TIM-1, TIM-3 and TIM-4: A gene family that regulates tolerance and immunity

项目总结（见说明）： 使用同源小鼠模型鉴定TIM基因家族，其中TIM-1中的多态性 TIM-3与BALB/c和HBA小鼠Th1-Th2分化和变应原诱导的气道高反应性（AHR）有关。项目3的长期目标是了解Tim基因如何调节外周耐受、适应性免疫反应和过敏。在之前的研究中，我们发现TIM-1是T细胞的重要共刺激分子，TIM-1和TIM-4调节T细胞反应和耐受性的发展，TIM-1和TIM-4是磷脂酰丝氨酸（PtdSer）的受体，PtdSer是识别和摄取凋亡细胞的关键分子。我们已经发现，TIM-3，表达在Th1细胞和APC，也是PtdSer的受体，并与哮喘相关的TIM-3的等位基因变异体在他们的PtdSer的识别不同。这些结果共同表明了TIM蛋白作为PtdSer受体的新范例，其通过调节凋亡细胞的识别和清除，可以调节组织稳态、T细胞应答和外周耐受的诱导。 在具体目标1中，我们将确定TIM-4在APC上表达的机制，以及TIM-1， 在活化的T细胞和Th2细胞上表达，调节口服耐受和预防食物过敏。我们将 研究TIM-4阻断抑制口服耐受诱导的机制。在特定目标2中，我们将表征固有层和肠系膜淋巴结中表达TIM-4的细胞类型和APC亚群，这是暴露于危险信号（如引发食物过敏的细菌产物）后调节TIM-3和TIM-4表达的条件。我们将研究T细胞与表达TIM的APC相互作用对T细胞亚群分化的影响。在特定目标3中，我们将研究TIM-3多态性变体的作用，我们最近发现TIM-3多态性变体在识别凋亡细胞、调节BALB/c和HBA小鼠的免疫应答方面存在差异，并确定TIM-1和TIM-3在调节这些菌株中气道高反应性发展方面的作用。 我们开发了独特的试剂，使我们能够实现这些目标。我们有 在制备了抗TIM-1和TIM-4 mAb的组之后，我们已经制备了TIM-4和TIM-1转基因小鼠，并且T1M-1缺陷型小鼠现在正在我们的群体中繁殖。我们的实验室在耐受性研究方面拥有丰富的经验，耐受性是一种保护免受Th2驱动的免疫应答的机制，并且在树突状细胞（DC）和抗原特异性CD4 + Tpeg细胞的研究中具有丰富的经验。这些研究将大大提高我们对免疫调节的理解，并为炎症性疾病带来新的治疗方法。

PROJECT SUMMARY (See instructions): The TIM gene family was identified using a congenic mouse model in which polymorphisms in TIM-1 and TIM-3 wre associated with Th1-Th2 differentiation and allergen-induced ainway hyperreactivity (AHR) between BALB/c and congenic HBA mice. The long-term goals of Project 3 are to understand how the Tim genes regulate peripheral tolerance, adaptive immune responses, and allergy. In the previous grant period we showed that TIM-1 is an important costimulatory molecule for T cells, that TIM-1 and TIM-4 modulate T cell responses and the development of tolerance, and that TIM-1 and TIM-4 are receptors for phosphatidylserine (PtdSer), a key molecule for recognition and uptake of apoptotic cells. We have found that TIM-3, expressed on Th1 cells and APC, is also a receptor for PtdSer and that the allelic variants of TIM-3 associated with asthma differ in their recognition of PtdSer. These results together suggest a new paradigm for TIM proteins as PtdSer receptors that by regulating the recognition and clearance of apoptotic cells, can regulate tissue homeostasis, T cell responses and the induction of peripheral tolerance. In Specific Aim 1 we will determine the mechanisms by which TIM-4 expressed on APC, and TIM-1, expressed on activated T cells and Th2 cells, regulate oral tolerance and prevent food allergy. We will examine mechanisms by which TIM-4 blockade inhibits oral tolerance induction. In Specific Aim 2, we will characterize the cell types and APC subset(s) in the lamina propria and mesenteric lymph node that express TIM-4, the conditions that modulate expression of TIM-3 and TIM-4 following exposure to danger signals such as bacterial products that initiate food allergy. We will examine the consequences of T cell interaction with TIM-expressing APC on T cell subset differentiation. In Specific Aim 3 we will investigate the role of TIM-3 polymorphic variants, which we have recently shown differ in recognition of apoptotic cells, in modulation of immune responses in BALB/c and HBA mice, and determine the roles of TIM-1 and TIM-3 in modulating the development of airway hyperreactivity in these strains. We have developed unique reagents that will enable us to accomplish these goals. We have generated panels of anti-TIM-1 and TIM-4 mAbs, we have generated TIM-4 and TIM-1 transgenic mice, and TlM-1 deficient mice are now breeding in our colony. Our laboratory has extensive experience in the study of tolerance as a mechanism that protects against Th2-driven immune responses and in the study of dendritic cells (DCs) and antigen-specific CD4+ Tpeg cells. These studies will greatly improve our understanding of immune regulation and lead to new therapies for inflammatory diseases.