Role of CD47 in xenograft rejection by macrophages

CD47 在巨噬细胞异种移植排斥中的作用

• 批准号: 8436181
• 负责人: YONG-GUANG YANG
• 金额: $ 34.27万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-12-01 至 2017-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8436181
• 关键词: Accounting; Address; Alloantigen; Allogenic; Antibodies; Attenuated; Binding; Biological Assay; CD47 gene; Cardiac; Cells; Clinical; Complement; Data; Dendritic Cells; Dendritic cell activation; Family suidae; Funding; Goals; Graft Rejection; Hematopoietic; Hepatocyte; Human; Immune; Immune Cell Activation; Immune response; Immune system; Immunosuppression; In Vitro; Inbred BALB C Mice; Ligands; Measures; Mediating; Membrane; Memory; Modeling; Molecular; Mus; Natural Immunity; Natural Killer Cells; Organ Donor; PTPNS1 gene; Pathway interactions; Phagocytosis; Play; Population; Regulation; Role; Signal Transduction; Solutions; T cell response; T-Cell Activation; T-Lymphocyte; Testing; Transfusion; Transgenic Organisms; Transplantation; Transplantation Tolerance; Wild Type Mouse; Xenograft procedure; allograft rejection; allotransplant; base; immune activation; improved; insight; macrophage; monocyte; mouse model; prevent; receptor; response; transgene expression

DESCRIPTION (provided by applicant): Xenotransplantation from pigs has the potential to resolve the growing shortage of human organ donors. Because of the extensive molecular incompatibilities between the donor and host, innate immunity plays a much greater role in xenograft rejection than in allograft rejection. CD47 is ubiquitously expressed and serves as a ligand of SIRP?, an inhibitory receptor on macrophages and DCs. During the current funding period, we demonstrated that the lack of cross-species interaction in CD47-SIRP? pathway largely accounts for macrophage-mediated rejection of hematopoietic and non-hematopoietic cellular xenografts. Transplantation of CD47-deficient cells induces rapid innate immune activation in syngeneic wild-type (WT) mice. Furthermore, CD47-SIRP? signal is required to repress recipient CD11hiCD8?- DC activation and induce tolerance after donor-specific transfusion (DST). Based on these and other data presented in the application, we hypothesize that the interaction between donor CD47 and host SIRP? is essential for controlling activation of SIRP?+ macrophages and DCs, and that the absence of this interaction activates host macrophages and DCs, hence stimulating anti-donor T cell responses. Here, we propose 3 specific aims to test our hypothesis. Aim 1 is to elucidate the role of CD47-SIPR? signaling in the regulation of SIRP?+ innate immune cell activation after hepatocyte xenotransplantation. We will transplant CD47 KO mouse hepatocytes into syngeneic WT mice to analyze innate immune cell activation and graft rejection induced solely by CD47 disparity. We will also transplant human CD47 transgenic vs. control pig hepatocytes into humanized mice to determine whether human CD47 expression may inhibit human innate immune responses to pig xenografts. Aim 2 is to determine the role of "missing CD47"-induced innate immune cell activation in T cell xenoresponses after hepatocyte transplantation. We will first address this question in allotransplant models, in which CD47 KO mice will be used to mimic CD47-incompatible xenogeneic donors. We will examine anti-donor T cell responses by in vitro and adoptive T cell transfer assays. We will then investigate the potential of human CD47 expression on pig hepatocytes to attenuate human T cell xenoimmune responses using humanized mice with a functional human immune system. Aim 3 is to determine the mechanisms by which CD47 on donor cells facilitates tolerance induction in DST plus costimulatory blockade-treated recipients. We will identify the DC and macrophage populations that are rapidly activated after CD47-deficient DST and their roles in T cell activation and tolerance induction. We will address these questions in a mouse model of CD47-deficient cardiac allotransplantation, and a pig-to-mouse xenotransplantation model that involves DST from human CD47-transgenic pigs into humanized mice. These studies are expected to provide significant insights into the mechanisms by which CD47 incompatibility activates innate and adaptive xenoimmune responses, and the potential of using human CD47 transgenic pigs as donors to facilitate xenotolerance induction and xenograft survival.

描述（由申请人提供）：猪异种移植有可能解决日益严重的人体器官捐献者短缺问题。由于供体和宿主之间广泛的分子不相容性，先天免疫在异种移植排斥中比在同种异体移植排斥中发挥更大的作用。 CD47 广泛表达并作为 SIRP?（巨噬细胞和 DC 上的抑制性受体）的配体。在当前资助期间，我们证明了CD47-SIRP缺乏跨物种相互作用？该途径在很大程度上解释了巨噬细胞介导的造血和非造血细胞异种移植物的排斥反应。 CD47 缺陷细胞的移植可诱导同基因野生型 (WT) 小鼠快速先天免疫激活。此外，CD47-SIRP？需要信号来抑制受体 CD11hiCD8?- DC 激活并在供体特异性输血 (DST) 后诱导耐受。基于这些和申请中提供的其他数据，我们假设供体 CD47 和宿主 SIRP 之间的相互作用？对于控制 SIRP?+ 巨噬细胞和 DC 的激活至关重要，并且这种相互作用的缺失会激活宿主巨噬细胞和 DC，从而刺激抗供体 T 细胞反应。在这里，我们提出了 3 个具体目标来检验我们的假设。目的1是阐明CD47-SIPR的作用？肝细胞异种移植后 SIRP?+ 先天免疫细胞激活调节中的信号传导。我们将 CD47 KO 小鼠肝细胞移植到同基因 WT 小鼠中，以分析仅由 CD47 差异诱导的先天免疫细胞激活和移植物排斥。我们还将人 CD47 转基因肝细胞与对照猪肝细胞移植到人源化小鼠中，以确定人 CD47 表达是否可以抑制人对猪异种移植物的先天免疫反应。目标 2 是确定“缺失 CD47”诱导的先天免疫细胞激活在肝细胞移植后 T 细胞异种反应中的作用。我们将首先在同种异体移植模型中解决这个问题，其中 CD47 KO 小鼠将用于模拟 CD47 不相容的异种供体。我们将通过体外和过继性 T 细胞转移测定来检查抗供体 T 细胞反应。然后，我们将使用具有功能性人类免疫系统的人源化小鼠，研究猪肝细胞上人类 CD47 表达减弱人类 T 细胞异种免疫反应的潜力。目标 3 是确定供体细胞上的 CD47 促进 DST 加共刺激阻断治疗的受体耐受诱导的机制。我们将鉴定 CD47 缺陷 DST 后快速激活的 DC 和巨噬细胞群及其在 T 细胞激活和耐受诱导中的作用。我们将在 CD47 缺陷心脏同种异体移植的小鼠模型和涉及从人 CD47 转基因猪到人源化小鼠的 DST 的猪-小鼠异种移植模型中解决这些问题。这些研究预计将为 CD47 不相容性激活先天性和适应性异种免疫反应的机制提供重要见解，以及使用人 CD47 转基因猪作为供体促进异种耐受诱导和异种移植存活的潜力。