Role of CD4+ regulatory T cells in T cell vaccination

CD4 调节性 T 细胞在 T 细胞疫苗接种中的作用

• 批准号: 6804756
• 负责人: JINGWU Z ZHANG
• 金额: $ 34.8万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6804756
• 关键词: B lymphocyte; T lymphocyte; antiinflammatory agents; autoimmunity; cell cell interaction; cell proliferation; clinical research; clinical trials; clone cells; cytokine receptors; helper T lymphocyte; human subject; human tissue; immunization; inflammation; interleukin 2; leukocyte activation /transformation; leukocyte count; lymphocyte; major histocompatibility complex; monocyte; multiple sclerosis; myelin basic proteins; patient oriented research; protein structure function; recombinant proteins; tissue /cell culture; transfection

DESCRIPTION (provided by applicant): T cell vaccination (TCV) is proven to be an effective means of regulating autoreactive T cells through regulatory network of CD8+ and CD4+ T cell subsets. Both regulatory T cell (Treg) subsets are thought to contribute to suppression of circulating myelin basic protein (MBP)-reactive T cells and some clinical improvement seen in clinical trials in multiple sclerosis (MS). CD8+ T cells induced by TCV belong to cytotoxic anti-idiotypic T cell subset interacting with the T cell receptors of MBP-reactive T cells. In contrast, the nature of CD4+ Treg subset is poorly understood. They exhibit unique regulatory properties through the production of IL-10 but not Th1 cytokines, resulting in a potent inhibitory effect on MBP-reactive T cells. Their reactivity and inhibition appear restricted to activated T cells, regardless of antigen specificity, but not resting cells. Further evidence suggests that CD4+ Treg cells induced by TCV react with and are activated by endogenously processed IL-2 receptor alpha chain (IL-2Ra). These findings have begun to unfold the unique properties and functional role of CD4+ Treg induced by TCV in the regulation of autoreactive T cells in humans. In this study, we propose to investigate the central hypothesis that TCV induces the activation and in vivo expansion of CD4+ Treg cells through interaction with IL-2Ra expressed on activated autoreactive T cells and that IL-2Ra has an anti-inflammatory property by inducing a CD4+ Treg response. The study has three specific aims. In Aim 1, the role of TCV in in vivo expansion of pre-existing CD4+ Treg pool will be determined by examining the precursor frequency of CD4+ Treg cells in peripheral blood mononuclear cells (PBMC) derived from MS patients before and after TCV. The results will be analyzed to correlate with serum cytokines, the frequency of MBP-reactive T cells and other parameters in the same patients. Cloned CD4+ Treg cell lines will be characterized in detail to address their functional role and heterogeneity, reactivity and MHC restriction, mode of induction and interaction with various target T cells. Aim 2 will focus on the reactivity pattern and interaction of CD4+ Treg cells with IL-2Ra using well-characterized T cell lines in two experimental systems by testing the reactivity of CD4+ Treg T cell lines to endogenously processed IL-2Ra using autologous B cell transfectants and to soluble IL-2Rot using recombinant protein in functional assays. Additional experiments will delineate the region(s) of IL-2Ra preferably recognized by CD4+ Treg using target cells transfected with truncated gene segments and overlapping peptides. In Aim 3, we will define the potency and specificity of IL-2Rc_ protein as a specific agent for the direct induction of CD4+ Treg cell response in PBMC as well as the role of TCV in this process by analyzing the T cell responses, as the frequency of reactive CD4+ Treg cells, to IL-2R(x protein or preferably recognized peptides in pre- and postvaccination PBMC and those of controls. Parallel experiments are designed to evaluate the inhibitory effect of IL-2Ra on MBP-reactive T cell responses through its intrinsic property of inducing CD4+ Treg cell response in MBP-primed PBMC cultures. The overall results will provide new insights into the role of IL- 2Ro_ in regulation of pro-inflammatory T cell response in autoimmune conditions.

描述（由申请人提供）：T细胞疫苗接种（TCV）被证明是通过CD8+和CD4+T细胞亚群的调节网络调节自身反应性T细胞的有效手段。两种调节性 T 细胞 (Treg) 亚群都被认为有助于抑制循环髓磷脂碱性蛋白 (MBP) 反应性 T 细胞，并在多发性硬化症 (MS) 的临床试验中看到一些临床改善。 TCV 诱导的 CD8+ T 细胞属于细胞毒性抗独特型 T 细胞亚群，与 MBP 反应性 T 细胞的 T 细胞受体相互作用。相比之下，人们对 CD4+ Treg 子集的性质知之甚少。它们通过产生 IL-10 而不是 Th1 细胞因子而表现出独特的调节特性，从而对 MBP 反应性 T 细胞产生有效的抑制作用。无论抗原特异性如何，它们的反应性和抑制似乎仅限于激活的 T 细胞，但不限于静息细胞。进一步的证据表明，TCV 诱导的 CD4+ Treg 细胞与内源加工的 IL-2 受体 α 链 (IL-2Ra) 发生反应并被其激活。这些发现已经开始揭示 TCV 诱导的 CD4+ Treg 在调节人类自身反应性 T 细胞中的独特特性和功能作用。在本研究中，我们建议研究中心假设，即 TCV 通过与激活的自身反应性 T 细胞上表达的 IL-2Ra 相互作用，诱导 CD4+ Treg 细胞的激活和体内扩增，并且 IL-2Ra 通过诱导 CD4+ Treg 细胞具有抗炎特性。 CD4+ Treg 反应。该研究有三个具体目标。在目标 1 中，TCV 在体内扩增已有 CD4+ Treg 池中的作用将通过检查 TCV 前后 MS 患者外周血单核细胞 (PBMC) 中 CD4+ Treg 细胞的前体频率来确定。将对结果进行分析，以与同一患者的血清细胞因子、MBP 反应性 T 细胞的频率和其他参数相关。克隆的 CD4+ Treg 细胞系将​​被详细表征，以解决其功能作用和异质性、反应性和 MHC 限制、诱导模式以及与各种靶 T 细胞的相互作用。目标 2 将通过使用自体 B 细胞转染子测试 CD4+ Treg T 细胞系对内源加工的 IL-2Ra 的反应性，在两个实验系统中使用已充分表征的 T 细胞系，重点研究 CD4+ Treg 细胞与 IL-2Ra 的反应模式和相互作用并在功能测定中使用重组蛋白转化为可溶性 IL-2Rot。额外的实验将使用用截短的基因片段和重叠肽转染的靶细胞来描绘优选被CD4+Treg识别的IL-2Ra区域。在目标 3 中，我们将通过分析 T 细胞反应来定义 IL-2Rc_ 蛋白作为直接诱导 PBMC 中 CD4+ Treg 细胞反应的特异性试剂的效力和特异性，以及 TCV 在此过程中的作用，如接种前和接种后 PBMC 以及对照中 CD4+ Treg 细胞对 IL-2R(x 蛋白或优选识别肽的反应性频率。平行实验旨在评估IL-2Ra 通过其在 MBP 引发的 PBMC 培养物中诱导 CD4+ Treg 细胞反应的内在特性来影响 MBP 反应性 T 细胞反应。总体结果将为 IL-2Ro_ 在促炎性 T 细胞反应调节中的作用提供新的见解。在自身免疫条件下。