Macrophages have been shown to support DENV infection in animal models, and have been proposed to play an important role during early phases of dengue virus infection [39, 40] . We tested if monocyte-derived macrophages (MDMs) when infected with DENV were able to produce type I IFN. Figure 8D shows that macrophages are efficiently infected with DENV, with an early peak of replication and produce TNFa and IL-6 after DENV infection and after SFV expressing the WT and mutant versions of the NS2B3 DENV protease complex (Figures 8E, 8F ). Under these experimental conditions we were unable to detect IFNa released by macrophages after DENV infection. Interestingly, when compared to MDDCs infected with the same viruses ( Figure 8H) , macrophages produce at least 10-fold lower levels of IFNa after SFV infection, and the inhibitory effect of the DENV protease in this system was less apparent (8G and 8H).