101
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Falta MT, Pinilla C, Mack DG, Tinega AN, Crawford F, Giulianotti M, Santos R, Clayton GM, Wang Y, Zhang X, Maier LA, Marrack P, Kappler JW, Fontenot AP. Identification of beryllium-dependent peptides recognized by CD4+ T cells in chronic beryllium disease. ACTA ACUST UNITED AC 2013; 210:1403-18. [PMID: 23797096 PMCID: PMC3698527 DOI: 10.1084/jem.20122426] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Identification of peptides that form complexes with beryllium and class II HLA molecules and are recognized by CD4+ T cells from patients with chronic beryllium disease. Chronic beryllium disease (CBD) is a granulomatous disorder characterized by an influx of beryllium (Be)-specific CD4+ T cells into the lung. The vast majority of these T cells recognize Be in an HLA-DP–restricted manner, and peptide is required for T cell recognition. However, the peptides that stimulate Be-specific T cells are unknown. Using positional scanning libraries and fibroblasts expressing HLA-DP2, the most prevalent HLA-DP molecule linked to disease, we identified mimotopes and endogenous self-peptides that bind to MHCII and Be, forming a complex recognized by pathogenic CD4+ T cells in CBD. These peptides possess aspartic and glutamic acid residues at p4 and p7, respectively, that surround the putative Be-binding site and cooperate with HLA-DP2 in Be coordination. Endogenous plexin A peptides and proteins, which share the core motif and are expressed in lung, also stimulate these TCRs. Be-loaded HLA-DP2–mimotope and HLA-DP2–plexin A4 tetramers detected high frequencies of CD4+ T cells specific for these ligands in all HLA-DP2+ CBD patients tested. Thus, our findings identify the first ligand for a CD4+ T cell involved in metal-induced hypersensitivity and suggest a unique role of these peptides in metal ion coordination and the generation of a common antigen specificity in CBD.
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Affiliation(s)
- Michael T Falta
- Department of Medicine, University of Colorado, Denver, Aurora, CO 80045, USA
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102
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Baker RL, Delong T, Barbour G, Bradley B, Nakayama M, Haskins K. Cutting edge: CD4 T cells reactive to an islet amyloid polypeptide peptide accumulate in the pancreas and contribute to disease pathogenesis in nonobese diabetic mice. THE JOURNAL OF IMMUNOLOGY 2013; 191:3990-4. [PMID: 24043895 DOI: 10.4049/jimmunol.1301480] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We previously reported a peptide KS20 from islet amyloid polypeptide (IAPP) to be the target Ag for a highly diabetogenic CD4 T cell clone BDC-5.2.9. To track IAPP-reactive T cells in NOD mice and determine how they contribute to the pathogenesis of type 1 diabetes, we designed a new I-Ag7 tetramer with high affinity for BDC-5.2.9 that contains the peptide KS20. We found that significant numbers of KS20 tetramer(+) CD4 T cells can be detected in the pancreas of prediabetic and diabetic NOD mice. To verify pathogenicity of IAPP-reactive cells, we sorted KS20 tetramer(+) cells and cloned them from uncloned T cell lines isolated from spleen and lymph nodes of diabetic mice. We isolated a new KS20-reactive Th1 CD4 T cell clone that rapidly transfers diabetes. Our results suggest that IAPP triggers a broad autoimmune response by CD4 T cells in NOD mice.
