MARROW TRANSPLANTATION ACROSS MINOR HISTOCOMPATIBILITY BARRIERS

在我们和其他机构进行的大多数同种异体移植 包括匹配的捐赠者。 尽管HLA匹配， （GVHD）仍然发生在50%的病例中。 已经尝试在我们的 通过从供体移植物中去除T细胞来对抗GVHD 移植前。 这种T细胞耗竭（TCD），虽然减少了 GVHD的严重程度增加了移植物排斥反应的频率。 在这 我们打算利用我们在小鼠移植模型方面的专业知识， 建立小鼠TCD诱导的移植物排斥模型， 组织相容性屏障。 我们将使用这些模型来评估 免疫毒素作为克服移植排斥的潜在试剂。 免疫毒素（IT）是单克隆抗体（moab）， 催化毒素如蓖麻毒素A链（RTA），并被设计成 对表达特定抗原的靶细胞进行致命打击。 这些 药物目前正在我们的GVHD治疗的临床评估中， 其他机构。 我们的具体目标是检验RTA的假设， 体内IT给药将促进未成年人的植入 组织相容性屏障 由于在体内试图定义的作用， 免疫细胞在识别次要组织相容性抗原时， 由于无法获得能够可靠和 选择性地耗尽靶细胞群，我们打算使用我们的 使用RTA IT的经验，以确定参与 植人网 将对各种RTA IT进行体外研究 选择性和效力，然后在体内研究。 我们将确定 每个IT的最佳结合条件、剂量、途径和方案。 植入促进的功效将在短期和长期两种情况下测量。 长期的移植系统。 靶细胞的体内消耗将是 使用荧光染料标记的MOAB和流式细胞术和功能进行监测。 我们还打算测试的假设，即存在的 毒素的易位增强区域使IT更好。许多催化 毒素如蓖麻毒素和假单胞菌外毒素A（PE）具有增强的 促进A链易位到靶细胞中的区域。 这 区域与使这些毒素 对人类是危险的。现在的技术水平允许我们生产 缺乏天然结合区，但含有 毒性A链和易位增强区。 在本提案中，我们 我将研究这种称为PE 40的毒素，作为我们BMT模型PE 40 IT中的IT 将进行研究并与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.