Tolerance Induction in a GalT-KO Pig-to-Baboon Model Through Mixed Chimerism

通过混合嵌合现象在 GalT-KO 猪狒狒模型中诱导耐受

• 批准号: 8190115
• 负责人: DAVID H SACHS
• 金额: $ 33.78万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-15 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8190115
• 关键词: Acute; Allogenic; Animals; Antibodies; Antibody Formation; Antigens; B-Lymphocytes; Binding; Blood Circulation; Bone Marrow; Bone Marrow Cells; Bortezomib; CD47 gene; Cell Line; Cell Membrane Proteins; Cell surface; Cells; Chimerism; Clear Cell; Clinic; Clinical; Data; Engraftment; Event; Failure; Family suidae; Goals; Hematopoietic; Hematopoietic stem cells; Human; Immune system; Immunity; Immunologics; Immunosorbents; Immunosuppression; Immunosuppressive Agents; In Vitro; Inbreeding; Infusion procedures; Kidney; Knock-out; Liver; MS4A1 gene; Marrow; Mediating; Membrane Glycoproteins; Methodology; Miniature Swine; Modality; Modeling; Molecular; Mus; Natural Killer Cells; Organ; Organ Donor; Organ Transplantation; Papio; Pathway interactions; Phagocytosis; Pharmaceutical Preparations; Plasma Cells; Play; Primates; Protocols documentation; Publications; Reagent; Regimen; Role; Solutions; Source; Stem cells; Subfamily lentivirinae; T-Lymphocyte; Testing; Transplantation; Transplantation Tolerance; Velcade; Weight; Xeno; Xenograft procedure; blood perfusion; clinical application; design; expression vector; homologous recombination; intravenous administration; kidney xenograft; macrophage; meetings; mouse model; nuclear transfer; peripheral blood; pre-clinical; prevent; programs; receptor; reconstitution; research study; response; rituximab; success; thymus transplantation

Since mixed chimerism has been shown in mouse and humanized mouse models (Project 3) to have the ability not only to induce central T cell tolerance, but also to prevent new antibody responses and turn off existing antibody responses, the establishment of xenogeneic mixed chimerism remains an attractive means for achieving xenograft tolerance. Before GalT-KO miniature swine were available, the failure of attempts to achieve mixed chimerism across the pig-to-primate barrier was attributed to high levels of primate natural antibodies to the Gal antigen. However, despite the absence of the Gal antigen on the cell surface of GalT-KO hematopoeitic cells (HSC), we have found that these cells are rapidly cleared from the circulation of baboons shortly after infusion, eluding the establishment of mixed chimerism. Our data indicate that two of the most important factors playing a role in this clearance are: 1) natural antibodies to non-Gal determinants, which are variably present in different baboons; and 2) absence of the species-specific cell-membrane protein, CD47, which is required to inhibit the innate immune system from rapidly clearing cells from the circulation. The goal of this proposal is to overcome these two barriers in order to establish mixed xenogeneic chimerism of GalT-KO HSC in baboons. Specifically, we will: 1) Optimize xenogeneic bone marrow engraftment by avoiding natural and induced anti-non-Gal antibodies; 2) Test effect of human CD47 on engraftment of porcine marrow in baboons using GalT-KO pig bone marrow transduced with a human CD47 expression vector; and 3) Test the effect of GalT-KO pig HSC engraftment in baboons, either alone or in combination with vascularized porcine thymus transplantation, on the induction of tolerance of GalT-KO renal xenografts. Aim 3 will apply the findings of Aims 1 and 2, as well as strategies developed in Project 1 of this Program Project, to the mixed chimerism approach for inducing transplantation tolerance to organ xenografts in this preclinical, discordant species combination. In addition, the experiments planned will provide basic information on xenogeneic stem cell engrafment and on the immunologic pathways responsible for xenogeneic rejection and tolerance induction in primates. As such, these studies should have both theoretical and practical implications for the eventual application of xenotransplantation as a clinical modality.

由于在小鼠和人源化的小鼠模型中显示了混合嵌合作用（项目3）具有 不仅能够诱导中央T细胞耐受性，还可以防止新的抗体反应并关闭 现有的抗体反应，异构混合嵌合体的建立仍然是一个有吸引力的手段 用于实现异种移植耐受性。在Galt-Ko微型猪可用之前，未能尝试 在整个猪到顶峰的障碍物中实现混合的嵌合体归因于高水平的灵长类动物自然 GAL抗原的抗体。然而，尽管没有GALT-KO的细胞表面上的GAL抗原 造血细胞（HSC），我们发现这些细胞从循环中迅速清除 注入后不久，狒狒避免建立混合的嵌合体。我们的数据表明其中两个 在此清除率中起作用的最重要因素是：1）对非gal决定因素的天然抗体， 在不同的狒狒中有多种存在； 2）缺乏物种特异性的细胞膜 蛋白质，CD47，这是抑制先天免疫系统从快速清除细胞中的蛋白质CD47 循环。该提议的目的是克服这两个障碍，以确立混合 狒狒的Galt-ko HSC的异构嵌合。具体来说，我们将：1）优化异构骨 通过避免自然和诱导的抗杀性抗体，骨髓植入； 2）人类的测试效果 CD47使用galt-ko猪骨骨髓在狒狒中植入猪骨髓的植入 人类CD47表达载体； 3）测试Galt-ko Pig HSC在狒狒中植入的影响， 单独或与血管化猪胸腺移植结合，诱导 Galt-KO肾异种移植物的耐受性。 AIM 3将应用目标1和2的发现以及策略 在该计划项目的项目1中开发，以诱导移植的混合嵌合主义方法 在这种临床前不一致的物种组合中对器官异种移植的耐受性。另外，实验 计划的将提供有关异构干细胞雕刻和免疫学的基本信息 负责异种排斥和耐受性诱导灵长类动物的途径。因此，这些研究 应该对最终的异种移植的应用具有理论和实际含义 临床方式。