Fig. 2. The PSMα3 induced activation of the neutrophil NADPH-oxidase is inhibited by PSMβ1.

a NADPH oxidase-induced superoxide anion release (O₂⁻, y-axis) by neutrophils was measured by isoluminol-amplified chemiluminescence over time (min, x-axis). The cells were preincubated at 37 °C for 5 min before being first challenged with one agonist (arrow to the left) and then with a second agonist PSMα3 (50 nM, arrow to the right) once the first response had returned to baseline. Shown is one representative trace out of four individual experiments for neutrophils first stimulated with PSMβ1 (500 nM) or buffer (control) and then PSMα3 (50 nM). b The peaks O₂⁻ release by neutrophils stimulated with PSMβ1 (500 nM) or buffer control followed by PSMα3 (50 nM) were compared. c The representative bar graphs show the peak O₂⁻ release from the neutrophils first stimulated with different concentrations of PSMβ1 (500 nM, 250 nM, 125 nM, 62.5 nM, 31.25 nM, 0 nM), and then challenged with PSMα3 (50 nM). The experiment was performed 3 times with different buffy coats. All experiments showed the similar pattern. Statistical comparison was done using paired t test, with data expressed as mean ± standard error of the mean b. **P < 0.01.