Fig. 7

IFN-λ1 inhibits DENV-2 replication in cells lacking type I IFN. Vero cells were treated with increasing concentrations of IFN-α (a) or IFN-λ1 (b) or IFN-λ1 plus IFN-α (c), and then infected by DENV-2 (MOI = 0.1). The doses used were 10–40 ng/ml of IFN-λ1 or 100–400 UI/ml of IFN-α. Forty-eight hours post-infection, the viral titer was obtained by plaque assay. Plots show the percentage inhibition of the viral titer in each group compared to untreated cells. Dotted lines represent the IC₅₀ values corresponding to IFN-λ1 = 37.15 ng/ml, IFN-λ1 in presence of IFN-α = 14.12 ng/ml, the value of IC50 for IFN-α was not calculated because 50 % inhibition was not reached under the conditions of experiment. Error bars represent standard deviations of means from two independent experiment *p < 0.01, **p < 0.001