THE ENDOTHELIUM IN ORGAN SPECIFIC CD8 T CELL RECRUITMENT

描述（由申请人提供）：对仅在特定组织中表达的抗原具有特异性的CD 8 + T细胞在器官特异性自身免疫性疾病和同种异体移植物排斥的发病机制中很重要，但对这些情况下T细胞募集的机制知之甚少。组织抗原特异性T细胞的募集可能有独特的方面，这是由于组织抗原的丰度、感染的缺乏以及每个器官血管床的特定特征。该项目将重点关注致病组织抗原特异性CD 8 + T细胞的内皮依赖性募集机制。该方法将依赖于转基因小鼠模型，其中将明确定义的特异于确定抗原的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中。 在具体目标#1中，将检查选择素在组织抗原特异性CD 8 * 募集中的作用。该目的将检验选择素依赖性粘附于内皮细胞是这些CD 8 * T细胞募集的关键步骤的假设。这些研究将检查不同的CD 8 * T细胞亚群和不同的组织。实验将涉及CD 8 * T细胞介导的自身免疫性心肌炎、胰岛炎症、肾炎和细支气管炎的转基因模型。将具有改变的选择素-配体表达的CD 8- T细胞的募集和致病性与对照T细胞进行定量比较。 具体目标#2将集中于趋化因子如何影响组织抗原特异性CD 8 + T细胞的募集。潜在的假设是，在组织中表达的趋化因子将差异地影响CD 8 + T细胞的募集，这取决于血管床和T细胞的亚群表型。重点将放在CXCR和CCR 5结合趋化因子。实验方法将依赖于Aim 1中使用的自体反应性T细胞募集的相同转基因模型，结合药理学趋化因子受体阻断和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直接T细胞募集中的作用。这些实验将直接检查体内CD 8 + T细胞和内皮细胞的抗原特异性相互作用，使用敏感的技术，包括活体显微镜。

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.