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Affiliation(s)
- Rocky L Baker
- Integrated Department of Immunology, University of Colorado at Denver School of Medicine and National Jewish Health, Denver, CO 80206
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103
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Vaitaitis GM, Wagner DH. CD40 interacts directly with RAG1 and RAG2 in autoaggressive T cells and Fas prevents CD40-induced RAG expression. Cell Mol Immunol 2013; 10:483-9. [PMID: 24037181 DOI: 10.1038/cmi.2013.24] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 05/02/2013] [Accepted: 05/16/2013] [Indexed: 12/20/2022] Open
Abstract
CD4(+) T cells expressing CD40 (Th40 cells) constitute a pathogenic T-cell subset that is necessary and sufficient to transfer autoimmune disease. We have previously demonstrated that CD40 signals peripheral Th40 cells to induce RAG1 and RAG2 expression, proteins necessary for the expression of T-cell receptor (TCR), leading to TCR revision. The dependency of TCR expression in the thymus on RAG proteins has long been known. However, despite numerous publications, there is controversy as to whether TCR expression can be altered in the periphery, post-thymic selective pressures. Therefore, a better understanding of TCR expression in primary peripheral cells is needed. We now show that the CD40 protein itself interacts with RAG1 and RAG2 as well as with Ku70 and translocates to the nucleus in Th40 cells. This indicates that the CD40 molecule is closely involved in the mechanism of TCR expression in the periphery. In addition, Fas signals act as a silencing mechanism for CD40-induced RAGs and prevent CD40 translocation to the nucleus. It will be important to further understand the involvement of CD40 in peripheral TCR expression and how TCR revision impacts auto-antigen recognition in order to effectively target and tolerize autoaggressive T cells in autoimmune disease.
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104
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Yadav M, Stephan S, Bluestone JA. Peripherally induced tregs - role in immune homeostasis and autoimmunity. Front Immunol 2013; 4:232. [PMID: 23966994 PMCID: PMC3736167 DOI: 10.3389/fimmu.2013.00232] [Citation(s) in RCA: 188] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 07/22/2013] [Indexed: 12/16/2022] Open
Abstract
Thymically derived Foxp3(+) regulatory T cells (tTregs) constitute a unique T cell lineage that is essential for maintaining immune tolerance to self and immune homeostasis. However, Foxp3 can also be turned on in conventional T cells as a consequence of antigen exposure in the periphery, under both non-inflammatory and inflammatory conditions. These so-called peripheral Tregs (pTregs) participate in the control of immunity at sites of inflammation, especially at the mucosal surfaces. Although numerous studies have assessed in vitro generated Tregs (termed induced or iTregs), these cells most often do not recapitulate the functional or phenotypic characteristics of in vivo generated pTregs. Thus, there are still many unanswered questions regarding the T cell receptor (TCR) repertoire and function of pTregs as well as conditions under which they are generated in vivo, and the degree to which these characteristics identify specialized features of pTregs versus features that are shared with tTregs. In this review, we summarize the current state of our understanding of pTregs and their relationship to the tTreg subset. We describe the recent discovery of unique cell surface markers and transcription factors (including Neuropilin-1 and Helios) that can be used to distinguish tTreg and pTreg subsets in vivo. Additionally, we discuss how the improved ability to distinguish these subsets provided new insights into the biology of tTregs versus pTregs and suggested differences in their function and TCR repertoire, consistent with a unique role of pTregs in certain inflammatory settings. Finally, these recent advances will be used to speculate on the role of individual Treg subsets in both tolerance and autoimmunity.
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Affiliation(s)
- Mahesh Yadav
- Diabetes Center, University of California San Francisco , San Francisco, CA , USA
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105
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Therapeutic opportunities for manipulating T(Reg) cells in autoimmunity and cancer. Nat Rev Drug Discov 2013; 12:51-63. [PMID: 23274471 DOI: 10.1038/nrd3683] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Forkhead box P3 (FOXP3)-expressing regulatory T (T(Reg)) cells have a pivotal role in the regulation of immune responses and in the maintenance of immunological self-tolerance. These cells have emerged as attractive targets for strategies that allow the steering of immune responses in desired directions - arming the immune system to destroy infected cells and cancer cells or downregulating it to limit tissue destruction in autoimmunity. Efforts to understand the generation, activation and function of T(Reg) cells should permit the development of therapeutics for reprogramming the immune system. In this Review, we discuss insights into the generation of T(Reg) cells, their involvement in disease and the molecular basis of the dominant tolerance exerted by FOXP3(+) T(Reg) cells that could permit their safe and specific manipulation in humans.
