Effect of Bid overexpression on anti-Fas induced apoptosis of RA FLS. Rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) were transfected with pDsRed2-Bid or pDsRed2 control vector, 48 hours after transfection Bid expression was analysed by (a) immunofluorescence and (b) western blot. Representative experiments are shown. (c) After transfection, cells were left untreated (Basal) or treated for 12 hours with 1 μg/ml anti-Fas antibody or pretreated for one hour with Wortmannine (Wort) or with Wort and the caspase-9 inhibitor, Z-LE(OMe) HD (O Me) FMK (LEHD), before Fas stimulation. Apoptosis was analysed by ELISA. Data are the mean (standard error of the mean) of six RA FLS lines. * indicates P < 0.05 versus basal, # indicates P < 0.05 versus anti-Fas-only treatment and † indicates P < 0.05 versus anti-Fas and Wort treatment.