CTL effector functions after DC transfer. (A) Experimental set-up as outlined for Figure 2. CD8⁺ T cells harvested from spleens at day 5 after DC transfer were incubated in vitro for 5 hours in the presence or absence of OVA_257-264 peptide and stained intracellularly for IFN-γ. Numbers in quadrants indicate the percentages of IFN-γ⁺ cells within the CD8⁺ T-cell population as means (±SEM) derived from 2 independent experiments with 2 mice per group. Flow cytometric plots are representative. (B-D) CD27^−/− recipients were challenged subcutaneously with 10⁵ B16-OVA tumor cells. Three days later, these mice received WT or CD27^−/− OT-I T cells and the subsequent day OVA peptide-loaded or unloaded DCs derived from CD27^−/− (control) or CD70tg;CD27^−/− (CD70tg) donor mice. Test groups are indicated in the box. (B) Accumulation of OVA-specific CD8⁺ T cells, measured as outlined for Figure 2A. (C) Tumor size measured by caliper. Data represent mean values (+SEM) for 5 mice per group. (D) Survival data for the indicated groups of recipient tumor bearing mice. Asterisks indicate statistical significance between the groups that received control or CD70tg peptide-loaded DCs and WT T cells according to Student t test for *P < .05, **P < .01, and ***P < .001.