FIGURE 6. DC Cross-priming of tumor cells is inhibited by cross-linking with anti-DR5 mAbs.

(A) CD11c⁺ BM-DCs (5 × 10⁵) were cultured for 24 hr in control mAbs or anti-DR5 mAbs-coated 24-well plates or in control wells (PBS). The DCs (2 × 10⁴) were then cocultured for 4 days with CFSE-labeled OVA-specfic OT-I T cells (5 × 10⁴) and P815/tOVA cells (2 × 10⁴). Numbers represent percentage of proliferating T cells. A representative result of four independent experiments is shown as mean ± SEM of triplicate. (B) BM-DCs (5 × 10⁴) were cultured for 24 hr in control mAbs or anti-DR5 mAbs-coated 96-well plates and then incubated with P815/tOVA cells (5 × 10⁴, PKH26⁺). Percentages refer to PKH26⁺ cells within the CD11c⁺ gated cells (DCs). The MFI of PKH26 (C, E) and percentages of PKH26 positive DCs (D) are indicated for each time point (30 min, 1 hr and 4 hr). Cumulative data from three independent experiments are shown as mean ± SEM. Wt (F) or DR5^−/− (G) BM-DCs alone or DCs with tumor cells were cocultured for 24 h before staining with 25-D1.16 and anti-CD11c-mAbs. A representative result of two independent experiments is shown as mean ± SEM of triplicates. *, p < 0.05; ***, p < 0.001.