^(99m)Tc标记抗癌胚抗原单抗C50片段Fab’及其生物分布研究  

Studies of ^(99m)Tc labeled carcinoembyronic antigen monoclonal antibody C50 fragment Fab’ and biodistrobution

作　　者：杨志[1] 林保和[1] 韩燕[1] 牟阿平[1] 孔健[2] 张梅颖[1] 

机构地区：[1]北京大学临床肿瘤学院(北京市肿瘤防治研究所)核医学科,北京100036 [2]北京生物制品研究所

出　　处：《北京医科大学学报》2000年第6期536-539,共4页Journal of Peking University(Health Sciences)

摘　　要：目的 :研究克服99mTc标记抗癌胚抗原 (carcinoembryonicantigen ,CEA)单抗体内生物半衰期长、血液廓清速度慢、晚时相放射性信号弱等缺点的方法 ,用直接标记法进行了99mTc标记抗CEA抗体C5 0片断Fab’的研究。方法 :经胃蛋白酶切得的C5 0片断F(ab’) 2 用适量的 2 巯基乙醇还原 ,SephadexG5 0柱分离获得纯度大于 90 %的Fab’片断。取 0 .6～ 1.0mg纯化的片段Fab’(体积 <1.0ml) ,加入 0 .4～ 0 .8mg葡庚糖酸钠及新鲜配制的SnCl2溶液 5～ 10 μg ,然后加入新鲜淋洗的Na99mTcO4 淋洗液 ,反应 10～ 15min。用高压液相色谱监测放化纯度和抗体纯度。荷CL 187(结肠癌 )裸鼠静脉注射99mTc Fab’ ,观察标记抗体片段在不同时相的体内分布。结果 :标记率大于 90 %。荷瘤裸鼠体内分布结果显示 :在注射99mTc Fab’ 4h后瘤 /血、瘤 /肝、瘤 /肺放射性摄取比分别为 1.93、2 .35和 3 .13 ,2 4h后则分别为 4.91、2 .6 2和 5 .2 6 ,肿瘤的ID(% ) / g(每克组织的摄取率 )为 2 .73。虽然注射99mTc标记的全抗C5 0后 2 4h ,肿瘤的ID(% ) /g高达 12 .5 ,但瘤 /血比值仅为 1.5 1。结论 :采用99mTc直接法标记Fab’是成功的 ,肿瘤与非肿瘤 (T/NT)的比值除肾外在早期 4h时均大于 2 .0 ,明显高于全抗的T/NT比值 。Objective:To study 99m Tc labeled anti CEA antibody C50 fragment Fab’ and its biodistribution. Methods: F(ab)’ 2 of C50 was reduced by 2 mercapthonal and purified by Sephadex G50 column. Fab’ was obtained with a purity of over 90%. 0.6 1.0 mg Fab’(<1.0 ml) was mixed with 0.4 0.8 mg glucoheptonate, followed by adding 5 10 μl freshly prepared SnCl 2 solution (1.0 mg SnCl 2 in 0.01 mol·L -1 HCl). Then about 1.0 ml of freshly eluted Na 99m TcO 4 was added to the mixture mentioned above and the mixture was slightly shaken. The solution was incubated at room temperature for 15 min. The labeling efficiency was determined by HPLC or ITLC SG method.Nude mice bearing CL 187 tumor xenografts were injected with 99m Tc Fab’ via vein tail and the ID(%)/g (% injected doses /g) of organs were obtained at various time points of postinjection. Results: The labeling efficiency of 99m Tc Fab’ was more than 90%. The ratios of tumor to blood, liver and lung were 1.93, 2.35 and 3.13 4 hours after injection. In addition, these ratios reached up to 4.91, 2.62, and 5.26, 24 hours after injection respectively. 4 hours and 24 hours after injection of 99m Tc Fab’, the ID(%)/g of tumor was 4.53 and 2.73 respectively. Although at the 24 th hour, the ID(%)/g of tumor of 99m Tc C50(intact) reached up to 12.5, the ratio of tumor/blood was only about 1.5. Conclusion: 99m Tc labeled Fab' was successfully prepared by direct labeling technique, and the T/NT ratios were more than 2.0 except that with the kidney which was significantly higher than that of 99m Tc labeled C50 (intact). These are favorable to get clear images at earlier time after injection of 99m Tc Fab'. These indicate that 99m Tc C50 Fab' seems to be a good radiopharmaceutical for RII.

关 键 词：单克隆抗体 癌胚抗原 同位素标记 锝^99M 肿瘤 

分 类 号：R730.4[医药卫生—肿瘤]