Arachidonic acid metabolism of the murine eosinophil. II. Involvement of the lipoxygenase pathway in the response to the lymphokine eosinophil stimulation promoter

Eosinophil stimulation promoter (ESP) is a murine lymphokine that enhances the migration of eosinophils. Exogenous arachidonic acid between 0.5 and 2 μg/ml potentiated the activity of ESP on murine eosinophil migration, whereas such concentrations did not affect migration in the absence of ESP. Among the lipoxygenase products identified from an enriched population of murine eosinophils, leukotriene B₄ (optimal activity at 100 ng/ml) and 12-HETE (optimal activity at 2 μg/ml) stimulated migration of these cells. Another lipoxygenase product from these cells 15-HETE inhibited ESP-induced migration; between 5 and 20 μg/ml 15-HETE decreased by one-half both stimulated migration and 12-HETE biosynthesis. Structurally diverse drugs at concentrations that inhibited HETE biosynthesis inhibited ESP-induced migration. The concentrations that decreased migration activity by one-half were 5 μM NDGA, 10 μM ETYA, and 150 μMBW755C. Aspirin and indomethacin at concentrations reported to inhibit prostaglandin biosynthesis did not substantially inhibit ESP activity, but concentrations of indomethacin above 10 μM caused concentration-dependent inhibition of migration. The selective lipoxygenase inhibitor 4, 7, 10, 13-eicosatetraynoic acid was more potent than ETYA in inhibition of ESP-induced migration, and the selective cyclooxygenase inhibitor 6, 9, 12-octadecatriynoic acid did not effect inhibition. These results are consistent with the hypothesis that stimulation of eosinophils by the lymphokine ESP involves the generation of lipoxygenase products from arachidonic acid, which positively and negatively regulate the migratory activities of these cells.