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）是一种非经典的MHCII蛋白，用作特定的竞争抑制剂 肽交换因子HLA-DM / H2-M（DM），调节肽在抗原中的MHCII分子上的肽 - 呈现细胞。在CD4 T细胞发育过程中，选择胸腺细胞转化为常规幼稚 CD4 T细胞或自我耐受性调节T细胞，或通过负选择删除，具体取决于强度 与胸腺中抗原呈现细胞上显示的MHCII结合的胡椒体相互作用。我们洗脱了 来自野生型C57BL/6和DO-KNOCKOUT胸腺的肽，发现肽光谱的改变 由MHCII分子提出。我们检查了DO缺陷小鼠中的CD4 T细胞发育，发现 Treg数量和功能的改变，并增加了对病毒感染的敏感性。总体假设 该提案是通过限制DM在中的肽编辑活性来调节抗原表现 为了允许在细胞表面呈现的Petides广泛表示，此活动对于 适当选择自耐用的常规和调节性T细胞。有两个具体的目标。目标1 是评估DO依赖性抗原在选择CD4 TCONV和TREG种群中的作用。 在存在或不存在的情况下，我们将在胸腺中识别出不同的宠物 在WT和DO-KO TCR限制的小鼠中进行胸腺的选择时，单个TCR clonotypes compine 这些结果是指责Treg偏斜的身份DO肽，最后表征了的功能效应 DO-KO小鼠的Treg失调。这些实验将检验辣椒缩小的假设 由删除DO诱导的MHCII分子提出的曲目会导致胸腺选择改变和 调节T细胞的外围调节。 AIM 2是确定HLA-DO / H2-O在调节性TCONV中的作用 感染模型中的Treg人群。我们将评估DO诱导的功能后果 BL/6小鼠对CD4 T细胞种群的TCR库和激活状态的变化 主要影响力感染。 Treg先前已显示用于调节CD4和CD8 T细胞反应，并 募集先天效应细胞的募集，我们观察到这些作用在Do-Ko小鼠中的改变，这表明是 在没有DO的情况下，Treg的失调。我们将使用FOXP3-DTR系统交换来检验此假设 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 使用影响力感染模型，诱导的抗原表现和TCR曲目改变了。长期 该项目的术语目标是定义DM介导的肽编辑的控制如何调节选择 在MHCII上显示的自我和病原体衍生的宠物，并破译了DO受调节的影响 关于CD4 T细胞库的发育和功能的肽表现。 1