Effect of interferon-gamma on membrane conformation in the macrophage-like cell line P388D.

Interferon-gamma (IFN-gamma) specifically induced the uptake of the unsaturated fatty acid [14C]linoleic acid into membrane phospholipids of the murine macrophage-like P388D cell lineage, but did not alter the incorporation of the saturated fatty acid [14C]stearic acid. Spin label ESR spectroscopy was used to examine any effects of these IFN-gamma-induced changes on membrane fluidity and the results revealed significant increases in plasma membrane fluidity. This alteration in membrane fluidity may have important consequences in the dynamic properties of cellular physiochemical interactions and some of the stimulatory effects of IFN-gamma on macrophages might be attributed to its effects on the plasma membrane composition.