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 α细胞（或iCD 8 α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 群体是表达CD 8 αα，缺乏T和B细胞受体， 细胞因子/趋化因子，其指示先天免疫表型。iCD 8 α细胞是一种主要来源， 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 α的小鼠品系， 细胞（E8 I小鼠; E8 I是IEL中CD 8 αα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 α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 α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 α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 α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。目标二。到 明确iCD 8 α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 α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 iCD 8 α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 α细胞的活化提供刺激。在本节中，我们将确定a）IL-12在 iCD 8 α细胞的活化，以及对OPN分泌和IEL存活的影响，和B）我们将确定 IEL响应iCD 8 α细胞/OPN刺激的基因表达特征。

SUMMARY In this application we propose to investigate the biological features of innate CD8α cells (or iCD8α cells), a novel lymphoid population present in the intestinal epithelium discovered by our group. A hallmark of this population is the expression of CD8αα, lack of T and B cell receptors, and the production of cytokines/chemokines that indicate an innate immune phenotype. iCD8α 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 iCD8α cells (E8I mice; E8I is an essential enhancer for CD8αα 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 iCD8α 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 iCD8α cells and osteopontin to IEL maintenance and survival. In this aim we will determine: a) the impact of iCD8α cells and osteopontin in the survival and proliferation of different IEL subsets; b) the impact of iCD8α 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 iCD8α cells and osteopontin during intestinal inflammation. In this section we will determine the role of iCD8α 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 iCD8α cells. Our previous publication indicates that IL-12 provides stimulus for activation of iCD8α cells. In this section we will determine a) the impact of IL-12 in activation of iCD8α cells, with implications on OPN secretion and IEL survival, and b) we will determine the gene expression signature of IEL responding to iCD8α cell/OPN stimulation.