Achieving Xenograft Tolerance through Thymic Programming in Primates

通过灵长类动物的胸腺编程实现异种移植耐受

• 批准号: 9073458
• 负责人: KAZUHIKO YAMADA
• 金额: $ 27.96万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9073458
• 关键词: Acids; Address; Adolescent; Antibodies; Autoimmunity; Autologous; B-Lymphocytes; Binding; CD47 gene; CD80 gene; CTLA4-Ig; Cell physiology; Cesarean section; Chimerism; Collagen; Creatinine; Cytomegalovirus; Data; Development; Doctor of Philosophy; Edema; Engraftment; Family suidae; Funding; Gel; Goals; Graft Survival; Grant; Homeostasis; Human; Hybrids; Immune Tolerance; Immune response; Immunity; Immunoglobulins; In Vitro; Inbreeding; Infection; Kidney; Kidney Diseases; Kidney Transplantation; Lead; Life; Link; Macrophage Activation; Natural Killer Cells; Nephrotic Syndrome; Organ; Papio; Peripheral; Phenotype; Primates; Proteins; Proteinuria; Protocols documentation; Recovery; Regimen; Residual state; Serum; Solid; Sphingomyelinase; T-Lymphocyte; TNFRSF5 gene; Therapeutic; Thymic epithelial cell; Thymus Gland; Transgenic Organisms; Transplantation; Treatment Protocols; Up-Regulation; Xenograft procedure; adaptive immunity; base; bone; cytokine; design; effective therapy; humanized mouse; immune activation; immune function; improved; in vivo; innovation; kidney xenograft; podocyte; prevent; programs; protective effect; reconstitution; rituximab; thymus transplantation; tositumomab; treatment strategy

Project 1 aims to induce tolerance of porcine kidneys in baboons by co-transplantation (Tx) of vascularized thymus. We have induced donor-specific T cell unresponsiveness and prevented anti-donor elicited antibodies (Abs), but have not achieved long-term survival of xenograft kidneys. During the previous project period, we identified two major obstacles to this goal and developed strategies to overcome them. These are: (i) early loss of xeno- thymokidneys (TKs) due to activation of latent porcine CMV (pCMV); long-term graft survival was restored by elimination of pCMV through cesarean section of donors; and (ii) development of severe proteinuria; this problem could be delayed (but not prevented) by preventing SMPDL-3b-dependent disruption of pig podocytes through treatment with Rituximab in the peri-Tx period. The remaining major obstacles addressed in the current proposal are: 1) eventual development of nephrotic syndrome due to progressive proteinuria; and 2) development of infections due both to loss of immunoglobulins from proteinuria and presumably insufficient recovery of protective T cell immunity from porcine thymic grafts. Based upon the data developed by this team (Projects 2, 3, and 4), we have designed innovative strategies to overcome these obstacles. In Aim 1, we will first identify the mechanism responsible for continuing proteinuria despite Rituximab treatment and develop effective treatment strategies. We have found both loss of SMPDL-3b and upregulation of porcine CD80 on podocytes to be associated with xenograft nephropathy. Our preliminary data indicate that Rituximab, which binds to porcine podocyte SMPDL-3B and Belatacept, which inhibits CD80 activation, can both partially stabilize protein loss. The latest transplant with this combined therapy currently survives >70 days, with normal creatinine levels and only minimal proteinuria. Our data suggest that CD47 and SIRP-alpha incompatibility between species may promote innate immune activation that culminates in podocyte activation. In Aim 1, we will overcome proteinuria by optimizing Rituximab/CTLA-4 Ig therapy and using hCD47 transgenic (Tg) GalT-KO pig TK donors to prevent baboon macrophage activation. In Aim 2, we will achieve xenograft tolerance with more rapid reconstitution of host- and donor-restricted protective T cell immunity. Studies in Project 3 demonstrated limitations in human T cell function and homeostasis following development in a pig thymus. We will address the hypothesis that these abnormalities will be corrected by adding recipient TEC to the porcine thymus graft combined with mixed chimerism. We will now optimize the construction of hybrid thymic grafts, assess their impact on immune function and combine this protocol with strategies developed in Project 2 to achieve durable mixed xenogeneic chimerism (Aim 3). The combination of hybrid thymic grafting and durable mixed chimerism will assure tolerance of both innate and adaptive immune responses. The combined approach will also optimize functions of T cells providing protective immunity against infections for the donor graft and recipient and of Tregs that protect against residual donor-reactive T cells and autoimmunity, respectively.

项目 1 旨在通过血管化胸腺联合移植 (Tx) 诱导狒狒对猪肾的耐受性。 我们诱导了供体特异性 T 细胞无反应并阻止了抗供体引发的抗体 (Ab)，但是 尚未实现异种移植肾的长期存活。在上一个项目期间，我们确定了两个 实现这一目标的主要障碍并制定了克服这些障碍的战略。它们是： (i) 异种物质的早期丧失 由于潜伏的猪 CMV (pCMV) 激活而导致胸肾 (TK)；通过以下方法恢复了移植物的长期存活 通过对捐赠者进行剖腹产消除 pCMV； (ii) 出现严重蛋白尿；这 通过防止猪足细胞的 SMPDL-3b 依赖性破坏可以延迟（但不能阻止）问题 通过在围 Tx 期间使用利妥昔单抗治疗。当前解决的剩余主要障碍 建议是：1）由于进行性蛋白尿最终发展为肾病综合征； 2）开发 由于蛋白尿导致免疫球蛋白丢失以及可能的免疫球蛋白恢复不充分而导致的感染 猪胸腺移植物的保护性 T 细胞免疫。基于该团队开发的数据（项目 2、3、 4）我们设计了创新策略来克服这些障碍。在目标 1 中，我们首先要确定 尽管利妥昔单抗治疗仍导致持续蛋白尿的机制，并开发有效的治疗方法 策略。我们发现足细胞上 SMPDL-3b 的缺失和猪 CD80 的上调都与 与异种移植肾病有关。我们的初步数据表明，利妥昔单抗（Rituximab）与猪结合 足细胞 SMPDL-3B 和抑制 CD80 激活的 Belatacept 都可以部分稳定蛋白质损失。这 采用这种联合疗法的最新移植目前存活 >70 天，肌酐水平正常，并且仅 最少的蛋白尿。我们的数据表明，物种间 CD47 和 SIRP-α 的不相容性可能会促进 先天免疫激活最终导致足细胞激活。在目标 1 中，我们将通过以下方式克服蛋白尿： 优化 Rituximab/CTLA-4 Ig 疗法并使用 hCD47 转基因 (Tg) GalT-KO 猪 TK 供体来预防 狒狒巨噬细胞激活。在目标 2 中，我们将通过更快速地重建异种移植物来实现异种移植耐受。 宿主和供体限制的保护性 T 细胞免疫。项目 3 的研究证明了人类 T 细胞的局限性 猪胸腺发育后的功能和稳态。我们将提出这样一个假设：这些 通过将受体 TEC 添加到猪胸腺移植物中并结合混合 嵌合现象。我们现在将优化混合胸腺移植物的构建，评估其对免疫功能的影响 并将该协议与项目 2 中开发的策略相结合，以实现持久的混合异种嵌合 （目标 3）。杂交胸腺移植和持久的混合嵌合体的结合将确保两者的耐受性 先天性和适应性免疫反应。该组合方法还将优化 T 细胞的功能，提供 供体移植物和受体以及 Treg 的保护性免疫力，以防止残留 分别是供体反应性 T 细胞和自身免疫。