Cell Surface Receptors on T cells and Macrophages

描述(申请人提供)：SLAM受体家族的成员及其适配器SAP End 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的突变导致XLP-疾病。SLAM(CD150，SLAMF1)最初被鉴定为T细胞和APC之间的自体配体受体，但现在有充分的证据表明，SLAM具有多种不同的功能，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菌功能中。我们的初步研究表明，由于吞噬小体成熟延迟和吞噬细胞NADPH-氧化酶功能降低，SLAM-/-巨噬细胞杀死主要寄生虫L和几种细菌的能力减弱。相比之下，编码受体HUMP的SlamFS基因突变的巨噬细胞表现出更高的NADPH-氧化酶活性，并加速了吞噬小体的成熟。因此，这些数据强烈表明，在wt小鼠中，不结合EAT-2的DOWN对相同的依赖于PI3P的途径产生负面干扰，从而影响巨噬细胞的吞噬小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上PI3P的产生来控制吞噬小体成熟和NADPH-氧化酶组装，而HUMP是相同过程的负向调节。PI3P的下调是结核分枝杆菌为了在巨噬细胞内生存而阻止吞噬小体成熟的一种机制。因此，我们将检验这样一种假设，即对结核分枝杆菌的杀灭是在缺乏责备、SLAM和/或EAT-2的巨噬细胞中改变的。本申请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是巨噬细胞中吞噬-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：验证这一假设，即这是吞噬溶酶体融合和吞噬小体NADPH-氧化酶功能的负调节因子。。SA#3：为了测试SLAM-、EAT-2和非特异性缺陷巨噬细胞对结核分枝杆菌感染的免疫反应改变的假设(SA#3)。总而言之，这些实验应该澄清巨噬细胞中杀菌机制的调节。他们的结果应该根据吞噬小体中这些受体调节的机制，建议针对特定传染病的治疗策略，例如结核病。

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.