Cell Therapy of Refractory Leukemia

描述（由申请人提供）：在大约20%的急性淋巴细胞白血病（ALL）儿童和65%的成人患者中，尽管进行了强化化疗，白血病细胞仍然存在，通常导致致命的复发。该研究提出的假设是免疫细胞，即T淋巴细胞和自然杀伤（NK）细胞，通过基因工程（“嵌合”）抗原受体重定向可以根除耐药ALL。在初步研究中，识别CD19的受体（一种在ALL细胞中高度表达的分子，除B淋巴细胞外在所有正常细胞中都不存在）向免疫细胞传递刺激信号，从而对CD19+ ALL细胞产生强大的细胞毒性。特异性目的1是鉴定在NK细胞中诱导最大增殖和抗cd19细胞毒性的刺激信号分子。这些研究源于NK细胞中抗cd19受体的表达绕过抑制机制并赋予抗all细胞毒性，并依赖于一种新的方法来有效地转导NK细胞中的受体。该结果将引导NK细胞在难治性ALL患者中的临床研究，并可能扩大NK细胞在癌症治疗中的临床应用。特异性目的2的研究将确定表达抗cd19受体的免疫细胞是否能根除异种小鼠白血病模型中的ALL。将评估NK细胞和T细胞的相对抗白血病能力，4-1BB和CD28共刺激的潜在益处，以及针对两种不同的白血病相关抗原注入细胞的有效性。如果有希望，该结果将为在耐药ALL患者中进行受体修饰的自体和异体免疫细胞的临床试验提供强有力的依据。特异性目的3是提高受体修饰免疫细胞的临床安全性。允许受体和CD20同时表达的基因构建将被开发出来，以使转导的细胞对利妥昔单抗（一种临床使用的抗CD20抗体）介导的细胞毒性敏感。T细胞和NK细胞的功能以及它们对利妥昔单抗的敏感性将在体内和体外进行测试。嵌合受体定向免疫治疗是癌症研究的一个新兴领域。这项研究不仅可以促进难治性ALL患者免疫细胞的临床研究，还可以促进其他肿瘤有效细胞疗法的发展。

DESCRIPTION (provided by applicant): In approximately 20% of children and 65% of adults with acute lymphoblastic leukemia (ALL), leukemic cells persist despite intensive chemotherapy, leading to often fatal relapse. The hypothesis underlying the research proposed is that immune cells, i.e., T lymphocytes and natural killer (NK) cells, redirected by genetically-engineered ("chimeric") antigen receptors can eradicate drug-resistant ALL. In preliminary studies, receptors that recognize CD19 (a molecule highly expressed in ALL cells and absent in all normal cells except B lymphocytes) deliver stimulatory signals to immune cells resulting in powerful cytotoxicity against CD19+ ALL cells. Specific Aim 1 is to identify stimulatory signaling molecules that induce maximum expansion and anti-CD19 cytotoxicity in NK cells. These studies stem from the observation that expression of anti-CD19 receptors in NK cells bypasses inhibitory mechanisms and confers anti-ALL cytotoxicity, and rely on a novel method to efficiently transduce the receptors in NK cells. The results should lead to clinical studies of NK cells in patients with refractory ALL and may expand the clinical use of these cells in cancer therapy. Studies in Specific Aim 2 will determine whether immune cells expressing anti-CD19 receptors can eradicate ALL in xenogeneic murine models of leukemia. The relative anti-leukemic capacity of NK cells and T cells, the potential benefits of 4-1BB and CD28 co-stimulation, and the effectiveness of infusing cells directed against two different leukemia-associated antigens will be assessed. If promising, the results should provide a strong rationale for clinical testing of receptor-modified autologous and allogeneic immune cells in patients with drug-resistant ALL. Specific Aim 3 is to increase the clinical safety of receptor-modified immune cells. Gene constructs that allow simultaneous expression of the receptors and of CD20 will be developed in efforts to render transduced cells susceptible to cytotoxicity mediated by Rituximab, an anti-CD20 antibody used clinically. The function of T and NK cells transduced with these constructs and their sensitivity to Rituximab will be tested in vitro and in vivo. Chimeric receptor-directed immunotherapy is an emerging area of cancer research. The research proposed should not only spur clinical studies of immune cells in patients with refractory ALL but also facilitate the development of effective cell therapies for other neoplasms.