The effect of GM-CSF rescue from apoptosis on Bcl-2 levels in TF-1 cells. TF-1 cells were treated with γ radiation (5 Gy), incubated in either the presence or absence of GM-CSF (100 U/mL) in complete RPMI supplemented with 20% FBS, and harvested at 24 hours postirradiation. Whole cell lysates were analyzed for Bcl-2 expression by immunoblotting. The autoradiograph shows one of two blots assaying Bcl-2 expression.