Fig. 5. Modulation of the oxidative response. Each pair of histograms shows the mean±s.d. of DCHFC-zymosan fluorescence (sum intensity) before and 200 seconds after phagosome closure in cells which were treated as follows: control, untreated (n=15); Ni, in the presence of the Ca²⁺ channel-blocking ion Ni²⁺ (2 mM, n=6); LY, pretreated for 15 minutes with the PI(3) kinase inhibitor LY294002 (50 µM, n=3); Az, in the presence of the MPO inhibitor, azide (10 mM, n=6); MPO-, myeloperoxidase-deficient cells (n=2); NiAZ, the presence of both Ni²⁺ (2 mM) and azide (10 mM, n=2). The asterisks indicate the level statistical significance for the difference between the control column and the others; where *P<0.05, **P<0.01, ***P<0.001.