Formation of interferon-gamma and tumor necrosis factor in mice during Salmonella typhimurium infection

Formation of interferon-gamma (IFN-gamma) and tumor necrosis factor (TNF) during Salmonella typhimurium infection was investigated in lipopolysaccharide (LPS)-sensitive C3H/HeN and C57BL/10ScSn(B10ScSn), and LPS-resistant (lpsd mutant) C3H/HeJ and C57BL/10ScCr(B10ScCr) mice. When infected with 50 colony-forming units (CFU) of S. typhimurium C5, C3H/HeN and B10ScSn mice became hypersensitive to the lethal effect of LPS. In the case of lpsd mutants, only C3H/HeJ mice became hypersensitive to LPS, while B10ScCr mice remained resistant. C3H/HeJ as well as B10ScSn mice produced significant amounts of plasma IFN-gamma on day 3 after infection. By this time bacterial CFU in the liver of B10ScSn and C3H/HeJ mice were 10(6.7) and 10(7.1), respectively. In B10ScCr mice, however, IFN-gamma was not detectable although bacteria present in the liver exceeded 10(8) CFU. On the other hand, plasma TNF was not detectable in any of the mouse strains during S. typhimurium infection. When S. typhimurium-infected mice were challenged with LPS on day 3, significant amounts of plasma TNF were measured in C3H/HeN and B10ScSn mice, while in the lpsd mutant C3H/HeJ and B10ScCr mice plasma TNF was undetectable.