Intracellular IL-8 staining in PMNs and monocytes.

Purified PMNs or MNCs (2 × 10⁵) were incubated for 4 hours at 37°C with 7.5% CO₂ with the indicated stimuli in the presence of brefeldin A (1 μg/mL) or monensin (GolgiStop, 2 μM). Cells were washed and stained as described in “Materials and methods.” FITC-labeled mAbs against CD66b or CD14 were used to identify PMNs or monocytes, respectively, and a PE-labeled mAb against IL-8 was used to evaluate the amount of IL-8 produced by the cells. The shaded histograms represent the fluorescence of stimulated cells; the white histograms, the respective medium control. The results shown are representative of 3 independent experiments. The increase in mean fluorescence of Gp96 or LPS-stimulated monocytes was statistically significant compared with the medium control (P < .05 by Student ttest).