Murine monoclonal antibody RS5-4H6 is an IgG1, which was raised against a crude membrane preparation of Calu-3, a human adenocarcinoma of the lung cell line. MAb RS5-4H6 reacts with the majority (14 of 15) of surgical specimens of non-small cell carcinomas of the lung by immunoperoxidase staining. Reactivity with this antibody was not limited to tumors of the lung but rather exhibited pancarcinoma reactivity, staining 87% of tumors from all organs tested. In this study we examined the potential of radiolabeled RS5-4H6 to target Calu-3 xenografts in nude mice. The monoclonal antibody was found to localize preferentially to the heterotransplanted tumors, with 6.6% of the injected dose/g accreting in the tumor at 7 days, a 3-fold higher level than an anti-carcinoembryonic antigen monoclonal antibody which was used as a negative control.
Presented at the “Second Conference on Radioimmunodetection and Radioimmunotherapy of Cancer,” September 8–10, 1988, Princeton, NJ. Supported in part by NIH Grant CA39841 and the Essex Northwest Health and Breath Association.