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106
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Blanchfield JL, Shorter SK, Evavold BD. Monitoring the Dynamics of T Cell Clonal Diversity Using Recombinant Peptide:MHC Technology. Front Immunol 2013; 4:170. [PMID: 23840195 PMCID: PMC3699728 DOI: 10.3389/fimmu.2013.00170] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 06/14/2013] [Indexed: 12/31/2022] Open
Abstract
The capacity to probe antigen specific T cells within the polyclonal repertoire has been revolutionized by the advent of recombinant peptide:MHC (pMHC) technology. Monomers and multimers of pMHC molecules can enrich for and identify antigen specific T cells to elucidate the contributions of T cell frequency, localization, and T cell receptor (TCR) affinity during immune responses. Two-dimensional (2D) measurements of TCR–pMHC interactions are at the forefront of this field because the biological topography is replicated such that TCR and pMHC are membrane anchored on opposing cells, allowing for biologically pertinent measures of TCR antigen specificity and diversity. 2D measurements of TCR-pMHC kinetics have also demonstrated increased fidelity compared to three-dimensional surface plasmon resonance data and are capable of detecting T cell affinities that are below the detection level of most pMHC multimers. Importantly, 2D techniques provide a platform to evaluate T cell affinity and antigen specificity against multiple protein epitopes within the polyclonal repertoire directly ex vivo from sites of ongoing immune responses. This review will discuss how antigen specific pMHC molecules, with a focus on 2D technologies, can be used as effective tools to evaluate the range of TCR affinities that comprise an immune response and more importantly how the breadth of affinities determine functional outcome against a given exposure to antigen.
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Affiliation(s)
- J Lori Blanchfield
- Department of Microbiology and Immunology, Emory University, Atlanta, GA , USA
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107
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Ahmed ST, Akirav E, Bradshaw E, Buckner J, McKinney E, Quintana FJ, Waldron-Lynch F, Nepom J. Immunological biomarkers: catalysts for translational advances in autoimmune diabetes. Clin Exp Immunol 2013; 172:178-85. [PMID: 23574315 DOI: 10.1111/cei.12063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2012] [Indexed: 12/20/2022] Open
Abstract
In a recent workshop organized by the JDRF focused on the 'Identification and Utilization of Robust Biomarkers in Type1 Diabetes', leaders in the field of type 1 diabetes (T1D)/autoimmunity and assay technology came together from academia, government and industry to assess the current state of the field, evaluate available resources/technologies and identify gaps that need to be filled for moving the field of T1D research forward. The highlights of this workshop are discussed in this paper, as well as the proposal for a larger, planned consortium effort, incorporating a JDRF Biomarker Core, to foster collaboration and accelerate progress in this critically needed area of T1D research.
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Affiliation(s)
- S T Ahmed
- JDRF, 26, Broadway, 14th Floor, New York, NY 10004, USA.
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108
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Abstract
Type 1A diabetes (autoimmune) is now immunologically predictable in man, but preventable only in animal models. What triggers the development of autoimmunity in genetically susceptible individuals remains unknown. Studies of non-obese diabetic (NOD) mice reveal that interactions between T-cell receptors of diabetogenic T cell and an MHC class II loaded with an autoantigen are key determinates of the disease. With insulin as the primary target in the NOD mouse, likely man, and possibly the RT1-U rat models, therapeutic targeting of the components of these anti-insulin trimolecular complexes we believe provide a fulcrum for development of preventive therapy. In particular for the NOD mouse model, there is extensive evidence that the dominant insulin peptide driving disease initiation is insulin B chain amino acids 9-23 (SHLVEALYLVCGERG) recognized predominantly by germ-line sequences of a specific T-cell receptor Valpha (TRAV5D-4), and small molecules or monoclonal antibodies directed at this recognition complex can prevent diabetes.
