STAT1 and Hand-foot syndrome: To interrogate the IFN-independent, IRF3-dependent response to HCMV HFs have been engineered (92, 93) to lack either IRF3 through expression of the nPro protein of bovine viral diarrhea virus (BVDV) (nPro/HFs) which binds and degrades IRF3 (94) or STAT1, by expression of the parainfluenza virus type 5 (PIV-5) V protein (V/HFs) which targets STAT1 for proteasomal degradation (95).