Adoptive Cellular Therapy for Myeloid Leukemia

越来越多的证据表明，淋巴细胞可以靶向并抑制髓系白血病细胞 和自动设置。异基因干细胞相关的强大移植物抗白血病(GVL)效应 移植(SCT)传递抗白血病的活性，并有助于降低复发风险 没有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整体效果。我们 假设GVL会被增强，GVHD会减少或消除，如果驱动这些的靶抗原 如果能分离出具有GVL抗原特异性的T细胞并过继转移到 白血病患者处于异基因环境中，这种效果可以通过接种以下疫苗来增强 适当的白血病抗原。我们已经确定了一种人类白细胞抗原A2限制性单体多肽PR1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， PR1是由异常表达的蛋白酶3(PRTN3)和中性粒细胞弹性蛋白酶(ELA2)加工而成的 得了白血病。接种PR1疫苗后，大多数患者出现免疫反应， 在一些AML、CML和MDS患者中有持续缓解的记录。基于免疫的治疗方法 低毒性可用于联合治疗策略，以诱导白血病患者的缓解 同种异体设置，以增强GVL和最大限度地减少GVHD。在这项建议中，我们将(1)确定表型， 免疫后PR1-CTL的功能和T细胞受体(TCR)亲和力与免疫前不同 来自健康供者；(2)确定异常贩运PRTN3和ELA2是否可以逆转耐受性 和(3)确定PR1-CTL是否高表达 亲和TCR可以在T细胞耗尽的半相合SCT后转移到AML患者，以提高GVL和 减少GVHD。 干细胞移植已被成功地用于治疗白血病患者，但 移植物抗宿主病的并发症和合适的干细胞捐赠者的有限限制了我们对 这项原本可以挽救生命的治疗只有不到25%的潜在患者可以受益。为了改善 SCT的有效性，我们已经确定了一些白血病相关的靶分子，这些靶分子是由 供者淋巴细胞，调节对患者白血病的免疫效果。我们用了其中一个 抗原，PR1，作为疫苗来提高一些难治性疾病患者对白血病的免疫力。我们 发现接种PR1疫苗毒性很小，它提高了大多数患者的免疫力 并在一些患者中诱导缓解，这种缓解持续了长达七年。在这项建议中，我们将研究 对这一目标免疫的分子基础，我们将使用在上一次赠款期间确定的策略来 针对这种抗原扩大供者淋巴细胞，然后我们将其转移到白血病患者身上。如果成功，这将是 这项技术最终可以用来减少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.