FIG 5.

F. alocis challenge does not induce azurophil granule exocytosis. Neutrophils were left unchallenged (basal), were pretreated with latrunculin-A (1 μM, 30 min) followed by fMLF stimulation (Lat + fMLF, 300 nM, 5 min), challenged with TNF (2 ng/ml, 10 min) followed by fMLF stimulation (TNF + fMLF, 300 nM, 5 min), or challenged with F. alocis (MOI of 10, 25, and 50 for 30 or 60 min). (A) Azurophil granule exocytosis was determined by the increase in plasma membrane expression of CD63 by flow cytometry. Data are expressed as mean mcf ± SEM from 3 independent experiments. (B) Extracellular release of myeloperoxidase (MPO), to determine azurophil granule exocytosis, was measured as described in Materials and Methods. Data from MPO release are expressed as means ± SEM in nM from 3 independent experiments.