Fig. 5

a Normal lung fibroblasts in serum-free media were treated with the combination of TNF-α (10 ng/ml) and IFN-γ (50 U/ml) for the indicated times up to 48 h. For the groups receiving inflammatory cytokines for 6–24 h, at the end of the exposure cells were washed with PBS and replaced in serum free media. After 48 h, the cells were washed again with PBS and placed in serum free media with/without TGF-β1 (10 ng/ml) for another 24 h. Whole cell lysates were then assessed for Fas expression. Additional experiments were done to confirm the effects at 24 and 48 h, and the densitometry represents three independent experiments at those time points. b Normal lung fibroblasts were treated with/without TNF-α (10 ng/ml) and IFN-γ (50 U/ml) for 24 h, washed with PBS and then exposed to Fas-activating antibody (Fas-Ab; 250 ng/ml) with/without TGF-β1 (10 ng/ml) for 16 h. Whole cell lysates were assessed for PARP. Lane 7 is from control fibroblasts treated with the Fas-activating antibody in combination with cycloheximide (CHX; 500 ng/ml) as a positive control for apoptosis