Fig. 4.

(a) Western blot analysis to detect dose-dependency of caspase-3 activation and consecutive poly-adenosine diphosphate-ribose-polymerase (PARP) cleavage after treatment of human colon epithelial cells (HT-29) with interferon (IFN)-γ for 48 h. Controls were cultured for 48 h in serum-free medium. (b) Time–course for detection of IFN-γ-dependent activation of caspase-3 and consecutive PARP cleavage in HT-29 cells using Western blot analysis. (c) DNA-laddering after stimulation of HT-29 cells for 12–48 h with IFN-γ (100 ng/ml). Controls were cultured for 48 h in serum-free medium.