101
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Wang J, Wicker LS, Santamaria P. IL-2 and its high-affinity receptor: genetic control of immunoregulation and autoimmunity. Semin Immunol 2009; 21:363-71. [PMID: 19447046 DOI: 10.1016/j.smim.2009.04.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Accepted: 04/09/2009] [Indexed: 10/20/2022]
Abstract
Type 1 diabetes (T1D) is an organ-specific autoimmune disease featured by destruction of the insulin producing beta-cells of the pancreas by autoreactive T-lymphocytes. Putative environmental triggers conspire with a constellation of genetic elements scattered throughout the genome to elicit a multifactorial autoimmune response involving virtually every cell type of the immune system against pancreatic beta-cells. Recent highly powered genome-wide association studies have confirmed and identified fifteen chromosomal regions harboring several candidate T1D-associated gene loci. Here, we summarize what we know about the genetics of T1D with an emphasis on the contributions of mouse Il2 and human IL2RA polymorphisms and the IL-2-IL-2R pathway to autoimmunity and, more specifically, Treg development and function.
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Affiliation(s)
- Jinguo Wang
- Julia McFarlane Diabetes Research Centre (JMDRC) and Department of Microbiology and Infectious Diseases, Institute of Inflammation, Infection and Immunity, Faculty of Medicine, The University of Calgary, Calgary, Alberta, Canada T2N 4N1
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102
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Nandakumar S, Miller CWT, Kumaraguru U. T regulatory cells: an overview and intervention techniques to modulate allergy outcome. Clin Mol Allergy 2009; 7:5. [PMID: 19284628 PMCID: PMC2664789 DOI: 10.1186/1476-7961-7-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2009] [Accepted: 03/12/2009] [Indexed: 12/22/2022] Open
Abstract
Dysregulated immune response results in inflammatory symptoms in the respiratory mucosa leading to asthma and allergy in susceptible individuals. The T helper type 2 (Th2) subsets are primarily involved in this disease process. Nevertheless, there is growing evidence in support of T cells with regulatory potential that operates in non-allergic individuals. These regulatory T cells occur naturally are called natural T regulatory cells (nTregs) and express the transcription factor Foxp3. They are selected in the thymus and move to the periphery. The CD4 Th cells in the periphery can be induced to become regulatory T cells and hence called induced or adaptive T regulatory cells. These cells can make IL-10 or TGF-b or both, by which they attain most of their suppressive activity. This review gives an overview of the regulatory T cells, their role in allergic diseases and explores possible interventionist approaches to manipulate Tregs for achieving therapeutic goals.
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Affiliation(s)
- Subhadra Nandakumar
- Department of Microbiology, College of Medicine, East Tennessee State University, Johnson City, TN-37614, USA
| | - Christopher WT Miller
- Division of Allergy and Immunology, Department of Internal Medicine, College of Medicine, East Tennessee State University, Johnson City, TN-37614, USA
| | - Uday Kumaraguru
- Department of Microbiology, College of Medicine, East Tennessee State University, Johnson City, TN-37614, USA
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103
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Sgouroudis E, Piccirillo CA. Control of type 1 diabetes by CD4+Foxp3+ regulatory T cells: lessons from mouse models and implications for human disease. Diabetes Metab Res Rev 2009; 25:208-18. [PMID: 19214972 DOI: 10.1002/dmrr.945] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In recent years, there has been a revival of the concept of CD4(+) regulatory T (T(reg)) cells as being a central control point in various immune responses, including autoimmune responses and immunity to transplants, allergens, tumours and infectious microbes. The current literature suggests that T(reg) cells are diverse in their phenotype and mechanism(s) of action, and as such, may constitute a myriad of naturally occurring and induced T cell precursors with variable degrees of regulatory potential. In this review, we summarize research from various laboratories, including our own, showing that CD4(+)Foxp3(+) T(reg) cells are critical in the control of type 1 diabetes (T1D) in mouse models and humans. In this review, we also discuss cellular and molecular determinants that impact CD4(+)Foxp3(+) T(reg) cell development and function and consequential resistance to organ-specific autoimmune disease. Recent advances in the use of CD4(+)Foxp3(+) T(reg) cellular therapy to promote immunological tolerance in the absence of long-term generalized immunosuppression are also presented.
