Flow cytometric analysis. Cells were first incubated with 2.4G2 mAb for 20 min. Cells were then stained with mAbs specific for cell surface markers or isotype controls for 30 min at 4 8C. Cells were then washed and fixed in 2% paraformaldehyde in PBS. Intracellular staining for Ki-67, IFN-c, and IL-12 was performed using the Cytofix/ Cytoperm kit (BD Pharmingen). Intracellular staining for IFN-a/b was performed as previously described [35] . Depending on the experiments, 2.5 3 10 5 to 2 3 10 7 events were collected on a FACSCalibur. The data were acquired and analyzed using CellQuest software (BD Biosciences). Isotype controls were used to set gates for the presented FACS analyses.