Intracellular catabolism of radiolabeled anti-mu antibodies by malignant B-cells.
Intracellular catabolism of radiolabeled anti-mu antibodies by malignant B-cells.
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发表时间：
1992-05
期刊：
影响因子：
11.2
通讯作者：
F. Geissler;S. K. Anderson;P. Venkatesan;O. Press
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文献类型：
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作者：
F. Geissler;S. K. Anderson;P. Venkatesan;O. Press
采用生化、色谱、电泳、放射自显影和电镜技术研究了125i标记的抗mu单克隆抗体DA4-4在伯基特淋巴瘤细胞株的内吞和降解。125I-DA4-4被Ramos细胞迅速内化并从核内体传递到溶酶体。放射性标记抗体的蛋白水解始于内体晚期，但溶酶体主要负责125I-DA4-4的最终降解。125I-DA4-4的分解代谢可被抑制74-95%，通过18℃孵育阻断其传递到晚期核内体和溶酶体，用莫能菌素或氯化铵中和胞内细胞器的pH，或用胰肽抑制溶酶体酶。使用氯胺T或碘- gen技术合成的放射性标记抗体的降解速度比使用不可代谢的125i -酪胺纤维素二糖加合物的结合物快三倍。125I-DA4-4在细胞内分解代谢过程中产生了5种主要的中间代谢物（Mr 48,000, 42,000, 25,000, 15,000和10,000），但细胞释放到培养基中的小分子量代谢物中有95%是由125i -酪氨酸产生的。我们预计，对肿瘤细胞放射标记抗体分解代谢的充分理解将使临床干预措施的发展成为可能，这些干预措施将增强血液恶性肿瘤的放射免疫偶联物的保留，并提高放射免疫治疗的疗效。
The endocytosis and degradation of 125I-labeled anti-mu monoclonal antibody DA4-4 by a Burkitt's lymphoma cell line was investigated using biochemical, chromatographic, electrophoretic, radioautographic, and electron microscopic techniques. 125I-DA4-4 was rapidly internalized by Ramos cells and routed from endosomes to lysosomes. Proteolysis of radiolabeled antibodies began in a late endosomal compartment, but lysosomes were primarily responsible for the terminal degradation of 125I-DA4-4. Catabolism of 125I-DA4-4 could be inhibited by 74-95% by blocking its delivery to late endosomes and lysosomes by incubation at 18 degrees C, by neutralizing the pH in intracellular organelles with monensin or ammonium chloride, or by inhibiting lysosomal enzymes with leupeptin. Radiolabeled antibodies synthesized using the chloramine T or Iodo-Gen techniques were degraded three times faster than conjugates made using a nonmetabolizable 125I-tyramine cellobiose adduct. Five major intermediate metabolites (Mr 48,000, 42,000, 25,000, 15,000, and 10,000) were generated during the intracellular catabolism of 125I-DA4-4, but 125I-tyrosine was responsible for 95% of the small-molecular-weight metabolites released by cells into the culture medium. We anticipate that a full comprehension of the catabolism of radiolabeled antibodies by tumor cells will make possible the development of clinical interventions which will enhance the retention of radioimmunoconjugates by hematologic malignancies and improve the efficacy of radioimmunotherapy.