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Affiliation(s)
- Evridiki Sgouroudis
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada, H3A 2B4
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104
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Lu LF, Thai TH, Calado DP, Chaudhry A, Kubo M, Tanaka K, Loeb GB, Lee H, Yoshimura A, Rajewsky K, Rudensky AY. Foxp3-dependent microRNA155 confers competitive fitness to regulatory T cells by targeting SOCS1 protein. Immunity 2009; 30:80-91. [PMID: 19144316 PMCID: PMC2654249 DOI: 10.1016/j.immuni.2008.11.010] [Citation(s) in RCA: 655] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 09/22/2008] [Accepted: 11/06/2008] [Indexed: 10/21/2022]
Abstract
Foxp3(+) regulatory T (Treg) cells limit pathogenic immune responses to self-antigens and foreign antigens. An essential role for microRNA (miRNA) in the maintenance and function of Treg cells, revealed by the Treg cell-specific Dicer ablation, raised a question as to a specific miRNA contribution. We found that Foxp3 controlled the elevated miR155 expression required for maintaining Treg cell proliferative activity and numbers under nonlymphopenic conditions. Moreover, miR155 deficiency in Treg cells resulted in increased suppressor of cytokine signaling 1 (SOCS1) expression accompanied by impaired activation of signal transducer and activator of transcription 5 (STAT5) transcription factor in response to limiting amounts of interleukin-2. Our studies suggest that Foxp3-dependent regulation of miR155 maintains competitive fitness of Treg cell subsets by targeting SOCS1, and they provide experimental support for a proposed role for miRNAs in ensuring the robustness of cellular phenotypes.
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Affiliation(s)
- Li-Fan Lu
- Department of Immunology and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
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105
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Yu A, Zhu L, Altman NH, Malek TR. A low interleukin-2 receptor signaling threshold supports the development and homeostasis of T regulatory cells. Immunity 2009; 30:204-17. [PMID: 19185518 DOI: 10.1016/j.immuni.2008.11.014] [Citation(s) in RCA: 205] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 10/16/2008] [Accepted: 11/22/2008] [Indexed: 01/01/2023]
Abstract
Interleukin-2 receptor (IL-2R) signaling is essential for T regulatory (Treg) cell development and homeostasis. Here, we show that expression of IL-2Rbeta chains that lack tyrosine residues important for the association of the adaptor Shc and the transcription factor STAT5 in IL-2Rbeta-deficient mice resulted in production of a normal proportion of natural Treg cells that suppressed severe autoimmunity related with deficiency in IL-2 or IL-2R. These mutant IL-2Rbeta chains supported suboptimal and transient STAT5 activation that upregulate the transcription factor Foxp3 to normal amounts in natural, but not induced, Treg cells. Nevertheless, gene expression profiling revealed many targets in peripheral natural Treg cells that were IL-2 dependent and a substantial overlap between the Treg cell IL-2-dependent gene program and the Treg cell transcriptional signature. Collectively, these findings demonstrate that a critical, and perhaps minor, subset of IL-2-dependent targets is indexed to a low IL-2R signaling threshold and that a substantial proportion of the Treg cell gene program is regulated by IL-2.
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Affiliation(s)
- Aixin Yu
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, FL 33101, USA
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106
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Sgouroudis E, Albanese A, Piccirillo CA. Impact of protective IL-2 allelic variants on CD4+ Foxp3+ regulatory T cell function in situ and resistance to autoimmune diabetes in NOD mice. THE JOURNAL OF IMMUNOLOGY 2009; 181:6283-92. [PMID: 18941219 DOI: 10.4049/jimmunol.181.9.6283] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Type I diabetes (T1D) susceptibility is inherited through multiple insulin-dependent diabetes (Idd) genes. NOD.B6 Idd3 congenic mice, introgressed with an Idd3 allele from T1D-resistant C57BL/6 mice (Idd3(B6)), show a marked resistance to T1D compared with control NOD mice. The protective function of the Idd3 locus is confined to the Il2 gene, whose expression is critical for naturally occurring CD4(+)Foxp3(+) regulatory T (nT(reg)) cell development and function. In this study, we asked whether Idd3(B6) protective alleles in the NOD mouse model confer T1D resistance by promoting the cellular frequency, function, or homeostasis of nT(reg) cells in vivo. We show that resistance to T1D in NOD.B6 Idd3 congenic mice correlates with increased levels of IL-2 mRNA and protein production in Ag-activated diabetogenic CD4(+) T cells. We also observe that protective IL2 allelic variants (Idd3(B6) resistance allele) also favor the expansion and suppressive functions of CD4(+)Foxp3(+) nT(reg) cells in vitro, as well as restrain the proliferation, IL-17 production, and pathogenicity of diabetogenic CD4(+) T cells in vivo more efficiently than control do nT(reg) cells. Lastly, the resistance to T1D in Idd3 congenic mice does not correlate with an augmented systemic frequency of CD4(+)Foxp3(+) nT(reg) cells but more so with the ability of protective IL2 allelic variants to promote the expansion of CD4(+)Foxp3(+) nT(reg) cells directly in the target organ undergoing autoimmune attack. Thus, protective, IL2 allelic variants impinge the development of organ-specific autoimmunity by bolstering the IL-2 producing capacity of self-reactive CD4(+) T cells and, in turn, favor the function and homeostasis of CD4(+)Foxp3(+) nT(reg) cells in vivo.
