Macrophage migration inhibitory factor is a pro-inflammatory cytokine that acts at the interface between the immune system and the hypothalamus –pituitary–adrenal stress axis, but its complete role in infectious diseases remains unclear. In September 23 Proceedings of the National Academies of Sciences, Heidrun Koebernick and colleagues at the Max Planck Institute for Infection Biology, Berlin, Germany, show that MIF plays a pivotal role in immunity against Salmonella typhimurium (PNAS, 10.1073/pnas.212488699, September 23, 2002).

Koebernick et al. used MIF^-/- knockout mice and observed that these animals could not control infections with wild-type Salmonella typhimurium. They found that increased susceptibility to Salmonella infection was accompanied by a reduced Th1 response with decreased levels of IL-12, IFN and tumor necrosis factor. In addition, they showed that in Salmonella-infected MIF^-/- mice, levels of IL-1β, and serum levels of nitric oxide and corticosterone were markedly increased compared with control mice....