TOLERANCE IN ORGAN TRANSPLANTATION AND AUTOIMMUNE DISEASE BY T CELL IMMUNOTOXIN

T 细胞免疫毒素对器官移植和自身免疫性疾病的耐受性

• 批准号: 6432850
• 负责人: David M. Neville
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF MENTAL HEALTH
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6432850
• 关键词: B lymphocyte; CD3 molecule; Macaca mulatta; T lymphocyte; antileukocyte isoantibody; autoimmune disorder; diphtheria toxin; graft versus host disease; immune tolerance /unresponsiveness; immunoconjugates; immunotoxicity; kidney transplantation; recombinant proteins; tissue /cell culture; transplant rejection; transplantation immunology

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.

本项目的总体目标是研究免疫毒素诱导的瞬时T细胞耗竭对T细胞从免疫应答向耐受应答的调节的影响，并将这些知识用于T细胞驱动的自身免疫性疾病、移植物抗宿主病以及诱导对错配器官和细胞移植的耐受的实验和临床治疗。我们先前表明，用CRM 9（白喉毒素的结合位点突变体）构建的抗恒河猴CD 3免疫毒素的2-3天疗程在48小时滞后期后消耗99%的淋巴结和血液T细胞。这一过程与不匹配的功能性恒河猴肾移植的存活期显著延长以及在约50%的病例中诱导长期耐受而无需进一步的免疫抑制治疗有关。 当发生排斥反应时，先出现抗移植物抗体（用S。Knechtle和J.托马斯）。 为了避免这种不利的T细胞介导的B细胞应答，其显然是在免疫毒素诱导的T细胞杀伤延迟期间启动的，我们加入了短疗程的被认为阻断抗原呈递的试剂，如脱氧精胍菌素（DSG）。移植物的长期存活率已经上升到83%（由J.托马斯完成）。 这些移植物是耐受的，如通过接受供体皮肤移植30天和第三方皮肤移植的快速排斥来判断的。在患有自发性胰岛素依赖性糖尿病的猴中进行同源胰岛细胞移植已显示出逆转糖尿病，如通过在不存在外源性胰岛素的情况下使非空腹血糖和糖化血红蛋白值恢复正常所判断的。 短期免疫毒素，甲基强的松龙和环孢素提供诱导稳定的操作耐受胰岛，已持续一年以上的情况。 这是第一次报道使用不依赖于慢性免疫抑制的耐受方案逆转糖尿病，慢性免疫抑制是一个先前显示损害移植胰岛功能的过程（由J.托马斯完成）。 已经开发了针对人和恒河猴T细胞的重组单链抗CD 3抗体。 在真核生物表达系统中，它们作为高亲和力二价二聚体分泌。这些缺乏显著的Fc受体相互作用，并且没有我们目前的化学偶联抗CD 3免疫毒素发生的细胞因子释放综合征的并发症。这些重组抗体形成了目前正在开发的重组抗CD 3免疫毒素的基础。