Utilizing Hybrid Antigen-Presenting Neutrophils to Prime WT1-Specific Immune Responses as Therapy for Acute Leukemia

虽然化疗可以缓解急性白血病患者的病情，但通常 遇到复发的可能性很高。目前对替代治疗方法的需求尚未得到满足。 有效防止复发或可用于治疗复发或难治性疾病的药物。压倒性的 有证据表明异基因造血干细胞移植成功维持完整 白血病患者的缓解依赖于肿瘤特异性T细胞免疫(移植物抗白血病 效果)。Wilms Tumor 1(WT1)在几乎所有儿童和成人急性白血病中都有过度表达，有证据表明 WT1特异性CD8+T细胞在患者中自发产生，突显其作为一种普遍白血病的潜力- 特定的抗原。我们的长期目标是开发一种结合全长WT1的免疫治疗策略。 在患者体内诱导强大的抗白血病免疫的抗原。此应用程序的总体目标是 确定我们的基于沙门氏菌的治疗性药物SHIDO-ST在通过以下途径诱导WT1特异性免疫方面的效用 一组独特的抗原呈递的中性粒细胞(APC-PMN)。APC-PMN可以 用粒细胞巨噬细胞集落刺激因子(GM-CSF)体外培养PMN和 已被证明能激发T细胞对外来抗原和癌症相关抗原的反应。我们的中心假设 将WT1基因整合到SHIDO-ST(WT1-SHIDO-ST)中将有利于坐标的生成 提出WT1表位的杂合APC-PMN可诱导有效的抗白血病免疫。我们的假设已经 是根据我们自己的初步数据制定的，证实了SHIDO-ST治疗的能力 在体内产生能够启动抗原特异性T细胞反应的APC-PMN。该计划的基本原理 拟议的研究是WT1-Shido-ST疗法引起的WT1特异性反应的更大范围 代表了一种治疗白血病患者的通用方法。中心假设和总体目标意志 通过追求两个特定的目标进行测试：1)确定WT1诱导的WT1特异性免疫的关键特征- 2)确定WT1-SHIDO-ST治疗白血病模型的疗效。 靶向体内最丰富的白细胞以产生APC-PMN，同时还利用它们的抗原- 呈现功能是本研究的创新之处。这项拟议的研究具有重要意义，因为它提供了 一种诱导WT1特异性免疫的新方法，并可扩展到加入其他特异性抗原 恶性肿瘤或传染病。因此，这项工作将开发基础资源，可供 寻求在预防或治疗环境中引起抗原特异性反应的研究人员。最接近的 这项工作的预期结果将是对影响WT1的免疫亚群有更好的理解。 WT1-shido-ST治疗后的特异性免疫及其消除白血病细胞的潜力。结果是 这项研究的结果将产生重要的积极影响，因为他们将建立一种新的方法来诱导抗原- 从长远来看，这为许多疾病提供了一种替代的免疫治疗策略。

PROJECT SUMMARY Although chemotherapy can induce remission in patients with acute leukemia, it is often met with high probability of relapse. There is currently an unmet need for alternative therapeutic approaches that effectively prevent relapse or that can be used to treat relapsed or refractory disease. Overwhelming evidence suggests that the success of allogeneic hematopoietic stem cell transplantation to sustain complete remission in leukemia patients relies on the presence of tumor-specific T cell immunity (graft-versus-leukemia effect). Wilms tumor 1 (WT1) is overexpressed in nearly all pediatric and adult acute leukemias with evidence of WT1-specific CD8+ T cells spontaneously arising in patients, highlighting its potential as a universal leukemia- specific antigen. Our long-term goal is to develop an immunotherapeutic strategy incorporating full-length WT1 antigen to induce robust, anti-leukemic immunity in patients. The overall objective of this application is to determine the utility of our Salmonella-based therapeutic, shIDO-ST, in eliciting WT1-specific immunity through a unique population of antigen-presenting, polymorphonuclear neutrophils (APC-PMN). APC-PMN can be generated in vitro by culturing of PMN with granulocyte macrophage-colony stimulating factor (GM-CSF) and have been shown to prime T cell responses to foreign and cancer-associated antigens. Our central hypothesis is that incorporating the WT1 transgene into shIDO-ST (WT1-shIDO-ST) will facilitate the coordinate generation of hybrid APC-PMN presenting WT1 epitopes to induce effective anti-leukemic immunity. Our hypothesis has been formulated on the basis of our own preliminary data confirming the ability of shIDO-ST treatment to generate APC-PMNs in vivo that are capable of priming antigen-specific T cell responses. The rationale for the proposed research is that a greater breadth of WT1-specific responses elicited by WT1-shIDO-ST therapy represents a universal approach for treating leukemia patients. The central hypothesis and overall objective will be tested by pursuing two specific aims: 1) Identify key features of WT1-specific immunity induced by WT1- shIDO-ST therapy and 2) Determine the therapeutic efficacy of WT1-shIDO-ST treatment in leukemia models. Targeting the most abundant leukocyte in the body to generate APC-PMN while also harnessing their antigen- presenting functions are innovative aspects of our study. The proposed research is significant because it offers a novel approach to elicit WT1-specific immunity and can be extended to incorporate antigens specific to other malignancies or infectious diseases. Thus, this work will develop foundational resources that can be used by researchers seeking to elicit antigen-specific responses in the prophylactic or therapeutic setting. The proximate expected outcome of this work will be a greater understanding of the immune subsets contributing to WT1- specific immunity, following WT1-shIDO-ST treatment, and their potential to eliminate leukemic cells. The results of this study will have an important positive impact because they will establish a novel approach to elicit antigen- specific responses, which in the long-term offers an alternative immunotherapeutic strategy for many diseases.