Tolerance In Organ Transplantation And Autoimmune Diseas

器官移植和自身免疫性疾病的耐受性

• 批准号: 7312867
• 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/7312867
• 关键词: Tolerance; Organ; Transplantation; Autoimmune; Diseas

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, 50% over 9 months without further immunosuppressive therapy. Rejections, 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). Out of 5 bilaterally rephrectomized recipients long term tolerance was achieved in 3 without further immunosuppresion as judged by a graft survival of 4 years or longer. 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). Streptozotocin induced diabetes in monkeys has been successfully reversed by using anti-T cell immunotoxin in combination with 14 days of DSG and allografted pancreatic islets (done with J. Thomas). Three out of seven are long term tolerant survivors (6-7 years). A recombinant divalent anti-human anti-T cell immunotoxin has been developed that has 20-fold the potency of the previous chemical conjugates. This is expressed in Pichia pastoris. This material is now under production for a phase I clinical trial in T cell leukemia and aplastic anemia, a T cell driven autoimmune disease. In order to aid the production of immunotoxin and other bioactive proteins in Pichia pastoris, new strains have been constructed that exhibit toxin resistance and increased heterologous protein production in the presence of an active unfolded-protein response.

该项目的总体目标是研究免疫毒素诱导的短暂 T 细胞耗竭对 T 细胞从免疫反应到耐受反应的调节的影响，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不匹配的器官和细胞移植的耐受性的实验和临床治疗。我们之前表明，用 CRM9（白喉毒素的结合位点突变体）构建的抗恒河猴 CD3 免疫毒素的 2-3 天疗程，在 48 小时滞后期后可将淋巴结和血液 T 细胞消耗 99%。这一过程与功能不匹配的恒河猴肾移植的存活率显着延长有关，在不进行进一步免疫抑制治疗的情况下，9个月内存活率提高了50%。在拒绝之前，出现了抗移植物抗体（由 S. Knechtle 和 J. Thomas 完成）。为了避免这种不利的 T 细胞介导的 B 细胞反应（这种反应显然是在免疫毒素诱导的 T 细胞杀伤延迟期间启动的），我们添加了短期的药物，据信可以阻断抗原呈递，例如脱氧精胍菌素 (DSG)。根据移植物存活 4 年或更长时间来判断，5 名双侧肾切除受者中有 3 名在没有进一步免疫抑制的情况下实现了长期耐受。患有自发性胰岛素依赖型糖尿病的猴子的同种胰岛细胞移植已被证明可以逆转糖尿病，这是通过在不存在外源胰岛素的情况下将非空腹血糖和糖化血红蛋白值恢复到正常来判断的。短期疗程的免疫毒素、甲基泼尼松龙和环孢菌素可诱导对胰岛的稳定操作耐受，在一个病例中这种耐受持续了一年多。这是首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，此前已证明慢性免疫抑制会损害移植的胰岛功能（由 J. Thomas 完成）。通过使用抗 T 细胞免疫毒素并结合 14 天的 DSG 和同种异体移植胰岛（由 J. Thomas 完成），链脲佐菌素诱导的猴子糖尿病已成功逆转。七分之三是长期耐受的幸存者（6-7 年）。一种重组二价抗人抗 T 细胞免疫毒素已被开发出来，其效力是之前化学缀合物的 20 倍。这在毕赤酵母中得到表达。该材料目前正在生产用于 T 细胞白血病和再生障碍性贫血（一种 T 细胞驱动的自身免疫性疾病）的 I 期临床试验。为了帮助巴斯德毕赤酵母产生免疫毒素和其他生物活性蛋白，我们构建了新菌株，在存在活性未折叠蛋白反应的情况下表现出毒素抗性并增加异源蛋白产量。