Immunosuppreession induced by Salmonella infection is correlated with augmentation of interleukin-2 receptor α chain expression in murine splenic lymphocytes

Abstract

In a previous study, we observed that the suppression of T-cell proliferation induced by Salmonella cell-free extract was associated with augmentation of IL-2 receptor (IL-2R) α chain expression. In this study, we also observed this kind of augmentation of IL-2Rα in Salmonella-infected mice. Phytohaemagglutinin (PHA)-stimulated proliferation of murine spleen cells was significantly suppressed when the mice were infected with Salmonella typhimurium. However, expression of the α chain but not the β chain of IL-2R in lymphocytes was augmented by the infection. Analysis of the IL-2R-positive cell-populylation showed that the augmentation of IL-2Rα was not specific to certain cell subpopulations. Furthermore, the inhibition of PHA-stimulated murine spleen cell proliferation and the augmentation of IL-2Rα expression induced by the infection in lymphocytes was completely reversed by treatment with anti-interferon-γ monoclonal antibody (anti-IFN-γ Ab). These results suggest that the suppression of T-cell proliferation induced by Salmonella infection was associated with augmentation of IL-2Rα expression in an IFN-γ production-dependent manner in the same way as the suppression of T-cell proliferation induced by Salmonella cell-free extract.