Phagosomal delivery of the oxidase in response to IgG-SRBCs is dependent on Rab27a. Primed BMNs from WT (black squares/bars) or ashen Rab27a−/− (Rab27a KO, gray triangles/bars) animals were preincubated with luminol/SOD (intracellular) or isoluminol/HRP (extracellular; A) or NBT (B) as described in “Measurement of ROS production” and in the supplemental Methods. Cells (5 × 105) were added to either serum-S aureus (i) or IgG-SRBCs (ii), prepared as described in the supplemental Methods. ROS responses (A) and formazan deposition (B) were measured as described in Figures 3A and 1, respectively. Shown are (A) data (mean ± range) from 1 experiment representative of at least 3, expressed as RLU/s, as well as accumulated light emission (ROS production) over 20 minutes for a combination of ≥ 3 experiments (mean ± SEM), expressed as a percentage of the response in WT mouse neutrophils. *P < .0001, paired Student t test compared with WT response and (B) representative images.
