ApoFasL: a Novel Immunotherapeutic for T1D

描述(申请人提供)：1型糖尿病(T1D)是一种自身免疫性疾病，其目标是破坏分泌胰岛素的胰岛β细胞，在全球超过1%的人口中仍是发病率和死亡率的主要原因。虽然胰岛素治疗和胰岛移植是目前最有效的治疗方法，但这两种方法都面临着重大限制，包括胰岛素治疗无法完全预防糖尿病相关的并发症，可供移植的人胰岛有限，以及无论是否使用免疫抑制药物，同种异体胰岛移植都存在排斥反应。因此，使用不同物种的胰岛，如猪，在不长期使用免疫抑制药物的情况下诱导耐受，将是临床有效治疗T1D所需的重要治疗进展。这项建议的主要目的是为一种名为ApoFasL的新颖、安全和实用的方法建立原则证明，以诱导异种胰岛的移植耐受，作为治疗1型糖尿病的干预措施鉴于Fas/FasL系统在自身抗原免疫耐受、免疫豁免和淋巴细胞动态平衡方面发挥的重要作用，以及FasL在各种环境下诱导同种移植物耐受的广泛使用，这项赠款的首席研究员Haval Shirwan博士利用ApoImmune的Protex(Tm)技术开发了一种具有强大凋亡活性的新型FasL。Protex(Tm)包括用修饰形式的核心链霉亲和素生成嵌合免疫配体，用生物素修饰细胞膜，以及用嵌合蛋白修饰生物素化膜。初步数据表明，在同种异体移植模型中，使用Protex(Tm)在胰岛上展示FasL(ApoFasL疗法)可以预防移植物排斥反应和治疗化学诱导的糖尿病。在这些数据的基础上，这项建议的重点是开发一种有效的、临床适用的方法来在治疗糖尿病的大鼠到小鼠模型中诱导对异种胰岛移植的免疫耐受的原则证明。FasL将在大鼠供体胰岛上展示，用于移植到化学诱导的糖尿病小鼠和表现出破坏性自身免疫性胰腺炎的自发性糖尿病非肥胖糖尿病(NOD)小鼠。移植手术将在雷帕霉素存在的情况下进行，雷帕霉素是临床上用于预防移植排斥反应的药物。我们假设，用FasL装饰的胰岛将通过凋亡和扩大T调节细胞来消除异种反应性淋巴细胞，从而诱导耐受。雷帕霉素有望通过消除T效应细胞和/或扩大T调节细胞来进一步增强这种反应，从而产生供者特异性免疫耐受，从而导致移植胰岛的存活。在原理证明之后，将进行第二阶段STTR应用，通过在猪到非人类灵长类异种移植模型中测试ApoFasL的有效性，进一步将ApoFasL开发成铅产品。对异种胰岛的耐受性将是将这一新方法转化为临床治疗T1D的第一步。如果被证明有效，ApoFasL可能会改善全球数百万人的生活质量，带来数十亿美元的经济影响。与传统的同种异体胰岛移植和胰岛素治疗相比，异种胰岛移植是治疗1型糖尿病的一种替代治疗方法，并有望产生更明确的解决方案。如果ApoFasL方法成功，将确保一条治疗1型糖尿病的途径。

DESCRIPTION (provided by applicant): Type 1 Diabetes (T1D) is an autoimmune disease that targets insulin secreting pancreatic beta cells for destruction and remains a major cause of morbidity and mortality in over 1% of the population worldwide. Although insulin therapy and islet transplantation are currently the most effective treatments, both of these approaches suffer from major limitations including the inability of insulin therapy to totally prevent diabetes- associated complications, the limited availability of human islets for transplantation, and the rejection of islet allografts irrespective of the use of immunosuppressive drugs. Therefore, the use of islets from a different species, such as pigs, and induction of tolerance without the chronic use of immunosuppressive drugs will be important therapeutic advancements required for the efficient treatment of T1D in the clinic. The main objective of this proposal is to establish proof-of-principle for a novel, safe, and practical approach designated as ApoFasL to induce transplantation tolerance to xenogeneic pancreatic islets as a therapeutic intervention for the treatment of Type 1 diabetes Given the important role played by Fas/FasL system in immune tolerance to self antigens, immune privilege, and lymphocyte homeostasis, and the extensive use of FasL to induce allograft tolerance in various settings, the Principle Investigator of this grant, Dr. Haval Shirwan, developed a novel form of FasL with potent apoptotic activity using ApoImmune's ProtEx(tm) technology. ProtEx(tm) involves the generation of chimeric immunological ligands with a modified form of core streptavidin, modification of a cell membrane with biotin, and decoration of biotinylated membrane with chimeric proteins. Preliminary data have demonstrated that the display of FasL on pancreatic islets (ApoFasL therapy) using ProtEx(tm) resulted in the prevention of graft rejection and treatment of chemically-induced diabetes in an allogeneic transplant model. Expanding on these data, the focus of this proposal is to develop proof-of-principle for an effective, clinically applicable approach to induce immune tolerance to xenogeneic islet grafts in a rat-to-mouse model for the treatment of diabetes. FasL will be displayed on rat donor islets for transplantation into both chemically-induced diabetic mice and spontaneously diabetic non-obese diabetic (NOD) mice, which exhibit destructive autoimmune pancreatic insulitis. Transplants will be done in the presence of rapamycin a pharmaceutical agent used in the clinic for the prevention of graft rejection. We hypothesize that islets decorated with FasL will induce tolerance by eliminating xenoreactive lymphocytes via apoptosis and expanding T regulatory cells. Rapamycin is expected to further augment this response by eliminating T effector cells and/or expanding T regulatory cells, thereby creating donor specific immune tolerance, leading to the survival of transplanted islets. Proof-of-principle will be followed by a Phase II STTR application to further develop ApoFasL into a lead product by testing its efficacy in a pig-to-nonhuman primate xenograft model. Tolerance to xenogeneic islets will serve as the first step towards the translation of this novel approach to the clinic for the treatment of T1D. If proven effective, ApoFasL may improve the quality of life of millions of individuals worldwide with an economic impact in billions of dollars. Xenograft islet transplantation represents an alternative therapeutic approach for Type 1 diabetes over classic allogeneic islet transplantation and insulin treatment therapies, and promises to yield a more definitive solution. The ApoFasL approach, when successful, will ensure a pathway to the treatment of Type 1 diabetes.