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109
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Delong T, Baker RL, He J, Haskins K. Novel autoantigens for diabetogenic CD4 T cells in autoimmune diabetes. Immunol Res 2013; 55:167-72. [PMID: 22971988 DOI: 10.1007/s12026-012-8375-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Autoreactive CD4 T cells play a central role in the development of type 1 diabetes. The BDC panel of diabetogenic T cell clones was originally isolated from non-obese diabetic mice and has been used to study the role of autoreactive CD4 T cells and T cell autoantigens in the development of diabetes. Recent studies by our group have led to the identification of two new target antigens for clones of this panel. This review describes the proteomic strategy used for antigen identification, the antigens identified, and the potential contribution of post-translational modification to autoantigen generation. In addition, we compare peptide epitopes for the T cell clones and discuss their potential applications in investigating the role of T cell autoantigens in the pathogenesis and regulation of disease.
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Affiliation(s)
- Thomas Delong
- Integrated Department of Immunology, University of Colorado School of Medicine and National Jewish Health, Denver, CO 80206, USA
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110
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Affiliation(s)
- Alberto Pugliese
- Diabetes Research Institute, Miller School of Medicine, University of Miami, Miami, Florida, USA.
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111
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Michels AW. Targeting the trimolecular complex: the pathway towards type 1 diabetes prevention. Diabetes Technol Ther 2013; 15 Suppl 2:S2-8-S2-12. [PMID: 23786298 PMCID: PMC3676662 DOI: 10.1089/dia.2013.0114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
George Eisenbarth devoted his life to understanding the basic immunology of the autoimmune polyglandular syndromes and type 1 diabetes, while providing exceptional clinical care to individuals afflicted with these disorders. Over the last 5 years, I was privileged to know George Eisenbarth as a mentor, colleague, and friend. His enthusiasm for science and specifically understanding the basic immunology of type 1 diabetes was infectious. George was the first to initially hypothesize that type 1 diabetes is a chronic autoimmune disorder. He made diabetes a predictable disease by developing biochemical assays to measure islet autoantibodies and provided this technology worldwide to researchers and the medical community. His work identifying and detecting islet autoantibodies allowed for clinical intervention trials aimed at preventing type 1 diabetes. George worked fervently to prevent the disease. During my time as a fellow in George's laboratory and faculty member at the Barbara Davis Center for Diabetes, we focused our efforts for diabetes prevention at the trimolecular complex (human leukocyte antigen molecule, self-peptide, and T cell receptor), which plays a pivotal role in diabetes pathogenesis. It is our belief that targeting this complex with safe and specific therapies will lead to the prevention of type 1 diabetes and an improved understanding as to why diabetes develops.
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Affiliation(s)
- Aaron W Michels
- Barbara Davis Center for Childhood Diabetes, University of Colorado Denver, Aurora, Colorado 80045, USA.
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112
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Herold KC, Vignali DAA, Cooke A, Bluestone JA. Type 1 diabetes: translating mechanistic observations into effective clinical outcomes. Nat Rev Immunol 2013; 13:243-56. [PMID: 23524461 PMCID: PMC4172461 DOI: 10.1038/nri3422] [Citation(s) in RCA: 167] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Type 1 diabetes (T1D) remains an important health problem, particularly in western countries, where the incidence has been increasing in younger children. In 1986, Eisenbarth described T1D as a chronic autoimmune disease. Work over the past three-and-a-half decades has identified many of the genetic, immunological and environmental factors that are involved in the disease and have led to hypotheses concerning its pathogenesis. Clinical trials have been conducted to test these hypotheses but have had mixed results. Here, we discuss the findings that have led to our current concepts of the disease mechanisms involved in T1D and the clinical studies promoted by these studies. The findings from preclinical and clinical studies support the original proposed model for how T1D develops but have also suggested that this disease is more complex than was originally thought and will require broader treatment approaches.
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Affiliation(s)
- Kevan C Herold
- Department of Immunobiology, Yale University, New Haven, Connecticut 06520, USA.
