FAS and infection: Shaw et al. reported upregulation of TLR3, caspase-8, Noxa, and TRAIL expression in ex vivo porcine skin fibroblast cultures following IFN treatment (49), while Renson et al. found elements of the Fas and TRAIL signaling pathways to be upregulated in uninfected bystander peripheral blood mononuclear cells (PBMCs) during in vivo infection with a related pestivirus, bovine viral diarrhea virus (BVDV) (50).