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Affiliation(s)
- Evridiki Sgouroudis
- Department of Microbiology and Immunology, and McGill Center for the Study of Host Resistance, McGill University, Montreal, Québec, Canada
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107
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Abstract
In certain situations mature post-thymic T cells are able to leave their residence in the secondary lymphoid tissues and re-enter the thymus. The physiological significance of this phenomenon is discussed.
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108
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Wu HY. Induction of mucosal tolerance in SLE: a sniff or a sip away from ameliorating lupus? Clin Immunol 2008; 130:111-22. [PMID: 18938110 DOI: 10.1016/j.clim.2008.08.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 08/27/2008] [Accepted: 08/27/2008] [Indexed: 11/26/2022]
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by aberrant immune responses against intracellularly derived self antigens. Treatment for SLE relies on the use of aggressive immunosuppressants and steroids that are nonspecific and can cause serious adverse effects. The observation that a systemic immune tolerance to self antigens or generation of regulatory T cells may follow mucosal (nasal or oral) exposure to self proteins or monoclonal antibody against CD3 respectively suggests that induction of mucosal tolerance offers the basis of a side effect-free therapy that could re-establish the ability to distinguish self from non-self and restore peripheral tolerance in individuals susceptible to developing autoimmune diseases. Here I review studies on mucosal tolerance in autoimmune diseases and discuss the therapeutic potential of inducing tolerance for the treatment of SLE.
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Affiliation(s)
- Henry Yim Wu
- Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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109
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alpha1-Antitrypsin monotherapy induces immune tolerance during islet allograft transplantation in mice. Proc Natl Acad Sci U S A 2008; 105:16236-41. [PMID: 18852465 DOI: 10.1073/pnas.0807627105] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Human pancreatic islet transplantation offers diabetic patients tight glucose control but has low graft survival rates. The immunosuppressive drugs that are administered to graft recipients lack the antiinflammatory benefits of corticosteroids because of their diabetogenic effects. The serum protease inhibitor alpha1-antitrypsin (AAT) possesses antiinflammatory properties and reduces cytokine-mediated islet damage. In the present study, diabetic mice were grafted with allogeneic islets and treated with AAT monotherapy (n = 24). After 14 days of treatment, mice remained normoglycemic and islet allografts were functional for up to 120 treatment-free days. After graft removal and retransplantation, mice accepted same-strain islets but rejected third-strain islets, thus confirming that specific immune tolerance had been induced. Explanted grafts exhibited a population of T regulatory cells in transplant sites. According to RT-PCR, grafts contained high levels of mRNA for foxp3, cytotoxic T lymphocyte antigen-4, TGF-beta, IL-10, and IL-1 receptor antagonist; expression of proinflammatory mediators was low or absent. After implantation of skin allografts, AAT-treated mice had greater numbers of foxp3-positive cells in draining lymph nodes (DLNs) compared with control treatment mice. Moreover, dendritic cells in DLNs exhibited an immature phenotype with decreased CD86 activation marker. Although the number of CD3 transcripts decreased in the DLNs, AAT did not affect IL-2 activity in vitro. Thus, AAT monotherapy provides allografts with antiinflammatory conditions that favor development of antigen-specific T regulatory cells. Because AAT treatment in humans is safe, its use during human islet transplantation may be considered.
