Duran A P, Asurmendi S, D'Orio E, Horenstein A L, de Castiglia S G
Oncologic Center of Nuclear Medicine, Institute of Oncology, Angel H. Roffo, Buenos Aires, Argentina.
J Nucl Biol Med (1991). 1994 Dec;38(4 Suppl 1):33-7.
Two anti-CEA antibodies, B2C114 and IORCEA1, were radiolabeled with 99mTc by two direct methods (mercaptoethanol and ascorbic acid reduction), and the radio-immunoimaging properties of B2C114 were assessed in mice bearing an M3-reactive tumor. The labeling efficiency was greater than 90% as measured by ITLC in saline, methylethylketone and with serum albumin impregnated sheets using ethanol: water: NH4OH (2:5:1). The label was stable to challenge with excess DTPA, and in the case of ascorbic acid reduction, serum analysis showed that 10-15% of the radioactivity was lost during incubation. In vitro studies demonstrated that the radiolabeled antibodies retained their immunoreactivity. Biodistribution studies in normal Balb/c mice showed that the pattern of uptake was quite similar for both antibodies. Biodistribution of the 99mTc-B2C114 and image studies in the animal model showed that the tumor was clearly visualized and that B2C114 labeled with 99mTc is a possible candidate for human radioimmunodetection of CEA-expressing tumors.
两种抗癌胚抗原（CEA）抗体，B2C114和IORCEA1，通过两种直接方法（巯基乙醇和抗坏血酸还原法）用99mTc进行放射性标记，并在携带M3反应性肿瘤的小鼠中评估了B2C114的放射免疫成像特性。在生理盐水、甲乙酮以及使用乙醇：水：氢氧化铵（2:5:1）浸渍血清白蛋白的薄板上，通过离子交换薄层层析法（ITLC）测定，标记效率大于90%。该标记物对过量二乙三胺五乙酸（DTPA）的挑战具有稳定性，在抗坏血酸还原法的情况下，血清分析表明，在孵育过程中有10 - 15%的放射性丢失。体外研究表明，放射性标记的抗体保留了它们的免疫反应性。在正常Balb/c小鼠中的生物分布研究表明，两种抗体的摄取模式非常相似。99mTc - B2C114在动物模型中的生物分布和成像研究表明，肿瘤能够清晰地显现出来，并且用99mTc标记的B2C114可能是用于表达CEA肿瘤的人体放射免疫检测的候选物。
