PRECLINICAL STUDIES OF ISLET TRANSPLANT TOLERANCE

胰岛移植耐受性的临床前研究

• 批准号: 6666377
• 负责人: FRANCIS T. THOMAS
• 金额: $ 17.24万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6666377
• 关键词: BCL2 gene /protein; CD3 molecule; Macaca mulatta; artificial immunosuppression; biological models; combination chemotherapy; cooperative study; cyclosporines; cytoprotection; diabetes mellitus therapy; diphtheria toxin; gene therapy; genetic transduction; guanidines; homologous transplantation; immune tolerance /unresponsiveness; immunoconjugates; immunosuppressive; insulin dependent diabetes mellitus; leukocyte depletion therapy; monoclonal antibody; pancreatic islet function; pancreatic islet transplantation; pancreatic islets; transplantation immunology

Project 2 is focused on development of a treatment for insulin-dependent diabetes mellitus based on transplantation of isolated pancreatic islet cells (IPITx). This will be accomplished by induction of immunologic tolerance to IPITx in a preclinical macaque model, which offers a rigorous proof of principle for clinical utility. We will apply a tolerance induction protocol originally developed in the same macaque model for kidney transplantation to IPITx. This application will involve the use of anti-macaque CD3 epsilon directed diphtheria immunotoxin (IT), currently in an iteration constructed with a F(Ab)2 mAb. We have learned that combining IT with an immunosuppressive drug, 15-deoxyspergualin, creates an early environment for tolerance induction which has proven to be robust and practical. Based on these facts, in Aim 1, we propose to first determine the optimum protocol for establishment of IPITx tolerance in cyclosporine A (CsA). The criteria for evaluation will be graft functional, functional islet mass measured metabolically, and immunological changes (cytokine expression, CTLp changes, etc.) After transplantation. We will directly test the tolerance specificity and immunologic competence of the transplanted subjects with challenge donor and 3rd party skin grafts. When the optimized protocol is selected, we will next perform experiments in Aim 2 to determine if the critical problem of islet graft primary non-function can be circumvented through protecting the grafts with transgenic expression of Bcl-2. This gene therapy approach has proven to be very effective in our hands in prolonging macaque islet graft function (as judged by euglycemia) in SCID mice as compared to unmodified or sham-induced islets. We will first optimize the ex vivo transduction of macaque islets and evaluate their performance metabolically and immunologically. The end result should yield a tolerance induction and gene therapy strategy which will prolong graft survival and euglycemia, possibly with the use of fewer islets. Taken together, these findings could translate into effective, economical and efficient treatments of diabetes.

项目 2 的重点是开发基于分离胰岛细胞 (IPITx) 移植的胰岛素依赖性糖尿病治疗方法。 这将通过在临床前猕猴模型中诱导对 IPITx 的免疫耐受来实现，这为临床实用性提供了严格的原理证明。 我们将应用最初在用于肾移植的同一猕猴模型中开发的耐受诱导方案到 IPITx。 该应用将涉及使用抗猕猴 CD3 ε 定向白喉免疫毒素 (IT)，该毒素目前处于使用 F(Ab)2 mAb 构建的迭代中。 我们了解到，将 IT 与免疫抑制药物 15-脱氧精胍菌素相结合，可以创建耐受诱导的早期环境，该环境已被证明是稳健且实用的。 基于这些事实，在目标 1 中，我们建议首先确定建立环孢素 A (CsA) 中 IPITx 耐受性的最佳方案。 评估标准将是移植物功能、代谢测量的功能性胰岛质量以及移植后的免疫学变化（细胞因子表达、CTLp变化等）。 我们将使用挑战供体和第三方皮肤移植物直接测试移植受试者的耐受特异性和免疫能力。当选择了优化方案后，我们接下来将进行目标 2 中的实验，以确定是否可以通过保护具有 Bcl-2 转基因表达的移植物来规避胰岛移植物原发性无功能的关键问题。 与未修饰或假诱导的胰岛相比，这种基因治疗方法已被证明在延长 SCID 小鼠的猕猴胰岛移植功能（根据血糖正常来判断）方面非常有效。 我们将首先优化猕猴胰岛的离体转导，并评估其代谢和免疫学性能。 最终结果应该产生耐受诱导和基因治疗策略，这将延长移植物存活和血糖正常，可能需要使用更少的胰岛。 总而言之，这些发现可以转化为有效、经济且高效的糖尿病治疗方法。