Cord Blood T Cell Therapy for Myeloid Malignancies

项目总结 急性髓系白血病(AML)对免疫治疗敏感，异基因治疗的成功证明了这一点 (Allo)干细胞移植(SCT)在本病中的应用。虽然异基因干细胞移植可以治愈白血病，但它携带一种 与治疗相关的死亡率和发病率很高。这主要是非靶标免疫反应的结果。 供者来源的细胞毒性T细胞(CTL)在SCT移植物内对正常组织的诱导，这是一种现象 被称为移植物抗宿主病(GvHD)，这种疾病在异基因干细胞移植后高达50%的患者中发生。 此外，AML复发仍然是allo-SCT后死亡的主要原因，突出了这一不足 异基因干细胞移植在提供长效治疗方面的作用。为了尽量减少GvHD，同时利用移植物 针对白血病(GVL)效应，大量的白血病相关抗原(LAAs)已被识别和显示 以激发白血病特异性免疫反应。PR1是我们在实验室中发现的一种受HLA-A2限制的LAA 并使用单抗T细胞受体(TCR)样抗体(8F4)、PR1多肽疫苗和PR1- CTL.在目前的方案中，我们计划设计针对PR1/HLA-T细胞的嵌合抗原受体(CAR)T细胞。 A2在AML表面使用8F4构建。这项建议的理由是，鉴于 与allo-SCT相关的缺点和显著毒性，与AML对 免疫疗法(即allo-SCT)，迫切需要开发新的免疫疗法来实现疾病 以最小的脱靶毒性消除。我们计划使用8F4作为汽车，因为它对 AML提出的PR1/HLAA2表位。我们计划使用脐带血T细胞作为细胞来源 8F4-CAR T细胞的工程设计由于我们最近在工程和 利用脐带血产品扩增足够数量的有效8F4-CAR T细胞。此外，我们还展示了 脐带血来源的8F4-CAR-T细胞在小鼠异种移植模型中治疗人AML的效力。我们 还将在汽车结构中引入caspase 9(ICP9)自杀基因，以提高 8F4-CAR-T细胞。我们的中心假设是用iCP9-8F4-CAR T细胞进行免疫治疗 脐带血T细胞将消除PR1表达的AML，并具有最小的靶外毒性。我们将(1)验证 ICP9-8F4-CAR-T细胞在原发急性髓系白血病动物模型中的安全性和抗白血病活性 (2)检测iCP9-8F4-CAR-T细胞在急性髓系白血病患者中的安全性和有效性 桥到allo-SCT；以及(3)研究免疫重建，并利用血液和骨骼进行相关研究 来自iCP9-8F4-CAR-T细胞受者的骨髓样本。在完成我们建议的研究后，我们预计 使用8F4-CAR-T细胞进行PR1靶向过继细胞治疗可能成为治疗 髓系白血病患者。此外，我们的研究还将阐明脐带血T细胞在 用于癌症治疗的CAR-T细胞工程学。

PROJECT SUMMARY Acute myeloid leukemia (AML) is susceptible to immunotherapy as evidenced by the success of allogeneic (allo) stem cell transplantation (SCT) in this disease. Although allo-SCT can be curative in leukemia, it carries a high rate of treatment-related mortality and morbidity. This is primarily a result of off-target immune responses elicited by donor-derived cytotoxic T cells (CTL) within the SCT graft against normal tissues, a phenomenon known as graft-versus-host disease (GvHD), which occurs in up to 50% of patients following allo-SCT. Furthermore, AML relapse remains the leading cause of mortality following allo-SCT, highlighting the shortfalls of allo-SCT in providing long-lasting cures. In order to minimize GvHD, while taking advantage of the graft versus leukemia (GvL) effect, numerous leukemia-associated antigens (LAAs) have been identified and shown to elicit leukemia-specific immune responses. PR1 is an HLA-A2-restricted LAA that we identified in our lab and targeted using a monoclonal T cell receptor (TCR)-like antibody (8F4), a PR1-peptide vaccine, and PR1- CTL. In the current proposal, we plan to engineer chimeric antigen receptor (CAR) T cells that target PR1/HLA- A2 on the surface of AML using the 8F4 construct. The rationale for this proposal is that in view of the shortcomings and significant toxicities associated with allo-SCT, balanced by the susceptibility of AML to immunotherapy (i.e. allo-SCT), there is a critical need to develop novel immunotherapies to achieve disease elimination with minimal off-target toxicity. We plan to use 8F4 as the CAR since it has a very high affinity for the PR1/HLAA2 epitope presented by AML. We plan to use cord blood T cells as the cell source for engineering the 8F4-CAR T cells due to the success we have recently encountered in engineering and expanding sufficient numbers of effective 8F4-CAR T cells using cord blood products. Furthermore, we showed potency of the cord blood-derived 8F4-CAR-T cells in treating human AML in a mouse xenograft model. We will also introduce a caspase 9 (iCP9) suicide gene into the CAR construct, to increase the safety profile of the 8F4-CAR-T cells. Our central hypothesis is that immunotherapy with iCP9-8F4-CAR T cells engineered from cord blood T cells will eliminate PR1-expressing AML, with minimal off-target toxicity. We will (1) validate the safety and anti-leukemic activity of the iCP9-8F4-CAR-T cells in animal models using primary patient AML samples and cell lines; (2) test the safety and efficacy of the iCP9-8F4-CAR-T cells in patients with AML as a bridge to allo-SCT; and (3) study immune reconstitution and perform correlative studies using blood and bone marrow samples from iCP9-8F4-CAR-T cell recipients. After completion of our proposed studies, we anticipate that PR1-targeting adoptive cellular therapy using 8F4-CAR-T cells could become a standard therapy for patients with myeloid leukemia. In addition, our studies will elucidate the potential for cord blood T cells in the engineering of CAR-T cells for the treatment of cancer.