Rituximab Elicitation of Tumor Specific T-cell Responses in Lymphoma Patients

描述（由申请人提供）：Rituximab是一种靶向CD20的嵌合单克隆抗体，在滤泡性淋巴瘤（FL）患者中显示出显著的治疗活性，但其确切的作用机制尚未完全确定。虽然通过补体依赖性细胞溶解、抗体依赖性细胞毒性或直接诱导凋亡杀死CD20+ FL细胞可能有助于其有效性，但这些机制不太可能是其唯一的作用机制，因为；(a)对利妥昔单抗的临床和分子反应可能在最后一剂利妥昔单抗后持续数月；(b)利妥昔单抗第二次应答的中位持续时间比第一次应答的中位持续时间长，临床结果不能仅用上述机制来解释。利妥昔单抗诱导的FL细胞死亡预计会导致肿瘤抗原的释放，例如来自FL相关免疫球蛋白（Ig）重链（VH）和轻链（VL）可变区域的抗原，以及在促炎环境中尚未确定的肿瘤抗原。我们假设，利妥昔单抗诱导淋巴瘤相关抗原的释放将引发细胞介导的淋巴瘤特异性免疫反应。我们将通过Elispot、Fluorispot、Lysispot和细胞内细胞因子流式细胞术检测，监测新诊断的FL患者外周血和肿瘤浸润性淋巴瘤特异性效应和/或记忆性CD4+和CD8+ t细胞的存在，来验证这一假设。我们还将检验这一假设的两个推论，即利妥昔单抗引发活动性淋巴瘤特异性细胞反应；(a)导致淋巴瘤特异性CD4+和CD8+ T细胞的效应功能增加；(b)提供产生淋巴瘤特异性体液反应所需的T细胞帮助。利妥昔单抗产生淋巴瘤特异性免疫反应的证明，以及对该反应的靶抗原的了解，将对我们如何最佳地治疗FL患者产生深远的影响。例如，它将表明，利妥昔单抗与预期会增强淋巴瘤特异性t细胞反应的药物联合使用，如GM-CSF、CpG寡核苷酸和抗ctla -4单克隆抗体。会有潜在的临床益处。此外，本研究的结果应该适用于其他恶性肿瘤的抗体治疗，因此，我们预计这些研究将导致新的治疗策略，旨在提高单克隆抗体治疗癌症的有效性。滤泡性淋巴瘤（滤泡性淋巴瘤）是一种惰性的，但基本上无法治愈的疾病，然而新的治疗方法，包括利妥昔单抗治疗，为患有这种疾病的患者带来了新的希望。利妥昔单抗是一种抗体，它是一种蛋白质，可以靶向淋巴瘤细胞上的另一种蛋白质，导致淋巴瘤细胞死亡，但利妥昔单抗破坏淋巴瘤细胞的确切机制尚不清楚。我们的团队正在确定Rituximab是否通过刺激患者自身免疫系统来诱导淋巴瘤细胞死亡，以根除疾病，因为更好地了解Rituximab如何在淋巴瘤患者中起作用，将使我们能够开发新的治疗方法，我们预计将为这种疾病患者带来更多的益处。

DESCRIPTION (provided by applicant): Rituximab, a chimeric monoclonal antibody directed against CD20, has shown significant therapeutic activity in patients with follicular lymphoma (FL), yet it's exact mechanism of action has not been completely defined. Although killing of the CD20+ FL cells, either through complement dependent cytolysis, antibody dependent cellular cytotoxicity or direct induction of apoptosis may contribute to its effectiveness, these mechanisms are unlikely to be the only mechanisms of action as; (a) the clinical and molecular responses to Rituximab may continue for months after the last dose of Rituximab and; (b) the median duration of the second response to Rituximab is longer than that of the first response, clinical findings that cannot be explained solely by the mechanisms described above. Rituximab induced FL cell death is expected to result in the release of tumor antigens, for example antigens derived from the variable regions of the heavy (VH) and light chains (VL) of the FL associated immunoglobulin (Ig), and also as yet undefined tumor antigens, in a pro-inflammatory environment. We hypothesize that the Rituximab induced release of lymphoma-associated antigens will provoke a cell-mediated lymphoma specific immune response. We will test this hypothesis by monitoring newly diagnosed FL patients for the presence of both peripheral blood and tumor infitrating lymphoma specific effector and/or memory CD4+ and CD8+ T-cells, before and after Rituximab treatment using Elispot, Fluorispot, Lysispot and intracellular cytokine flow cytometric assays. We will also test two corollaries of this hypothesis, being that a Rituximab elicited active lymphoma specific cellular response would; (a) result in an increase in the effector functions of both the lymphoma-specific CD4+ and CD8+ T cells; and (b) provide the necessary T- cell help required to generate lymphoma-specific humoral responses. The demonstration that Rituximab generates a lymphoma specific immune response, as well as the knowledge of the target antigens of the response would have profound implications as to how we optimally treat patients with FL. For example, it would suggest that combining Rituximab with agents which would be anticipated to augment the elicitation of a lymphoma specific T-cell response, such as GM-CSF, CpG oligonucleotides, and anti-CTLA-4 monoclonal antibodies, would be of potential clinical benefit. In addition, the results of this study should be applicable to antibody therapy of other malignancies, and as such, we anticipate that these studies will lead to novel treatment strategies designed to enhance the effectiveness of monoclonal antibody therapy for cancer in general. Follicular lymphoma (FL) is an indolent, but essentially incurable disease, however new treatments, including Rituximab therapy, are offering new hope for patients suffering with this disease. Rituximab is an antibody, which is a