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110
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Host CD4+CD25+ T cells can expand and comprise a major component of the Treg compartment after experimental HCT. Blood 2008; 113:733-43. [PMID: 18832651 DOI: 10.1182/blood-2008-08-173179] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Reconstitution of the recipient lymphoid compartment following hematopoietic cell transplantation (HCT) is typically delayed. The present studies investigated the residual host CD4(+)CD25(+)Foxp3(+) (Treg) compartment after several conditioning regimens, including T cell-depleted and T cell-replete HCT and observed (1) a small number of recipient Treg cells survived aggressive conditioning; (2) the surviving, that is, residual Tregs underwent marked expansion; and (3) recipient CD4(+)FoxP3(+) cells composed the majority of the Treg compartment for several months post-syngeneic HCT. Notably, residual Tregs also dominated the compartment post-HCT with T cell-depleted (TCD) major histocompatibility complex-matched allogeneic bone marrow but not following T cell-replete transplantations. The residual Treg cell compartment was functionally competent as assessed by in vitro lymphoid suppression and in vivo autoimmune disease transfer assay. These observations support the notion that functional host Tregs initially occupy a niche in lymphopenic transplantation recipients, undergo significant expansion, and contribute to the compartment for an extended period before donor-derived CD4(+)FoxP3(+) T cells eventually compose the majority of the compartment. In total, the findings suggest that the presence of host Tregs may be important to consider regarding elicitation of immune (eg, antitumor, vaccine) responses in recipients during the early post-transplant period involving autologous and certain allogeneic HCT regimens.
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111
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Inaba H, Steeves M, Nguyen P, Geiger TL. In vivo suppression of naive CD4 T cell responses by IL-2- and antigen-stimulated T lymphocytes in the absence of APC competition. THE JOURNAL OF IMMUNOLOGY 2008; 181:3323-35. [PMID: 18714004 DOI: 10.4049/jimmunol.181.5.3323] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
After stimulation, T cells enter a transient refractory period, promoted by IL-2, during which they are resistant to re-stimulation. We previously demonstrated that these IL-2- and Ag-stimulated refractory T cells are able to suppress the Ag-induced proliferation of naive T cells in vitro. We show here that, after adoptive transfer, these T cells are also able to suppress naive T cell proliferation in vivo. More interestingly, potently suppressive T cells can be generated directly in vivo by stimulation with Ag and supplemental IL-2. The activity of the suppressive cells is dose dependent, and the suppressor and suppressed T cells need not be restricted to the same MHC or Ag. Similar to its role in promoting T cell-mediated suppression in vitro, IL-2 is critical for the induction of suppressive activity in activated T cells in vivo. Supplemental IL-2, however, cannot overcome the suppressive activity in target T cells, indicating that suppression is not mediated by competition for this cytokine. Although the activated T cells block naive T cell proliferation, the naive cells do engage Ag and up-regulate the CD25 and CD69 activation markers after stimulation. Therefore, activated T cells stimulated in the presence of IL-2 develop MHC- and Ag-unrestricted suppressive activity. These results provide a new mechanism for competition among CD4(+) T lymphocytes, in which initial waves of responding T cells may inhibit subsequently recruited naive T cells. They further suggest a novel negative feedback loop limiting the expansion of T cell responses that may be present during vigorous immune responses or after IL-2 immunotherapy.
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Affiliation(s)
- Hiroto Inaba
- Department of Oncology and Pathology, St. Jude Children's Research Hospital, Memphis, TN, USA
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112
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Laronne-Bar-On A, Zipori D, Haran-Ghera N. Increased regulatory versus effector T cell development is associated with thymus atrophy in mouse models of multiple myeloma. THE JOURNAL OF IMMUNOLOGY 2008; 181:3714-24. [PMID: 18714048 DOI: 10.4049/jimmunol.181.5.3714] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) play a central role in cancer tolerance. However, mechanisms leading to their accumulation in cancer remain unknown. Although the thymus is the main site of Treg development, thymic contribution to Treg expansion in cancer has not been directly examined. Herein, we used two murine models of multiple myeloma (MM), 5T2 MM and 5T33 MM, to examine Treg accumulation in peripheral lymphoid organs, including spleen, lymph nodes, bone marrow, and blood, and to explore thymic Treg development during malignancy. We found that peripheral ratios of suppressive-functional Tregs increased in both models of MM-inflicted mice. We found that thymic ratios of Treg development in MM increased, in strong association with thymus atrophy and altered developmental processes in the thymus. The CD4(+)CD8(+) double-positive population, normally the largest thymocyte subset, is significantly decreased, whereas the CD4(-)CD8(-) double-negative population is increased. Administration of thymocytes from MM-inflicted mice compared with control thymocytes resulted in increased progression of the disease, and this effect was shown to be mediated by Tregs in the thymus of MM-inflicted mice. Our data suggest that increased ratios of Treg development in the thymus may contribute to disease progression in MM-inflicted mice.
