RADIOLABELING OF TUMOR ANTIBODIES

肿瘤抗体的放射性标记

• 批准号: 3168146
• 负责人: RICHARD C. REBA
• 金额: $ 20.7万
• 依托单位: GEORGE WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-04-01 至 1990-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3168146
• 关键词: antibody specificity; antigen antibody reaction; antitumor antibody; chelating agents; chemical conjugate; gel electrophoresis; human tissue; immunological substance; immunopharmacology; laboratory rabbit; neoplasm /cancer immunology; neoplasm /cancer radionuclide diagnosis; radiopharmacology; radiotracer; serum albumin; technetium

The long range objectives of this proposal are to prepare radiolabeled antibodies that are tumor specific and organ non-specific for cancer diagnosis and therapy. To achieve these objectives an indirect approach will be used to radiolabel antibodies with 111-In, 99mTc, and 90-Y. The indirect approach consists of three steps. Bifunctional chelating agents are first synthesized. These chelators are then conjugated to antibodies. The chelators are radiolabeled with the metallic radionuclides either prior to or after the conjugation to antibodies. DTPA analogues will be used as bifunctional chelators because DTPA was reported to make stable complexes with various metallic ions. Once antibodies are radiolabeled through the above steps, the chemical stability of the radiolabeled antibodies will be tested by incubating the serum in vitro. The immunoreactivity will be determined by affinity binding assays. The labeled antibody will then be injected into mice or rats with tumor xenografts or pharmacokinetic studies and imaging. A successful radioimmunoimaging or therapy is mainly determined by a relative term, a tumor to background ratio. The maximum tumor uptake was reported to take place within 1 or 2 days postinjection of 111-In or 131I labeled antibodies and 6 hrs postinjection of the radiolabeled Fab fragments. However, successful radioimmunoimaging of tumor was achieved 2 to 7 days postinjection even though the time of maximum tumor concentration has passed and background activity persists. The limiting factor for 111-In and 99mTc labeled antibodies as successful tumor imaging agents was reported to be high activities in liver. spleen and kidney (especially for F(ab')2 and Fab fragments). The major aim of this proposal is to minimize the background activities. To achieve this goal, 1) we propose to develop reliable chemical methods to conjugate DTPA analogues to antibodies which result in minimum deactivation of immunoreactivity and optimum clearance from, blood, liver and kidney. We will place a spacer with a chemical bond, less stable than a peptide bond, between DTPA and antibody. 2) We will optimize conditions for radiolabeling the antibody DTPA conjugates with 111-In, 99mTc and 90-Y. 3) We will develop analytical methods to separate immunoreactive antibody from irrelevant or deactivated antibody. 4) We will investigate a system to amplify a tumor to background ratio. 5) We will investigate the effects of pharmacokinetic parameters such as antibody concentration, antigen concentration (or tumor size) and circulating antigen on the tumor to background ratio.

该提案的远距离目标是准备放射标记的 肿瘤特异性和器官非特异性癌症的抗体 诊断和治疗。 为了实现这些目标一种间接的方法 将用于具有111英寸，99mtc和90-Y的放射性标记抗体。 这 间接方法包括三个步骤。 双功能螯合剂 首先合成。 然后将这些螯合剂缀合至抗体。 螯合剂用金属放射性核素进行放射性标签 与抗体结合后或之后。 DTPA类似物将用作双功能螯合剂，因为DTPA为 据报道使各种金属离子具有稳定的复合物。 一次 抗体通过上述步骤进行放射性标记，即化学稳定性 放射标记的抗体将通过在血清中孵育 体外。 免疫反应性将由亲和力结合确定 测定。 然后将标记的抗体注射到小鼠或大鼠中 肿瘤异种移植物或药代动力学研究和成像。 成功 放射免疫影像学或治疗主要由相对项确定 肿瘤与背景比。 据报道，最大肿瘤吸收 注射111英寸或131i标记抗体后1或2天内放置 放射性标记的Fab碎片的注射后6小时。 然而， 成功的肿瘤成功放射免疫影像学2至7天 注射后即使最大肿瘤浓度的时间具有 通过，背景活动仍然存在。 111英寸的限制因素 99mTC将抗体标记为成功的肿瘤成像剂是 据报道是肝脏的高活动。脾脏和肾脏（尤其是 F（AB'）2和Fab碎片）。 该提议的主要目的是最小化 背景活动。 为了实现这一目标，1）我们建议开发 可靠的化学方法与DTPA类似于抗体的类似物 导致免疫反应性和最佳间隙的最小停用 来自血液，肝脏和肾脏。 我们将用化学物质放置一个垫片 DTPA和抗体之间的键，不如肽键稳定。 2）我们 将优化用于放射标记抗体DTPA偶联物的条件 111英寸，99mtc和90-y。 3）我们将开发分析方法 与无关或失活抗体的单独免疫反应性抗体。 4）我们将研究一个系统以扩大肿瘤与背景比率。 5） 我们将研究药代动力学参数的影响，例如 抗体浓度，抗原浓度（或肿瘤大小）和 肿瘤与背景比的循环抗原。