Control of lymphocyte homeostasis by iCD8a cells and osteopontin

摘要 在这项应用中，我们建议研究先天CD8细胞(或iCD8细胞)的生物学特性。 本课题组在肠上皮细胞中发现了新的淋巴样细胞群。这是它的一个标志 人群是表达CD8，缺乏T、B细胞受体，并产生 表明先天免疫表型的细胞因子/趋化因子。ICD8细胞是主要的来源 肠上皮细胞中的骨调素，一种已知在组织重塑中的作用的细胞因子，也是其 刺激Th1和Th17免疫反应的能力。有趣的是，使用一种缺乏iCD8的小鼠 细胞(E8I小鼠；E8I是IEL中CD8表达的重要增强子)我们发现 -/- 与野生型小鼠和E8I-/-小鼠相比，肠上皮细胞中的骨桥蛋白减少 NKp46+NK1.1+IEL有缺陷。这些和其他初步结果导致了这样的假设 ICD8细胞通过产生骨桥蛋白等因子，促进存活和 IEL的维护。为了推进这一假设，我们提出了以下补充，但 独立目标：目标1.ICD8细胞和骨桥蛋白在间质性白血病中的作用 维持和生存。在这一目标中，我们将确定：a)iCD8细胞和骨桥蛋白对 不同细胞亚群的存活和增殖；b)iCD8细胞和骨桥蛋白对人脐静脉内皮细胞生长的影响 肠道免疫环境；c)骨桥蛋白配体在IEL动态平衡中的作用。目标2.目标 明确iCD8细胞和骨桥蛋白在肠道炎症中的作用。在这一节中，我们将 确定iCD8细胞和骨桥蛋白在三种不同疾病模型中的作用：a)肠道 通过抗CD40抗体治疗引起的炎症，b)轮状柠檬酸杆菌感染，以及c)炎症 由过继将效应性T细胞转移到免疫缺陷小鼠引起的。目标3.确定 ICD8细胞控制IEL动态平衡的机制。我们之前的出版物表明，IL-12 为iCD8细胞的激活提供刺激。在这一部分中，我们将确定a)IL-12对 ICD8细胞的激活，对骨桥蛋白的分泌和IEL存活的影响，以及b)我们将确定 ICD8-细胞/骨桥蛋白刺激下IEL的基因表达特征

SUMMARY In this application we propose to investigate the biological features of innate CD8 cells (or iCD8 cells), a novel lymphoid population present in the intestinal epithelium discovered by our group. A hallmark of this population is the expression of CD8, lack of T and B cell receptors, and the production of cytokines/chemokines that indicate an innate immune phenotype. iCD8 cells are a main source of osteoponin in the intestinal epithelium, a cytokine known for its role in tissue remodeling but also for its capacity to stimulate Th1 and Th17 immune responses. Interestingly, using a strain of mice lacking iCD8 cells (E8I mice; E8I is an essential enhancer for CD8 expression in IEL) we found that the levels of -/- osteopontin in the intestinal epithelium are decreased in comparison to wild type mice, and that E8I-/- mice have a deficiency in NKp46+NK1.1+ IEL. These and other preliminary results have led to the hypothesis that iCD8 cells, through production of factors such as osteopontin, promote the survival and maintenance of IEL. In order to pursue this hypothesis, we propose the following complementary, yet independent aims: Aim1. To determine the contribution of iCD8 cells and osteopontin to IEL maintenance and survival. In this aim we will determine: a) the impact of iCD8 cells and osteopontin in the survival and proliferation of different IEL subsets; b) the impact of iCD8 cells and osteopontin in the immune environment of the intestines; and c) the role of osteopontin ligands in IEL homeostasis. Aim 2. To define the role of iCD8 cells and osteopontin during intestinal inflammation. In this section we will determine the role of iCD8 cells and osteopontin in three different disease models: a) intestinal inflammation by anti-CD40 antibody treatment, b) Citrobacter rodentium infection, and c) inflammation caused by adoptive transfer of effector T cells into immunodeficient mice. Aim 3. To determine the mechanisms controlling IEL homeostasis by iCD8 cells. Our previous publication indicates that IL-12 provides stimulus for activation of iCD8 cells. In this section we will determine a) the impact of IL-12 in activation of iCD8 cells, with implications on OPN secretion and IEL survival, and b) we will determine the gene expression signature of IEL responding to iCD8 cell/OPN stimulation.