Retroviral Immunotoxins for Leukemia

白血病的逆转录病毒免疫毒素

• 批准号: 6941396
• 负责人: Daniel A Vallera
• 金额: $ 31.41万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-04-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6941396
• 关键词: T lymphocyte; antigen antibody reaction; cytotoxic T lymphocyte; drug delivery systems; flow cytometry; genetic transduction; helper T lymphocyte; histology; immunoconjugates; immunotoxicity; interleukin 2; laboratory mouse; leukemia; neoplasm /cancer immunotherapy; neoplasm /cancer pharmacology; nonhuman therapy evaluation; transfection /expression vector

DESCRIPTION (provided by applicant): Immunotoxins (IT) are experimental pharmacologic agents that are made by linking antibodies or cytokines that specifically bind to cancer cells to potent catalytic toxins of which a single molecule can kill a cell. Their major purpose is to deliver therapy selectively to cancer cells instead of non-target organs, as does conventional chemotherapy. Although these agents selectively bind and kill cancer cells, clinically they have been limited by their 1) failure to penetrate and localize in adequate concentrations in cancer target tissue 2) localization in nontarget organs limiting the tolerated dose and collapsing the therapeutic window. In this proposal, we will explore a solution to this problem. Cells of the immune system such as T cells are the most prominent cell types which penetrate, attack, and destroy cancer cells and are naturally suited for the expression and production of cytokines in response to antigenic challenge. Therefore, in the first cycle of funding we took advantage of the a well-known property of T cells which is their ability to migrate to tumors and provided proof that they could be used to deliver immunotoxin to leukemia in vivo using gene therapy. We showed that T cells could deliver retroviral IT (retlT) consisting of IL-3 spliced to genetically modified toxin locally at the site of the leukemia and produce a significant anti-leukemia effect. Our studies have now generated several important questions concerning this new class of agent, and in this proposal, we will attempt to determine how they work. We have established a new model of retlT therapy which we will use as a foundation for future attempts to modify and improve retlT. The model takes advantage of the use of antigen specific T cell clones. We will use this to test the usefulness of retlT leukemia therapy. Previous studies focused us on a single ligand (IL-3). Now, in aim 1 we will characterize the role of T cells in this established model, determining whether it is better to use CD4+ or CD8+ T cell clones for delivery. Then in aims 2, 3, and 4 we will determine just how and why our approach works. Aim 2 will focus on the T cell component of the model and we will ask how many T cells localize to the tumor in vivo as compared to other extratumoral sites. Will the localization of T these retlT secreting T cells cause toxicity? Aim 3 focuses on the IT moiety and we will determine the role of secreted IT and how much is necessary. Finally in aim 4, we will determine if retlT can reduce toxicity compared to conventional IT and whether they have effects on components of the host immune system.

描述（由申请人提供）：免疫毒素（IT）是通过将特异性结合癌细胞的抗体或细胞因子与强效催化毒素（其单个分子可杀死细胞）连接而制备的实验药理学试剂。它们的主要目的是选择性地向癌细胞而不是非靶器官提供治疗，就像常规化疗一样。尽管这些药剂选择性地结合并杀死癌细胞，但在临床上它们受到以下限制：1）不能以足够的浓度渗透并定位在癌症靶组织中; 2）定位在非靶器官中，从而限制了耐受剂量并破坏了治疗窗。在本提案中，我们将探讨解决这一问题的办法。免疫系统的细胞如T细胞是穿透、攻击和破坏癌细胞的最突出的细胞类型，并且天然地适合于响应抗原攻击而表达和产生细胞因子。因此，在第一轮资助中，我们利用了T细胞的一个众所周知的特性，即它们迁移到肿瘤的能力，并提供了证据，证明它们可用于使用基因治疗在体内向白血病提供免疫毒素。我们发现T细胞可以在白血病部位局部递送由IL-3剪接到遗传修饰的毒素组成的逆转录病毒IT（retlT），并产生显著的抗白血病作用。我们的研究现在已经产生了几个重要的问题，关于这类新的代理，在这个建议中，我们将试图确定它们是如何工作的。我们已经建立了一个新的模型retlT治疗，我们将使用作为基础，为未来的尝试修改和改善retlT。该模型利用了抗原特异性T细胞克隆的使用。我们将用它来测试retlT白血病治疗的有效性。以前的研究集中在一个单一的配体（IL-3）。现在，在目标1中，我们将描述T细胞在这个建立的模型中的作用，确定使用CD 4+或CD 8 + T细胞克隆进行递送是否更好。然后在目标2、3和4中，我们将确定我们的方法如何以及为什么有效。目标2将集中于模型的T细胞成分，我们将询问与其他瘤外部位相比，体内有多少T细胞定位于肿瘤。这些分泌retlT的T细胞的定位会引起毒性吗？目标3侧重于IT部分，我们将确定分泌IT的作用以及需要多少。最后，在目标4中，我们将确定与常规IT相比，retlT是否可以降低毒性，以及它们是否对宿主免疫系统的组分具有影响。