Eosinophil migration in response to three molecular species of platelet activating factor

Multiple molecular species of the eosinophil chemoattractant platelet activating factor (PAF) are produced as a result of inflammatory processes. We therefore compared the ability of three naturally occurring PAF species (C16∶0, C18∶0, and C18∶1), which only varied at carbon 1, to induce eosinophil chemotaxis through naked 3-μm pore polycarbonate filters. Timecourse experiments indicated that all species of PAF tested induced significant and equivalent eosinophil migration at 1 h which peaked at 2 h. Overall, the rank order of chemotactic potency for the PAF species was relatively equivalent. The specific PAF antagonist WEB 2086 inhibited eosinophil migration induced by all three PAF species equally. We conclude that the degree of PAF-induced eosinophil migration is not dependent upon the molecular species of PAF.