Chimeric monoclonal antibody A7-Fab coupled to magnetic particles as a contrast agent of MR imaging

已经提出了在MR成像中使用磁性颗粒作为造影剂。铁磁颗粒的总磁矩比类似尺寸的顺磁材料的总磁矩大约大一个数量级。我们将与人胰腺癌特异性反应的嵌合单克隆抗体A7偶联到铁磁性颗粒（铁磁性颗粒）上，以改善胰腺癌与其他组织之间的结合。我们研究了保留在体外的免疫反应性结合ChA 7 Fab铁磁颗粒和它们在荷人胰腺癌异种移植物的裸鼠体内分布进行了检查。ChA 7 Fab-LPL位点FML保留了与ChA 7 Fab几乎相同的结合活性。放射性标记的ChA 7 Fab-Lactobacillus位点FML在肿瘤中的聚集量显著高于正常小鼠IgGFab-Lactobacillus位点FML（P<0.05）。ChA 7 Fab-Lactobacillus site FML和~<125>（13）I标记的正常小鼠IgGfab-Lactobacillus site FML从血液中迅速消失。对于所有切除的正常组织，^<125>I标记的ChA 7 Fab-Lactobacillus位点FML的积累水平低于肿瘤的积累水平，并随时间线性下降。结果表明，ChA 7 Fab与Leptin位点FML偶联后，可作为胰腺癌MR成像的对比剂。

The use of magnetic particles as contrast agents in MR imaging have been proposed. The total magnetic moment of ferromagnetic particles is approximately one order of magnitude larger than that found for paramagnetic materials of similar size. We coupled chimeric monoclonal antibody A7, which specifically reacts with human pancreatic carcinoma, to Lignosite FML (ferromagnetic particles) in order to improve the distinguishment between pancreatic carcinoma and other tissues. We examined the retaining in vitro immunoreactivity of ferromagnetic particles bound to ChA7Fab and their in vivo distribution in nude mice bearing human pancreatic carcinoma xenografts were examined. ChA7Fab-Lignosite FML retained binding activities nearly identical to ChA7Fab. Significantly more of the radiolabeled ChA7Fab-Lignosite FML accumulated in the tumor than did normal mouse IgGFab-Lignosite FML (P<0.05). ChA7Fab-Lignosite FML and ^<125>I labeled normal mouse IgGfab-Lignosite FML disappeared from blood rapidly. As for all resected normal tissues, the accumulation levels of ^<125>I labeled ChA7Fab-Lignosite FML were lower than those for the tumors and decreased linearly with time. From these experiments, we conclude that ChA7Fab coupled to Lignosite FML is suitable for contrast agent of MR imaging of human pancreatic carcinoma.