Radioimmunoimaging of tumors with radioactive antibody against a glycoprotein (GP68) found in developing mouse brain

Summary The in vivo localization of a polyclonal antibody (pAb) against a glycoprotein with a molecular mass of 68 kDa (GP68), which was found in developing mouse brain, was studied in murine tumor models to evaluate potential applications of this antibody for in vivo radioimmunodetection and/or therapy of cancer. The tissue distribution of¹²⁵I-labeled GP68 pAb 3 days after i.V. injection into mice bearing four different kinds of solid tumor revealed a high uptake ratio by adenocarcinoma 755 and Lewis 3LL lung cancer. In contrast, the uptake ratio was low in mice bearing Ehrlich solid tumor and sarcoma-180 (S-180). These uptake ratios accorded well with the in vitro binding activity of this antibody with the tumor cells. In an immunoscintigraphic study, adenocarcinoma 755 was successfully visualized with⁶⁷Ga-labeled GP68 pAb. The results of these biodistribution and in vivo radioimmunoscintigraphic studies suggest that GP68 antibody may be applicable to the diagnosis and/or therapy of cancer.Abbreviations pAb polyclonal antibody - AFP -fetoprotein - GP68 68-kDa glycoprotein