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Affiliation(s)
- Ayelet Laronne-Bar-On
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
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113
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The IL-2/CD25 pathway determines susceptibility to T1D in humans and NOD mice. J Clin Immunol 2008; 28:685-96. [PMID: 18780166 DOI: 10.1007/s10875-008-9237-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Accepted: 07/01/2008] [Indexed: 12/20/2022]
Abstract
Although the interleukin-2 (IL-2)/IL-2R signaling pathway has been the focus of numerous studies, certain aspects of its molecular regulation are not well characterized, especially in non-T cells, and a more complete understanding of the pathway is necessary to discern the functional basis of the genetic association between the IL-2-IL-21 and IL-2RA/CD25 gene regions and T1D in humans. Genetic variation in these regions may promote T1D susceptibility by influencing transcription and/or splicing and, hence, IL-2 and IL-2RA/CD25 expression at the protein level in different immune cell subsets; thus, there is a need to establish links between the genetic variation and immune cell phenotypes and functions in humans, which can be further investigated and validated in mouse models. The detection and characterization of genetically determined immunophenotypes should aid in elucidating disease mechanisms and may enable future monitoring of disease initiation and progression in prediabetic subjects and of responses to therapeutic intervention.
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114
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Yarkoni S, Kaminitz A, Sagiv Y, Yaniv I, Askenasy N. Involvement of IL-2 in homeostasis of regulatory T cells: the IL-2 cycle. Bioessays 2008; 30:875-88. [DOI: 10.1002/bies.20812] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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115
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Malek TR, Yu A, Zhu L, Matsutani T, Adeegbe D, Bayer AL. IL-2 Family of Cytokines in T Regulatory Cell Development and Homeostasis. J Clin Immunol 2008; 28:635-9. [DOI: 10.1007/s10875-008-9235-y] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Accepted: 02/15/2008] [Indexed: 12/24/2022]
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116
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Bayer AL, Lee JY, de la Barrera A, Surh CD, Malek TR. A function for IL-7R for CD4+CD25+Foxp3+ T regulatory cells. THE JOURNAL OF IMMUNOLOGY 2008; 181:225-34. [PMID: 18566388 DOI: 10.4049/jimmunol.181.1.225] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The IL-2/IL-2R interaction is important for development and peripheral homeostasis of T regulatory (Treg) cells. IL-2- and IL-2R-deficient mice are not completely devoid of Foxp3+ cells, but rather lack population of mature CD4+CD25+Foxp3high Treg cells and contain few immature CD4+CD25-Foxp3low T cells. Interestingly, common gamma chain (gammac) knockout mice have been shown to have a near complete absence of Foxp3+ Treg cells, including the immature CD25-Foxp3low subset. Therefore, other gammac-cytokine(s) must be critically important during thymic development of CD4+CD25+Foxp3+ Treg cells apart from the IL-2. The present study was undertaken to determine whether the gammac-cytokines IL-7 or IL-15 normally contribute to expression of Foxp3 and Treg cell production. These studies revealed that mice double deficient in IL-2Rbeta and IL-7Ralpha contained a striking lack in the CD4+Foxp3+ population and the Treg cell defect recapitulated the gammac knockout mice. In the absence of IL-7R signaling, IL-15/IL-15R interaction is dispensable for the production of CD4+CD25+Foxp3+ Treg cells, indicating that normal thymic Treg cell production likely depends on signaling through both IL-2 and IL-7 receptors. Selective thymic reconstitution of IL-2Rbeta in mice double deficient in IL-2Rbeta and IL-7Ralpha established that IL-2Rbeta is dominant and sufficient to restore production of Treg cells. Furthermore, the survival of peripheral CD4+Foxp3low cells in IL-2Rbeta-/- mice appears to depend upon IL-7R signaling. Collectively, these data indicate that IL-7R signaling contributes to Treg cell development and peripheral homeostasis.
