Regulation of Memory CD8 T cell Trafficking to Inflamed Tissues

描述(申请人提供)：在感染或成功接种疫苗后，原始CD8 T细胞经历一系列程序化的生物学事件，最终导致形成长期记忆群体。除了疫苗接种后抗原特异性CD8T细胞的总体数量增加外，还描述了几个质的差异，这些差异增强了记忆CD8T细胞防止再次感染的能力。具体地说，记忆性CD8T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CD8 T细胞在感染后以不依赖于抗原的方式迅速招募到炎症组织中。此外，这些新招募的细胞具有高度的细胞溶解能力，是对表达同源抗原的病原体进行保护性免疫的关键介质。尽管CD8记忆T细胞的抗原非依赖性募集到肺组织依赖于CCR5趋化因子受体，但控制CD8记忆T细胞募集到炎症组织的其他分子机制和生物学过程仍不清楚。完全了解控制记忆CD8 T细胞定位的机制可能会通过引导(针对病原体和肿瘤)或抑制(针对过敏和自身免疫)这些细胞的定位来潜在地导致新的疾病预防策略 特定的解剖位置。因此，该项目的目标是确定控制CD8记忆T细胞向炎症组织募集的分子机制。正如本提案的初步数据部分所详述的，我们表明，在炎症挑战之后，记忆性CD8 T细胞表现出独特的能力，快速和特异性地表达细胞表面的O-糖链，而不依赖于抗原识别，这导致了P-和E-选择素的功能性配体的形成。CD8 T细胞激活的体外研究表明，至少有两种糖转移酶可以表达，这两种糖转移酶被认为是在选择素配体上形成O-糖链的关键，即核心2？1-6-N-氨基葡萄糖转移酶-I(GcNT1)和-(1，3)-岩藻糖基转移酶-7(Fut7)。然而，这些糖转移酶在记忆性CD8T细胞中的调节目前尚不清楚。因此，这项提案中概述的实验将检验中心假设，即炎症推动记忆CD8 T细胞中Gcnt1和Fut7的表达，导致P-和E-选择素配体的形成并定位于炎症组织。 具体地说，我们将确定1)Gcnt1和Fut7基因的启动子区域是否经历了特定的表观遗传学变化，从而使它们能够快速表达，2)IL-15介导的记忆CD8 T细胞信号是否驱动了选择素配体的表达，以及3)PSGL-1是否调节了记忆CD8 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.