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113
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Abstract
Class II major histocompatibility molecules (MHC) confer disease risk for multiple autoimmune disorders including type 1 diabetes. The interaction between the components of the trimolecular complex (CD4(+) T cell receptors, self-peptide, and MHC class II molecules) plays a pivotal role in autoimmune disease pathogenesis. The development of therapies targeting various components of the trimolecular complex for the prevention of type 1 diabetes is actively being pursued. This review focuses on the components of the anti-insulin trimolecular complex, registers of insulin peptide binding to 'diabetogenic' MHC class II molecules, and therapies targeting each component of the trimolecular complex.
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Affiliation(s)
- Aaron W Michels
- Barbara Davis Center for Childhood Diabetes, University of Colorado Denver, 1775 Aurora Court, MS A140, Aurora, CO 80045, USA.
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114
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Kendall PL, Case JB, Sullivan AM, Holderness JS, Wells KS, Liu E, Thomas JW. Tolerant anti-insulin B cells are effective APCs. THE JOURNAL OF IMMUNOLOGY 2013; 190:2519-26. [PMID: 23396943 DOI: 10.4049/jimmunol.1202104] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Autoreactive B lymphocytes that are not culled by central tolerance in the bone marrow frequently enter the peripheral repertoire in a state of functional impairment, termed anergy. These cells are recognized as a liability for autoimmunity, but their contribution to disease is not well understood. Insulin-specific 125Tg B cells support T cell-mediated type 1 diabetes in NOD mice, despite being anergic to B cell mitogens and T cell-dependent immunization. Using this model, the potential of anergic, autoreactive B cells to present Ag and activate T cells was investigated. The data show that 1) insulin is captured and rapidly internalized by 125Tg BCRs, 2) these Ag-exposed B cells are competent to activate both experienced and naive CD4(+) T cells, 3) anergic 125Tg B cells are more efficient than naive B cells at activating T cells when Ag is limiting, and 4) 125Tg B cells are competent to generate low-affinity insulin B chain epitopes necessary for activation of diabetogenic anti-insulin BDC12-4.1 T cells, indicating the pathological relevance of anergic B cells in type 1 diabetes. Thus, phenotypically tolerant B cells that are retained in the repertoire may promote autoimmunity by driving activation and expansion of autoaggressive T cells via Ag presentation.
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Affiliation(s)
- Peggy L Kendall
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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115
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Abstract
Type 1 diabetes (T1D) is a chronic autoimmune disease affecting millions of people worldwide. The disease is characterized by the loss of self-tolerance to the insulin-producing β-cells in the pancreas, the destruction of β-cells, and finally the development of chronic hyperglycemia at diagnosis of T1D. Its incidence and prevalence are rising dramatically, highlighting the need for immunotherapeutic strategies able to prevent or treat the disease in a safe and specific manner. Immunotherapeutic strategies are being developed, and aim to restore immunological self-tolerance, thereby limiting unwanted immunity and β-cell destruction. Foxp3+ regulatory T (Treg) cells exert essential functions to maintain and restore immunological self-tolerance. The identification of the transcription factor Foxp3 as the specification factor for the Treg cell lineage facilitated our understanding in the biology of Treg generation and function. This review highlights the current understanding of immunotherapeutic approaches as preventative and curative measures for autoimmune T1D. It includes an overview on early immunointervention studies, which made use of general immunosuppressive agents such as cyclosporin A, followed by a discussion on newly emerging clinical trials. Besides non-antigen-specific therapies, particular attention is given to antigen-specific generation of Foxp3+ Treg cells and their potential use to limit autoimmunity such as T1D.
