MARROW TRANSPLANTATION ACROSS MINOR HISTOCOMPATIBILITY BARRIERS

在我们和其他机构进行的大部分同种异体移植 包括匹配的捐赠者。尽管人类白细胞抗原相合，移植物抗宿主病 在这些病例中，仍有50%发生移植物抗宿主病。已经有人尝试在我们的 自己的机构通过从捐赠者的移植物中移除T细胞来对抗GVHD 在移植之前。这种T细胞耗竭(TCD)，虽然减少了 移植物抗宿主病的严重程度增加了移植物排斥反应的发生率。在这 提议，我们打算利用我们在小鼠移植模型方面的专业知识来 TCD诱导小鼠小鼠肾移植排斥反应模型的建立 组织相容性障碍。我们将使用这些模型来评估 免疫毒素作为克服移植物排斥反应的潜在药物。 免疫毒素(IT)是一种与强效单抗(Moab)相连的单抗 催化性毒素，如蓖麻毒素A链(RTA)，旨在 对表达特定抗原的靶细胞进行致命一击。这些 目前，GVHD治疗的药物正在我们和 其他机构。我们的具体目标是测试RTA的假设 它在体内的应用将促进未成年人的植入 组织相容性屏障。由于在活体内试图定义 免疫细胞在识别次要组织相容抗原时有 由于无法获得能够可靠和 选择性地消耗目标细胞群，我们打算利用我们的 RTA IT的经验，以定义参与 嫁接网络。各种RTA IT将在体外进行研究 选择性和效价，然后进行体内研究。我们将决定 每个IT的最佳结合条件、用量、路线和时间表。 植入推广的效果将在短期和中期两方面进行衡量 长期的嫁接制度。体内靶细胞的耗尽将是 用荧光标记的单抗和流式细胞仪监测和功能。 我们还打算检验这样一种假设，即 毒素的易位增强区使IT变得更好。许多催化剂 蓖麻毒素和假单胞菌外毒素A(PE)等毒素具有增强作用 促进A链移位到靶细胞的区域。这 该区域与产生这些毒素的天然结合部位是分开的 对人类来说很危险。最先进的技术现在允许我们生产 重组毒素不含天然结合区，但含有 毒素A链和易位增强区。在这份提案中，我们 我将研究一种名为PE40的毒素，作为我们BMT模型PE40IT的IT 将被研究并与RTA IT进行比较。

Most of the allogeneic transplants performed at our and other institutions involve matched donors. Despite HLA-matching, graft-versus-host-disease (GVHD) still occurs in 50% of these cases. Attempts have been made at our own institution to combat GVHD by removing T cells from the donor graft prior to transplant. This T cell depletion (TCD), although reducing the severity of GVHD, has increased the frequency of graft rejection. In this proposal, we intend to utilize our expertise in murine transplant models to construct a murine model of TCD-induced graft rejection across minor histocompatability barriers. We will use these models to evaluate immunotoxins as potential agents for overcoming graft rejection. Immunotoxins (IT) are monoclonal antibodies (moab) linked to potent catalytic toxins such as ricin toxin A chain (RTA) and are designed to deliver a lethal hit to specific antigen expressing target cells. These agents are currently under clinical evaluation for GVHD therapy at our and other institutions. Our specific aims are to test the hypothesis that RTA IT administered in vivo will promote engraftment across the minor histocompatibility barrier. Since in vivo attempts to define the role of immune cells in the recognition of minor histocompatibility antigens have been hampered by the unavailability of agents that can reliably and selectively deplete target cell populations, we intend to use our experience with RTA IT to define the cell populations involved in the engraftment network. Various RTA IT will be studied for in vitro selectivity and potency and then studied in vivo. We will determine optimal conjugation conditions, dosage, route, and schedule for each IT. Efficacy of engraftment promotion will be measured in both short-term and long-term engraftment systems. In vivo depletion of target cells will be monitored using fluorochrome labeled moab and flow cytometry and function. We also intend to test the hypothesis that the presence of the translocation-enhancing regions of toxin makes better IT. Many catalytic toxins such as ricin and pseudomonas exotoxin A (PE) have an enhancing region that promotes translocation of the A chain into target cells. This region is separate from the native binding site that renders these toxins dangerous to man. The state of the art now permits us to produce recombinant toxin devoid of the native binding region, but containing the toxic A chain and the translocation enhancing region. In this proposal we will study such a toxin, called PE40, as an IT in our BMT model, PE40IT will be studied and compared to RTA IT.