IRF3 and infection: Figure 4A shows that ΔN146 infection triggered a robust increase in mRNA levels of IFN-β, RANTES and IL-6 at 3 h post infection. Such response became more evident at 6 h post infection. In parallel experiments, we evaluated the impact of ΔN146 on IRF3 and NF-κB in immature DCs. As shown in Fig. 4B, ΔN146 infection drastically induced the phosphorylation of IRF3 at serine 396, a hallmark of IRF3 activation.