抗EGFR单抗放免显像三步法预定位技术的实验研究

Experimental study of three step pretargeting technique for anti EGFR McAb radioimmunoimaging

目的 提高抗表皮生长因子受体（ＥＧＦＲ） 单抗放免显像的诊断效果。方法 应用三步法（ 抗ＥＧＦＲ单抗生物素亲和素，ＩｇＭ生物素，１１１ＩｎＤＴＰＡ生物素）给药，在注射放射性标记物后２ ～４ｈ 对荷Ａ５４９ 肿瘤细胞裸鼠进行γ显像并测定生物学分布。结果 三步法组２ ｈ 已见肿瘤部位放射性浓聚，４ ｈ 明显显影；对照组无明显显影。三步法组显像瘤／血比值为２－３５４ ±０－４３２ ，明显高于对照组（ 两步法组、放射性标记物组和直接标记法组分别为１－４１５ ±０－３３２，０－９６１ ±０－４４６ ，１－４３８ ±０－３６１） ，Ｐ＜０－０５。结论 三步法给药能迅速降低本底，提高靶／ 非靶比值，缩短显像时间。

Objective Three step pretargeting technique was used to promote the diagnostic efficacy of anti EGFR McAb radioimmunoimaging Methods Experimental A549 tumor bearing nude mice model was used Anti EGFR McAb conjugated with Biotin and Avidin was injected, followed by IgM Biotin 24 h later and 111 In DTPA Biotin 27 h later 2 h to 4 h afterwards, γ imaging and biodistribution study were also performed Results With three step pretargeting technique, the tumor was clearly visualized at 2 h and clearlier at 4 h in γ imaging At the time of imaging, tumor/blood pool ratio was 2 354±0 432, while for control group were 1 415±0 332, 0 961±0 446, 1 438±0 361, respectively The T/NT of all organs was also higher in three step pretargeting group than that in controls In controls, the tumor was not visualized Conclusions Three step pretargeting technique can elevate the T/NT ratio and decrease the blood background; earlier and better images can be obtained using this technique The using of this technique for radioimmunotherapy is promising