CCL22-deficient DCs strongly increase T cell immunity. (A) OVA_257–264-pulsed Ccl22^−/− or WT DCs were injected into C57BL/6 WT mice three times every 14 d, and CpG together with Alum were used as adjuvant (n = 15 mice per group injected with DCs and n = 4 mice without treatment). The frequency of splenic OVA-specific cytotoxic T cells was determined by pentamer (left) and intracellular IFN-γ staining (right) as described in Fig. 3 1 wk after the last injection. Data are shown as mean ± SEM and are pooled from two independent experiments. In total, four experiments with similar results were performed. (B) OVA_257–264-pulsed Ccl22^−/− or WT DCs were injected into either Ccr4^−/− or WT recipient mice. The experiment was performed as described in A (n = 7 mice per group injected with DCs and n = 2 mice per group without treatment). Data are shown as mean ± SEM and are representative of two independent experiments. *, P < 0.05; **, P < 0.01; ***, P < 0.001 (two-sided Student’s t test).