in Nude Mice 1,2,3

ABSTRACT-The antibody 3F8, an IgG3 murine monoclonal anti-body (MoAb) against disialoganglioside G02, could target iodine-131 (131 1) to established subcutaneous human neuroblastoma (NB) xenografts in BALB/c nude mice. 1311-radiolabeled MoAb (0.125-1 mCi) was injected iv. Tumor radioactivity over time was calculated from scintigraphy, and radiation dose to individual tumors was cal-culated. Tumor shrinkage occurred only with 131 I-labeled 3F8, but not with nonradioactive 3F8 or radiolabeled irrelevant antibody. While the tumor of the control mice enlarged by tenfold, the treated tumor showed over 95 % shrinkage by 12 days. Both the rate of shrinkage and duration of tumor response were dose dependent. Calculated doses of more than 10,000 rad could be achieved. Only those tumors that received more than 4,200 rad were completely ablated without recurrence. Recurrent tumors were not antigen negative or radioresistant. These results confirmed the predictio