ORALLY-ADMINISTERED INTERFERON-GAMMA BUT NOT TUMOR-NECROSIS-FACTOR-ALPHA SUPPRESS INFECTION WITH SALMONELLA-TYPHIMURIUM IN A MOUSE MODEL

Intragastrically inoculated Salmonella typhimurium produces a systemic infection in mice with high mortality. We have examined the effect of interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha on the d evelopment of the disease. IFN-gamma reduced penetration of bacteria i nto the gut epithelial cells, reduced the development of bacteremia, r educed mortality and prolonged the length of survival of mice both aft er peroral and after intraperitoneal administration. On the other hand TNF-alpha had a similar effect only when given intraperitoneally but not by peroral route. These findings indicate that the mechanisms by w hich these two cytokines influence the development of S. typhimurium i nfection ave different. This is the first observation that perorally a dministered cytokines may have local and systemic effects on bacterial infection.