Beta-cell self-antigen recognition by diabetogenic CD8 T cells

致糖尿病 CD8 T 细胞识别 β 细胞自身抗原

• 批准号: 10638081
• 负责人: Baoyu Liu
• 金额: $ 38.46万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-03-01 至 2028-02-29
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10638081
• 关键词: Affinity; Antigen-Presenting Cells; Antigens; Autoantigens; Autoimmune; Autoimmune Diabetes; Autoimmunity; Avidity; Beta Cell; Binding; Biological; Biological Markers; Biophysics; CD8 receptor; CD8-Positive T-Lymphocytes; CD8B1 gene; Cell Communication; Cells; Clone Cells; Data; Development; Diabetes Mellitus; Disease; Endowment; Environment; Event; Future; G6PC2 gene; Immune response; Immune system; Immunology procedure; Inbred NOD Mice; Insulin; Insulin-Dependent Diabetes Mellitus; Investigation; Islets of Langerhans; Kinetics; Life; MHC Interaction; Measures; Mediating; Methods; Molecular; Outcome; Pancreas; Pathogenicity; Patient Care; Pattern; Peptide Fragments; Peptide/MHC Complex; Peripheral; Phenotype; Polysaccharides; Reporting; Role; Self Tolerance; Surface; T cell response; T-Cell Receptor; T-Lymphocyte; TCR Activation; Testing; Thymocyte Selection; Thymus Gland; Time; Tissues; Travel; antigen-specific T cells; autoreactive T cell; autoreactivity; central tolerance; diabetes pathogenesis; diabetogenic; effector T cell; glycosylation; insight; mouse model; novel; novel therapeutic intervention; peripheral tolerance; receptor; receptor binding; single molecule; therapeutic target; transcriptomics; two-dimensional

Project summary Type 1 diabetes (T1D) is a result of T-cell mediated destruction of insulin-producing beta-cells in the pancreatic islets. Autoreactive CD8 T cells are required in this “mistaken” immune response but how they drive disease is ill-defined. There are two key time points during the life of autoreactive T cells closely related to disease, namely, their creation in the thymus and activation in the periphery. The former fails to eliminate the potentially pathogenic T cells whereas the latter allows them to travel to and stay in the target tissue to mediate damage. Both events are strictly dependent on recognition of beta-cell self-antigens. However, little is known about how diabetogenic CD8 T cells recognize beta-cell antigens. We have over the years studied T cell antigen recognition using novel ultrasensitive two-dimensional (2D) force-based methods, showing 2D TCR affinity and bond lifetime with peptide:MHC as two main kinetics parameters that dictate thymocyte selection outcome and T cell effector functions. The current project aims to use these 2D methods to define binding kinetics of beta- cell antigen recognition by diabetogenic CD8 T cells in the context of their thymic development, peripheral effector function, and T1D pathogenesis. Our preliminary data show that CD8 T cells form weak bonds with beta-cell antigens during thymocyte selection but increase bond strength upon activation. Such change of self- reactivity is mediated by coreceptor CD8. In contrast, the same parameters did not change for foreign antigen recognition. These data support our central hypothesis that, in autoimmune diabetes, CD8 fundamentally alters self-antigen recognition through modulation of TCR binding kinetics, thereby endowing CD8 T cells with heightened self-reactivity that overcomes self-tolerance to mediate beta-cell destruction. We propose two specific aims to test this hypothesis. In Aim1, we will define 2D affinity and bond lifetime of beta-cell antigen recognition by CD8 T cells. We hypothesize that diabetogenic CD8 T cells, even at a single clonal level, are highly adaptive in antigen recognition such that they use weak binding kinetics to survive central and peripheral tolerance but greatly increase self-reactivity to precipitate disease. We will use a panel of monoclonal diabetogenic TCR cell clones based on the NOD mouse model of T1D to systemically characterize beta-cell antigen recognition during diabetogenic CD8 T cell thymocyte selection and peripheral activation and investigate a causal relationship between plasticity of beta-cell antigen recognition and autoimmune diabetes. In Aim2, we will elucidate the underlying mechanisms of beta-cell antigen recognition. We hypothesize that plasticity of beta-cell antigen recognition by diabetogenic CD8 T cells is due to CD8 binding kinetics with MHC. We will first define the role of CD8 in the overall beta-cell antigen recognition. We will then test a sub- hypothesis that unique patterns of CD8 glycosylation determine adaptability of CD8 binding kinetics by T cell glycan profiling, phenotyping, and single cell transcriptomic analysis.

项目摘要 1型糖尿病（T1 D）是T细胞介导的胰腺中产生胰岛素的β细胞破坏的结果。 小岛自身反应性CD 8 T细胞在这种“错误的”免疫反应中是必需的，但它们如何驱动疾病， 定义不清在自身反应性T细胞的生命过程中有两个关键时间点与疾病密切相关， 也就是说，它们在胸腺中产生，在外周中激活。前者未能消除潜在的 病原性T细胞，而后者允许它们旅行并停留在靶组织中以介导损伤。 这两个事件都严格依赖于β细胞自身抗原的识别。然而，人们对如何做到这一点知之甚少。 致糖尿病性CD 8 T细胞识别β-细胞抗原。多年来我们研究了T细胞抗原 使用新的超灵敏二维（2D）力为基础的方法识别，显示2D TCR亲和力， 与肽的结合寿命：MHC是决定胸腺细胞选择结果的两个主要动力学参数， T细胞效应器功能。目前的项目旨在使用这些二维方法来定义β- 致糖尿病性CD 8 T细胞在胸腺发育、外周血淋巴细胞增殖和淋巴细胞增殖中的细胞抗原识别 效应子功能和T1 D发病机制。我们的初步数据表明，CD 8 T细胞与 在胸腺细胞选择过程中结合β-细胞抗原，但在活化时增加结合强度。如此的自我改变- 反应性由辅助受体CD 8介导。相反，对于外源抗原，相同参数没有改变 识别.这些数据支持我们的中心假设，即在自身免疫性糖尿病中，CD 8从根本上改变了 通过调节TCR结合动力学进行自身抗原识别，从而赋予CD 8 T细胞 增强的自身反应性，克服自身耐受性以介导β细胞破坏。我们提出了两 具体目的是检验这一假设。在Aim 1中，我们将定义β细胞抗原的2D亲和力和键寿命 通过CD 8 T细胞识别。我们假设致糖尿病的CD 8 T细胞，即使在单克隆水平， 在抗原识别中具有高度适应性，使得它们使用弱结合动力学来存活于中枢和外周 耐受性，但大大增加了自身反应性，以加速疾病。我们将使用一组单克隆 基于T1 D的NOD小鼠模型的致糖尿病TCR细胞克隆，以系统地表征β细胞 致糖尿病性CD 8 T细胞胸腺细胞选择和外周活化过程中的抗原识别， 研究β细胞抗原识别可塑性和自身免疫性糖尿病之间的因果关系。 在Aim 2中，我们将阐明β细胞抗原识别的潜在机制。我们假设 致糖尿病性CD 8 T细胞对β细胞抗原识别的可塑性是由于CD 8与MHC的结合动力学。 我们将首先定义CD 8在整个β细胞抗原识别中的作用。然后我们将测试一个子- CD 8糖基化独特模式决定T细胞对CD 8结合动力学的适应性的假设 聚糖谱分析、表型分析和单细胞转录组学分析。