MAPK8 and infection: Consistent with previous studies [17, 18, 28], infection with S. Typhimurium resulted in increased phosphorylation of the MAPKs Erk, Jnk, and p38 as well as in the activation of NF-κB as indicated by the degradation of I-κB, an inhibitor of NF-κB, and the activation of a luciferase reporter (Fig 3A–3G).