Arachidonic acid inhibits 5-lipoxygenase in human T cells.

The data on whether T cells produce leukotrienes or other 5-lipoxygenase metabolites of arachidonic acid is conflicting. We report that exogenous arachidonic acid added to phytohemagglutin-stimulated human T cells profoundly inhibits leukotriene B4 production, with 90% inhibition caused by 10(-6) M arachidonic acid. The 12- and 15-lipoxygenase pathways were also inhibited by arachidonic acid. Recent reports that human T cells produce no 5-lipoxygenase metabolites of arachidonic acid might be explained by the fact that the studies used greater than or equal to 10(-5)M arachidonic acid in the incubation media.