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Affiliation(s)
- Benno Weigmann
- Research Campus of the Friedrich-Alexander University Erlangen-Nuernberg, Medical Clinic I, 91052 Erlangen, Germany
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116
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Bluestone JA, Bour-Jordan H. Current and future immunomodulation strategies to restore tolerance in autoimmune diseases. Cold Spring Harb Perspect Biol 2012; 4:4/11/a007542. [PMID: 23125012 DOI: 10.1101/cshperspect.a007542] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Autoimmune diseases reflect a breakdown in self-tolerance that results from defects in thymic deletion of potentially autoreactive T cells (central tolerance) and in T-cell intrinsic and extrinsic mechanisms that normally control potentially autoreactive T cells in the periphery (peripheral tolerance). The mechanisms leading to autoimmune diseases are multifactorial and depend on a complex combination of genetic, epigenetic, molecular, and cellular elements that result in pathogenic inflammatory responses in peripheral tissues driven by self-antigen-specific T cells. In this article, we describe the different checkpoints of tolerance that are defective in autoimmune diseases as well as specific events in the autoimmune response which represent therapeutic opportunities to restore long-term tolerance in autoimmune diseases. We present evidence for the role of different pathways in animal models and the therapeutic strategies targeting these pathways in clinical trials in autoimmune diseases.
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Affiliation(s)
- Jeffrey A Bluestone
- UCSF Diabetes Center, University of California at San Francisco, 94143, USA.
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117
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Weigmann B, Daniel C. Treg vaccination with a strong-agonistic insulin mimetope. Curr Diab Rep 2012; 12:463-70. [PMID: 22763731 DOI: 10.1007/s11892-012-0295-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Foxp3(+) regulatory T (Treg) cells serve as a vital mechanism of negative regulation to maintain immunological self-tolerance thereby suppressing immune-mediated inflammation. The identification of the transcription factor Foxp3 as the specification factor for the Treg cell lineage facilitated our understanding in the biology of Treg generation and function. In the past, we carefully studied the extrathymic conversion of naive CD4(+) T cells into Foxp3(+) expressing Treg cells and found that this process is most efficient upon subimmunogenic supply of strong-agonistic T cell receptor (TCR) ligands avoiding activation of antigen-presenting and T cells. In contrast, weak-agonistic antigens fail to efficiently induce stable Foxp3(+) Treg cells irrespective of the applied dose. Here, we discuss the specific requirements for the establishment of Treg vaccination protocols to interfere with autoimmunity such as Type 1 diabetes.
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Affiliation(s)
- Benno Weigmann
- Research Campus of the Friedrich-Alexander University Erlangen-Nuernberg, Medical Clinic I, 91052, Erlangen, Germany.
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118
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Pietropaolo M, Towns R, Eisenbarth GS. Humoral autoimmunity in type 1 diabetes: prediction, significance, and detection of distinct disease subtypes. Cold Spring Harb Perspect Med 2012; 2:a012831. [PMID: 23028135 PMCID: PMC3475400 DOI: 10.1101/cshperspect.a012831] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Type 1 diabetes mellitus (T1D) is an autoimmune disease encompassing the T-cell-mediated destruction of pancreatic β cells and the production of autoantibodies against islet proteins. In humoral autoimmunity in T1D, the detection of islet autoantibodies and the examination of their associations with genetic factors and cellular autoimmunity constitute major areas in both basic research and clinical practice. Although insulin is a key autoantigen and may be primus inter pares in importance among T1D autoantigens, an abundant body of research has also revealed other autoantigens associated with the disease process. Solid evidence indicates that autoantibodies against islet targets serve as key markers to enroll newly diagnosed T1D patients and their family members in intervention trials aimed at preventing or halting the disease process. The next challenge is perfecting mechanistic bioassays to be used as end points for disease amelioration following immunomodulatory therapies aimed at blocking immune-mediated β-cell injury and, in turn, preserving β-cell function in type 1 diabetes mellitus.
