Control of lymphocyte homeostasis by iCD8a cells and osteopontin

总结 在本申请中，我们提出研究先天性CD 8+细胞（或iCD 8+细胞）的生物学特征， 本研究组发现了存在于肠上皮中的新淋巴样细胞群。这其中的一个标志是 群体的主要特征是表达CD 8受体，缺乏T和B细胞受体，以及产生 细胞因子/趋化因子，其指示先天免疫表型。iCD 8巨噬细胞是 肠上皮中的骨桥蛋白是一种细胞因子，以其在组织重塑中的作用而闻名， 刺激Th 1和Th 17免疫应答的能力。有趣的是，使用缺乏iCD 8的小鼠品系， 细胞（E8 I小鼠; E8 I是IEL中CD 8受体表达的重要增强剂），我们发现， -/- 与野生型小鼠相比，肠上皮中的骨桥蛋白减少，并且E8 I-/-小鼠 NKp 46 +NK1.1+ IEL缺乏。这些和其他初步结果导致了这样的假设， iCD 8 β细胞通过产生骨桥蛋白等因子，促进存活， IEL的维护为了实现这一假设，我们提出了以下补充，但 独立目标：Aim 1.确定iCD 8 β细胞和骨桥蛋白对IEL的贡献 维持和生存。在这个目标中，我们将确定：a）iCD 8 β细胞和骨桥蛋白对骨形成的影响。 不同IEL亚群的存活和增殖; B）iCD 8+细胞和骨桥蛋白在IEL亚群中的影响。 肠的免疫环境;和c）骨桥蛋白配体在IEL稳态中的作用。目标2.到 明确iCD 8巨噬细胞和骨桥蛋白在肠道炎症中的作用。本节我们将 确定iCD 8 β细胞和骨桥蛋白在三种不同疾病模型中的作用： 通过抗CD 40抗体治疗的炎症，B）啮齿类柠檬酸杆菌感染，和c）炎症 由效应T细胞过继转移到免疫缺陷小鼠引起。目标3：确定 通过iCD 8 β细胞控制IEL稳态的机制。我们先前的出版物表明IL-12 为iCD 8 β细胞的活化提供刺激。在本节中，我们将确定a）IL-12在 iCD 8 β细胞的活化，对OPN分泌和IEL存活的影响，和B）我们将确定 IEL对iCD 8+细胞/OPN刺激的响应的基因表达特征。

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.