HLA-DO / H2-O: modulation of MHC-II peptide diversity and Treg population control

HLA-DO / H2-O：MHC-II 肽多样性的调节和 Treg 群体控制

• 批准号: 10308470
• 负责人: Lawrence J. Stern
• 金额: $ 54.12万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-12-12 至 2023-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10308470
• 关键词: Address; Adopted; Animals; Antigen Presentation; Antigen-Presenting Cells; Antigens; Antinuclear Antibodies; Autoimmune; Autoimmunity; B-Lymphocytes; Biochemical; Biological; Body Weight decreased; CD4 Positive T Lymphocytes; CD8-Positive T-Lymphocytes; Cell surface; Cellular Immunology; Development; Effector Cell; Equilibrium; Exhibits; FOXP3 gene; Frequencies; Generations; Goals; Guanine Nucleotide Exchange Factors; Histocompatibility; Immune response; Individual; Infection; Influenza; Knock-out; Knockout Mice; Lysosomes; Masks; Mediating; Modeling; Molecular Conformation; Mus; Pathway interactions; Peptide/MHC Complex; Peptides; Peripheral; Phenotype; Population; Population Control; Production; Proteins; Publishing; Pulmonary Inflammation; Reaction; Recovery; Regulation; Regulatory T-Lymphocyte; Reporting; Research; Resolution; Role; Self Tolerance; Signal Transduction; System; T cell response; T-Cell Development; T-Lymphocyte; T-cell receptor repertoire; TCR Activation; Testing; Thinking; Thymic epithelial cell; Thymus Gland; Viral; Virus Diseases; antigen processing; catalyst; cell type; density; effector T cell; experimental study; immunopathology; influenza infection; influenzavirus; inhibitor; innovation; late endosome; mortality; neoplastic cell; pathogen; prevent; protein function; recruit; response; thymocyte

HLA-DO / H2-O (DO) is a non-classical MHCII protein that functions as a specific competitive inhibitor of the peptide exchange factor HLA-DM / H2-M (DM), regulating peptide loading onto MHCII molecules in antigen- presenting cells. During CD4 T cell development, thymocytes are selected for conversion to conventional naïve CD4 T cells or self-tolerant regulatory T cells, or are deleted by negative selection, depending on the strength of interaction with MHCII-bound peptides displayed on antigen presenting cells in the thymus. We eluted peptides from wild-type C57BL/6 and DO-knockout thymus, and found alterations in the spectrum of peptides presented by MHCII molecules. We examined CD4 T cell development in DO-deficient mice, and found alterations in Treg number and function, and increased sensitivity to viral infection. The overarching hypothesis of this proposal is that DO regulates antigen presentation by restraining the peptide editing activity of DM in order to allow a broad representation of peptides presented at the cell surface, and this activity is essential for proper thymic selection of self-tolerant conventional and regulatory T cells. There are two specific aims. Aim 1 is to evaluate the role of DO-dependent antigen presentation in selection of CD4 Tconv and Treg populations. We will identify peptides differentially presented in the thymus in the presence or absence of DO, follow individual TCR clonotypes as they undergo thymic selection in WT and DO-KO TCR-restricted mice, combine these results to identity DO-peptides responsible for Treg skewing, and finally characterize functional effects of Treg dysregulation in DO-KO mice. These experiments will test the hypothesis that narrowing of the peptide repertoire presented by MHCII molecules induced by deletion of DO results in altered thymic selection and peripheral regulation of regulatory T cells. Aim 2 is to determine the role of HLA-DO / H2-O in regulating Tconv and Treg populations in an infection model. We will evaluate the functional consequences of DO-induced changes in the TCR repertoire and activation state of CD4 T cell populations in the response of BL/6 mice to primary influenza infection. Tregs have been shown previously to regulate CD4 and CD8 T cell responses and recruitment of innate effector cells, and we observe alterations in these effects in DO-KO mice, suggesting a dysregulation of Tregs in the absence of DO. We will test this hypothesis, using a FoxP3-DTR system to swap Treg compartments between mice. A second part of this aim is to evaluate the functional consequences of DO- induced alterations in antigen presentation and TCR repertoires using the influenza infection model. The long- term goals of this project are to define how control of DM-mediated peptide editing by DO regulates selection of self- and pathogen-derived peptides displayed on MHCII, and to decipher the impact of DO-regulated peptide presentation on the development and function of the CD4 T cell repertoire. 1

HLA-DO / H2-O (DO) 是一种非经典 MHCII 蛋白，可作为 HLA-DO / H2-O (DO) 的特异性竞争性抑制剂 肽交换因子 HLA-DM / H2-M (DM)，调节抗原中 MHCII 分子上的肽负载 呈现细胞。在 CD4 T 细胞发育过程中，胸腺细胞被选择转化为传统的幼稚细胞 CD4 T 细胞或自我耐受的调节性 T 细胞，或通过负选择删除，具体取决于强度 与胸腺中抗原呈递细胞上展示的 MHCII 结合肽的相互作用。我们洗脱了 来自野生型 C57BL/6 和 DO 敲除胸腺的肽，发现肽谱发生变化 由 MHCII 分子呈现。我们检查了 DO 缺陷小鼠中 CD4 T 细胞的发育，发现 Treg 数量和功能的改变，以及对病毒感染的敏感性增加。总体假设 该提案的主要内容是，DO 通过抑制 DM 的肽编辑活性来调节抗原呈递。 为了允许在细胞表面呈现的肽的广泛代表性，并且这种活性对于 自我耐受的常规和调节性 T 细胞的适当胸腺选择。有两个具体目标。目标1 目的是评估 DO 依赖性抗原呈递在 CD4 Tconv 和 Treg 群体选择中的作用。 我们将鉴定在存在或不存在 DO 的情况下胸腺中差异呈现的肽，如下 个体 TCR 克隆型在 WT 和 DO-KO TCR 限制性小鼠中进行胸腺选择时，结合 这些结果鉴定了负责 Treg 偏差的 DO 肽，并最终表征了 DO-KO 小鼠中 Treg 失调。这些实验将检验肽变窄的假设 DO 缺失诱导的 MHCII 分子呈现的全部功能导致胸腺选择发生改变， 调节性 T 细胞的外周调节。目标 2 是确定 HLA-DO / H2-O 在调节 Tconv 中的作用 和感染模型中的 Treg 群体。我们将评估 DO 引起的功能后果 BL/6 小鼠响应中 TCR 库和 CD4 T 细胞群激活状态的变化 原发性流感感染。先前已证明 Tregs 可以调节 CD4 和 CD8 T 细胞反应 先天效应细胞的募集，我们在 DO-KO 小鼠中观察到这些效应的变化，这表明 在缺乏 DO 的情况下，Tregs 失调。我们将使用 FoxP3-DTR 系统来测试这个假设 小鼠之间的 Treg 隔室。该目标的第二部分是评估 DO-的功能后果 使用流感感染模型诱导抗原呈递和 TCR 库的改变。长- 该项目的长期目标是定义 DO 如何控制 DM 介导的肽编辑来调节选择 自身和病原体衍生的肽在 MHCII 上展示，并破译 DO 调节的影响 肽呈递对 CD4 T 细胞库的发育和功能的影响。 1