Biodistribution and radioimmunoscintigraphy studies of renal cell carcinoma using tumor-preferential monoclonal antibodies and F(ab')2 fragments.

The in vivo localization of renal cell carcinoma-preferential monoclonal antibodies A6H, D5D, and C5H was evaluated and the biodistribution of F(ab')2 antibody fragments of A6H and the intact Mab were compared in over 100 nude mice. A6H localized well to most renal cell carcinoma xenografts studied; the median tumor to blood ratios ranged from 6.4 to 11.5 for various xenografts. C5H also localized well to most renal cell carcinoma xenografts tested. However, D5D did not localize well to renal cell carcinoma xenografts in vivo despite its highly restrictive in vitro reactivity. The F(ab')2 fragments of A6H produced higher tumor to blood ratios, which probably resulted from fast clearance of the fragments from the circulation. Preliminary results showed that indium-111 labeling may further improve imaging.