TOLERANCE IN ORGAN TRANSPLANTATION AND AUTOIMMUNE DISEASE BY T CELL IMMUNOTOXIN

本项目的总体目标是研究 免疫毒素诱导的短暂T细胞耗竭 调节T细胞从免疫应答向 容忍反应，并将这些知识用于实验 和临床治疗T细胞驱动的自身免疫性疾病，移植- 抗宿主病，以及诱导对错配的 器官和细胞移植我们之前的研究表明， CRM 9构建抗恒河猴CD 3免疫毒素的研究进展 白喉毒素结合位点突变体，消耗淋巴结， 在48小时的滞后期后，血液T细胞减少了99%。该过程 与显著延长的不匹配的 功能性恒河猴肾移植和诱导长期 在约50%的情况下， 免疫抑制治疗当拒绝发生时， 在出现抗移植物抗体之前（用S. Knechtle和J.托马斯）。为了避开这种不利的T细胞 介导的B细胞应答，该应答显然在 延迟免疫毒素诱导的T细胞杀伤，我们增加了一个短的 被认为阻断抗原呈递的药剂的过程 如脱氧精胍菌素（DSG）。移植物的长期存活率 到83%（由J.托马斯完成）。根据判断，这些移植物是耐受的 通过接受供体皮肤移植30天， 第三方皮肤移植排斥反应。同种胰岛细胞 移植在患有自发胰岛素的猴子身上 依赖性糖尿病已被证明可以逆转糖尿病， 通过返回非空腹血糖和糖基化 在没有外源性胰岛素的情况下，血红蛋白值恢复正常。一 免疫毒素、甲基强的松龙和环孢霉素短程治疗 为胰岛提供稳定的操作耐受性诱导， 在一个案例中持续了一年多。这是第一次报道的逆转 使用不依赖于药物的耐受方案来治疗糖尿病 慢性免疫抑制，这一过程以前被证明是 损害移植的胰岛功能（由J.托马斯完成）。 重组单链抗CD 3抗体，针对 已经开发了人和恒河猴T细胞。在真核生物中 在表达系统中，这些作为高亲和力二价 二聚体。它们缺乏显著的Fc受体相互作用， 细胞因子释放综合征的并发症， 我们现有的化学偶联抗CD 3免疫毒素这些 重组抗体形成了重组抗CD 3的基础 免疫毒素正在开发中。

The general aim of this project is to study the effects of immunotoxin induced transient T-cell depletion on the modulation of T cells from immunization responses towards tolerizing responses, and to use this knowledge for the experimental and clinical treatment of T cell driven autoimmune diseases, graft- versus-host disease, and the induction of tolerance to mismatched organ and cell transplants. We previously showed that a 2-3 day course of anti-rhesus CD3 immunotoxin constructed with CRM9, a binding site mutant of diphtheria toxin, depletes lymph node and blood T cells by 99% after a 48 hour lag period. This process was associated with a marked prolongation of survival of mismatched functioning rhesus kidney transplants and the induction of long term tolerance in about 50% of the cases without further immunosuppressive therapy. Rejections, when they occurred, were preceded by the appearance of anti-graft antibodies (done with S. Knechtle and J. Thomas). To circumvent this adverse T cell mediated B cell response that is apparently initiated during the delay in immunotoxin induced T cell killing, we have added a short course of agents that are believed to block antigen presentation such as deoxyspergualin (DSG). Long term graft survival has risen to 83% (done with J. Thomas). These grafts are tolerized as judged by the acceptance of donor skin grafts for 30 days and the rapid rejection of third party skin grafts. Congeneic pancreatic islet cell transplants in monkeys suffering from spontaneous insulin dependent diabetes have been shown to reverse diabetes as judged by returning non-fasting blood glucose and glycosylated hemoglobin values to normal in the absence of exogenous insulin. A short course of immunotoxin, methyl prednisolone and cyclosporine provide induction of stable operational tolerance to islets that has lasted over one year in one case. This is the first reported reversal of diabetes using a tolerizing protocol that does not depend on chronic immunosuppression, a process previously shown to compromise transplanted islet function (done with J. Thomas). Recombinant single chain anti-CD3 antibodies directed at both human and rhesus T cells have been developed. In eukaryote expression systems these are secreted as high affinity divalent dimers. These lack significant Fc receptor interactions and are free from the complications of cytokine release syndrome which occur with our present chemically coupled anti-CD3 immunotoxin. These recombinant antibodies form the basis of recombinant anti- CD3 immunotoxins now under development.