Avidity Maturation of T Cells in Mutiple Sclerosis

描述（由申请人提供）：多发性硬化症（MS）是一种中枢神经系统（CNS）的慢性炎症性和脱髓鞘疾病，被认为是由T细胞错误攻击中枢神经系统（CNS）中存在的髓鞘自身抗原介导的。MS患者中靶向的T细胞表位的表征在技术上仍然具有挑战性，并且神经抗原特异性T细胞（特别是CNS中的神经抗原特异性T细胞）的功能特征仍然没有得到解决。我们已经获得了初步的结果，显示强烈的T细胞反应的MS患者PBL中的MOG肽细胞因子ELISPOT测定。基于这些结果，我们想要在MS过程中纵向检查个体患者中的MOG特异性T细胞应答，并测试这些细胞的表位特异性和功能亲合力。为了克服出现的困难时，检查M0 G反应直接从MS患者的大脑离体，我们建议研究T细胞的反应，在中枢神经系统的“人源化”HLA-DR 2和-DR 4转基因小鼠。我们的初步研究表明，在HLA-DR转基因小鼠的T细胞反应是针对类似的MOG表位的MS患者与此HLA-DR单倍型的T细胞反应。我们将检验MOG特异性T细胞在MS过程中经历亲合力成熟的假设，并且高亲合力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，我们将通过研究这些细胞在CNS中的精细特异性和功能亲合力来测试MOG特异性T细胞的功能。我们将在以下目标中检验这一假设：在目标1中，我们将通过细胞因子ELISPOT检查MS患者中随时间推移的MOG表位特异性T细胞应答。在目标2中，我们将测试MS患者中MOG特异性T细胞在疾病过程中的亲合力成熟。在目标3中，我们将测试在EAE的过程中HLA-DR 2和-DR 4转基因小鼠的CNS中的MOG特异性T细胞库。在目的4中，我们将测试在EAE过程中转基因小鼠的CNS和血液中MOG特异性T细胞的亲合力成熟。在这个项目结束时，我们将了解MOG特异性T细胞是否在MS患者中经历亲合力成熟，以及这与复发/缓解的关系。在HLA-DR转基因小鼠中的实验将补充人类研究，并确定CNS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.