Phagocytosis of irradiated 38C13 lymphoma cells by DCs. Tumor cells were labeled with PKH 26, irradiated (30 Gy), and incubated for 30 minutes on ice with media alone, control mouse IgG2a mAb, or anti-idiotype antibody. The tumor cells were then cocultured for 0 hours or overnight with DCs prelabeled with PKH 67, and analyzed via flow cytometry. The percentage of DCs double-positive for both PKH 26 and PKH 67 is reported in the top right of each panel.