Adoptive Cellular Therapy for Myeloid Leukemia

越来越多的证据表明，淋巴细胞可以靶向和抑制髓系白血病细胞，无论是在同种异体移植， 和自体设置。异基因造血干细胞的移植物抗白血病效应 移植（SCT）传达了抗白血病的活性，并有助于降低复发风险， 未接受同种异体移植的患者。虽然GVL可以诱导长期缓解，但潜在的致命性 移植物抗宿主病（GVHD）的并发症限制了这种治疗方法的总体有效性。我们 假设如果驱动这些细胞的靶抗原被抑制，GVL将被增强，GVHD将被减少或消除， 如果可以分离出具有GVL抗原特异性的T细胞并过继转移到 在同种异体环境中的白血病患者，这种效果可以通过接种 合适的白血病抗原我们已经确定了一个HLA-A2-限制性的免疫肽，PR 1，作为靶抗原 抑制髓系白血病祖细胞并杀死髓系白血病骨髓细胞的CTL。我们发现 PR 1由蛋白酶3（PRTN 3）和中性粒细胞弹性蛋白酶（ELA 2）加工而成，这两种酶异常表达 在白血病中。接种PR 1疫苗后，在大多数患者中观察到免疫应答， 在一些AML、CML和MDS患者中记录了持续缓解。基于免疫的疗法， 低毒性可用于联合治疗策略，以诱导白血病患者缓解， 同种异体环境以增强GVL和最小化GVHD。在这个建议中，我们将（1）确定是否表型， 免疫接种后引发的PR 1-CTL与免疫接种后引发的PR 1-CTL相比， （2）确定PRTN 3和ELA 2的异常运输是否可以逆转耐受性 并便于中央存储器PR 1-CTL的扩充;（3）确定PR 1-CTL是否高表达 亲和TCR可以在T细胞耗尽的单倍相同SCT后转移至AML患者以加强GVL， 减少GVHD。 干细胞移植已被用于成功治疗白血病患者，但 移植物抗宿主病的并发症和合适的干细胞供体的有限可用性限制了我们使用 这种原本可以挽救生命的治疗方法只适用于不到25%的可能受益的患者。提高 为了提高SCT的有效性，我们已经确定了一些白血病相关的靶分子， 介导针对患者白血病的免疫作用的供体淋巴细胞。我们用了其中一个 PR 1抗原作为疫苗，在一些难治性疾病患者中增强对白血病的免疫力。我们 发现PR 1疫苗接种几乎没有毒性，并且它增强了大多数患者的免疫力 并在一些患者中诱导缓解，持续长达7年。在本建议中，我们会研究 免疫的分子基础，我们将使用在前一个赠款期间确定的策略， 扩增供者的淋巴细胞对抗这种抗原，然后我们将其转移到白血病患者身上。如果成功，这 这项技术最终可用于减少GVHD，同时保留长期缓解的有益效果 SCT后。

There is increasing evidence that lymphocytes can target and inhibit myeloid leukemia cells both in the allogeneic and autologous settings. The potent graft versus leukemia (GVL) effect associated with allogeneic stem cell transplant (SCT) conveys activity against leukemia and contributes to the decreased relapse risk compared with patients who do not receive an allogeneic graft. While GVL can induce long-term remission, the potentially lethal complication of graft-versus-host disease (GVHD) limits overall effectiveness of this treatment approach. We hypothesize that GVL would be enhanced, and GVHD reduced or eliminated, if the target antigens that drove those responses were identified, and if T cells with GVL antigen specificity could be isolated and adoptively transferred to patients with leukemia in the allogeneic setting, and that this effect could be increased by vaccination with appropriate leukemia antigens. We have identified an HLA-A2-restricted nonomer peptide, PR1, as a target antigen of CTL that inhibits myeloid leukemia progenitors and kills myeloid leukemia bone marrow cells. We have found that PR1 is processed from both proteinase 3 (PRTN3) and neutrophil elastase (ELA2), which are aberrantly expressed in leukemia. After vaccination with PR1, immune responses were observed in the majority of patients, and persistent remission was documented in some patients with AML, CML, and MDS. Immune-based therapies with low toxicity could be useful in combined treatment strategies to induce remission in patients with leukemia in the allogeneic setting to enhance GVL and minimize GVHD. In this proposal, we will (1) determine whether phenotype, function, and T cell receptor (TCR) affinity differ between PR1-CTL elicited after vaccination compared to those derived from healthy donors; (2) determine whether aberrant trafficking of PRTN3 and ELA2 can reverse tolerance and facilitate the expansion of central memory PR1-CTL; and (3) determine whether PR1-CTL expressing high affinity TCR can be transferred to patients with AML after T cell-depleted haplo-identical SCT to boost GVL and diminish GVHD. Lay Description: Stem cell transplantation has been used to successfully treat patients with leukemia, but the complication of graft-versus-host disease and the limited availability of suitable stem cell donors limit our use of this otherwise life-saving treatment to less than 25% of the potential patients who could benefit. To improve the effectiveness of SCT, we have identified some of the leukemia-associated target molecules recognized by the donor lymphocytes that mediate an immune effect against the patient's leukemia. We used one of these antigens, PR1, as a vaccine to boost immunity against leukemia in some patients with refractory disease. We found that PR1 vaccination was associated with little toxicity, and it boosted immunity in the majority of patients and induced remission in some patients, which has lasted up to seven years. In this proposal, we will study the molecular basis for immunity to this target, and we will use a strategy identified during the previous grant period to expand donor lymphocytes against this antigen, that we then transfer to patients with leukemia. If successful, this technique could eventually be used to reduce GVHD while retaining the beneficial effect of long-term remission after SCT.