Comparison of immature and mature DCs in tumor rejection. CD27^−/− recipients were challenged subcutaneously with 4 × 10⁵ B16-OVA tumor cells on the shaved flank. Five days later, those mice in which tumor take was palpable were injected with WT OT-I cells, and the subsequent day (arrow, C) the same mice were injected with CD27^−/− (control) or CD70tg;CD27^−/− (CD70tg) DCs. These DCs had been loaded with OVA peptide for 3 hours and subsequently kept overnight either on ice (−LPS) or under culture conditions with LPS (+LPS). Maturation status of DCs was examined before transfer by flow cytometric analysis of cell surface expression of CD40, CD86, and CD70 within the PI⁻B220⁻CD11c⁺ gate (live cDCs) (A), and the equivalent of 2 × 10⁶ viable DCs was injected per recipient. (B) Accumulation of OVA-specific CD8⁺ T cells, measured as outlined for Figure 2A. (C) Tumor size, as measured by caliper. Data represent mean values (+SEM) for 4 to 6 mice per group. Asterisks indicate statistical significance between the groups indicated by brackets according to Student t test for *P < .05, **P < .01, and ***P < .001.