Macrophage activation by lipopolysaccharide, interferon-γ and interleukin-4: effect of fatty acid metabolism

The aim of this study was to investigate the effects of interferon-γ and -β (IFN-γ, -β), interleukin-4 and -10 (IL-4, -10) and Hpopolysaccharide (LPS) on the metabolism and composition of phospholipid fatty acids in macrophages. Murine J774.2 macrophages were incubated with radiolabelled fatty acids and the appropriate stimulus and the incorporation and composition of the phospholipid classes was determined. IFN-γ and IL-4 specifically stimulated enhanced incorporation of [(14)C]-linoleic acid into the phosphatidytethanolamine fraction. IL-4 (in contrast to IFN-γ and LPS) reduced incorporation of [(14)C]- arachidonic acid into phosphatidylinositol. Incubation of J774.2 cells with linoleic acid significantly increased TNFα and nitric oxide production; arachidonic acid enhanced TNFα production but reduced nitric oxide production. It is concluded that IFN-γ, IL-4 and IL-10 may differentially regulate macrophage activation via effects on the metabolism of polyunsaturated fatty acids.