Effect of γ-interferon on phagosome-lysosome fusion in Salmonella typhimurium-infected murine macrophages

Abstract Effect of recombinant γ-interferon (rIFN-γ) on phagosome-lysosome fusion in Salmonella typhimurium -infected murine macrophages was examined. rIFN-γ enhanced phagosome-lysosome fusion in macrophages infected with S. typhimurium in a dose-dependent manner, and over a range of 10² to 10³ U/ml of rIFN-γ exhibited maximum phagosome-lysosome fusion, although phagocytosis was slightly decreased. The enhancement of phagosome-lysosome fusion occured > 3 h post-treatment with rIFN-γ. Furthermore, the macrophage activation for phagosome-lysosome fusion was found to persist for 4 days even when rIFN-γ had been removed. These results demonstrate that INF-γ may serve as a mediator for the activation of phagosome-lysosome fusion in murine macrophages.