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

Abstract

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 of 125I-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 with 67Ga-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.

Expressions of a 68kDa-Glycoprotein (GP68) and Laminin in the Mesodermal Tissue of the Developing Mouse Embryo

“…So far, GP68 has also been detected in various malignant/benign tumours (Akimoto et al, 1991;Mochizuki et al, 1990) and uptake of anti-GP68 antibody into murine solid tumours has been shown (Kojima et aL, 1990). GP68 is therefore a possible candidate non-integrin LBP.…”

“…Supernatant was applied to an RCA-I agarose column equilibrated with the same buffer and washed with 0.01 M Tris-HC1 buffer (pH 7.6), containing 0.1% Triton X-100, 0.015 M NaC1 and 0.005% PMSF. GP68 was eluted in buffer containing 0.1 M lactose and 0.1% Triton X-100 (Kojima et al, 1990). The purified protein was confirmed to be a single band of approximately 68 kDa on SDS-PAGE (Lane 2 in Fig.…”