Regulation of Memory CD8 T cell Trafficking to Inflamed Tissues

描述（由申请人提供）：在感染或成功接种疫苗后，初始CD 8 T细胞经历一系列程序化的生物学事件，最终导致形成长寿的记忆群体。除了疫苗接种后发生的抗原特异性CD 8 T细胞的总体定量增加之外，还描述了增强记忆性CD 8 T细胞防止再感染的能力的几种定性差异。具体而言，记忆性CD 8 T细胞能够定位于外周组织，表达包括穿孔素和颗粒酶在内的细胞溶解介质，并在抗原识别后立即产生细胞因子。此外，最近的实验证据表明，记忆性CD 8 T细胞在感染后以抗原非依赖性方式迅速募集到发炎组织。此外，这些新募集的细胞是高度溶细胞的，并且是针对表达同源抗原的病原体的保护性免疫的关键介质。虽然记忆性CD 8 T细胞向肺气道的抗原非依赖性募集已显示依赖于CCR 5趋化因子受体，但控制记忆性CD 8 T细胞向发炎组织募集的其他分子机制和生物学过程仍然未知。对控制记忆性CD 8 T细胞定位的机制的完全理解可能潜在地导致新的疾病预防策略，通过引导（对于病原体和肿瘤）或抑制（对于过敏和自身免疫）这些细胞的定位， 特定的解剖位置。因此，本项目的目标是确定控制记忆性CD 8 T细胞向炎症组织募集的分子机制。如本提案的初步数据部分所述，我们表明，在炎症激发后，记忆性CD 8 T细胞表现出快速特异性表达细胞表面O-聚糖的独特能力，不依赖于抗原识别，这导致P-和E-选择素的功能性配体的形成。CD 8 T细胞活化的体外研究表明，至少有两种糖基转移酶可以表达，它们被认为是选择素配体上O-聚糖形成的关键，即核心2 - 1-6-N-葡糖胺基转移酶-I（Gcnt 1）和-（1，3）-岩藻糖基转移酶-VII（Fut 7）。然而，这些糖基转移酶在记忆性CD 8 T细胞中的调节目前尚不清楚。因此，本提案中概述的实验将检验中心假设，即炎症驱动记忆CD 8 T细胞中Gcnt 1和Fut 7的表达，导致P-和E-选择素配体的形成并定位于炎症组织。 具体来说，我们将确定1）Gcnt 1和Fut 7基因的启动子区域是否经历了特定的表观遗传变化，使它们能够快速表达，2）记忆CD 8 T细胞中IL-15介导的信号传导是否驱动选择素配体表达，以及3）PSGL-1是否调节记忆CD 8 T细胞向炎症组织的募集。

DESCRIPTION (provided by applicant): Following infection or successful vaccination, na¿ve CD8 T cells undergo a programmed series of biological events that ultimately results in the formation of a long-lived memory population. Besides the overall quantitative increase in antigen-specific CD8 T cells that occurs following vaccination, several qualitative differences have also been described that enhance the ability for memory CD8 T cells to protect against re-infection. Specifically, memory CD8 T cells are able to localize to peripheral tissues, express mediators of cytolysis including perforin and granzymes, and immediately produce cytokines following antigen recognition. In addition, recent experimental evidence has demonstrated that memory CD8 T cells are rapidly recruited to inflamed tissues following infection in an antigen-independent manner. Furthermore, these newly recruited cells are highly cytolytic and are critical mediators of protective immunity against pathogens expressing cognate antigen. Although antigen-independent recruitment of memory CD8 T cells to the lung airways has been shown to be dependent upon the CCR5 chemokine receptor, additional molecular mechanisms and biological processes that control the recruitment of memory CD8 T cells to inflamed tissues remain unknown. A complete understanding of the mechanisms controlling memory CD8 T cell localization could potentially lead to new disease prevention strategies by either directing (for pathogens and tumors) or inhibiting (for allergies and autoimmunity) localization of these cells to specific anatomical locations. Thus, the goal of this project is to determine the molecular mechanisms that control memory CD8 T cell recruitment to inflamed tissues. As detailed in the preliminary data section of this proposal, we show that following an inflammatory challenge, memory CD8 T cells exhibit the unique ability to rapidly and specifically express cell surface O-glycans, independent of antigen recognition, that results in the formation of functional ligands fo both P- and E-Selectin. In vitro studies of CD8 T cell activation have suggested that at least two glycotransferases can become expressed that are thought to be critical for the formation of O-glycans on selectin ligands, core 2 ¿1-6-N- glucosaminyltransferase-I (Gcnt1) and ¿-(1,3)-fucosyltransferase-VII (Fut7). However, the regulation of these glycotransferases in memory CD8 T cells is currently unknown. Therefore, the experiments outlined in this proposal will test the central hypothesis that inflammation drives expression of Gcnt1 and Fut7 in memory CD8 T cells, resulting in the formation of P- and E-selectin ligands and localization to inflamed tissue. Specifically, we will determine 1) whether the promoter regions of the Gcnt1 and Fut7 genes have undergone specific epigenetic changes that allow them to be rapidly expressed, 2) whether IL-15-mediated signaling in memory CD8 T cells drives selectin ligand expression, and 3) if PSGL-1 regulates recruitment of memory CD8 T cells to inflamed tissues.