The early immune response in the liver of BALB/c mice infected with S-typhimurium

Gram-negative bacteria acquired through gastrointestinal infection can be a serious cause for the development of septic shock especially in immunosupp ressed patients. Thus, the aim of this study was to examine the early event s of the immune reaction against S. typhimurium. Bacteria were injected int o mice at different concentrations. Four animals from each group were kille d at five different points of time. Liver cytokine mRNA expression was dete rmined by semiquantitative rt-PCR and liver histology was examined. Serum c ytokine levels of interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha , interleukin (IL)-6, IL-4 and IL-10 were determined. intravenous (i.v.) in fection with 10(9) bacteria led to lethal septic shock within 24 h. A delay ed production of IFN-gamma, TNF-alpha, IL-18 and IL-10 and milder histologi cal alterations in the liver were observed in these animals. The highest ex pression of cytokines in the liver and the strongest histological alteratio ns were seen after infection with 10(7) bacteria. Here, an increased mRNA e xpression of all proinflammatory cytokines began 1 h after infection. Anima ls infected with 1 x 10(2) bacteria had the highest detectable serum levels of IL-6 and IL-10. These data indicate that the immediate events in the im mune reaction within the liver after infection with S. typhimurium are asso ciated with the outcome of the subsequent sepsis.