THE ENDOTHELIUM IN ORGAN SPECIFIC CD8 T CELL RECRUITMENT

描述(由申请人提供)：CD8+T细胞仅针对特定组织表达的抗原，在器官特异性自身免疫性疾病和同种异体移植排斥反应的发病机制中起重要作用，但T细胞在这些环境中的募集机制尚不清楚。由于组织抗原的丰富，没有感染，以及每个器官血管床的特殊特征，组织抗原特异性T细胞的募集可能有独特的方面。该项目将重点研究致病组织抗原特异性CD8+T细胞的内皮依赖募集机制。该方法将依赖于转基因小鼠模型，在该模型中，将针对特定抗原的明确定义的TCR转基因T细胞群体引入以器官特异性方式表达转基因编码抗原的小鼠。 在特定目标#1中，将研究选择素在组织抗原特异性CD8*募集中的作用。这一目标将检验选择素依赖的内皮黏附是这些CD8*T细胞招募的关键步骤的假设。这项研究将检测CD8*T细胞的不同亚群和不同的组织。这些实验将涉及CD8*T细胞介导的自身免疫性心肌炎、胰岛炎症、肾炎和毛细支气管炎的转基因模型。选择素配体表达改变的CD8-T细胞的募集和致病能力将与对照T细胞进行定量比较。 具体目标#2将侧重于趋化因子如何影响组织抗原特异性CD8+T细胞的募集。潜在的假设是，在组织中表达的趋化因子将根据血管床和T细胞的亚群表型而不同地影响CD8+T细胞的募集。重点将放在CXCR和CCR5结合趋化因子上。实验方法将依赖于AIM 1中使用的自体反应性T细胞招募的转基因模型，结合药理学趋化因子受体阻断，以及趋化因子或趋化因子受体基因敲除小鼠。 在具体目标#3中，将研究内皮抗原呈递在T细胞直接募集中的作用。这些实验将使用包括活体显微镜在内的敏感技术，直接检测体内CD8+T细胞和内皮细胞的抗原特异性相互作用。

DESCRIPTION (provided by applicant): CD8+ T cells specific for antigens expressed only in particular tissues are important in the pathogenesis of organ-specific autoimmune diseases and allograft rejection, but the mechanisms of recruitment of T cells in these settings are poorly understood. There are likely to be unique aspects of recruitment of tissue antigen-specific T cells, due to the abundance of the tissue antigens, the absence of infection, and the particular characteristics of each organ's vascular bed. This project will focus on endothelial-dependent recruitment mechanisms of pathogenic tissue antigen-specific CD8 + T cells. The approach will rely on transgenic mouse models in which well-defined populations of TCR-transgenic T cells specific for a defined antigen are introduced into mice that express transgene-encoded antigen in an organ specific manner. In Specific Aim #1, the role of selectins in tissue antigen-specific CD8* recruitment will be examined. This Aim will test the hypothesis that selectin-dependent adhesion to endothelium is a key step in the recruitment of these CD8* T cells. The studies will examine different subsets of CD8* T cells, and different tissues. The experiments will involve transgenic models of CD8* T cell-mediated autoimmune myocarditis, pancreatic islet inflammation, nephritis, and bronchiolitis. The recruitment and pathogenicity of CD8- T cells with altered selectin-ligand expression will be quantitatively compared with control T cells. Specific Aim #2 will focus on how chemokines influence recruitment of tissue antigen-specific CD8+ T cells. The underlying hypothesis is that chemokines expressed in tissues will differentially effect the recruitment of CD8+ T cells, depending on the vascular bed and the subset-phenotype of the T cells. The emphasis will be on CXCR and CCR5 binding chemokines. The experimental approach will rely on the same transgenic models of autoreactive T cell recruitment used in Aim 1, in combination with pharmacologic chemokine receptor blockade, and chemokine or chemokine receptor gene knock-out mice. In Specific Aim #3, the role of endothelial antigen-presentation in direct T cell recruitment will be studied. The experiments will directly examine antigen-specific interactions of CD8+ T cells and endothelium in vivo, using sensitive techniques including intravital microscopy.