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

项目总结/摘要 这项研究的目的是确定小鼠骨髓树突状细胞（DC）的亚群 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 与自然杀伤T（NKT）细胞和Treg细胞，以促进对联合器官和骨髓的耐受性 移植我们以前的研究表明，在这个模型系统中，稳定的混合嵌合体和耐受性是 依赖于I型不变NKT细胞和CD 8+抗原交叉致敏亚群的存在， DC，因为在野生型小鼠中观察到的耐受性在Jalpha 18-/-和Batf 3-/-受体中被消除。此外，本发明还提供了一种方法， 所述预处理方案改变免疫细胞的平衡以有利于CD 8 + DC和NKT细胞，并且 导致其激活。研究旨在阐明表面标志物、细胞因子分泌的变化 受者DC亚群和NKT细胞的模式、基因表达以及体外和体内功能， 调节，以及这些变化是如何需要的DC和NKT细胞之间的相互作用， 促进宽容。我们将通过以下方式检验相互作用需要DC应激蛋白识别的假设： NKT细胞上的NKG 2D受体导致Treg细胞和髓源性抑制因子的NKT细胞刺激 细胞（MDSC）以IL-4依赖的方式。我们还将测试TLI-1中髓样DC的机制。 条件性肾移植患者介导T细胞活化的抑制，包括基因改变， 表达和细胞因子分泌。因为我们假设激活的免疫抑制细胞允许 接受供体造血祖细胞，嵌合体和相关的克隆缺失，这些研究 应该提供重要的新信息，影响目前的临床试验的耐受性在HLA不匹配 使用基于TLI的调节的肾和造血细胞移植受者。

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.