Coadministration of IL-2 enhances the survival of mice bearing orthotopic kidney cancer. Groups of mice bearing 10-day established kidney tumors were treated with either Tri-mAb alone (days 10, 14 and 18), IL-2 alone (105 IU i.p. daily for 4 to 6 days) or the combination of Tri-mAb + IL-2. Other groups were non-treated (NT). Numbers in parentheses depict the number of mice per group. Pooled results of 4 experiments are shown. (P2 < 0.0001 for Tri-mAb + HD IL-2 vs Tri-mAb alone, Log-rank Test). (NT = non-treated, HD = high dose).