Cysteine Proteases in MHC Class II Antigen Presentation

MHC II 类抗原呈递中的半胱氨酸蛋白酶

• 批准号: 6580160
• 负责人: Harold A Chapman
• 金额: $ 33.96万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6580160
• 关键词: MHC class II antigen; T lymphocyte; active sites; antigen presentation; asthma; autoimmunity; cellular immunity; cellular polarity; clinical research; cysteine endopeptidases; dendritic cells; enzyme activity; flow cytometry; gene targeting; genetically modified animals; human subject; immunoglobulin E; immunoregulation; laboratory mouse; lung disorder; mast cell; molecular chaperones; protease inhibitor; site directed mutagenesis; tissue /cell culture

DESCRIPTION: (provided by applicant): The endosomal cysteine protease, cathepsin S, has a key role in MHC class II (MHCII)-dependent immunity through its role in degradation of the MHCII-associated chaperone, the invariant chain (Ii). But studies of cathepsin S -/- mice also reveal unexpected findings. Cathepsin S deficiency predominantly affects Thl dependent immunity. IgE responses and Th2-driven pulmonary inflammation, while dependent on cysteine proteases, are normal or increased in cathepsin S -/- mice. Indeed baseline IgE levels and lung mRNA of proinflammatory cytokines in these mice are elevated. Surprisingly, high IgE levels and cytokines are mast cell-dependent. These observations imply additional proteases, and perhaps additional antigen presenting cells (APC), are important to MHCII function and that protease dysregulation can skew, not just block, MHCII-dependent immune responses. Experiments are directed toward understanding how proteases can effect polarization of T and B cell development relevant to lung disease. Mechanisms of peptide loading in cathepsin S-deficient APC will be defined. Mice deficient in the Ii-degrading APC protease cathepsin F have been recently generated and will be used to test the hypothesis that cathepsin F rescues MHC class II peptide display in myeloid APCs, thereby favoring Th2 polarization. Selective protease inhibitors will be used to determine if a set of protease activities in human APC are required for Th2 cytokine production by allergen stimulated T cells. The mechanisms by which mast cells promote APC-dependent IgE production will be explored by reconstitution of mast cell deficient mice (Wsh) with mast cells cultured from S-/- or cytokine deficient mice. The overall goal of this application is to understand the molecular basis for protease dependent polarization of T cell and B cell immune responses and to learn how to exploit this process to ameliorate CD4+ T cell driven disorders such as autoimmunity and asthma.

产品说明：（申请人提供）：内体半胱氨酸蛋白酶，组织蛋白酶S，通过其在MHCII相关的伴侣蛋白，不变链（Ii）的降解中的作用，在MHCII类（MHCII）依赖性免疫中具有关键作用。但是对组织蛋白酶S -/-小鼠的研究也揭示了意想不到的发现。组织蛋白酶S缺乏主要影响Thl依赖性免疫。IgE应答和Th 2驱动的肺部炎症，虽然依赖于半胱氨酸蛋白酶，但在组织蛋白酶S -/-小鼠中是正常的或增加的。事实上，这些小鼠中的基线IgE水平和促炎细胞因子的肺mRNA升高。令人惊讶的是，高IgE水平和细胞因子是肥大细胞依赖性的。这些观察结果意味着额外的蛋白酶，也许还有额外的抗原呈递细胞（APC），对MHCII功能很重要，并且蛋白酶失调可以扭曲，而不仅仅是阻断MHCII依赖性免疫应答。实验旨在了解蛋白酶如何影响与肺部疾病相关的T和B细胞发育的极化。将定义在组织蛋白酶S缺陷型APC中肽加载的机制。最近已经产生了II-降解APC蛋白酶组织蛋白酶F缺陷的小鼠，并将其用于测试组织蛋白酶F拯救髓样APC中的MHC II类肽展示，从而有利于Th 2极化的假设。选择性蛋白酶抑制剂将用于确定人APC中的一组蛋白酶活性是否是过敏原刺激的T细胞产生Th 2细胞因子所需的。肥大细胞促进APC依赖性IgE产生的机制将通过用从S-/-或细胞因子缺陷小鼠培养的肥大细胞重建肥大细胞缺陷小鼠（Wsh）来探索。本申请的总体目标是了解T细胞和B细胞免疫应答的蛋白酶依赖性极化的分子基础，并了解如何利用该过程来改善CD 4 + T细胞驱动的疾病，例如自身免疫和哮喘。