerance-promoting function is not primarily positive selection of regulatory T cells, but rather negative selection of T effector cells. Surprisingly, supplementing its influence on the transcription of genes encoding peripheral-tissue antigens, Aire somehow enhances the antigen-presentation capability of medullary epithelial cells. Thus, this transcriptional control element promotes central tolerance both by furnishing a specific thymic stromal cell type with a repertoire of self antigens and by better arming such cells to present these antigens to differentiating thymocytes. In Aire's absence, autoimmunity and ultimately overt autoimmune disease develops.
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Affiliation(s)
- Mark S Anderson
- Section on Immunology and Immunogenetics, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02215, USA
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Abstract
In a small number of patients with multiple myeloma (MM), long-term disease-free survival has been achieved by harnessing the immune phenomenon, 'graft-versus-tumour' effect, induced by allogeneic haemopoietic stem cell transplantation. This has prompted many investigators to examine ways in which a patient's own immune system can be more effectively directed against their disease, with the ultimate aim of tumour eradication. In this review we assess the current understanding of immunobiology in MM, and how the different components of the immune system, such as dendritic cells, T cells and natural killer cells, may be harnessed using in-vitro and in-vivo priming techniques. We look at the clinical immunotherapy trials reported to date and whether, in light of the current information, immunotherapy for MM is an achievable goal.
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Affiliation(s)
- S J Harrison
- ATMU and Cancer Division, Section of Experimental Haematology, University of Glasgow, Glasgow, UK
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Lycke N. ADP-ribosylating bacterial enzymes for the targeted control of mucosal tolerance and immunity. Ann N Y Acad Sci 2005; 1029:193-208. [PMID: 15681758 DOI: 10.1196/annals.1309.036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The questions of whether mucosal tolerance and IgA immunity are mutually exclusive or can coexist and whether they represent priming of the local immune system through the same or different activation pathways are addressed. Two strategies were attempted: the first using cholera toxin (CT) or the enzymatically inactive receptor-binding B subunit of CT (CTB), and the second using CTA1-DD or an enzymatically inactive mutant thereof, CTA1R7K-DD. The CTA1-DD adjuvant is a fusion protein composed of the ADP-ribosylating part of CT, CTA1, and DD, which is derived from Staphylococcus areus protein A and targets the molecule to B cells. Here, we provide compelling evidence that delivery of antigen in the absence of ADP ribosylation can promote tolerance, whereas ADP-ribosyltransferase activity induces IgA immunity and prevents tolerance. By linking antigen to the ADP-ribosylating enzymes we could show that CT, although potentially binding to all nucleated cells, in fact, bound preferentially to dendritic cells (DCs) in vivo. On the other hand, DD-bound antigen was distinctly targeted to B cells and probably also to follicular dendritic cells (FDCs) in vivo. Interestingly, the CT and CTA1-DD adjuvants gave equally enhancing effects on mucosal and systemic responses, but appeared to target different APCs in vivo. CT- or CTB-conjugated antigen accumulated in mucosal and systemic DCs. Whereas only CT promoted an active IgA response, CTB induced tolerance to the conjugated antigen. Following intravenous injection of CT-conjugated antigen, DCs in the marginal zone (MZ) of the spleen were selectively targeted. Interestingly, CTB delivered antigen to the same MZ DCs, but failed to induce maturation and upregulation of costimulatory molecules in these cells. Thus, ADP-ribosylation was necessary for a strong enhancing effect of immune responses following CT/CTB-dependent delivery of antigen to the MZ DCs. Moreover, using CTA1-DD, antigen was targeted to the B cell follicle and FDC in the spleen after intravenous injection. Only active CTA1-DD, but not the inactive mutant CTA1R7K-DD, provided enhancing effects on immune responses. By contrast, antigen delivered by the CTA1R7K-DD stimulated specific tolerance in adoptively transferred T cell receptor transgenic CD4(+) T cells. Whether targeting of B cells suffices for tolerance induction or requires participation of DCs remains to be investigated. With CT we found that enzyme-dependent modulation of DCs affects migration, maturation, and differentiation of DCs, which resulted in CD4(+) T cell help for IgA B cell development. On the contrary, antigen presentation in the absence of ADP-ribosylating enzyme, as seen with CTB or CTA1R7K-DD, appears to expand specific T cells to a similar extent as enzymatically active CT or CTA1-DD, but fails to recruit help for germinal center (GC) formation and the necessary expansion of activated B cells. Also, the CD41 T cells that are primed in a suboptimal, tolerogenic, fashion do not migrate to the B cell follicle to provide T cell help. Thus, ADP-ribosylating enzymes may be used to selectively control the induction of an active IgA response or promote the development of tolerance. In particular, on the targeted APC, modulation of the expression of costimulatory molecules, CD80, CD86, CD83, and B7RP-1, plays an important role in the effect of the ADP-ribosylating CTA1-based adjuvants on the development of tolerance or active IgA immunity. For example, the expression of CD86 in vivo was a prominent feature of the enzymatically active CT or CTA1-DD adjuvants. By contrast, CD80 expression appeared not to be important in CTA1-augmented APCs for an adjuvant function.