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Affiliation(s)
- Allison L Bayer
- Department of Microbiology and Immunology, Diabetes Research Institute, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
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117
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Abstract
Much data support an essential role for interleukin (IL)-2 in immune tolerance. This idea is much different from the early paradigm in which IL-2 is central for protective immune responses. This change in thinking occurred when a T regulatory cell defect was shown to be responsible for the lethal autoimmunity associated with IL-2/IL-2R deficiency. This realization allowed investigators to explore immune responses in IL-2-nonresponsive mice rendered autoimmune-free. Such studies established that IL-2 sometimes contributes to optimal primary immune responses, but it is not mandatory. Emerging findings, however, suggest an essential role for IL-2 in immune memory. Here, the current understanding of the dual role of IL-2 in maintaining tolerance and contributing to immunity in vivo is reviewed with some emphasis on T regulatory cell production and homeostasis. Also discussed are implications of this new appreciation concerning the immunobiology of IL-2 with respect to targeting IL-2 or its receptor in immunotherapy.
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Affiliation(s)
- Thomas R Malek
- Department of Microbiology and Immunology and the Diabetes Research Institute, Miller School of Medicine, University of Miami, Miami, Florida 33101, USA.
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118
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Hogan TV, Ang DKY, Gleeson PA, van Driel IR. Extrathymic mechanisms of T cell tolerance: lessons from autoimmune gastritis. J Autoimmun 2008; 31:268-73. [PMID: 18499395 DOI: 10.1016/j.jaut.2008.04.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
While the thymus plays a key role in the prevention of many autoimmune phenomena it is clear that robust mechanisms external to the thymus are also vital in controlling self-reactive T cells. Here we review the current concepts in the field of extrathymic tolerance and use recent studies of autoimmune gastritis to illustrate how T cells directed to a prominent, clinically relevant autoantigen, namely the gastric proton pump, can be silenced with little or no thymic involvement. Autoimmune gastritis represents one of the most thoroughly characterised autoimmune systems and the knowledge and tools available to study this disease will continue to allow a thorough assessment of the genetic, cellular and molecular events that underlie tolerance and autoimmunity.
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Affiliation(s)
- Thea V Hogan
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
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119
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Impact of Immunosuppressive Drugs on CD4+CD25+FOXP3+ Regulatory T Cells: Does In Vitro Evidence Translate to the Clinical Setting? Transplantation 2008; 85:783-9. [DOI: 10.1097/tp.0b013e318166910b] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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120
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Lio CWJ, Hsieh CS. A two-step process for thymic regulatory T cell development. Immunity 2008; 28:100-11. [PMID: 18199417 DOI: 10.1016/j.immuni.2007.11.021] [Citation(s) in RCA: 492] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Revised: 10/17/2007] [Accepted: 11/13/2007] [Indexed: 12/13/2022]
Abstract
Recognition of self-antigens is required for regulatory T (Treg) cells to exert dominant tolerance. However, the mechanism by which self-reactive thymocytes are diverted into the Treg cell subset is unclear. To address this question, we looked for the immediate precursors to Treg cells within Foxp3(-)CD4+CD8(-) thymocytes. By using intrathymic transfer, we found that the CD25hi subset is highly enriched in Treg cell precursors. This was supported by tracking of thymocyte development via analysis of T cell receptor (TCR) repertoires in a TCR-beta transgenic model. These Treg cell precursors exist at a developmental stage where they are poised to express Foxp3 without further TCR engagement, requiring only stimulation by interleukin-2 (IL-2) or IL-15. Thus, we propose that the selection of self-reactive thymocytes into the Treg cell subset occurs via an instructive rather than stochastic-selective model whereby TCR signals result in the expression of proximal IL-2 signaling components facilitating cytokine-mediated induction of Foxp3.
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Affiliation(s)
- Chan-Wang Joaquim Lio
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, St. Louis, MO 63110, USA
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121
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Blais MÈ, Brochu S, Giroux M, Bélanger MP, Dulude G, Sékaly RP, Perreault C. Why T Cells of Thymic Versus Extrathymic Origin Are Functionally Different. THE JOURNAL OF IMMUNOLOGY 2008; 180:2299-312. [DOI: 10.4049/jimmunol.180.4.2299] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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122
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Spence PJ, Green EA. Foxp3+ regulatory T cells promiscuously accept thymic signals critical for their development. Proc Natl Acad Sci U S A 2008; 105:973-8. [PMID: 18198277 PMCID: PMC2242703 DOI: 10.1073/pnas.0709071105] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Indexed: 01/18/2023] Open
Abstract
Foxp3(+) regulatory T cells develop in the thymus and are essential for maintaining peripheral tolerance to self tissues. We report the critical requirement for CD154 up-regulation specifically on, and during the thymic development of, Foxp3(+) regulatory T cells for the induction of their clonal expansion within the medulla. In the absence of this signal, there was a severe reduction in their thymic generation and output, leading to decreased peripheral numbers. Importantly, CD40 expression on either thymic dendritic or epithelial cells was sufficient to promote the development of normal numbers of Foxp3(+) regulatory T cells. This work suggests that CD154-transduced signals promote Foxp3(+) regulatory T cell development and highlights the plasticity of the thymic stroma for supporting their generation. Crucially, this study demonstrates that Foxp3(+) regulatory T cells can promiscuously accept a single critical signal necessary for their thymic development from different cellular sources, redefining our understanding of their generation.
