Rescue of TF-1 cells from apoptosis with GM-CSF. TF-1 cells were treated with γ radiation (0, 7.5, 10, 15, or 25 Gy) at a rate of 6.41 Gy/minute in either the presence or absence of GM-CSF (100 U/mL) in complete RPMI supplemented with 20% FBS. Cells were subsequently incubated for 6 hours in complete RPMI supplemented with 20% FBS in either the presence or absence of growth factor. Postincubation, DNA was harvested for DNA fragmentation analysis. DNA was separated at 80 V for 2 hours on a 2% agarose-TBE gel, stained with EtBr, and visualized using UV transmission. This is a representative gel of three experiments.