Figure 7.

The effect of tobramycin and CuT on NE activity and inhibition by α1-AT. Neutrophils at 10⁷ mL⁻¹ suspended in HBSS with Ca/Mg + 20 mM HEPES, pH 7.4 were pretreated without or with tobramycin and CuT (0.5 mM), as indicated, for 15 min and activated with freshly prepared OPZ (1 mg·mL⁻¹) at 37°C with gentle shaking for 1 h. NE activity was measured using N-methoxysuccinyl-ala-ala-pro-val-p-nitroanilide in supernatants (A) and whole cell lysates (B). The optical density (OD) was monitored at 550 nm in the absence and presence α1-AT (2 mg·mL⁻¹). The data are expressed as mean ± SEM and analysed using two-tailed, paired t-test, all assays were carried out in duplicate in three independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001 for comparison of the effect of the treatments with OPZ alone (OPZ) and ^#P < 0.05, ^##P < 0.01 for the comparison between neutrophil elastase activity in the absence and presence of α1-AT.