Separating Antitumor & GvHD in Allogeneic T-Cells

描述（由申请人提供）：拟议研究的长期目标是提高接受同种异体造血祖细胞移植（HPCT）的患者的生存率。 HPCT 接受者将受益于增强移植物抗肿瘤 (GvT) 效应同时最大限度减少移植物抗宿主病 (GvHD) 的新疗法。最近的数据表明，“记忆”CD44（高）CD4 供体 T 细胞具有 GvT 活性，而没有剂量限制性 GvHD。申请人开发了一种使用离体暴露于氟达拉滨选择性耗尽CD44（低）并保留CD44（高）CD4 T细胞供体T细胞的新方法，该方法将针对三个具体目标进行研究：＃1：表征初始CD44（低）与CD44（高）CD4 T细胞的GvHD和GvT活性。假设氟达拉滨通过增强细胞凋亡减少同种异体反应性幼稚 T 细胞来选择性删除 CD44(Iow) 幼稚 T 细胞。将在同种异体 BMT 中比较 FACS 分选的 CD44（低）和 CD44（高）CD4 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）删除CD4（Iow）CD4 T细胞后促炎细胞因子的合成减少； 2) 减少同种异体反应性 T 细胞归巢至胃肠上皮； 3) 调节/抑制性T细胞的富集。 #3 确定 CD44（高）CD4 T 细胞转移抗原特异性细胞免疫而不引起 GvHD 的能力。假设是抗原特异性记忆 T 细胞在氟达拉滨暴露下存活并在同种异体 BMT 接受者中增殖，而不产生促炎细胞因子。同种异体 BMT 和 CMV 肽-MHC 四聚体试剂后建立的 CMV 感染小鼠模型将用于测量抗 mCMV 供体 T 细胞。这些研究的总体目标是开发一种同种异体移植工程的新方法，以改善免疫重建并增强 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.