Confirming the importance of NF-κB and ERK1/2 in mediating innate immune response to MVA infection, pre-incubation of THP-1 cells with drugs (i.e. NEMO and U0126, see Materials and Methods) selectively inhibiting the NF-κB and ERK-1/2 signalling pathways impaired, albeit to a different extent, IL-1β (70% and 65% inhibition), IL-8 (75% and 72% inhibition) and IFNβ (28% and 42% inhibition) mRNA expression (p<0.05 for all conditions). This evidence concerns the gene MAPK3 and infection.