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Tiberti C, D’Onofrio L, Panimolle F, Zampetti S, Maddaloni E, Buzzetti R. Immunoreactivities Against Different Tyrosine-Phosphatase 2 (IA-2)(256-760) Protein Domains Characterize Distinct Phenotypes in Subjects With LADA. Front Endocrinol (Lausanne) 2022; 13:921886. [PMID: 35813648 PMCID: PMC9263087 DOI: 10.3389/fendo.2022.921886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
Antibodies (Abs) against intracellular epitopes of the tyrosine-phosphatase 2 (IA-2) are detected in type 1 diabetes. Abs directed against the IA-2(256-760) portion, with both intra- and extracellular epitopes, are present in people with latent autoimmune diabetes in adults (LADA) and in obese subjects with normal glucose tolerance (NGT). We aim to characterize distribution and clinical features of intra- and extra-cellular IA-2(256-760) immunoreactivities in people with LADA compared to obese people with NGT. The intracellular immunoreactivity represented by immune response against two intracellular IA-2 constructs (IA-2JM(601-630) and IA-2IC(605-979)) was analyzed and related to clinical and biochemical features in 101 people with LADA and in 20 NGT obese subjects, all testing positive for IA-2(256-760) Abs. IA-2 intracellular immunoreactivity showed a frequency of 40.6% in LADA while it was not detected among NGT obese (p<0.001). Amongst LADA, the presence of immunoreactivity against the IA-2 intracellular domains was associated with lower BMI, waist circumference, higher HDL cholesterol and lower triglycerides, lower prevalence of hypertension and higher prevalence of other autoimmune disorders. Immunoreactivity against IA-2 does not involve intracellular domains in the majority of LADA and in obese people with NGT. This study shows that there is heterogeneity in the IA-2 epitopes, associated with different clinical features.
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McLaughlin KA, Tombs MA, Christie MR. Autoimmunity to tetraspanin-7 in type 1 diabetes. Med Microbiol Immunol 2020; 209:437-445. [PMID: 32314012 PMCID: PMC7395010 DOI: 10.1007/s00430-020-00674-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/03/2020] [Indexed: 01/05/2023]
Abstract
Type 1 diabetes is an autoimmune disease whereby components of insulin-secreting pancreatic beta cells are targeted by the adaptive immune system leading to the destruction of these cells and insulin deficiency. There is much interest in the development of antigen-specific immune intervention as an approach to prevent disease development in individuals identified as being at risk of disease. It is now recognised that there are multiple targets of the autoimmune response in type 1 diabetes, the most recently identified being a member of the tetraspanin family, tetraspanin-7. The heterogeneity of autoimmune responses to different target antigens complicates the assessment of diabetes risk by the detection of autoantibodies, as well as creating challenges for the design of strategies to intervene in the immune response to these autoantigens. This review describes the discovery of tetraspanin-7 as a target of autoantibodies in type 1 diabetes and how the detection of autoantibodies to the protein provides a valuable marker for future loss of pancreatic beta-cell function.
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Affiliation(s)
- Kerry A McLaughlin
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, UK
| | | | - Michael R Christie
- School of Life Sciences, University of Lincoln, Lincoln, UK.
- School of Life Sciences, Joseph Banks Laboratories, University of Lincoln, Lincoln, LN6 7DL, UK.
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Acevedo-Calado M, James EA, Morran MP, Pietropaolo SL, Ouyang Q, Arribas-Layton D, Songini M, Liguori M, Casu A, Auchus RJ, Huang S, Yu L, Michels A, Gianani R, Pietropaolo M. Identification of Unique Antigenic Determinants in the Amino Terminus of IA-2 (ICA512) in Childhood and Adult Autoimmune Diabetes: New Biomarker Development. Diabetes Care 2017; 40:561-568. [PMID: 28174261 PMCID: PMC5360285 DOI: 10.2337/dc16-1527] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 01/11/2017] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The characterization of diverse subtypes of diabetes is a dynamic field of clinical research and an active area of discussion. The objective of this study was to identify new antigenic determinants in the neuroendocrine autoantigen IA-2 (ICA512) and assess whether circulating autoantibodies directed to new IA-2 epitopes identify autoimmune diabetes in young and adult populations with diabetes. RESEARCH DESIGN AND METHODS Clinically diagnosed patients with type 2 diabetes (n = 258; diabetes duration: 0.01-31 years) were evaluated using a new biomarker detecting autoantibodies directed to the extracellular domain of the neuroendocrine autoantigen IA-2 (IA-2ec). The proportion of IA-2ec autoantibodies was also evaluated in newly diagnosed patients with type 1 diabetes (n = 150; diabetes duration: 0.04-0.49 years). In addition, IA-2 (intracellular domain), GAD65, and zinc transporter 8 autoantibodies were assayed. RESULTS IA-2ec autoantibodies were detected in patients with type 1 diabetes and, surprisingly, in 5% of patients with type 2 diabetes without serologic responses to other IA-2 antigenic epitopes or other islet autoantigens. We also assessed the ability of IA-2ec-derived peptides to elicit CD4+ T-cell responses by stimulating peripheral blood mononuclear cells from patients with type 1 diabetes (n = 18) and HLA-matched healthy subjects (n = 13) with peptides and staining with the peptide/DQ8-specific tetramers, observing disease-associated responses to previously unreported epitopes within IA-2ec. CONCLUSIONS We developed a new antibody biomarker identifying novel antigenic determinants within the N terminus of IA-2. IA-2ec autoantibodies can be detected in patients with type 1 diabetes and in a subgroup of adult autoimmune patients with type 2 diabetes phenotype negative for conventional islet autoantibody testing. These observations suggest that islet autoimmunity may be more common in clinically diagnosed type 2 diabetes than previously observed.
