The cytokine balance in the maintenance of a persistent infection with Salmonella enterica serovar Typhimurium in mice

ClpXP, serine protease-disrupted mutant of Salmonella enterica serovar Typhimurium χ3306 exhibits attenuated but persistent infection in mice. During infection with S. enterica serovar Typhimurium ClpXP-disrupted mutant, gamma interferon (IFN-γ) produced by CD4+ cells was up-regulated on day 10 and tumor necrosis factor-alpha (TNF-α) produced by CD8+ cells was up-regulated on day 30 after infection. Treatment of monoclonal antibodies against cytokines showed that IFN-γ and interleukin 10 (IL-10) were involved in maintenance of growth of S. Typhimurium mutant on day 10 after infection, and IFN-γ, TNF-α and transforming growth factor-beta (TGF-β) were involved in maintenance of growth of this bacterium on day 30 after infection. During persistent infection of S. Typhimurium mutant, IFN-γ, TNF-α, IL-10 and TGF-β may play different roles to maintain the persistent infection. The cytokine balance might be important in persistent infection with ClpXP-disrupted S. enterica serovar Typhimurium.