Achieving Xenograft Tolerance through Thymic Programming in Primates

项目1总结：项目1的总体目标是诱导猪肾耐受， 狒狒通过共移植（Tx）血管化供体胸腺。我们取得了重大进展 在本项目期间（2016-2020年）。首先，我们确定了负责 蛋白尿，在我们的GalT-KO猪-狒狒肾异种移植（XTx）模型中的一个显著障碍， 维持生命的异种肾移植的长期存活，并制定了有效的治疗策略 神经鞘磷脂磷酸二酯酶酸性样3b的下调和 研究发现，猪足细胞上的CD 80在蛋白尿和种属不相容性中起关键作用 在猪CD 47和狒狒SIRPα之间，其引起猪内皮细胞的吞噬作用， 足细胞的狒狒巨噬细胞，观察。我们了解到， CTLA 4-IG和利妥昔单抗mAb用于GalT-KO移植物或使用hCD 47转基因（Tg）GalT-KO肾 移植物抑制了移植后蛋白尿的发展，并显著延长了狒狒的存活时间 长达193天。虽然猪移植物的指数增长或药物相关的副作用引发了 接受者狒狒的安乐死，没有观察到移植排斥的证据， 在体外无反应性，新的狒狒T细胞的发展，观察到在多个 接收者VT+K XTx。第二，通过与项目2的合作，我们实现了长期的外围设备 血液巨嵌合体持续>60天，伴有抗非Gal抗体（abs）的逐渐丧失 在hCD 47+猪骨内骨髓Tx.这种持久的猪嵌合体 这是任何灵长类动物都无法做到的。我们的更新集中在实现两个目标。目标1： 通过确定以下参数优化猪肾XTx与血管化胸腺移植物的方案：（1） 可接受的非Gal ab水平;（2）接受者对人补体调节蛋白Tg的要求 具有高非Gal ab水平的受者;（3）防止具有高非Gal ab的受者中的排斥的策略;（4） 使用FDA批准的连续保存时间， 器官保存机;和（5）完全终止免疫抑制的能力。目标二： 使用hCD 47+人IL 3受体（hIL 3r）测定组合的VT+KTx和IBBMTx的能力 作为BM供体的转基因（Tg）猪（通过联合免疫治疗实现稳健的、持久的T细胞耐受性） 删除和管理机制。此外，我们还将探讨这种能力， 联合方法使高非Gal血症狒狒长期异种肾移植耐受 天然抗体水平。我们预计，上述研究将导致实现短期- 长期目标是在未来五年内将猪胸腺+KTx移植物扩展到临床应用，长期目标是 长期目标是诱导猪异种移植物的稳健耐受性。

Project 1 Summary: The overall goal of Project 1 is to induce tolerance of porcine kidneys in baboons by co-transplantation (Tx) of vascularized donor thymus. We have made significant progress during the current project period (2016-2020). First, we have identified the mechanism responsible for proteinuria, a significant obstacle in our GalT-KO pig-to-baboon kidney xenotransplant (XTx) model for the long-term survival of life-supporting kidney xenografts, and developed effective treatment strategies for overcoming it. Down-regulation of sphingomyelin phosphodiesterase acid-like 3b and up-regulation of CD80 on pig podocytes were found to play critical roles in proteinuria and species incompatibility between pig CD47 and baboon SIRPα, which caused phagocytosis of pig endothelial cells and podocytes by baboon macrophages, was observed. We learned that either the administration of CTLA4-Ig and rituximab mAb for GalT-KO grafts or the use hCD47 transgenic (Tg) GalT-KO kidney grafts inhibited the development of post-transplant proteinuria, and markedly prolonged baboon survival up to 193 days. While the exponential growth of pig grafts or drug-related side effects triggered the euthanasia of recipient baboons, no evidence of graft rejection was seen and both pig-specific unresponsiveness in vitro, and the development of new baboon T cells were observed in multiple recipients VT+K XTx. Second, in collaboration with Project 2, we have achieved prolonged peripheral blood macrochimerism lasting >60 days accompanied by gradual loss of anti-non-Gal antibodies (abs) in baboons following hCD47+ pig intra-bone bone marrow Tx. Such durable porcine chimerism has not been previously achieved in any primate. Our renewal is focused on achieving two aims. Aim 1: Optimize the protocol for pig kidney XTx with vascularized thymic grafts by determining: (1) acceptable non-Gal ab levels; (2) requirement for human complement regulatory protein Tg for recipients with high non-Gal ab levels; (3) a strategy to prevent rejection in recipients with high non-Gal abs; (4) acceptable preservation times of pig kidney and thymus grafts using an FDA-approved continuous organ preservation machine; and (5) the ability to completely terminate immunosuppression. Aim 2: Determine the ability of combined VT+KTx and IBBMTx using hCD47+ human IL3 receptor (hIL3r) transgenic (Tg) pigs as BM donors on (achieve robust, durable T cell tolerance by combined deletional and regulatory mechanisms. Additionally, we will also explore the ability of this combined approach to permit long-term kidney xenograft tolerance in baboons with high non-Gal natural antibody levels. We anticipate that the above studies will lead to achievement of the short- term goal of extending pig VTL+KTx grafts to clinical applications in the next five years, and the long- term goal of inducing robust tolerance of pig xenografts, respectively.