FIG. 8.

Pretreatment with IFN and ribavirin enhances anti-CD95-induced cleavage of caspase-3, caspase-7, and caspase-8. HepG2 cells were pretreated for 24 h with medium (lanes 1 to 3), ribavirin (lanes 4 and 5), IFN (lanes 6 and 7), or the combination of ribavirin and IFN (lanes 8 and 9). Subsequently the cells were stimulated for 4 h with medium (lane 3), 0.25 μg of anti-CD95 (lanes 1, 2, and 4 to 9), or anti-CD95 plus CHX (lane 1) as a positive control. Cell lysates were then assayed by immunoblot analysis for caspase-3 (A), caspase-7 (B), and caspase-8 (C). Uncleaved procaspases are indicated by open arrowheads, and cleavage products are indicated by solid arrowheads. Note that procaspase-8 is not shown; instead, another nonspecific band from the same blot (NS) is shown; this band serves as a loading control.