Production of leukotrienes from mouse peritoneal macrophages by treatment with a neutral subfraction of bakers' yeast mannan.

We concluded that a neutral subfraction of mannan from bakers' yeast (Saccharomyces cerevisiae wild type strain), abbreviated as WNM, was able to induce the release of leukotrienes from mouse peritoneal macrophages (M phi). The culture supernatant fluid of M phi from normal mice cultured with WNM caused a marked contraction of guinea pig ileum. This activity was inhibited by pretreatment of M phi with inhibitor of phospholipase A2 or lipoxygenase before M phi were treated with WNM, and by treatment of the incubation bath with a slow reacting substance antagonist, FPL55712. On the other hand, pretreatment of M phi with a cyclooxygenase inhibitor potentiated contractile response of ileum by culture supernatant fluid of M phi. A high performance liquid chromatographic analysis of a culture supernatant fluid of M phi treated with WNM demonstrated the presence of leukotrienes C4 and D4, and their related compounds.