FIG. 5.

Effects of PD 98059 on ERK activation and oxidative burst. (A) Sample Western blot for activated ERK 1 and 2 from neutrophils of adults incubated with PD 98059. (B) Neutrophils from adults were incubated with LPS (5 ng/ml) with 5% plasma and the indicated PD 98059 concentrations for 20 min. Activation of ERK 1 and 2 (⧫) was measured by Western blotting as described previously and expressed relative to values obtained for no inhibitor (plus LPS). For measurement of oxidative burst, neutrophils were incubated with (×) or without (□) LPS (5 ng/ml) with 5% plasma and a range of PD 98059 concentrations. After stimulation with fMLP, oxidative burst was measured as integrated chemiluminescence intensity for 4 min and expressed relative to values obtained for no inhibitor (plus LPS). Each data point represents the mean ± range or standard error of the mean of at least two independent measurements; oxidative burst (plus LPS) was significantly greater than ERK activity at PD 98059 concentrations of ≥10 μM (P < 0.05).