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

Effect of recombinant gamma-interferon (rIFN-gamma) on phagosome-lysosome fusion in Salmonella typhimurium-infected murine macrophages was examined. rIFN-gamma enhanced phagosome-lysosome fusion in macrophages infected with S. typhimurium in a dose-dependent manner, and over a range of 10(2) to 10(3) U/ml of rIFN-gamma exhibited maximum phagosome-lysosome fusion, although phagocytosis was slightly decreased. The enhancement of phagosome-lysosome fusion occurred greater than 3 h post-treatment with rIFN-gamma. Furthermore, the macrophage activation for phagosome-lysosome fusion was found to persist for 4 days even when rIFN-gamma had been removed. These results demonstrate that IFN-gamma may serve as a mediator for the activation of phagosome-lysosome fusion in murine macrophages.