Effects of PBEF knock down on IL-8 secretion in A549 cells. A. A representative western blotting image of IL-8, PBEF and β-actin protein detections. After starving for serum overnight, A549 cells were transfected with the vehicle control (C), scrambled siRNA (Sc), or PBEF stealth siRNA (Si) for 48 h before subjected to treatment without or with IL-1β (15 ng/ml) for 24 hours. Secreted IL-8, cell lysate PBEF and β-actin protein were immunodetected as described in Figure 1 B. Quantitation of cell lysate PBEF protein levels by densitometry analysis. C. Quantitation of secreted IL-8 levels by densitometry analysis. Cell lysate PBEF and secreted IL-8 protein levels in various treatments of A549 cells were quantified by densitometry analyses in the same way as described above in Figure 1.**, p<0.01.