DcR3.Fc and TRAIL synergistically induce DC apoptosis. (A,B) Analysis of apoptotic cells cotreated with DcR3.Fc and TRAIL. DCs (5 × 105) were incubated with Fc-fusion proteins (10 μg/mL) in conjunction with TRAIL (100 ng/mL) for 36 hours. Cell viability was determined by annexin V/7-AAD double staining (A) or PI staining (B). (C) Cell lysates of DCs incubated with TRAIL and DcR3.Fc for 12 hours or 36 hours were incubated with fluorescent probes MCA-IETD.APK (DNP) or MCA-AEVD.APK (DNP) to determine caspase-8 activity. *P < .05 compared with control group. Error bars represent SD of the mean. (D,E) Analysis of apoptotic cells cotreated with HBD.Fc and TRAIL or FasL. The experiment is performed as described in panels A and B except that DcR3.Fc was replaced with HBD.Fc. Fas ligand was added at 100 ng/mL. The numbers in the quadrants represent the percentage from total cell population.
