Separating Antitumor & GvHD in Allogeneic T-Cells

描述（由申请人提供）：拟定研究的长期目标是改善接受异基因造血祖细胞移植（HPCT）患者的生存率。HPCT接受者将受益于增强移植物抗肿瘤（GvT）效应同时最小化移植物抗宿主病（GvHD）的新型疗法。最近的数据表明，“记忆”CD 44（高）CD 4+供体T细胞具有GvT活性，而没有剂量限制性GvHD。申请人已经开发了一种使用离体暴露于氟达拉滨来选择性地消耗CD 44（低）和保存CD 44（高）CD 4 + T细胞供体T细胞的新方法，将以三个特定目的研究该方法：#1：表征初始CD 44（低）相对于CD 44（高）CD 4 + T细胞的GvHD和GvT活性。假设是氟达拉滨通过增强的细胞凋亡减少同种异体反应性幼稚T细胞来选择性地删除CD 44（低）幼稚T细胞。将在同种异体BMT中比较FACS分选的CD 44（低）和CD 44（高）CD 4 + T细胞亚群的GvHD和GvT活性。#2：确定氟达拉滨治疗导致供体T细胞同种异体反应性降低的机制。体外和体内模型系统将测试以下假设：1）在CD 4（低）CD 4 + T细胞缺失后促炎细胞因子的合成减少; 2）同种异体反应性T细胞向胃肠上皮的归巢减少; 3）调节性/抑制性T细胞的富集。#3确定CD 44（高）CD 4 + T细胞转移抗原特异性细胞免疫而不引起GvHD的能力。假设抗原特异性记忆T细胞在氟达拉滨暴露后存活，并在同种异体BMT接受者中增殖，而不产生促炎细胞因子。将使用同种异体BMT和CMV肽-MHC四聚体试剂后建立的CMV感染小鼠模型测量抗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物工程方法，以改善免疫重建和增强GvT活性，而不增加GvHD。我们的研究将提高对供体细胞在同种异体HPCT后诱导GvHD和GvT效应中的作用的理解，并促进免疫治疗癌症患者的新方法的开发。

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.