Yamada Laboratory, Department of Surgery, Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY, USA.
Methods Mol Biol. 2020;2110:151-171. doi: 10.1007/978-1-0716-0255-3_11.
Using advanced gene editing technologies, xenotransplantation from multi-transgenic alpha-1,3-galactosyltransferase knockout pigs has demonstrated marked prolongation of renal xenograft survival, ranging from days to greater than several months for life-supporting kidneys and >2 years in a heterotopic non-life-supporting cardiac xenograft model. However, continuous administration of multiple immunosuppressive drugs continues to be required, and attempts to taper immunosuppression have been unsuccessful. These data are consistent with previous reports indicating that the human-anti-porcine T cell response is similar or stronger than that across allogeneic barriers. Due to the strength of both the innate and adaptive immune responses in xenotransplantation, the level of continuous immunosuppression needed to control these responses and prolong xenograft survival has been associated with prohibitive morbidity and mortality. These facts provide compelling rationale to pursue a clinically applicable strategy for the induction of tolerance.Mixed chimerism and thymic tissue transplantation have both achieved xenogeneic tolerance in pig-to-mouse models, and both have recently been extended to pig-to-baboon models. Although these strategies are promising in small animal models, neither direct intravenous injection of porcine bone marrow cells nor direct fetal thymic tissue transplantation into recipients was able to achieve >2 days chimerism following BM Tx or the engraftment of thymic tissues across xenogeneic barriers in pig-to-nonhuman primate models. Several innovative procedures have been largely developed by Kazuhiko Yamada to overcome these failures. These include vascularized thymic transplantation, combined with either thymokidney (TK) or vascularized thymic lobe (VTL) transplantation. Utilizing the strategy of transplanting vascularized thymic grafts with kidney from the same GalT-KO donor without further gene modification, we have achieved longer than 6 months survival of life-supporting kidneys in a baboon. Notably, the recipient became donor specific unresponsive and developed new thymic emigrants. In this chapter, we introduce a brief summary of our achievements to date toward the successful induction of tolerance by utilizing our novel strategy of vascularized thymic transplantation (including thymokidney transplantation), as well as describe the step-by-step methodology of surgical and in vitro procedures which are required for this experiment.
利用先进的基因编辑技术，来自多转基因α-1,3-半乳糖基转移酶敲除猪的异种移植已证明肾异种移植物的存活时间显著延长，从数天到数天以上支持生命的肾脏和> 2 年在异位非支持生命的心脏异种移植模型中。然而，仍然需要持续给予多种免疫抑制药物，并且尝试减少免疫抑制作用的尝试均未成功。这些数据与先前的报告一致，表明人与猪 T 细胞反应相似或强于同种异体障碍。由于异种移植中固有和适应性免疫反应的强度，需要控制这些反应并延长异种移植物存活的连续免疫抑制水平与可避免的发病率和死亡率相关。这些事实为寻求临床适用的诱导耐受策略提供了有力的理由。混合嵌合体和胸腺组织移植在猪到鼠模型中均实现了异种免疫耐受，并且最近都已扩展到猪到狒狒模型。尽管这些策略在小动物模型中很有前途，但在 BM Tx 后或在猪到非人类灵长类动物模型中跨越异种异体障碍进行胸腺组织移植后，直接静脉内注射猪骨髓细胞或直接胎儿胸腺组织移植均无法实现> 2 天的嵌合体。几种创新的程序主要由山田和彦（Kazuhiko Yamada）开发，以克服这些失败。这些程序包括血管化胸腺移植，结合胸腺肾（TK）或血管化胸腺叶（VTL）移植。利用从相同 GalT-KO 供体移植血管化胸腺移植物与肾的策略，而无需进一步基因修饰，我们已经在狒狒中实现了超过 6 个月的生命支持肾脏的存活。值得注意的是，受者变得对供体特异性无反应，并产生了新的胸腺移民。在本章中，我们介绍了我们迄今为止利用我们的新型血管化胸腺移植（包括胸腺肾移植）策略成功诱导耐受的简要总结，以及描述了进行此实验所需的手术和体外程序的分步方法。