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Affiliation(s)
- Maria Acevedo-Calado
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Baylor College of Medicine, Houston, TX
| | - Eddie A James
- Benaroya Research Institute, University of Washington, Seattle, WA
| | - Michael P Morran
- Department of Medicinal Chemistry, College of Pharmacy, University of Toledo, Toledo, OH
| | - Susan L Pietropaolo
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Baylor College of Medicine, Houston, TX
| | - Qin Ouyang
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Baylor College of Medicine, Houston, TX
| | | | - Marco Songini
- Diabetes Clinic, Department of Internal Medicine, and Laboratory of Microbiology & Immunology, Azienda Ospedaliera G. Brotzu, Cagliari, Italy
| | - Marco Liguori
- Diabetes Clinic, Department of Internal Medicine, and Laboratory of Microbiology & Immunology, Azienda Ospedaliera G. Brotzu, Cagliari, Italy
| | - Anna Casu
- Istituto Mediterraneo per i Trapianti e Terapie ad Alta Specializzazione, Palermo, Italy
| | - Richard J Auchus
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - Shuai Huang
- Department of Industrial and Systems Engineering, University of Washington, Seattle, WA
| | - Liping Yu
- Barbara Davis Center for Childhood Diabetes, University of Colorado School of Medicine, Aurora, CO
| | - Aaron Michels
- Barbara Davis Center for Childhood Diabetes, University of Colorado School of Medicine, Aurora, CO
| | - Roberto Gianani
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Baylor College of Medicine, Houston, TX.,Rocky Vista University College of Osteopathic Medicine, Parker, CO
| | - Massimo Pietropaolo
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Baylor College of Medicine, Houston, TX
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Abstract
Islet autoantibodies are the main markers of pancreatic autoimmunity in type 1 diabetes (T1D). Islet autoantibodies recognize insulin (IAA), glutamic acid decarboxylase (GADA), protein phosphatase-like IA-2 (IA-2A), and ZnT8 (ZnT8A), all antigens that are found on secretory granules within pancreatic beta cells. Islet antibodies, measured by sensitive and specific liquid phase assays, are the key parameters of the autoimmune response monitored for diagnostics or prognostics in patients with T1D or for disease prediction in at-risk individuals before T1D onset. Islet autoantibodies have been the main tool used to explore the natural history of T1D; this review summarizes the current knowledge about the autoantigens and the phenotype of islets autoantibodies acquired in large prospective studies from birth in children at risk of developing T1D.
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Affiliation(s)
- Vito Lampasona
- Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milano, Italy.
- Diabetes Research Institute, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milano, Italy.
