In Vivo Properties of Ex vivo Expanded CD25+ T Cells

描述(由申请人提供)： 造血细胞移植有可能治愈多种血液病。然而，移植物抗宿主病(GVHD)和缺乏捐赠者限制了它们的广泛应用。CD4+CD25+调节性T细胞(Treg)可以抑制异常免疫反应，调节外周T细胞的动态平衡。我们最近在一种小鼠模型中显示Treg抑制移植物抗肿瘤效应的情况下抑制GVHD。然而，它们的稀有和我们对其免疫调节的缺乏限制了它们在临床环境中的使用。这份提案详细说明了一项为期5年的培训计划。该项目的长期目标是确定体外扩增的Treg是否会增加HCT的益处。本项目的目的是评价体外扩增的Treg在HCT动物模型中的作用。这项工作的中心假设是Treg可以在体外扩大，这样的群体在后HCT时期提供了好处。该假说将通过追求三个特定目标来验证：1)使用ICFSE标记、流式细胞仪和生物发光成像技术评估体外扩增的Treg在体内的存活和转运；2)通过L-选择素和α4-β7整合素基因敲除的方法评估改变的Treg归巢和迁移对移植物抗肿瘤和移植物抗肿瘤的影响；3)通过光谱分析、流式细胞仪检测淋巴器官和外周血单核细胞的表型以及巨细胞病毒感染的功能分析来确定体外扩增的Treg如何改变供体移植物的免疫重建。这项拟议的工作具有创新性，因为我们在GVHD和GVT的敏感动物模型中使用非侵入性技术研究了罕见的细胞群体。预计我们的研究将提供对人类研究重要的临床前信息。拟议的培训方案处于支持性和动态的研究环境中。因此，候选人将获得必要的技能，成为移植免疫学领域的一名成功的独立研究员。

DESCRIPTION (provided by applicant): Hematopoietic cell transplantation is potentially curative for a variety of hematologic cancers. However, graft vs host disease (GVHD) and the lack of donors limit their wide application. CD4+CD25+ regulatory T cells (Treg) can suppress aberrant immune responses and regulate peripheral T cell homeostasis. We recently show that Treg suppress GVHD without abrogating the graft vs tumor effect in a murine model. However, their rarity and our lack of understanding of their immunoregulation limit their use in the clinical setting. This proposal details a 5-year training program. The long-range goal of this project is to determine whether ex vivo expanded Treg add benefit to HCT. The objective of this project is to evaluate the role of ex vivo expanded Treg in animal models of HCT. The central hypothesis to this work is that Treg can be expanded ex vivo and that such population provide benefits in the post-HCT period. This hypothesis will be tested by pursuing three specific aims: 1) evaluate the in vivo survival and trafficking of ex vivo expanded Treg using ICFSE labeling, flow cytometry, and bioluminescence imaging of Treg from luciferase transgenic mice; 2) evaluate the effects of altered Treg homing and migration on GVHD and the graft vs tumor (GVT) using knockouts of L-selectin and alpha4-beta7 integrin; 3) determine how ex vivo expanded Treg alter the immune reconstitution of the donor graft with spectratype analysis, phenotyping of lymphoid organ and peripheral blood mononuclear cells via flow cytometry, and functional analysis by CMV infection. The proposed work is innovative because we study a rare population of cells using noninvasive techniques in sensitive animal models of GVHD and GVT. It is expected that our studies will provide preclinical information that is important for human studies. The proposed training program is in a supportive and dynamic research setting. Thus, the candidate will gain the necessary skills to become a successful independent investigator in the field of transplant immunology.