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Affiliation(s)
- Massimo Pietropaolo
- Laboratory of Immunogenetics, The Brehm Center for Diabetes Research, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48105, USA
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119
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Marrack P, Kappler JW. Do MHCII-presented neoantigens drive type 1 diabetes and other autoimmune diseases? Cold Spring Harb Perspect Med 2012; 2:a007765. [PMID: 22951444 PMCID: PMC3426820 DOI: 10.1101/cshperspect.a007765] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The strong association between particular MHCII alleles and type 1 diabetes is not fully understood. Two ideas that have been considered for many years are that autoimmunity is driven by (1) low-affinity CD4(+) T cells that escape thymic negative selection and respond to certain autoantigen peptides that are particularly well presented by particular MHCII molecules, or (2) CD4(+) T cells responding to neoantigens that are absent in the thymus, but uniquely created in the target tissue in the periphery and presented by particular MHCII alleles. Here we discuss the recent structural data in favor of the second idea. We review studies suggesting that peptide antigens recognized by autoimmune T cells are uniquely proteolytically processed and/or posttranslationally modified in the target tissue, thus allowing these T cells to escape deletion in the thymus during T-cell development. We postulate that an encounter with these tissue-specific neoantigenic peptides presented by the particular susceptible MHCII alleles in the peripheral tissues when accompanied by the appropriate inflammatory milieu activates these T-cell escapees leading to the onset of autoimmune disease.
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Affiliation(s)
- Philippa Marrack
- Howard Hughes Medical Institute and Integrated Department of Immunology, National Jewish Health, University of Colorado Denver, School of Medicine, Denver, CO 80206, USA
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120
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Current world literature. Curr Opin Endocrinol Diabetes Obes 2012; 19:328-37. [PMID: 22760515 DOI: 10.1097/med.0b013e3283567080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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121
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Dunne JL, Overbergh L, Purcell AW, Mathieu C. Posttranslational modifications of proteins in type 1 diabetes: the next step in finding the cure? Diabetes 2012; 61:1907-14. [PMID: 22826307 PMCID: PMC3402302 DOI: 10.2337/db11-1675] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The overall role of modification of β-cell antigens in type 1 diabetes has not been elucidated and was the focus of a recent workshop on posttranslational modification of proteins in type 1 diabetes. The prevailing opinion of the workshop attendees was that novel insights into the mechanism of loss of immune tolerance might be gained and that novel diagnostic and therapeutic approaches could be developed for type 1 diabetes if protein modifications were shown to play a critical role in the disease.
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Affiliation(s)
- Jessica L Dunne
- Juvenile Diabetes Research Foundation, New York, New York, USA.
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122
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Making the most of major histocompatibility complex molecule multimers: applications in type 1 diabetes. Clin Dev Immunol 2012; 2012:380289. [PMID: 22693523 PMCID: PMC3368179 DOI: 10.1155/2012/380289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 03/22/2012] [Indexed: 01/11/2023]
Abstract
Classical major histocompatibility complex (MHC) class I and II molecules present peptides to cognate T-cell receptors on the surface of T lymphocytes. The specificity with which T cells recognize peptide-MHC (pMHC) complexes has allowed for the utilization of recombinant, multimeric pMHC ligands for the study of minute antigen-specific T-cell populations. In type 1 diabetes (T1D), CD8+ cytotoxic T lymphocytes, in conjunction with CD4+ T helper cells, destroy the insulin-producing β cells within the pancreatic islets of Langerhans. Due to the importance of T cells in the progression of T1D, the ability to monitor and therapeutically target diabetogenic clonotypes of T cells provides a critical tool that could result in the amelioration of the disease. By administering pMHC multimers coupled to fluorophores, nanoparticles, or toxic moieties, researchers have demonstrated the ability to enumerate, track, and delete diabetogenic T-cell clonotypes that are, at least in part, responsible for insulitis; some studies even delay or prevent diabetes onset in the murine model of T1D. This paper will provide a brief overview of pMHC multimer usage in defining the role T-cell subsets play in T1D etiology and the therapeutic potential of pMHC for antigen-specific identification and modulation of diabetogenic T cells.
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Abstract
MHC class II tetramers have emerged as an important tool for characterization of the specificity and phenotype of CD4 T cell immune responses, useful in a large variety of disease and vaccine studies. Issues of specific T cell frequency, biodistribution, and avidity, coupled with the large genetic diversity of potential class II restriction elements, require targeted experimental design. Translational opportunities for immune disease monitoring are driving the rapid development of HLA class II tetramer use in clinical applications, together with innovations in tetramer production and epitope discovery.
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