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Affiliation(s)
- Philip J. Spence
- Department of Pathology, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - E. Allison Green
- Department of Pathology, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
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Carrio R, Rolle CE, Malek TR. Non-redundant role for IL-7R signaling for the survival of CD8+ memory T cells. Eur J Immunol 2007; 37:3078-88. [PMID: 17935075 DOI: 10.1002/eji.200737585] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
IL-7 and IL-15 are important cytokines for CD8 memory T cells. However, the extent that IL-7 is essential for CD8 T cell memory remains unclear because blocking IL-7 in vivo results in near complete inhibition of T cell development with the few mature T cells exhibiting functional abnormalities. To bypass this complication, CD8 memory development was examined utilizing a mouse model where transgenic IL-7Ralpha was selectively expressed in the thymus of IL-7Ralpha(-/-) mice. T cell development was corrected but the resulting peripheral T cells were essentially IL-7 non-responsive. Activation of IL-7R-defective OT-I CD8(+) T cells with OVA(257-264) and IL-2 readily yielded CTL. Upon further culture with IL-15, these CTL expressed phenotypic and functional properties of central memory-like cells. Thus, IL-7R-defective CD8(+) T cells do not exhibit intrinsic defects in effector or memory development. When IL-7R-defective OT-I CTL were adoptively transferred into normal or IL-15(-/-) recipient mice in a non-inflammatory setting, they converted into memory-like cells, but did not persist, which was even more striking in IL-15(-/-) recipients. This poor persistence was rescued after expression of transgenic Bcl-2 in IL-7R-defective OT-I T cells. Collectively, these data indicate that IL-7 is non-redundantly required for the survival of CD8 memory T cells.
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Affiliation(s)
- Roberto Carrio
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, FL 33101, USA
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124
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Burchill MA, Yang J, Vang KB, Farrar MA. Interleukin-2 receptor signaling in regulatory T cell development and homeostasis. Immunol Lett 2007; 114:1-8. [PMID: 17936914 PMCID: PMC2094047 DOI: 10.1016/j.imlet.2007.08.005] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Revised: 08/17/2007] [Accepted: 08/21/2007] [Indexed: 01/17/2023]
Abstract
Interleukin-2 (IL2) was initially identified from supernatants of activated lymphocytes over 30 years ago. In the ensuing 15 years, the cDNAs for both IL2 and the three chains of the interleukin-2 receptor (IL2R) were cloned. Subsequently, many of the downstream biochemical pathways activated by the IL2 receptor complex were identified and the structure of IL2 bound to this tripartite receptor complex was solved. Thus, we now have a very good understanding of how each chain contributes to high affinity IL2 binding and signal transduction. In contrast, over the past 30 years the role that IL2 plays in regulating lymphocyte function has involved many surprising twists and turns. For example, IL2 has been shown, paradoxically, to regulate both lymphocyte proliferation and lymphocyte death. In this review, we briefly outline the original findings suggesting a role for IL2 as a T cell growth factor, as well as subsequent studies pointing to its function as an initiator of activation-induced cell death, but then focus on the newly appreciated role for IL2 and IL2R signaling in the development and homeostasis of regulatory T cells.
