Regulation of CD8 T Cell Immunity by TNF Receptors

描述（由申请人提供）：CD 8 + T细胞在以下方面发挥关键作用： 防御病毒、细胞内细菌和原生动物感染。到 提供保护性免疫力，针对这些因子的疫苗需要引起有效的 CD 8 + T细胞记忆。尽管认识到它们在疫苗接种中的重要性， 记忆T细胞产生的基本机制仍然很差， 明白T细胞记忆的大小取决于 克隆扩增和随后的活化抗原特异性T细胞死亡， 细胞理解记忆T细胞的产生取决于 阐明调节细胞增殖和凋亡的机制， 体内活化的CD 8 + T细胞。我们的长期目标是了解 CD 8 + T细胞记忆的分子和细胞基础。我们已经开始研究 研究肿瘤坏死因子受体（TNFRs）在调节肿瘤细胞生成中的作用， 使用淋巴细胞性脉络丛脑膜炎病毒（LCMV）模型的CD 8+记忆T细胞 对小鼠初步研究显示， 在TNFR I-和TNFR I &中LCMV特异性记忆CD 8 + T细胞的数量中， II缺陷型小鼠，与野生型（+1+）小鼠相比。这个目标 应用是为了了解TNFRs调节生成的机制， 记忆性CD 8 + T细胞我们假设，缺乏凋亡信号， TNFR缺陷小鼠导致记忆性CD 8 + T细胞数量增加， 否则将被删除。这项建议的目的是 三个方面：第一，阐明下调CD 8 + T细胞的机制基础， 细胞反应的TNFR，通过（1）检查TNFR缺乏的影响， LCMV特异性CD 8 + T细胞在体外和体内的增殖和凋亡; (2)确定负责TNFR介导的作用的配体：TNFa与LTa。 第二，为了剖析TNFR信号在CD 8 + T细胞上的重要性（直接作用）， 效应）与非CD 8 + T细胞（间接效应）在调节生成 的LCMV特异性记忆CD 8 + T细胞，通过使用骨髓嵌合体， CD 4缺陷小鼠。第三，研究TNFRs对功能性 LCMV特异性CD 8 + T细胞在体外和体内的特性。免疫 存储器可以通过两个定量（增加的数量）来解释， 抗原特异性T细胞）和定性（灵敏度提高）差异 记忆T细胞我们的初步研究表明，TNFR I的缺失导致 增加的记忆性CD 8 + T细胞的数量。我们将检查 TNFR缺陷和+/+ LCMV特异性记忆之间的定性差异 通过比较产生细胞因子的活化阈值和 执行细胞介导的细胞毒性作为抗原浓度的函数，CD 8 要求和时间。TNFR缺陷型记忆性CD 8 + T细胞的功能将 在（1）LCMV免疫小鼠和（2）DNA疫苗免疫小鼠中进行体内测试， 研究针对致死性CD 8 + T细胞介导的CNS的保护性免疫 免疫病理学尽管有几条证据表明， TNF在T细胞介导的自身免疫中，潜在的调节机制是 没有被很好地理解。本申请中提出的实验将提供 为㈠研制有效疫苗提供关键信息; ㈡ 了解自身免疫性疾病的发病机制，和（iii）制定 针对免疫介导疾病的免疫疗法。

DESCRIPTION (provided by applicant): CD8+ T cells play a critical role in defense against viral, intracellular bacterial, and protozoan infections. To confer protective immunity, vaccines against these agents need to elicit potent CD8+ T-cell memory. Despite recognition of their importance in vaccinations, the underlying mechanisms in the generation of memory T cells remains poorly understood. The magnitude of T cell memory is dependent upon, the extent of clonal expansion and, the subsequent death of activated antigen-specific T cells. Understanding the generation of memory T cells is contingent upon elucidating the mechanisms that regulate proliferation and apoptosis of activated CD8+ T cells in vivo. Our long-term goal is to understand the molecular and cellular basis of CD8+ T cell memory. We have initiated studies investigating the role of TNF receptors (TNFRs) in regulating the generation of CD8+ memory T cells using the lymphocytic choriomeningitis virus (LCMV) model in mice. Preliminary studies have revealed that there is a dramatic enhancement in the number of LCMV-specific memory CD8+ T cells in TNFR I-and TNFR I & II-deficient mice, as compared to wild type (+1+) mice. The goal of this application is to understand the mechanisms by which TNFRs regulate generation of memory CD8+ T cells. We hypothesize that lack of apoptotic signals in TNFR-deficient mice leads to increased number of memory CD8+ T cells, that otherwise would be slated for deletion. The objectives of this proposal are three fold: First, to elucidate the mechanistic basis of downregulating CD8+ T cell responses by TNFRs, by (1) examining the effect of TNFR deficiency on the proliferation and apoptosis of LCMV-specific CD8+ T cells in vitro and in vivo; (2) determining the ligand responsible for TNFR-mediated effects:TNFa vs. LTa. Second, to dissect the importance of TNFR signaling on CD8+ T cells (direct effects) vs. non-CD8+ T cells (indirect effects) in regulating the generation of LCMV-specific memory CD8+ T cells, by using bone marrow chimeras and CD4-deficient mice. Third, to examine the role of TNFRs on the functional attributes of LCMV specific CD8+ T cells in vitro and in vivo. Immunological memory can be accounted for by both quantitative (increased number of antigen-specific T cells) and qualitative (heightened sensitivity) differences in memory T cells. Our preliminary studies show that loss of TNFR I lead to increased number ("quantity") of memory CD8+ T cells. We will examine for qualitative differences between TNFR-deficient and +/+ LCMV-specific memory CD8+ T cells by comparing the activation thresholds to produce cytokines and perform cell-mediated cytotoxicity as a function of antigen concentration, CD8 requirement, and time. The function of TNFR deficient memory CD8+ T cells will be tested in vivo in (1) LCMV-immune mice and (2) DNA vaccine-immunized mice by studying protective immunity against lethal CD8+ T cell-mediated CNS immunopathology. Despite several lines of evidence of a suppressive role for TNF in T-cell-mediated autoimmunity, the underlying regulatory mechanisms are not well understood. The proposed experiments in this application will provide critical information towards (i) development of effective vaccines; (ii) understanding the pathogenesis of autoimmune disorders, and (iii) formulating immunotherapies against immune-mediated diseases.