protein that targets another protein on the lymphoma cell, resulting in lymphoma cell death, however the exact mechanism(s) by which Rituximab destroys lymphoma cells is not yet clearly defined. Our group is determining whether Rituximab induces lymphoma cell death by stimulating the patient's own immune system to eradicate the disease, as a better understanding of how Rituximab works in patients with lymphoma will allow us to develop new approaches to treatment that we anticipate will lead to increased benefit for patients with this disease. PROJECT SUMMARY/ABSTRACT Rituximab, a chimeric monoclonal antibody directed against CD20, has shown significant therapeutic activity in patients with follicular lymphoma (FL), yet it's exact mechanism of action has not been completely defined. Although killing of the CD20+ FL cells, either through complement dependent cytolysis, antibody dependent cellular cytotoxicity or direct induction of apoptosis may contribute to its effectiveness, these mechanisms are unlikely to be the only mechanisms of action as; (a) the clinical and molecular responses to Rituximab may continue for months after the last dose of Rituximab and; (b) the median duration of the second response to Rituximab is longer than that of the first response, clinical findings that cannot be explained solely by the mechanisms described above. Rituximab induced FL cell death is expected to result in the release of tumor antigens, for example antigens derived from the variable regions of the heavy (VH) and light chains (VL) of the FL associated immunoglobulin (Ig), and also as yet undefined tumor antigens, in a pro-inflammatory environment. We hypothesize that the Rituximab induced release of lymphoma-associated antigens will provoke a cell-mediated lymphoma specific immune response. We will test this hypothesis by monitoring newly diagnosed FL patients for the presence of both peripheral blood and tumor infitrating lymphoma specific effector and/or memory CD4+ and CD8+ T-cells, before and after Rituximab treatment using Elispot, Fluorispot, Lysispot and intracellular cytokine flow cytometric assays. We will also test two corollaries of this hypothesis, being that a Rituximab elicited active lymphoma specific cellular response would; (a) result in an increase in the effector functions of both the lymphoma-specific CD4+ and CD8+ T cells; and (b) provide the necessary T- cell help required to generate lymphoma-specific humoral responses. The demonstration that Rituximab generates a lymphoma specific immune response, as well as the knowledge of the target antigens of the response would have profound implications as to how we optimally treat patients with FL. For example, it would suggest that combining Rituximab with agents which would be anticipated to augment the elicitation of a lymphoma specific T-cell response, such as GM-CSF, CpG oligonucleotides, and anti-CTLA-4 monoclonal antibodies, would be of potential clinical benefit. In addition, the results of this study should be applicable to antibody therapy of other malignancies, and as such, we anticipate that these studies will lead to novel treatment strategies designed to enhance the effectiveness of monoclonal antibody therapy for cancer in general.PROJECT NARRATIVE Follicular lymphoma (FL) is an indolent, but essentially incurable disease, however new treatments, including Rituximab therapy, are offering new hope for patients suffering with this disease. Rituximab is an antibody, which is a protein that targets another protein on the lymphoma cell, resulting in lymphoma cell death, however the exact mechanism(s) by which Rituximab destroys lymphoma cells is not yet clearly defined. Our group is determining whether Rituximab induces lymphoma cell death by stimulating the patient's own immune system to eradicate the disease, as a better understanding of how Rituximab works in patients with lymphoma will allow us to develop new approaches to treatment that we anticipate will lead to increased benefit for patients with this disease.