4.6. Apoptosis Assay

Glioblastoma cells stained with 5(6)-carboxyfluorescein diacetate N-succinimidyl ester (CFSE) fluorescent dye (2 μM; Molecular probes, Inc., Eugene, OR, USA) were incubated with IFN-DCs at a ratio DCs:tumor cells 10:1 for 18 h. Percentage of tumor cells apoptosis was measured using annexin V-APC apoptosis detection kit (BD Pharmingen™, USA). Briefly, cells were washed with PBS and labeled with APC-conjugated annexin V and propidium iodide (PI) for 15 min at room temperature, followed by analysis on a FACSCalibur flow cytometer. A minimum of 10,000 events within the CFSE-positive gate region were collected for each sample.