| | - Daniela Liberati
- Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milano, Italy
- Diabetes Research Institute, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milano, Italy
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Christie MR. Delving Into the Type 1 Diabetic Islet: Evidence That B-Cell Infiltration of Islets Is Linked to Local Hyperimmunity and Accelerated Progression to Disease. Diabetes 2016; 65:1146-8. [PMID: 27208181 DOI: 10.2337/dbi16-0008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Smigoc Schweiger D, Mendez A, Kunilo Jamnik S, Bratanic N, Bratina N, Battelino T, Brecelj J, Vidan-Jeras B. High-risk genotypes HLA-DR3-DQ2/DR3-DQ2 and DR3-DQ2/DR4-DQ8 in co-occurrence of type 1 diabetes and celiac disease. Autoimmunity 2016; 49:240-7. [PMID: 27138053 DOI: 10.3109/08916934.2016.1164144] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Shared susceptibility alleles in the HLA region contribute to the co-existence of type 1 diabetes (T1D) and celiac disease (CD). The aim of our study was to identify HLA genotype variations that influence co-occurrence of T1D and CD (T1D + CD) and the order of their onset. Totally 244 patients, 67 with T1D, 68 with CD and 69 with T1D + CD, (split into "T1D first" and "CD first"), were analyzed. Control group consisted of 130 healthy unrelated individuals. Two-tailed Fisher's exact test was used for statistical analysis. The genetic background of Slovenian CD patients resembled more northern than southern European populations with DR3-DQ2/DR3-DQ2 (odds ratio [OR] = 19.68) conferring the highest risk. The T1D + CD was associated with DR3-DQ2/DR3-DQ2 (OR = 45.53) and even more with DR3-DQ2/DR4-DQ8 (OR = 93.76). DR3-DQ2/DR7-DQ2 played a neutral role in susceptibility for T1D + CD. The order of the onset of T1D or CD in patients with co-occurring diseases was not influenced by HLA risk genotype profile. DR3-DQ2/DR3-DQ2 was associated with an increased risk for developing CD in patients with T1D, whereas patients with CD carrying DR3-DQ2/DR4-DQ8 were at higher risk for developing T1D. In addition to other genetic factors including HLA class I alleles present on DR3-DQ2 extended haplotype, the second extended haplotype may moderate the risk for T1D + CD conferred by DR3-DQ2. Our results suggested that individuals carrying high-risk genotypes DR3-DQ2/DR3-DQ2 or DR3-DQ2/DR4-DQ8 would more likely develop both T1D and CD than either disease alone.
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Affiliation(s)
- Darja Smigoc Schweiger
- a Department of Pediatric Endocrinology , Diabetes and Metabolic Diseases, UMC - University Children's Hospital , Ljubljana , Slovenia
| | - Andrijana Mendez
- b Blood Transfusion Center of Slovenia, Tissue Typing Centre , Ljubljana , Slovenia
| | - Sabina Kunilo Jamnik
- b Blood Transfusion Center of Slovenia, Tissue Typing Centre , Ljubljana , Slovenia
| | - Nina Bratanic
- a Department of Pediatric Endocrinology , Diabetes and Metabolic Diseases, UMC - University Children's Hospital , Ljubljana , Slovenia
| | - Natasa Bratina
- a Department of Pediatric Endocrinology , Diabetes and Metabolic Diseases, UMC - University Children's Hospital , Ljubljana , Slovenia
| | - Tadej Battelino
- a Department of Pediatric Endocrinology , Diabetes and Metabolic Diseases, UMC - University Children's Hospital , Ljubljana , Slovenia .,c Faculty of Medicine , University of Ljubljana , Ljubljana , Slovenia , and
| | - Jernej Brecelj
- c Faculty of Medicine , University of Ljubljana , Ljubljana , Slovenia , and.,d Department of Gastroenterology , Hepatology and Nutrition, UMC - University Children's Hospital , Ljubljana , Slovenia
| | - Blanka Vidan-Jeras
- b Blood Transfusion Center of Slovenia, Tissue Typing Centre , Ljubljana , Slovenia
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Elvers KT, Williams AJK. Molecular Methods and Protein Synthesis for Definition of Autoantibody Epitopes. Methods Mol Biol 2016; 1433:179-207. [PMID: 27032951 DOI: 10.1007/7651_2016_339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Epitope mapping is the process of experimentally identifying the binding sites, or "epitopes," of antibodies on their target antigens. Understanding the antibody-epitope interaction provides a basis for the rational design of potential preventative vaccines. Islet autoantibodies are currently the best available biomarkers for predicting future type 1 diabetes. These include autoantibodies to the islet beta cell proteins, insulin and the tyrosine phosphatase islet antigen-2 (IA-2) which selectively bind to a small number of dominant epitopes associated with increased risk of disease progression. The major epitope regions of insulin and IA-2 autoantibodies have been identified, but need to be mapped more precisely. In order to characterize these epitopes more accurately, this article describes the methods of cloning and mutagenesis of insulin and IA-2 and subsequent purification of the proteins that can be tested in displacement analysis and used to monitor immune responses, in vivo, to native and mutated proteins in a humanized mouse model carrying the high-risk HLA class II susceptibility haplotype DRB1*04-DQ8.
