MOLECULAR MECHANISMS UNDERLYING ACAID INDUCTION

描述(申请人提供)：眼部抗原的免疫反应是独特的，因为它选择性地缺乏介导Th1效应器和补体固定免疫球蛋白的迟发型超敏反应(DTH)，而仍可检测到非补体固定免疫球蛋白和细胞毒性T细胞。这种与常规免疫反应的偏离被称为前房相关免疫偏离(ACAID)。众所周知，这种免疫反应有助于眼睛的免疫特权状态。驻留的眼部抗原提呈细胞(APC)被赋予以抗原特异性的方式诱导这种反应的能力，方法是迁移到受体脾并以产生调节细胞的方式将抗原递送给应答的T细胞。这些细胞反过来又被认为可以防止DTH反应。眼部APC诱导ACAID的能力主要归因于其在眼内暴露于TGFβ。来自非眼部来源的常规APC在暴露于TGFbeta时也可获得这种独特的ACAID诱导特性。了解APC这种功能转化的分子机制为开发预防眼部炎症的治疗策略以及在体外产生调节性APC用于各种需要调节不良免疫反应的临床应用提供了潜在的可能性。为此，我们试图鉴定在经转化生长因子β处理的APC中选择性表达的基因。应用基因差异分析(RAP-PCR和基因芯片芯片)对未经处理的APC和经TGFbeta处理的APC的RNA进行差异分析，我们分离了几个与ACAID诱导特性相关的差异表达基因。这种方法使我们能够选择到目前为止还没有被怀疑与ACAID诱导相关的潜在重要基因。首先，我们根据已知的特性和现有的关于ACAID和APC诱导的各个方面的现有信息以及独特的眼部微环境来选择基因。我们现在建议分析这些基因产物(血栓反应素、TNFR II和IkappaBetaAlpha)的参与及其在经TGFbeta处理的APC诱导ACAID中的作用。首先，将评估这些分子在ACAID各个方面发展中的意义，然后分析这些基因产物调控的个体机制。通过比较这些基因的作用并评估相关机制，我们建议测试有效使用经转化生长因子β治疗的APC来预防实验性自身免疫性葡萄膜炎(EAU)和皮肤移植排斥反应的可能性。

DESCRIPTION (provided by applicant): Immune response to ocular antigens is unique in that it is selectively deficient in delayed type hypersensitivity (DTH) mediating Th1 effectors and complement fixing immunoglobulins, while non-complement fixing immunglobulins and cytotoxic T cells remain detectable. Such deviation from a conventional immune response is referred to as Anterior Chamber Associated Immune Deviation (ACAID). This immune response is known to contribute to the immune privilege status of the eye. Resident ocular antigen presenting cells (APCs) are endowed with the ability to induce this response in an antigen specific manner by migrating out to the recipient spleen and presenting antigen to the responders T cells in a manner that generates regulatory cells. These cells in turn are known to prevent DTH responses. The ACAID-inducing ability of ocular APCs is mainly attributed to their exposure to TGFbeta in the eye. Conventional APCs derived from non-ocular sources are also known to acquire such unique ACAID-inducing properties when exposed to TGFbeta. Understanding molecular mechanisms underlying this functional transformation in APCs offers potential to develop therapeutic strategies to prevent ocular inflammation as well as to generate regulatory APCs ex vivo to be used for various clinical applications that require regulation of an undesirable immune response. To this end we have attempted identification of genes that are selectively expressed in TGFbeta-treated APCs. Applying differential analysis of genes (RAP-PCR and Genechip Microarrays) to RNA isolated from untreated APCs and TGFbeta-treated APCs, we isolated several differentially expressed genes that can be relevant in ACAID-inducing properties of APCs. Such an approach has allowed us to select potentially significant genes that have been unsuspected, so far, to be relevant in ACAID-induction. To begin with, we have chosen genes based on their known properties and as they relate to existing information available regarding various aspects of ACAID and APCs involved in its induction as well as the unique ocular microenvironment. We now propose to analyze the participation of these gene products (thrombospondin, TNFR II and IkappaBetaalpha) and their role in ACAID induction by TGFbeta-treated APCs. First, significance of these molecules in development of various aspects of ACAID will be evaluated followed by analysis of individual mechanisms regulated by these gene products. By comparing the effects of these genes and assessing interrelated mechanisms we propose to test a possibility to effectively use TGFbeta-treated APCs to prevent experimental autoimmune uveitis (EAU) and skin allograft rejection.