Figure 1. Treatment of HeLa cells with IFN-α stimulates phosphorylation of Stat3 at Tyr705 as detected by PathScan ® Phospho-Stat3 (Tyr705) Sandwich ELISA Kit #7300, but does not affect the level of β-actin as detected by PathScan ® Total β-Actin Sandwich ELISA Kit #7880. HeLa cells were treated with 100 ng/ml IFN-α for ten minutes at 37ºC before lysis. Absorbance at 450 nm is shown in the top figure, while the corresponding western blots using Phospho-Stat3 (Tyr705) (3E2) Mouse mAb #9138 (right panel) or Total β-Actin (13E5) Rabbit mAb #4970 (left panel) are shown in the bottom figure.