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Affiliation(s)
- Nils Lycke
- Department of Clinical Immunology, University of Göteborg, S413 46 Göteborg, Sweden.
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Hawiger D, Masilamani RF, Bettelli E, Kuchroo VK, Nussenzweig MC. Immunological Unresponsiveness Characterized by Increased Expression of CD5 on Peripheral T Cells Induced by Dendritic Cells In Vivo. Immunity 2004; 20:695-705. [PMID: 15189735 DOI: 10.1016/j.immuni.2004.05.002] [Citation(s) in RCA: 176] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2003] [Revised: 03/25/2004] [Accepted: 03/31/2004] [Indexed: 11/24/2022]
Abstract
In the steady state, interaction between T cells and antigen-presenting dendritic cells (DCs) leads to T cell tolerance. To examine the role of DC regulated peripheral tolerance in a model autoimmune disease, we delivered an encephalitogenic oligodendrocyte glycoprotein (MOG) peptide to DCs in vivo. We found that targeting MOG peptide to DCs resulted in a novel form of peripheral T cell tolerance that was sufficiently profound to prevent autoimmune experimental acute encephalomyelitis (EAE). The tolerized T cells were severely impaired in specific secondary responses to antigen in vivo but they were not intrinsically anergic since they remained highly responsive to T cell receptor (TCR) stimulation in vitro. The mechanism that mediates this dynamic antigen-specific T cell unresponsiveness differs from previously described forms of tolerance in that it requires that DCs induce CD5 expression on activated T cells.
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Affiliation(s)
- Daniel Hawiger
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10021 USA
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41
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Zhang Y, Joe G, Zhu J, Carroll R, Levine B, Hexner E, June C, Emerson SG. Dendritic cell–activated CD44hiCD8+ T cells are defective in mediating acute graft-versus-host disease but retain graft-versus-leukemia activity. Blood 2004; 103:3970-8. [PMID: 14764532 DOI: 10.1182/blood-2003-09-3135] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Abstract
Graft versus host disease (GVHD) is triggered by host antigen-presenting cells (APCs) that activate donor T cells to proliferate and differentiate, but which APC-activated donor T-cell subsets mediate GVHD versus beneficial antitumor effects is not known. Using a CD8+ T cell–dependent mouse model of human GVHD, we found that host dendritic cell (DC)–induced CD44hiCD8+ effector/memory T cells were functionally defective in inducing GVHD, whereas CD44loCD8+ naive phenotype T cells were extremely potent GVHD inducers. Depletion of CD44loCD8+ T cells from host DC-stimulated T cells before transplantation prevented GVHD without impairing their antitumor activity in vivo. Compared with CD44loCD8+ T cells, CD44hiCD8+ T cells expressed high levels of Fas and were efficiently deleted in vivo following transplantation. These results suggest that ex vivo allogeneic DC stimulation of donor CD8+ T cells may be useful for the prevention of GVHD and for optimizing antitumor therapies in vivo.
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Affiliation(s)
- Yi Zhang
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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42
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Abstract
The establishment and maintenance of immunological tolerance entails both central and peripheral mechanisms. The latter have been highlighted in the past several years, mostly because of great interest in the activities of regulatory T cells. However, an important role for central tolerance mechanisms has been reemphasized by recent results on human autoimmune diseases, including APECED and type 1 diabetes.
