Location of superoxide production sites in turbot neutrophils and giltheadseabream acidophilic granulocytes during phagocytosis of glucan particles

Here we show, by spectrophotometry and enzyme cytochemical methods, that tu rbot neutrophils and gilthead seabream acidophils responded in a similar wa y when incubated with PMA or with Particulate glucans. Cells stimulated wit h PMA released high amounts of superoxide both intra- and extracellularly. However, O-2(-) was mainly released intracellularly when cells were incubat ed with particulate glucans. Small glucan particles were quickly phagocytos ed and O-2(-) was initially produced in intracellular vesicles and tubular structures that later fused with the phagosome or with the cell membrane. L arge glucan filaments that were not phagocytosed also induced cell stimulat ion and O-2(-) was also produced in intracellular vesicles which then appea red to fuse with the cell membrane. We conclude that, in stimulated turbot neutrophils and gilthead seabream acidophils, superoxide production is carr ied out initially in intracellular compartments that are very similar to th ose described in mammalian neutrophils. (C) 2001 Elsevier Science Ltd. All rights reserved.