CD8+ T cells are necessary for optimal anti-tumor effects. Mice were injected with 1 × 105 Renca i.k. and then treated with Tri-mAb on day 11 only, and IL-2 at a dose of 105 IU i.p. on days 11 and 12. Some mice received MAC 4 and UC8-1B9 antibodies as control treatment. In addition, some groups received CD8-depleting mAb as described in Materials and Methods. Results from a single experiment with 8 mice per group, P = 0.035 for Tri-mAb + IL-2 vs CD8-depleted Tri-mAb + IL-2 group (Log-rank test).