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Affiliation(s)
- Diane Mathis
- Section on Immunology and Immunogenetics, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02215 USA
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43
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Abstract
Mucosally active vaccine adjuvants which will prime a full range of local and systemic immune responses against defined antigenic epitopes are much needed. Cholera toxin (CT) and lipophilic immune stimulating complexes (ISCOMs) containing Quil A can both act as adjuvants for orally administered antigens, but through separate pathways, as evidenced by the dependence on IL-12 for the effect of ISCOMs, whereas CT is independent of this cytokine. Unfortunately the toxicity of CT and recent findings of accumulation of CT in the olfactory nerve and bulb after intranasal administration precludes the clinical use of CT. However, we have been successful in separating the adjuvant and toxic effects of CT, by constructing a gene fusion protein, CTA1-DD, that combines the enzymatically active CTA1-subunit with a B cell targeting moiety, D, derived from Staphylococcus aureus protein A. The present review gives a background to mucosal immunization and the use of -adjuvants in general, followed by a description of a strategy to rationally design a vaccine adjuvant vector that fulfils the criteria of targeting and immunomodulating innate immunity in order to boost a strong adaptive immune response. We have combined CTA1-DD and ISCOMs into a new highly promising vaccine adjuvant vector, CTA1-DD/ISCOMs. The combined vector is immunogenic when given by the subcutaneous, oral or nasal routes, inducing strong cell--mediated and humoral immune responses, including local mucosal IgA. It requires the ADP ribosylating property of the CTA1-enzyme and the effect of the combined vector greatly exceeded the effect of either ISCOMs or CT used alone. Antigens could be incorporated into or just admixed with the new vector. Thus, we have demonstrated that rationally designed vectors consisting of CTA1-DD and ISCOMS may provide a novel strategy for the generation of potent and safe mucosal vaccines.
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Affiliation(s)
- Nils Lycke
- Department of Clinical Immunology, University of Göteborg, S413 46 Göteborg, Sweden.
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Oluwole SF, Oluwole OO, Adeyeri AO, DePaz HA. New strategies in immune tolerance induction. Cell Biochem Biophys 2004. [DOI: 10.1007/bf02739010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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45
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Roelen DL, Schuurhuis DH, van den Boogaardt DEM, Koekkoek K, van Miert PPMC, van Schip JJ, Laban S, Rea D, Melief CJM, Offringa R, Ossendorp F, Claas FHJ. Prolongation of skin graft survival by modulation of the alloimmune response with alternatively activated dendritic cells1. Transplantation 2003; 76:1608-15. [PMID: 14702533 DOI: 10.1097/01.tp.0000086340.30817.ba] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Activation of immature dendritic cells (DC) in the presence of the glucocorticoid hormone dexamethasone (DEX) results in alternatively matured DC that present antigen in the absence of a proper co-stimulatory context. This maturation process is irreversible, making these cells an attractive potential tool for the induction of antigen-specific T-cell tolerance in vivo. The authors explored the possibility of using these DC for the induction of transplantation tolerance in a fully allogeneic setting in mice. METHODS Immature dendritic cells (D1, an immature splenic DC line derived from B6 mice) were pretreated with DEX for 24 hr, after which lipopolysaccharide or nothing was added to the culture for another 48 hr. These cells were analyzed for their in vitro and in vivo stimulating or tolerizing capacities. RESULTS In line with their phenotype, including decreased interleukin (IL)-12 production, in vitro co-culture of alternatively matured D1 (B6 origin; H-2b) with completely allogeneic T cells of BALB/c origin led to a significant decrease in the alloreactive T-cell response. A single injection of 1 x 10(6) alternatively matured H-2b DC into BALB/c mice induced a different alloimmune response compared with mature DC. The responding T cells showed a lower proliferation rate and a lower interferon-gamma production, whereas a significantly higher proportion of the cells produced IL-10 as measured ex vivo by enzyme-linked immunospot assay. Furthermore, injection with alternatively matured DC, followed by transplantation of fully mismatched skin grafts (C57BL/6), led to a significantly prolonged survival compared with that of mature DC-pretreated mice or untreated mice. The immunomodulatory effect was antigen specific, as third-party reactive alloresponses were not affected. CONCLUSIONS The authors' data constitute the first direct demonstration that DC alternatively matured in the presence of glucocorticoid hormones can be exploited for the specific suppression of the alloreactive Th1 response, resulting in a delayed skin graft rejection in a complete major histocompatibility complex-incompatible strain combination.
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Affiliation(s)
- Dave L Roelen
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands.
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Morelli AE, Thomson AW. Dendritic cells: regulators of alloimmunity and opportunities for tolerance induction. Immunol Rev 2003; 196:125-46. [PMID: 14617202 DOI: 10.1046/j.1600-065x.2003.00079.x] [Citation(s) in RCA: 229] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Dendritic cells (DCs) are uniquely well-equipped antigen-presenting cells (APCs) regarded classically as sentinels of the immune response, which induce and regulate T-cell reactivity. They play critical roles in central tolerance and in the maintenance of peripheral tolerance in the normal steady state. Following cell or organ transplantation, DCs present antigen to T cells via the direct or indirect pathways of allorecognition. These functions of DCs set in train the rejection response, but they also serve as potential targets for suppression of alloimmune reactivity and promotion of tolerance induction. Much evidence from various model systems now indicates that DCs can induce specific T-cell tolerance. Although underlying mechanisms have not been fully elucidated, the capacity to induce T-regulatory cells may be an important property of tolerogenic or regulatory DCs. Efforts to generate "designer" DCs with tolerogenic properties in the laboratory using specific cytokines, immunologic or pharmacologic reagents, or genetic engineering approaches have already met with some success. Alternatively, targeting of DCs in vivo (e.g. by infusion of apoptotic allogeneic cells) to take advantage of their inherent tolerogenicity has also demonstrated exciting potential. The remarkable heterogeneity and plasticity of these important APCs present additional challenges to optimizing DC-based therapies that may lead to improved tolerance-enhancing strategies in the clinic.
