As day 2 post infection is beyond the peak of the type I IFN response following RSV infection, we measured the expression of interferon stimulated genes (ISGs); Mx1, Pkr and Viperin. The expression of Mx1 and Viperin were not significantly altered by monocyte depletion, whilst Pkr expression was significantly increased (Supplementary Fig. 8a-c). The gene discussed is RSAD2; the disease is infection.