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目的:探讨放射性核素125I标记单克隆抗体4E5的方法,观察标记物在正常小鼠体内的生物学分布。方法:采用Iodogen法进行单克隆抗体4E5的125I标记,标记产物用Sephadex G-50分离纯化,三氯醋酸(TCA)法测定标记率和放化纯,并对标记物的稳定性进行分析。取45只昆明小鼠随机分成9组,每只小鼠从尾静脉注入剂量为148KBq/0.2 ml的125I-4E5,分别于注药后5min、15min、30min及1h、2h、6h、24h、48h、72h各处死一组小鼠,取主要脏器称重并测量其放射性计数,计算各脏器每g组织百分注射剂量率(%ID/g)。结果:125I标记4E5的标记率为(79.2±2.6)%,放射化学纯度为(97.1±1.1)%,比活度为294.5MBq/mg;125I-4E5加入到血清及PBS中放置1w后,放化纯度仍>90%;体内分布显示125I-4E5在小鼠体内主要分布于肝、脾、肾,在血液中清除较快。结论:Iodogen法125I标记4E5的标记率和放化纯度高,方法简便,标记物的稳定性好;125I-4E5在小鼠体内主要通过肝和肾代谢,血液中清除较快。
Objective: To explore the method of 125I labeled monoclonal antibody 4E5 to observe the biological distribution of the marker in normal mice. Methods: Iodogen method was used to perform 125I labeling of monoclonal antibody 4E5. The products were separated and purified by Sephadex G-50. The labeling rate and radiochemical purity were determined by trichloroacetic acid (TCA) method. The stability of the marker was analyzed. Forty-five Kunming mice were randomly divided into 9 groups. Each mouse received a dose of 148KBq / 0.2 ml of 125I-4E5 from the caudal vein at 5min, 15min, 30min and 1h, 2h, 6h, 24h, 48h A group of mice were sacrificed at 72h. The main organs were weighed and their radioactivity counts were measured. The percentage of injected dose per gram of tissue (% ID / g) was calculated. Results: The labeling rate of 125I labeled 4E5 was (79.2 ± 2.6)%, the radiochemical purity was (97.1 ± 1.1)% and the specific activity was 294.5MBq / mg. After 125I-4E5 was added to serum and PBS for 1w, Purity is still> 90%; In vivo distribution of 125I-4E5 in mice mainly distributed in the liver, spleen, kidney, clear faster in the blood. Conclusion: Iodogen 125I-labeled 4E5 has high labeling rate and high radiochemical purity. The method is simple and the stability of the label is good. 125I-4E5 is mainly metabolized by the liver and kidneys in mice and cleared rapidly in the blood.