Chemotactic factor production by rat polymorphonuclear leukocytes: stimulation with opsonized zymosan particles and inhibition by dexamethasone.

Rat polymorphonuclear leukocytes exposed to opsonised zymosan particles in vitro instantaneously and continuously release a chemotactic factor in the medium. The activity of this factor was mainly attributed to leukotriene B4, based on the data with high performance liquid chromatography. Preincubation of the cells with an antiinflammatory steroid, dexamethasone, at a dose of 0.25 micrograms/ml caused suppression in generation of the chemotactic factor from the leukocytes in a time-dependent manner.