Interferon-y increases macrophage phospholipid polyunsaturation: apossible mechanism ofendotoxin sensitivity

Summary. Incubation ofmurinemacrophages orthemacrophage-like cell line P388Dwith interferon-y invitro induced asignificant increase inthepolyunsaturated fatty acid content of phosphatidylethanolamine. These increases weretimeanddose-dependent, being maximal at 12hours andwith5000U/miinterferon andwereinhibited inthepresence ofanti-interferonymonoclonal antibody. Interferon-y induced asignificant increase inlinoleate inperitoneal macrophages while inthecell line arachidonate wassignificantly increased. These results are ofinterest because suchincreases inthepolyunsaturated fatty acid content ofphosphatidylethanolamine werepreviously shownbyustobeassociated withincreased sensitivity to endotoxin inmiceinvivo. Theimplications forinterferon-y sensitizing toendotoxin are discussed.