The Antigen Repertoire of CD4 T cells from Pancreatic Islets

胰岛 CD4 T 细胞的抗原库

• 批准号: 10700133
• 负责人: Maki Nakayama
• 金额: $ 47.24万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-10 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10700133
• 关键词: Affinity; Alleles; Amino Acid Motifs; Antibodies; Antigen Targeting; Antigen-Presenting Cells; Antigens; Autoantibodies; Autoimmune Diseases; Automobile Driving; Bar Codes; Beta Cell; Biological; Biological Assay; Blood; CD4 Positive T Lymphocytes; Cell Separation; Cells; Clinical Trials Design; Computer Analysis; DNA; Development; Diabetes prevention; Disease; Disease Progression; Epitopes; Glutamate Decarboxylase; Goals; Grant; HLA-DR3 Antigen; HLA-DR4 Antigen; Health; Heterogeneity; Human; Hybridomas; Hybrids; Immune; Immunotherapy; Individual; Inflammatory; Insulin; Insulin-Dependent Diabetes Mellitus; Islet Cell; Islets of Langerhans; Link; MHC Class II Genes; Mass Spectrum Analysis; Organ Donor; Pancreas; Pathogenesis; Pathogenicity; Patients; Peptide Library; Peptides; Phenotype; Positioning Attribute; Process; Proinsulin; Protein Databases; Proteins; Reaction; Risk; Source; Specificity; Spleen; T-Cell Receptor; T-Lymphocyte; T-Lymphocyte Epitopes; Testing; Tissues; Virus; antigen-specific T cells; autoimmune pathogenesis; cell motility; cellular transduction; combinatorial; diabetes pathogenesis; diabetes risk; disease heterogeneity; genetic association; genomic locus; gut microbiome; improved; insulin secretion; islet; islet autoimmunity; islet cell antibody; lymph nodes; molecular phenotype; non-diabetic; preproinsulin; prevent; response; transcriptome; zinc-binding protein

Project Summary Type 1 diabetes (T1D) is a tissue-specific autoimmune disorder. Strong genetic association with the HLA class II gene locus suggests the importance of CD4 T cells in initiating and driving the disease process. We and others have isolated T cells from the pancreas of T1D organ donors and identified T cell epitopes specific to insulin, and its precursor preproinsulin, as well as fusion peptides. An important next step is to elucidate the phenotypes of such islet-derived T cells in health and disease. Concurrently, the previous studies uncovered the fact that antigens for the majority of T cells in the islets are still unknown, and we do not even know whether those T cells are islet antigen-specific. Identifying antigen specificity of islet-CD4 T cells is critical to dissect disease pathogenicity and heterogeneity to develop antigen-specific immunotherapy to halt disease progression using appropriate antigens in a given individual. Therefore, the goal of this grant is to identify antigen specificity of CD4 T cells in the islets and link antigen-specific responses to T cell phenotypes. Multiple lines of evidence suggest that there may be `common' or preferred CD4 T cell epitopes within subsets of T1D patients. First, the vast majority of T1D patients have risk HLA class II alleles, and specific class II alleles are associated with development of an initial islet autoantibody (e.g. insulin autoantibodies develop in those with HLA-DR4, and glutamic acid decarboxylase-65 antibodies with HLA-DR3). Second, CD4 T cells having the same antigen specificity (e.g. proinsulin peptides and hybrid insulin peptides) are detected in the pancreata from multiple T1D organ donors, and the same reactivity is found in the blood of those with early stages of T1D. Finally, CD4 T cells specific to these epitopes have an inflammatory phenotype in the blood of T1D patients compared to non-diabetic controls. This leads us to hypothesize that islet autoimmunity is promoted and regulated by CD4 T cells reacting to `common' antigens that are shared by T1D patients having specific HLA class II molecules. We will determine the proportion of tissue-specific CD4 T cells in the islets (Aim 1) and seek to identify epitopes targeted by CD4 T cells in the islets of T1D organ donors (Aim 2). Furthermore, we will determine the molecular phenotype of islet antigen-specific T cells in the pancreatic lymph nodes and spleen of organ donors with and without T1D (Aim 3). The successful completion of this proposal will: (1) identify antigens and epitopes targeted by CD4 T cells from pancreatic islets across the stages of T1D development and (2) elucidate the molecular phenotype and features that render these T cells pathogenic. Thus, these studies will enhance our understanding of human T1D pathogenesis, dissect disease heterogeneity, and aid in improving the design of clinical trials evaluating antigen-specific immunotherapy for diabetes prevention.

项目概要 1 型糖尿病 (T1D) 是一种组织特异性自身免疫性疾病。与 HLA 类别有很强的遗传关联 II 基因位点表明 CD4 T 细胞在启动和驱动疾病过程中的重要性。我们和其他人 从 T1D 器官捐献者的胰腺中分离出 T 细胞，并鉴定出胰岛素特异性的 T 细胞表位， 及其前体前胰岛素原，以及融合肽。下一步重要的是阐明表型 此类胰岛来源的 T 细胞在健康和疾病中的作用。同时，之前的研究也揭示了这样一个事实： 胰岛中大多数 T 细胞的抗原仍然未知，我们甚至不知道这些 T 细胞是否 是胰岛抗原特异性的。识别胰岛 CD4 T 细胞的抗原特异性对于剖析疾病至关重要 利用致病性和异质性开发抗原特异性免疫疗法来阻止疾病进展 给定个体的适当抗原。因此，本次资助的目标是鉴定 CD4 的抗原特异性 胰岛中的 T 细胞将抗原特异性反应与 T 细胞表型联系起来。 多种证据表明亚群内可能存在“共同”或首选的 CD4 T 细胞表位 T1D 患者。首先，绝大多数T1D患者都具有危险的HLA II类等位基因，以及特定的II类等位基因 与初始胰岛自身抗体的产生有关（例如，胰岛素自身抗体在患有以下疾病的人中产生） HLA-DR4 和谷氨酸脱羧酶 65 抗体与 HLA-DR3)。其次，CD4 T细胞具有相同的 在胰腺中检测到抗原特异性（例如胰岛素原肽和混合胰岛素肽） 多个 T1D 器官捐献者，并且在早期 T1D 患者的血液中也发现了相同的反应性。 最后，针对这些表位的 CD4 T 细胞在 T1D 患者的血液中具有炎症表型 与非糖尿病对照组相比。这使我们推测胰岛自身免疫被促进并且 受 CD4 T 细胞对具有特定 HLA 的 T1D 患者共有的“共同”抗原反应的调节 II 类分子。我们将确定胰岛中组织特异性 CD4 T 细胞的比例（目标 1）并寻求 鉴定 T1D 器官捐献者胰岛中 CD4 T 细胞靶向的表位（目标 2）。此外，我们将 确定胰腺淋巴结和脾脏中胰岛抗原特异性 T 细胞的分子表型 患有和不患有 T1D 的器官捐献者（目标 3）。该提案的成功完成将：（1）鉴定抗原 以及跨 T1D 发展阶段的胰岛 CD4 T 细胞靶向的表位和 (2) 阐明导致这些 T 细胞致病的分子表型和特征。因此，这些研究将 增强我们对人类 T1D 发病机制的理解，剖析疾病异质性，并帮助改善 评估抗原特异性免疫疗法预防糖尿病的临床试验设计。