两种方法标记^(99m)Tc抗CEA单抗及其鼠放免显像的比较研究

Comparative study of two methods of 99m Tc-lablled anti-CEA monoclonal Antibodies with nude mice radioinmunoimaging.

目的 评价两种方法^(99m)Tc标记抗CEA单抗与结肠癌肿瘤细胞表现相关抗原的亲和性。方法 分别采用2巯基乙醇法(2-ME)和亚氨基噻吩盐酸盐(2-IT)法,以新鲜^(99m)Tc淋洗液标记抗CEA单抗,并对荷人结肠癌裸鼠进行SPECT显像,比较两种标记方法的显像效果。结果 2-ME法标记单抗在实验所得最佳标记条件免疫活性(B/T％)69.1％,标记率为88.7％,胶体含量8.1％。2-IT法标记的单抗免疫活性可达73.2％,标记率为93.7％,胶体含量4.8％。稳定性以2-IT方法为佳标记后1、2、6、12小时放化纯皆在90％以上,标记操作时间和标记方法M者各有优缺点。二者在荷瘤裸鼠的瘤体内显像清晰,2-IT法标记抗体的瘤本比值(T/NT)为5.33±1.11,2ME法为4.11±1.53,血池和肝肾的放射性以2-ME法为高。结论 表明以2-IT法和2-MT法预处理抗CEA单抗皆具有达到外接巯基的目的,可有效进行^(99m)Tc标记,较少损伤蛋白活性,标记方法简单,放射性核素标记的抗 CEA单抗对瘤体具有较高的亲和力,适用于SPECT显像。其中以2-IT法标记率高,胶体含量少,稳定性强,T/NT值大等优点,更适用于放射免疫显像。

Purpose To evaluate the effect of two methods of 99mTc Anti - CEA monoclonal Antibodies with nude mice radiommunoimaging. Methods Labeled anti - CEA antibodies with fresh 99mTc,2 - mercaptoethanol (2 - ME) and 2 - iminohiolane (2 - IT) method was used respectively. Labeling rate and radiochemical purity were determined, and anti - CEA nude mice imaging were obtained. Results The highest radioimmunoac-tivity of labeling anti - CEA with 2 - ME was 69.1 % , the labeling rate was 88.7% and colloid content was 8.1% , whereas in 2 - IT method were 73.2% ,93.7%and 4.8% respectively. The radiochemical pruity were all above 90% at 2h,4h,6h and 24h after labeling. The stability of 2 - IT-method was better than that of 2 - ME method. The labeling time expanded and method used had their own characteristics. The radiommunoimaging showed significant radioactiviey in tumor ratio of 2 - IT and 2 - ME was 3.44 ± 0.61 and 2.92 ± 0.89 respectively. The radioactivity of blood pool, liver and kidney seems much less in mice of 2 - ME method by observation. Conclusion The pre-treatment methods of 2 - ME and 2 - IT could both satisfy the conjugation of hydrosulfide group, and also labeled 99mTc effectively with less protein injruy and simple in procedure. the Tc labeling anti - CEA antibodies had high affinity with tumor, and was suitable for radioimmunoimaging, among them the method of 2 - IT had higher labeling rate, less colloid conten, higher T/NT ratio and more stable, thereby it seemed that much more suitable for radioimmunoimaging.