Separating Antitumor & GvHD in Allogeneic T-Cells

描述(申请人提供)：拟议研究的长期目标是提高接受异基因造血祖细胞移植(HPCT)患者的存活率。HPCT接受者将受益于增强移植物抗肿瘤(GVT)效果的新疗法，同时将移植物抗宿主病(GvHD)降至最低。最近的数据表明，“记忆”的CD44(高)CD4供体T细胞具有GVT活性，而不受剂量限制的GvHD。申请人已经开发出一种新的方法，通过体外暴露于氟达拉滨来选择性地耗尽CD44(低)和保存CD44(高)CD4T细胞供者T细胞，该方法将进行三个特定目标的研究：#1：表征初始CD44(低)和CD44(高)CD44(高)CD4T细胞的GvHD和GVT活性。假说是，氟达拉滨通过促进凋亡，减少同种反应性的初始T细胞，选择性地删除CD44(低)初始T细胞。比较异基因骨髓移植患者FACS分选的CD44(低)和CD44(高)CD4T细胞亚群的GVHD和GVT活性。#2：确定氟达拉滨治疗导致供者T细胞同种反应性降低的机制。体外和体内模型系统将测试以下假设：1)在删除CD4(低)CD4T细胞后，促炎症细胞因子的合成减少；2)同种反应性T细胞减少对胃肠上皮的归巢；3)调节/抑制T细胞的浓缩。#3确定CD44(高)CD4T细胞在不引起GvHD的情况下转移抗原特异性细胞免疫的能力。假设抗原特异性记忆T细胞在氟达拉滨暴露下存活下来，并在异基因骨髓移植受者中增殖，而不产生促炎细胞因子。建立的小鼠异基因骨髓移植后巨细胞病毒感染模型和CMV多肽-MHC四聚体试剂将用于检测抗MCMV供体T细胞。这些研究的总体目标是开发一种新的同种异体移植工程方法，在不增加GvHD的情况下改善免疫重建和增强GVT活性。我们的研究将加深对供体细胞在异基因HPCT后诱导GvHD和GVT效应中作用的理解，并促进癌症患者免疫治疗新方法的开发。

DESCRIPTION (provided by applicant): The long-term goal for the proposed studies is to improve survival in patients who undergo allogeneic hematopoietic progenitor cell transplantation (HPCT). HPCT recipients will benefit from novel therapies that enhance graft versus tumor (GvT) effects while minimizing graft versus host disease (GvHD). Recent data indicate that "memory" CD44(high) CD4+ donor T-cells have GvT activity without dose-limiting GvHD. The applicant has developed a novel method of selectively depleting CD44(Iow) and preserving CD44(high) CD4+ T-cells donor T-cells using ex vivo exposure to fludarabine that will be studied with three specific aims: #1: To characterize the GvHD and GvT activity of naive CD44(Iow) versus CD44(high) CD4+ T-cells. The hypothesis is that fludarabine selectively deletes CD44(Iow) naive T-cells via enhanced apoptosis reducing allo-reactive naive T-cells. GvHD and GvT activity of FACS sorted CD44(Iow) and CD44(high) CD4+ T-cell subsets will be compared in allogeneic BMTs. #2: To determine the mechanisms by which fludarabine-treatment leads to reduction in the allo-reactivity of donor T-cells. In vitro and in vivo model systems will test the following hypotheses: 1) reduced synthesis of the pro-inflammatory cytokines following deletion of the CD4(Iow) CD4+ T-cells; 2) reduced homing of allo-reactive T-cells to the gastro-intestinal epithelium; 3) enrichment of regulatory/suppressor T-cells. #3 To determine the ability of CD44(high) CD4+ T-cells to transfer antigen-specific cellular immunity without causing GvHD. The hypothesis is that antigen specific memory T-cells survive fludarabine exposure and proliferate in allogeneic BMT recipients without producing pro-inflammatory cytokines. An established mouse model of CMV infection after allogeneic BMT and CMV peptide-MHC tetramer reagents will be used to measure anti-mCMV donor T-cells. The overall objective of these studies is to develop a novel methods of allograft engineering to improve immune reconstitution and enhance GvT activity without increasing GvHD. Our studies will improve the understanding of the role of donor cells in inducing GvHD and GvT effects after allogeneic HPCT and facilitate development of novel approaches in immunotherapy cancer patients.