Fig. 2. IFN- and TNF- sensitize human ESCs to Fas-mediated apoptosis. Decidualized (black bars) as well as undifferentiated (white bars) ESCs were treated with 50 ng/ml IFN-, 25 ng/ml TNF- and 1 U/ml hCG alone and in the indicated combinations for 24 hours before stimulating the cells with 100 ng/ml of an activating anti-Fas antibody for another 24 hours. The rate of apoptosis was determined by flow-cytometric detection of hypodiploid nuclei (*P<0.05 for both 6 and 7 versus 0-5). Bars show the mean ± s.e.m.