Gd标记抗人大肠癌单克隆抗体CL－3对裸鼠肿瘤模型MRI诊断的实验研究

目的（１）探索磁共振成像（ＭＲＩ）造影剂标记单克隆抗体（ＭｃＡｂ）的条件；（２）观察肿瘤特异性ＭＲＩ造影剂ＧｄＤＴＰＡＭｃＡｂ对肿瘤组织的增强效果。方法给９只１０周龄ＢＡＬＢ／ｃ裸鼠皮下注射ＬＳ１７４Ｔ大肠癌细胞以制作肿瘤的动物模型，将ＣＬ３单克隆抗体与ＤＴＰＡ环二酸酐（ｃ．ＤＴＰＡ）相偶联，再加入钆即得到ＧｄＤＴＰＡＭｃＡｂ。观察肿瘤组织在ＧｄＤＴＰＡＭｃＡｂ增强后的信号强度变化。结果（１）当ｐＨ＝８．０，Ｃ／Ｐ（ｃ．ＤＴＰＡ与抗体的摩尔比）＝１，ＣＬ３浓度＝１０ｍｇ／ｍｌ时，ｃ．ＤＴＰＡ与抗体的偶联率最高，达６８．２％。（２）ＧｄＤＴＰＡ及ＧｄＤＴＰＡＭｃＡｂ对肿瘤组织均有明显的强化作用，两者的区别在于：前者的强化是非特异性的，而后者的强化则具有肿瘤特异性。结论靶向ＭＲＩ（ＧｄＤＴＰＡＭｃＡｂ）为早期无创、定位定性诊断结肠癌（包括其他肿瘤）及其转移灶的显示提供了可行的方法。

Experimental study on gadolinium labeled anti human colonic carcinoma antibody CL 3 for magnetic resonance imaging diagnosis in nude mice with LS 174T cancer

Purpose The aims of this study were:(1)To find out the optimal measures for the conjugation of gadolinium and monoclonal antibody;(2)To observe the contrast enhancement effect of tissue specificity with MRI contrast medium McAb(gadolinium DTPA McAb). Methods Nine nude mice were used as animal models by subcutaneous injection of LS 174T cell.DTPA anhydride and CL 3 monoclonal antibody were first conjugated.Then,gadolinium acetate was added to label DTPA McAb and gadolinium DTPA McAb was thus available. MRI was performed with a Bruker/Spectrospin Tomikon BMT 1100 MRI system.The enhancing effect of Gd DTPA McAb was compared with that of Gd DTPA. Results (1) The optimal measures of the conjugation of DTPA anhydride and monoclonal antibody were as follows:pH=8.0,DTPA anhydride/antibody=1,CL 3=10mg/ml.The optimal conjugate rate was 68.2%. (2)Both Gd DTPA McAb and Gd DTPA showed significant enhancement effect in nude mice with LS 174T cancer. The enhancement effect of Gd DTPA McAb was tumor specific,while thaf of Gd DTPA was not(non specific). Conclusion Targeting MRI (Gd DTPA McAb) is probably a feasible and promising modality in the early detection of colon cancer (as well as other cancers) and their metastatises.