FOS and Salmonella Infections: In addition, mice lacking c-Fos also exhibit a marked increase of pro-inflammatory cytokines in the context of Salmonella infection or endotoxin exposure, and the nuclear factor kappa B (NF-kB) pathway was shown to be involved in the regulatory role of c-Fos in macrophages and in a mouse model (Okada et al., 2003; Ray et al., 2006; Maruyama et al., 2007).