Avidity Maturation of T Cells in Mutiple Sclerosis

描述(申请人提供)：多发性硬化症(MS)是中枢神经系统(CNS)的一种慢性炎症性和脱髓鞘疾病，被认为是由T细胞对中枢神经系统(CNS)中存在的髓鞘自身抗原的错误攻击所致。针对MS患者的T细胞表位的表征在技术上仍然具有挑战性，神经抗原特异性T细胞的功能特征，特别是在中枢神经系统，仍然没有解决。通过细胞因子ELISPOT实验，我们获得了MS患者PBL中对MOG多肽反应强烈的T细胞的初步结果。基于这些结果，我们希望在MS病程中纵向检测个体患者的MOG特异性T细胞反应，并测试这些细胞的表位特异性和功能亲和力。为了克服直接从MS患者的大脑中检测M0G反应时出现的困难，我们建议研究“人源化”的HLA-DR2和-DR4转基因小鼠中枢神经系统中的T细胞反应。我们的初步研究表明，在具有该单倍型的多发性硬化症患者中，人类白细胞抗原DR转基因小鼠的T细胞反应针对的是类似的MOG表位。我们将验证这样一种假设，即MOG特异性T细胞在MS的过程中经历亲和力成熟，高亲和力T细胞在疾病复发或恶化之前在患者的外周血中积累。此外，我们将通过研究中枢神经系统中MOG特异性T细胞的良好特异性和功能亲和力来测试这些细胞的功能。我们将在以下目标中验证这一假设：在目标1中，我们将通过细胞因子ELISPOT检测MS患者随时间的MOG表位特异性T细胞反应。在目标2中，我们将测试MS患者病程中MOG特异性T细胞的亲和力成熟度。在目的3中，我们将在EAE过程中检测人类白细胞抗原-DR2和-DR4转基因小鼠中枢神经系统中MOG特异性T细胞谱系。在目标4中，我们将测试转基因小鼠中枢神经系统和血液中MOG特异性T细胞在EAE过程中的亲和力成熟情况。在本项目结束时，我们将了解多发性硬化症患者中MOG特异性T细胞是否经历亲和力成熟，以及这与复发/缓解之间的关系。人类白细胞抗原DR转基因小鼠的实验将补充人类的研究，并确定中枢神经系统中MOG反应性T细胞的特异性和功能。

DESCRIPTION (provided by applicant): Multiple sclerosis (MS) is a chronic inflammatory and demyelinating disease of the central nervous system (CNS), which is thought to be mediated by an erroneous attack of T cells on myelin autoantigens present in the central nervous system (CNS). Characterization of the T cell epitopes targeted in MS patients has remained technically challenging, and the functional characteristics of the neuroantigen-specific T cells, particularly in the CNS, have remained unresolved. We have obtained preliminary results showing vigorous T cell responses to MOG peptides in PBL of MS patients by cytokine ELISPOT assay. Based on these results, we want to examine the MOG- specific T cell response in individual patients longitudinally over the course of MS, and test the epitope specificity and functional avidity of these cells. To overcome the difficulties that arise when examining M0G responses directly ex vivo from the brain of MS patients, we propose to study T cell responses in the CNS of "humanized" HLA-DR2 and -DR4 transgenic mice. Our preliminary studies have indicated that T cell responses in HLA-DR transgenic mice are directed against similar MOG epitopes as T cell responses in MS patients with this HLA-DR haplotype. We will test the hypothesis that MOG-specific T cells undergo avidity maturation over the course of MS, and high-avidity T cells accumulate in the peripheral blood of patients prior to relapses or exacerbation of disease. Furthermore, we will test the function of MOG-specific T cells by studying the fine specificity and functional avidity of these cells in the CNS. We will test this hypothesis in the fol1owing aims: In Aim 1 we will examine the MOG epitope-specific T cell response over time in MS patients by cytokine ELISPOT. In Aim 2 we will test the avidity maturation of MOG-specific T cells over the course of disease in MS patients. In Aim 3 we will test the MOG-specific T cell repertoire in the CNS of HLA-DR2 and -DR4 transgenic mice over the course of EAE. In Aim 4 we will test the avidity maturation of MOG-specific T cells in the CNS and blood of the transgenic mice over the course of EAE. At the end of this project, we will have learned whether MOG-specific T cells undergo avidity maturation in MS patients and how this relates to relapses/remissions. The experiments in the HLA-DR transgenic mice will complement the human studies and define the specificity and function of MOG-reactive T cells in the CNS.