Mouse fibroblast interferon modifies Salmonella typhimurium infection in infant mice.

The effect of mouse fibroblast interferon on Salmonella typhimurium infection in infant mice was examined. The lethality to mice that had been given S. typhimurium intragastrically was significantly reduced in a dose-dependent manner when the mice were pretreated with fibroblast interferon. Lower doses of interferon delayed the development of disease. Interferon neutralized with anti-interferon globulin did not influence the lethality of S. typhimurium to mice. In mice treated with interferon there was also a reduced invasiveness of S. typhimurium in intestinal epithelial cells in vivo. It was further demonstrated in an in vitro system that interferon pretreatment of mouse L-929 cells inhibited the invasiveness of the bacteria in a dose-dependent manner. The in vitro inhibition was neutralized with anti-interferon globulin. The results indicate that interferon inhibits Salmonella bacteria from invading cells and establishing an intracellular state of infection. This may represent an important factor in the pathogenesis of disease.