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Affiliation(s)
- Matthew A. Burchill
- Center for Immunology, The Cancer Center, Department of Laboratory Medicine and Pathology, University of Minnesota, 312 Church Street SE, 6-116 Nils Hasselmo Hall, Minneapolis, MN 55455 USA
| | - Jianying Yang
- Center for Immunology, The Cancer Center, Department of Laboratory Medicine and Pathology, University of Minnesota, 312 Church Street SE, 6-116 Nils Hasselmo Hall, Minneapolis, MN 55455 USA
| | - Kieng B. Vang
- Center for Immunology, The Cancer Center, Department of Laboratory Medicine and Pathology, University of Minnesota, 312 Church Street SE, 6-116 Nils Hasselmo Hall, Minneapolis, MN 55455 USA
| | - Michael A. Farrar
- Center for Immunology, The Cancer Center, Department of Laboratory Medicine and Pathology, University of Minnesota, 312 Church Street SE, 6-116 Nils Hasselmo Hall, Minneapolis, MN 55455 USA
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Yang M, Huang L, Liu W, Sheng Z, Xie H, Liao E. Prolactin may be a promising therapeutic target for myasthenia gravis: hypothesis and importance. Med Hypotheses 2007; 70:1017-20. [PMID: 17933471 DOI: 10.1016/j.mehy.2007.06.044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Accepted: 06/06/2007] [Indexed: 11/16/2022]
Abstract
Myasthenia gravis (MG) is an autoimmune disease that affects the transmission signals from nerves to muscles. The basic pathology is the production of anti-acetylcholine receptor (AChR) antibodies (AChRAb) which is the consequence for the generation of autoreactive T lymphocytes responsing to AChR. However, the molecular mechanism of MG and the production of autoreactive T lymphocytes remain elusive. Recently beside its pivotal role in reproduction, the pituitary hormone prolactin (PRL) has been attributed to an immunomodulatory function. Furthermore it has been shown to be expressed in T cells and conversely it also affects the function of T cells, such as directly stimulating the proliferation and survival of T lymphocytes. In addition, elevated PRL levels frequently are described in autoimmune diseases, such as systemic lupus erythematosus (SLE) and multiple sclerosis (MS). So we hypothesized that the stimulating effect of PRL on T-cells function may be implied in the pathogenesis of MG and, perhaps, prolactin may be a promising therapeutic target for MG.
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Affiliation(s)
- Min Yang
- Institute of Endocrinology and Metabolism, The Second Xiangya Hospital of Central South University, 86# Middle Renmin Road, Changsha, Hunan 410011, PR China
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Li S, Gowans EJ, Chougnet C, Plebanski M, Dittmer U. Natural regulatory T cells and persistent viral infection. J Virol 2007; 82:21-30. [PMID: 17855537 PMCID: PMC2224364 DOI: 10.1128/jvi.01768-07] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
- Shuo Li
- HCV Laboratory, Macfarlane Burnet Institute, GPO Box 2284, Melbourne, VIC 3001, Australia.
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Hafler DA, Compston A, Sawcer S, Lander ES, Daly MJ, De Jager PL, de Bakker PIW, Gabriel SB, Mirel DB, Ivinson AJ, Pericak-Vance MA, Gregory SG, Rioux JD, McCauley JL, Haines JL, Barcellos LF, Cree B, Oksenberg JR, Hauser SL. Risk alleles for multiple sclerosis identified by a genomewide study. N Engl J Med 2007; 357:851-62. [PMID: 17660530 DOI: 10.1056/nejmoa073493] [Citation(s) in RCA: 1203] [Impact Index Per Article: 70.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Multiple sclerosis has a clinically significant heritable component. We conducted a genomewide association study to identify alleles associated with the risk of multiple sclerosis. METHODS We used DNA microarray technology to identify common DNA sequence variants in 931 family trios (consisting of an affected child and both parents) and tested them for association. For replication, we genotyped another 609 family trios, 2322 case subjects, and 789 control subjects and used genotyping data from two external control data sets. A joint analysis of data from 12,360 subjects was performed to estimate the overall significance and effect size of associations between alleles and the risk of multiple sclerosis. RESULTS A transmission disequilibrium test of 334,923 single-nucleotide polymorphisms (SNPs) in 931 family trios revealed 49 SNPs having an association with multiple sclerosis (P<1x10(-4)); of these SNPs, 38 were selected for the second-stage analysis. A comparison between the 931 case subjects from the family trios and 2431 control subjects identified an additional nonoverlapping 32 SNPs (P<0.001). An additional 40 SNPs with less stringent P values (<0.01) were also selected, for a total of 110 SNPs for the second-stage analysis. Of these SNPs, two within the interleukin-2 receptor alpha gene (IL2RA) were strongly associated with multiple sclerosis (P=2.96x10(-8)), as were a nonsynonymous SNP in the interleukin-7 receptor alpha gene (IL7RA) (P=2.94x10(-7)) and multiple SNPs in the HLA-DRA locus (P=8.94x10(-81)). CONCLUSIONS Alleles of IL2RA and IL7RA and those in the HLA locus are identified as heritable risk factors for multiple sclerosis.
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