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Affiliation(s)
- Karen T Elvers
- Diabetes and Metabolism Unit, School of Clinical Sciences, Southmead Hospital, University of Bristol, Bristol, UK.
| | - Alistair J K Williams
- Diabetes and Metabolism Unit, School of Clinical Sciences, Southmead Hospital, University of Bristol, Bristol, UK
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Richardson CC, McLaughlin KA, Morgan D, Feltbower RG, Christie MR. Influence of HLA-DR and -DQ alleles on autoantibody recognition of distinct epitopes within the juxtamembrane domain of the IA-2 autoantigen in type 1 diabetes. Diabetologia 2016; 59:334-40. [PMID: 26564179 PMCID: PMC4705114 DOI: 10.1007/s00125-015-3803-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 10/19/2015] [Indexed: 12/04/2022]
Abstract
AIMS/HYPOTHESIS Insulinoma-associated protein 2 (IA-2) is a major target of autoimmunity in type 1 diabetes. When first detected, IA-2-autoantibodies commonly bind epitopes in the juxtamembrane (JM) domain of IA-2 and antibody responses subsequently spread to the tyrosine phosphatase domain. Definition of structures of epitopes in the JM domain, and genetic requirements for autoimmunity to these epitopes, is important for our understanding of initiation and progression of autoimmunity. The aims of this study were to investigate the contribution of individual amino acids in the IA-2 JM domain to antibody binding to these epitopes and the role of HLA genotypes in determining epitope specificity. METHODS Regions of the JM domain recognised by autoantibodies were identified by peptide competition and inhibitory effects of alanine substitutions of residues within the JM region. Antibody binding was determined by radioligand binding assays using sera from patients genotyped for HLA-DRB1 and -DQB1 alleles. RESULTS Patients were categorised into two distinct groups of JM antibody reactivity according to peptide inhibition. Inhibition by substitutions of individual amino acids within the JM domain differed between patients, indicating heterogeneity in epitope recognition. Cluster analysis defined six groups of residues having similar inhibitory effects on antibody binding, with three clusters showing differences in patients affected or unaffected by peptide. One cluster demonstrated significant differences in antibody binding between HLA-DRB1*04 and HLA-DRB1*07 patients and within DRB1*04 individuals; antibody recognition of a second cluster depended on expression of HLA-DQB1*0302. CONCLUSIONS/INTERPRETATION The results identify amino acids contributing to distinct epitopes on IA-2, with both HLA-DR and HLA-DQ alleles influencing epitope specificity.
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Affiliation(s)
- Carolyn C Richardson
- Division of Diabetes & Nutritional Sciences, King's College London Guy's Campus, London, UK
- School of Life Sciences, Joseph Banks Laboratories, University of Lincoln, Lincoln, LN6 7DL, UK
| | - Kerry A McLaughlin
- Division of Diabetes & Nutritional Sciences, King's College London Guy's Campus, London, UK
| | - Diana Morgan
- Division of Epidemiology & Biostatistics, School of Medicine, University of Leeds, Leeds, UK
| | - Richard G Feltbower
- Division of Epidemiology & Biostatistics, School of Medicine, University of Leeds, Leeds, UK
| | - Michael R Christie
- Division of Diabetes & Nutritional Sciences, King's College London Guy's Campus, London, UK.
- School of Life Sciences, Joseph Banks Laboratories, University of Lincoln, Lincoln, LN6 7DL, UK.
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Catani M, Walther D, Christie MR, McLaughlin KA, Bonifacio E, Eugster A. Isolation of human monoclonal autoantibodies derived from pancreatic lymph node and peripheral blood B cells of islet autoantibody-positive patients. Diabetologia 2016; 59:294-8. [PMID: 26493188 DOI: 10.1007/s00125-015-3792-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/30/2015] [Indexed: 12/17/2022]
Abstract
AIMS/HYPOTHESIS Autoantibodies against pancreatic islets and infections by enteroviruses are associated with type 1 diabetes, but the specificity of immune responses within the type 1 diabetic pancreas is poorly characterised. We investigated whether pancreatic lymph nodes could provide a source of antigen-specific B cells for analysis of immune responses within the (pre)diabetic pancreas. METHODS Human IgG antibodies were cloned from single B lymphocytes sorted from pancreatic lymph node cells of three organ donors positive for islet autoantibodies, and from the peripheral blood of a patient with type 1 diabetes. Antibodies to insulinoma-associated antigen 2 (IA-2), GAD65, zinc transporter 8 (ZnT8) and Coxsackie B virus proteins were assayed by immunoprecipitation and by immunofluorescence on pancreatic sections. RESULTS Human IgG antibodies (863) were successfully cloned and produced from 4,092 single B cells from lymph nodes and peripheral blood. Reactivity to the protein tyrosine phosphatase domain of the IA-2 autoantigen was detected in two cloned antibodies: one derived from a pancreatic lymph node and one from peripheral blood. Epitopes for these two antibodies were similar to each other and to those for circulating antibodies in type 1 diabetes. The remaining 861 antibodies were negative for reactivity to IA-2, GAD65 or ZnT8 by both assays tested. Reactivity to a Coxsackie viral protein 2 was detected in one antibody derived from a peripheral blood B cell, but not from lymph nodes. CONCLUSIONS/INTERPRETATION We show evidence for the infrequent presence of autoantigen-specific IgG+ B lymphocytes in the pancreatic-draining lymph nodes of islet autoantibody-positive individuals.
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