Salmonella typhimurium-induced cytokine production and surface molecule expression by murine macrophages

The influence of Salmonella enterica serovar Typhimurium (S. typhimurium) on co-stimulatory molecule expression, cytokine production and induction of nitric oxide synthase (iNOS) by murine macrophages (Mphi), as well as the influence of the phoP locus on these aspects of S. typhimurium-Mphi interaction, was characterized. Pulsing Mphi with S. typhimurium resulted in increased surface expression of MHC-I, MHC-II, CD86 and CD54. Furthermore, co-incubating S. typhimurium with Mphi resulted in interleukin (IL)-12p40, IL-6 and tumor necrosis factor-alpha production as well as iNOS induction while IL-12p70 was not detectable. Finally, although phoP did not influence the level of surface molecule expression or cytokine production by S. typhimurium-pulsed Mphi phoP did influence the level of iNOS induction. Together these data show that S. typhimurium interaction with Mphi activates these cells in ways that may enhance their ability to productively stimulate Salmonella-specific T cells following phagocytic processing and presentation of Salmonella antigens.