Cell Surface Receptors on T cells and Macrophages

描述（由申请人提供）：SLAM受体家族成员及其适配器SAP末端EAT-2在适应性和先天免疫反应中发挥着越来越重要的作用，特别是因为发现SAP突变导致xlp疾病。虽然SLAM （CD150, SLAMF1）最初被确定为T细胞和apc之间界面的自配体受体，但现在有充分的证据表明SLAM具有几种不同的功能，例如作为麻疹病毒的主要受体，在早期造血或巨噬细胞的杀微生物功能中。我们的初步研究表明，由于吞噬体成熟延迟和吞噬细胞NADPH氧化酶功能降低，SLAM-/-巨噬细胞杀死寄生虫L主和几种细菌的能力受损。相比之下，编码受体BLAME的SlamFS基因被破坏的巨噬细胞增加了nadph氧化酶活性，加速了吞噬体的成熟。因此，这些数据强烈表明，在wt小鼠中，不结合EAT-2的BLAME负性干扰相同的pi3p依赖途径，从而干扰巨噬细胞中的吞噬体成熟和活性氧产生。我们的总体假设是，SLAM通过正向调节吞噬体膜中PI3P的产生来控制吞噬体成熟和nadph氧化酶的组装，而BLAME是同一过程的负向调节因子。PI3P的下调是结核分枝杆菌阻止吞噬体成熟以在巨噬细胞内存活的一种机制。因此，我们将验证在BLAME-、SLAM-和/或eat -2缺陷巨噬细胞中对结核分枝杆菌的杀伤发生改变的假设。本应用中提出的实验分为以下几个具体目的：SA#1：验证细胞表面受体SLAM是巨噬细胞吞噬溶酶体融合和吞噬体nadph氧化酶功能的正调节因子的假设。SA#2：验证巨噬细胞中BLAME是吞噬溶酶体融合和吞噬体nadph氧化酶功能负调节因子的假设。SA#3：验证SLAM-、EAT-2和blame缺陷巨噬细胞对结核分枝杆菌感染的免疫反应发生改变的假设（SA#3）。总之，这些实验应该阐明巨噬细胞的杀微生物机制调控。他们的结果应该基于吞噬体中这些受体调节的机制，为特定传染病（如结核病）提供治疗策略。

DESCRIPTION (provided by applicant): Members of the SLAM family of receptors and their adapters, SAP end EAT-2, play an increasingly important role in adaptive and innate immune responses, particularly because of the finding that mutations in SAP cause XLP-disease. Whereas SLAM (CD150, SLAMF1) was first identified as a self-ligand receptor at the interface between T cells and APCs, there is now ample evidence that SLAM serves several distinct functions, e.g. as the primary receptor for Measles Virus, in early hematopoiesis or in microbicidal functions of macrophages. As our Preliminary Studies show, SLAM-/- macrophages are impaired in their ability to kill the parasite L major and several bacteria due to delayed phagosome maturation and a reduced phagocyte NADPH- oxidase function. Macrophages with a disrupted SlamFS gene, which encodes the receptor BLAME display, by contrast, increased NADPH-oxidase activity and accelerated phagosome maturation. The data therefore strongly suggest that in wt mice BLAME, which does not bind EAT-2, negatively interferes with the same PI3P-dependent pathways, and hence with phagosome maturation and reactive oxygen production in macrophages. Our overall hypothesis is that SLAM by positively regulating production of PI3P in the phagosome membrane controls both phagosome maturation and NADPH-oxidase assembly, while BLAME is a negative regulator of the same processes. Down-regulation of PI3P is a mechanism utilized by M. tuberculosis to halt phagosome maturation in order to survive within the macrophage. We will therefore test the hypothesis that killing of M. tuberculosis is altered in BLAME-, SLAM- and/or EAT-2-deficient macrophages. The experiments proposed in this application are grouped in the following specific aims: SA#1: To test the hypothesis that the cell surface receptor SLAM is a positive regulator regulator of phago-lysosomal fusion and phagosomal NADPH-oxidase function in macrophages. SA#2: To test the hypothesis that that BLAME is a negative regulator of phago-lysosomal fusion and phagosomal NADPH-oxidase function in macrophages. . SA#3: To test the hypothesis that immune responses of SLAM-, EAT-2 and BLAME-deficient macrophages to infection with M. tuberculosis are altered (SA#3). Together the experiments should clarify the regulation of microbicidal mechanisms in macrophages. Their outcomes should suggest therapeutic strategies for specific infectious diseases, e.g. tuberculosis, based upon the mechanisms that are regulated by these receptors in the phagosome.