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Affiliation(s)
- Adrian E Morelli
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, W1544 Biomedical Science Tower, 200 Lothrop Street, Pittsburgh, PA 15213, USA.
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47
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Abstract
Dendritic cells (DCs) have several functions in innate and adaptive immunity. In addition, there is increasing evidence that DCs in situ induce antigen-specific unresponsiveness or tolerance in central lymphoid organs and in the periphery. In the thymus DCs generate tolerance by deleting self-reactive T cells. In peripheral lymphoid organs DCs also induce tolerance to antigens captured by receptors that mediate efficient uptake of proteins and dying cells. Uptake by these receptors leads to the constitutive presentation of antigens on major histocompatibility complex (MHC) class I and II products. In the steady state the targeting of DC antigen capture receptors with low doses of antigens leads to deletion of the corresponding T cells and unresponsiveness to antigenic rechallenge with strong adjuvants. In contrast, if a stimulus for DC maturation is coadministered with the antigen, the mice develop immunity, including interferon-gamma-secreting effector T cells and memory T cells. There is also new evidence that DCs can contribute to the expansion and differentiation of T cells that regulate or suppress other immune T cells. One possibility is that distinct developmental stages and subsets of DCs and T cells can account for the different pathways to peripheral tolerance, such as deletion or suppression. We suggest that several clinical situations, including autoimmunity and certain infectious diseases, can be influenced by the antigen-specific tolerogenic role of DCs.
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Affiliation(s)
- Ralph M Steinman
- Laboratory of Cellular Physiology and Immunology, The Rockefeller University, New York, New York 10021-6399, USA.
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48
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Morel PA, Feili-Hariri M, Coates PT, Thomson AW. Dendritic cells, T cell tolerance and therapy of adverse immune reactions. Clin Exp Immunol 2003; 133:1-10. [PMID: 12823271 PMCID: PMC1808741 DOI: 10.1046/j.1365-2249.2003.02161.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2002] [Indexed: 01/07/2023] Open
Abstract
Dendritic cells (DC) are uniquely able to either induce immune responses or to maintain the state of self tolerance. Recent evidence has shown that the ability of DC to induce tolerance in the steady state is critical to the prevention of the autoimmune response. Likewise, DC have been shown to induce several type of regulatory T cells including Th2, Tr1, Ts and NKT cells, depending on the maturation state of the DC and the local microenvironment. DC have been shown to have therapeutic value in models of allograft rejection and autoimmunity, although no success has been reported in allergy. Several strategies, including the use of specific DC subsets, genetic modification of DC and the use of DC at various maturation stages for the treatment of allograft rejection and autoimmune disease are discussed. The challenge for the future use of DC therapy in human disease is to identify the appropriate DC for the proposed therapy; a task made more daunting by the extreme plasticity of DC that has recently been demonstrated. However, the progress achieved to date suggests that these are not insurmountable obstacles and that DC may become a useful therapeutic tool in transplantation and autoimmune disease.
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Affiliation(s)
- P A Morel
- Department of Immunology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
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49
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Abstract
Dead cells are a prominent feature of the thymic landscape as only 5% of developing thymocytes are exported as mature T cells. The remaining thymocytes die by one of two mechanisms; most thymocytes die because they are not positively selected and do not receive a survival signal, whereas a minority of thymocytes undergo T-cell receptor (TCR)-mediated apoptosis, a process known as negative selection. Negative selection is extremely important for establishing a functional immune system, as it provides an efficient mechanism for ridding the T-cell repertoire of self-reactive and potentially autoimmune lymphocytes. This review discusses several cellular and molecular aspects of negative selection.
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Affiliation(s)
- Ed Palmer
- Laboratory of Transplantation Immunology and Nephrology, University Hospital Basel, Hebelstrasse 20, CH-4031 Basel, Switzerland.
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50
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Blais ME, Louis I, Corneau S, Gérard G, Terra R, Perreault C. Extrathymic T-lymphocyte development. Exp Hematol 2003; 31:349-54. [PMID: 12763132 DOI: 10.1016/s0301-472x(03)00026-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Marie-Eve Blais
- Guy-Bernier Research Center, Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada
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