ANTIGEN PRESENTING CELLS AND COSTIMULATORY BLOCKADE FOR TOLERANCE INDUCTION

设计自身免疫性疾病新疗法的最终目标 而移植是诱导和维持一种状态 特异性免疫耐受。我们使用了一种新的方法来 T细胞缺失时抗原提呈的作用研究 用实验方法研究自身免疫反应中的共刺激 LEW大鼠自身免疫性脑脊髓炎模型的建立。系统性 体外培养的APC与脑源性APC的给药 髓鞘碱性蛋白多肽(MBP，p71-90)与CTLA41g的融合 阻止CD28-B7 T细胞共刺激的蛋白质，保护动物 从临床上发展为EAE。最近的初步数据显示， 这种方法在同种异体免疫中的潜在适用性；系统性 体外预育的应答大鼠APC与An的注射 免疫优势的MHC别肽和CTLA41g也导致 系统耐受性，表现为对延迟型的显著抑制 对别肽的过敏反应。这一行动的主要目标是 建议理解系统的效应机制。 已修改为呈现的APC诱导的耐受性 抗原，但不向T细胞传递共刺激信号。我们会 脑源性APC体外治疗的耐受性研究 多肽和CTLA41g在复发性小鼠EAE模型中的作用 它具有临床意义，因为它类似于患者的病程 患有多发性硬化症。我们将定义哪种骨髓来源于 APC负责诱导耐受并研究其作用 选择性阻断B7-1与B7-2分子。免疫组织学 体外研究将确定免疫反应的类型(Th1/Th2) 在被容忍的动物身上。收养转移研究将表明 可能影响感染型的调节细胞的存在 耐受性，一种可能由Th2细胞介导的现象。这个 将通过使用MBP来确认耐受的效应机制 TCR转基因小鼠研究无能/缺失或诱导 体内调节性Th2细胞。另一个主要目标是研究这一角色 体外治疗APC在系统耐受中的作用机制 带血管的同种异体心脏移植。我们将定义免疫显性 C57BL/6(H-2b)受者的Balb/c(H-2d)MHC多肽。我们会 然后研究受体APC体外预育的耐受性。 免疫优势的MHC别肽和CTLA41g。 耐受性的机制将通过体外增殖和 细胞因子研究，通过对同种异体心脏移植物的免疫组织学分析， 并通过采用迁移实验进行研究。克隆别构肽的能力 来自耐受动物的特定T细胞将帮助我们确认 体内Th2细胞的免疫调节功能。评选结果 拟议的研究应对发展产生重要影响 诱导抗原特异性耐受的新策略 自身免疫性疾病和移植。

The ultimate goal in designing new therapies for autoimmune diseases and transplantation is the induction and maintenance of a state of specific immunologic tolerance. We have used a novel approach to study the role of antigen presentation in the absence of T cell costimulation in autoimmune responses using the experimental autoimmune encephalomyelitis (EAE) model in LEW rats. Systemic administration of APCs preincubated ex-vivo with the encephalitogenic peptide of myelin basic protein (MBP, p71-90) and CTLA41g, a fusion protein which blocks CD28-B7 T cell costimulation, protects animals from developing clinical EAE. More recent preliminary data show the potential applicability of such an approach in alloimmunity; systemic injection of responder rat APCs preincubated ex-vivo with an immunodominant MHC allopeptide and CTLA41g also results in systemic tolerance, as indicated by significant inhibition of delayed type hypersensitivity responses to the allopeptide. The major goal of this proposal is to understand the effector mechanisms of systemic tolerance induced by APCs which have been modified to present antigen but to not deliver a costimulatory signal to T cells. We will study the tolerogenicity of ex-vivo treated APCs with encephalitogenic peptide and CTLA41g in the relapsing mouse EAE model, a model which has clinical relevance since it resembles the course of patients with multiple sclerosis. We will define which bone-marrow derived APC is responsible for induction of tolerance and study the role of selective blockade of B7-1 versus B7-2 molecules. Immunohistological and in vitro studies will define the type of immune response (Th1/Th2) in tolerized animals. Adoptive transfer studies will indicate the presence of regulatory cells which may effect an infectious-type tolerance, a phenomenon which may be mediated by Th2 cells. The effector mechanisms of tolerance will be confirmed by using MBP TCR transgenic mice to study anergy/deletion or induction of regulatory Th2 cells in vivo. The other major goal is to study the role and mechanisms of ex-vivo treated APCs in systemic tolerance to vascularized cardiac allograft. We will define the immunodominant Balb/c (H-2d) MHC peptides in C57BL/6 (H-2b) recipients. We will then study the tolerogenicity of recipient APCs preincubated ex-vivo with the immunodominant MHC allopeptides and CTLA41g. Mechanisms of tolerance will be studied by in vitro proliferative and cytokine studies, by immunohistological analysis of cardiac allograft, and by adoptive transfer experiments. The ability to clone allopeptide specific T cells from tolerized animals will help us confirm immunoregulatory function of Th2 cells in vivo. Results of the proposed studies should have important implications for development of novel strategies for induction of antigen-specific tolerance in autoimmune disease and transplantation.