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: 10617869
• 负责人: Peter Mannon
• 金额: --
• 依托单位: OMAHA 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 2023-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10617869
• 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细胞是动物模型中炎症损伤的主要作用 克罗恩病，仅在肠道菌群存在下引起T细胞介导的结肠炎。通过专注于 提出了T细胞在克罗恩的创新中的类似关键作用，我们假设抗氟糖蛋白抗体 由克罗恩的患者高度共享，并且表征异常B细胞反应，是潜在的标志物 存在于相同肠道共生抗原（但不同表位）的T细胞clonotypes。 值得注意的是，抗CBIR1鞭毛蛋白抗体的存在是严重，复杂的强烈预测指标 克罗恩病。 我们的初步数据证明了这两个对这个长期项目成功至关重要的功能。第一的， 有一个非常特异性的T细胞的疾病特异性曲目（由TCRβCDR3序列定义）非常非常 在克罗恩的患者中高度共享，研究了这些T细胞的抗原反应性与 大多数患者。其次，这种高度共享的T细胞库与共享序列的模式有关 抗鞭毛蛋白抗体本身仅限于克罗恩病患者，这表明潜在的联系 在异常B细胞和T细胞反应之间。 为了完成这项研究，我们将招募活跃的克罗恩的患者以及缓解Crohn的患者， 主动溃疡性结肠炎患者和健康对照，以测试 血清抗体对肠道微生物抗原和TCRβCDR3库的反应性。目标是 识别将夫妇与同源鞭毛蛋白抗原夫妇相对的高值CDR3序列。我们计划定义 这些TCRβCDR3序列在外周血和肠道组织T细胞亚群中的分布（效应子， 调节性和记忆）的目标是识别将隔离到特定隔室的序列或 表型，看看记忆T细胞子集是否是高度共享TCRβCDR3锁骨型的储层。 最后，我们将测量哪些TCRβCDR3克隆型在特定抗原后体外扩展 暴露以识别候选抗原特异性序列并测试其与抗原的显着关联 血清阳性和细胞表型。然后，这些数据将用于将单个T细胞与不同的不同 共享相同扩展的TCRβCDR3克隆型的个体，以比较 结构（α/β配对），MHC特异性和抗原的识别。重点将是高度针对的 共享TCRβCDR3序列已与抗原特异性反应（细胞因子 多个克罗恩患者的生产，增殖）和血清阳性。 该项目的长期目标以这些数据为基础，旨在定义机制的层次结构 （抗原肽结合基序，MHC滥交，例如），有助于共同的抗原反应性 克罗恩的患者，制定破坏抗原特异性T细胞激活的策略，并评估 靶向微生物抗原反应T细胞作为克罗恩病的治疗方法的可行性和价值。