Depletion of CD4+ CD25+ regulatory T cells has no effect on vaccine efficacy. 1 x 10⁵ TC-1 tumor cells were implanted s.c. at day 0 in six- to eight-week-old E6/E7 transgenic mice. For experimental groups, mice were depleted of regulatory T cells using i.p. injections of 0.5 mg of PC61 anti-CD25 mAb on days 4 and 6, which was then followed either by i.p. immunization with 1 x 10⁸ LM-LLO-E7 or the mice were left naive. In control groups, when palpable tumors formed seven days later, mice were i.p. immunized with 1 x 10⁸ LM-LLO-E7 or left naive. Mice were boosted with the same vaccine on day 14. Tumors were measured in two dimensions using a caliper, and the average of those values was plotted against days post tumor implantation for each mouse. Depicted is one of 2 experiments.