Molecular and Cellular Mechanisms of Tolerance to Combined Organ and Hematopoietic Cell Transplantation after TLI and ATS/ATG Conditioning

项目摘要/摘要 这项拟议的研究的目标是确定小鼠的髓系树突状细胞(DC)亚群 有条件的全淋巴照射(TLI)和抗T细胞抗体(抗胸腺细胞血清；ATS)相互作用 用自然杀伤T(NKT)细胞和Treg细胞促进对联合器官和骨髓的耐受 移植。我们以前的研究表明，该模型系统中稳定的混合嵌合体和耐受性是 依赖于I型不变NKT细胞和CD8抗原交叉激发亚群的存在 DCs，因为在野生型小鼠中观察到的耐受性在Jalpha18-/-和BATF3-/-受体中被废除。此外, 预适应方案改变了免疫细胞的平衡，有利于CD8 DC和NKT细胞，以及 导致它们被激活。研究旨在阐明表面标志物、细胞因子分泌的变化 移植后受者DC亚群和NKT细胞的模式、基因表达及其体内外功能 条件作用，以及DC和NKT细胞之间的相互作用如何需要这些变化 提倡宽容。我们将通过以下方式测试这种相互作用需要DC应激蛋白识别的假设 NKT细胞上的NKG2D受体导致NKT细胞刺激Treg细胞和髓系来源的抑制因子 细胞(MDSCs)以IL-4依赖的方式诱导分化。我们还将测试TLI中髓系树突状细胞的机制。 条件肾移植患者介导T细胞激活抑制，包括基因变化 表达和细胞因子的分泌。因为我们假设被激活的免疫抑制细胞允许 供者造血祖细胞的接受性、嵌合体和相关的克隆性缺失，这些研究 应提供重要的新信息，影响目前有关人类白细胞抗原不相合耐受性的临床试验 肾和造血细胞移植受者使用基于TLI的调节。

Project Summary/Abstract The goal of the proposed research is to determine how subsets of myeloid dendritic cells (DCs) in mice conditioned with total lymphoid irradiation (TLI) and anti-T cell antibodies (anti-thymocyte serum; ATS) interact with natural killer T (NKT) cells and Treg cells to promote tolerance to combined organ and bone marrow transplants . Our previous studies showed that stable mixed chimerism and tolerance in this model system are dependent on the presence of both type I invariant NKT cells and the CD8+ antigen cross priming subset of DCs, since tolerance observed in wild type mice is abrogated in Jalpha18-/- and Batf3-/- recipients. In addition, the conditioning regimen changes the balance of immune cells to favor the CD8+ DCs and NKT cells, and results in their activation. Studies are designed to elucidate the changes in surface markers, cytokine secretion patterns, gene expression and in vitro and in vivo functions of the DC subsets and NKT cells in recipients after conditioning, and how these changes are required for the interactions between the DCs and NKT cells that promote tolerance. We will test the hypothesis that the interactions require DC stress protein recognition by NKG2D receptors on NKT cells that lead to NKT cell stimulation of Treg cells and myeloid derived suppressor cells (MDSCs) in an IL-4 dependent manner. We will also test the mechanism by which myeloid DCs in TLI- conditioned kidney transplant patients mediate suppression of T cell activation, including changes in gene expression and cytokine secretion. Since we hypothesize that the activated immunosuppressive cells allow for the acceptance of donor hematopoietic progenitors, chimerism, and associated clonal deletion, these studies should provide important new information that impacts on current clinical trials of tolerance in HLA mismatched kidney and hematopoietic cell transplant recipients using TLI based conditioning.