The Role of Microbial Antigen-Specific T Cells in Crohn's disease

微生物抗原特异性 T 细胞在克罗恩病中的作用

• 批准号: 10307987
• 负责人: Peter Mannon
• 金额: --
• 依托单位: BIRMINGHAM VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2022-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10307987
• 关键词: Animal Model; Antibodies; Antigens; B-Lymphocytes; Back; Bacteria; Bacterial Proteins; Binding; Biological Markers; Biological Models; Cells; Clone Cells; Colitis; Crohn' s disease; Data; Disease; Disease remission; Enrollment; Epitopes; Exposure to; Flagellin; Gastrointestinal tract structure; Goals; High-Throughput Nucleotide Sequencing; In Vitro; Individual; Inflammation; Inflammatory; Inflammatory Response; J-Chain Immunoglobulins; Link; Measures; Mediating; Memory; Patients; Pattern; Peptides; Peripheral; Phenotype; Population; Production; Role; Serum; Specificity; Structure; T cell response; T memory cell; T-Cell Activation; T-Cell Receptor; T-Lymphocyte; T-Lymphocyte Subsets; Testing; Tissues; Ulcerative Colitis; antigen binding; antigen-specific T cells; antimicrobial; base; cytokine; gut microbiota; microorganism antigen; novel; peripheral blood; response; seropositive; success

Microbial-antigen reactive T cells are the primary effectors of inflammatory damage in animal models of Crohn's disease, causing T cell-mediated colitis only in the presence of gut microbiota. By focusing on a proposed similar key role for T cells in Crohn's inflammation, we hypothesize that anti-flagellin antibodies that are highly shared by Crohn's patients, and characterize an aberrant B cell response, are potential markers for the presence T cell clonotypes that are reactive to the same gut commensal antigens (but different epitopes). Of note, the presence of anti-CBir1 flagellin antibodies is the strongest predictor of severe, complicated Crohn's disease. Our preliminary data demonstrate two features critical to the success of this long-term project. First, there is a disease-specific repertoire of expanded T cells (defined by TCRβ CDR3 sequences) that is very highly shared among Crohn's patients, making the study of these T cells' antigen reactivity relevant for the majority of patients. Second, this highly shared T cell repertoire is associated with patterns of shared serum anti-flagellin antibodies that are themselves restricted to Crohn's disease patients, suggesting a potential link between aberrant B cell and T cell responses. To accomplish this study, we will enroll active Crohn's patients as well as remission Crohn's patients, active ulcerative colitis patients and healthy controls to test for significant associations between profiles of serum antibody reactivity to a panel of gut microbial antigens and the TCRβ CDR3 repertoire. The goal is to identify high value CDR3 sequences that couple with cognate flagellin antigens. We plan to define the distribution of these TCRβ CDR3 sequences among peripheral blood and gut tissue T cells subsets (effector, regulatory and memory) with the goal of identifying sequences that segregate to a particular compartment or phenotype and to see if the memory T cell subset is a reservoir of highly shared TCRβ CDR3 clonotypes. Lastly we will measure which TCRβ CDR3 clonotypes are expanded in vitro following specific antigen exposure to identify candidate antigen-specific sequences and test for their significant association with antigen seropositivity and cell phenotype. These data will then be used to isolate single T cells from different individuals who share identical expanded TCRβ CDR3 clonotypes in order to compare the similarity of structure (α/β pairing), MHC specificity, and recognition of antigen. The focus will be on targeting highly shared TCRβ CDR3 sequences that have been robustly linked with antigen-specific responses (cytokine production, proliferation) and seropositivity across multiple Crohn's patients. The long-term goals of this project build on these data and aim to define the hierarchy of mechanisms (antigen peptide binding motifs, MHC promiscuity, e.g.) that contribute to shared antigen reactivity among Crohn's patients, to develop strategies that disrupt the antigen-specific T cell activation, and to assess the feasibility and value of targeting microbial antigen-reactive T cells as a treatment approach in Crohn's disease.

微生物抗原反应性T细胞是炎性损伤的主要效应细胞 克罗恩病，只有在肠道微生物区系存在的情况下才会引起T细胞介导的结肠炎。通过专注于 提出了T细胞在克罗恩炎症中的类似关键作用，我们假设抗鞭毛蛋白抗体 在克罗恩病患者中高度共有，并具有异常B细胞反应的特征，是潜在的标志 存在对同一肠道共生抗原(但不同的表位)有反应的T细胞克隆型。 值得注意的是，抗CBir1鞭毛蛋白抗体的存在是严重、复杂 克罗恩病。 我们的初步数据显示了对这一长期项目的成功至关重要的两个特征。第一, 有一种疾病特异性的扩增T细胞(由TCRCDR3序列定义)是非常重要的 在克罗恩病患者中高度共享，使得对这些T细胞的抗原反应性的研究与 大多数患者。其次，这种高度共享的T细胞库与共享血清的模式有关 抗鞭毛蛋白抗体本身仅限于克罗恩病患者，这表明可能存在联系 在异常的B细胞和T细胞反应之间。 为了完成这项研究，我们将招募活动期克罗恩患者和缓解期克罗恩患者， 活动性溃疡性结肠炎患者和健康对照组之间的显著关联 血清对一组肠道微生物抗原和TCRβCDR3谱系的抗体反应性。我们的目标是 鉴定与同源鞭毛抗原偶联的高价值CDR3序列。我们计划定义 这些TCRCDR3CDR3序列在外周血和肠道组织T细胞亚群中的分布(效应器， 调节和记忆)，其目标是识别分离到特定隔室或 并观察记忆T细胞亚群是否为高度共享的TCRCDR3克隆型。 最后，我们将测量哪些tcrβCDR3克隆型在体外根据特定的抗原被扩增。 暴露以识别候选抗原特异性序列并测试其与抗原的显著关联 血清阳性和细胞表型。这些数据将被用来从不同的细胞中分离单个T细胞 具有相同扩展TcRβCDR3克隆类型的个体，以比较其相似性 结构(α/β配对)、MHC特异性和抗原识别。重点将放在高度针对性上 与抗原特异性反应(细胞因子)紧密相连的共享TCRCDR3序列 在多发性克罗恩病患者中，病毒的产生、增殖)和血清阳性率。 该项目的长期目标建立在这些数据的基础上，旨在定义机制的层次结构 (抗原肽结合基序，MHC混杂，例如)有助于共享抗原反应性 开发干扰抗原特异性T细胞激活的策略，并评估 靶向微生物抗原反应性T细胞作为克罗恩病治疗方法的可行性和价值。