Modulation of Type I Interferon System by African Swine Fever Virus

Figure 1. Cytokine gene expression in African Swine Fever Virus (ASFV)-infected macrophages. moMΦ were infected with the low virulence NH/P68 (blue) or the virulent 22653/14 (red) strains using an MOI 1. At 0, 3, 6, 9, 12, 21 h pi, gene expression of IFN-β and 17 IFN-α subtypes were determined using qPCR. Data were normalized on the values of un-infected control (0 h pi) and expressed as ΔΔCt, where ΔΔCt = (ΔCt observed in un-infected moMΦ) − (ΔCt observed in ASFV-infected moMΦ). The mean data + SD from six independent experiments utilizing different animals are shown. Values of ASFV-infected cells were compared to the corresponding mock-infected control using a one-way ANOVA (IFN-α12, IFN-α17) or a Kruskal-Wallis test (all the others), followed by Dunn’s multiple comparison test; *** p < 0.001, ** p < 0.01, * p < 0.05.

Figure 2. Cytokine gene expression in ASFV-infected IFN-α macrophages. moMΦ were activated for 24 h with IFN-α and then infected with the low virulence NH/P68 (blue) or the virulent 22653/14 (red) strains using an MOI 1. At 0, 3, 6, 9, 12, 21 h pi, gene expression of IFN-β and 17 IFN-α subtypes were determined using qPCR. Data were normalized on the values of un-infected control (0 h pi), and expressed as ΔΔCt, where ΔΔCt = (ΔCt observed in un-infected moMΦ) − (ΔCt observed in ASFV-infected moMΦ). The mean data + SD from six independent experiments utilizing different animals are shown. Values of ASFV-infected cells were compared to the corresponding mock-infected control using a Kruskal-Wallis test, followed by Dunn’s multiple comparison test; *** p < 0.001, ** p < 0.01, * p < 0.05.

Figure 3. IFN-β and IFN-α release by macrophage in response to infection with ASFV strains of diverse virulence. moMΦ were left untreated or activated with IFN-α. 24 h post-activation, supernatants were removed, then cells were infected with the low virulence NH/P68 or the virulent 22653/14 strains using an MOI 1, alongside mock-infected controls. At 21 h pi, the amount of IFN-β, IFN-α1 in culture supernatants were determined using commercial ELISA. The mean data + SD from four (IFN-β) or three (IFN-α) independent experiments utilizing different animals are shown. Values of ASFV-infected cells were compared to the corresponding mock-infected control using a Kruskal-Wallis test (IFN-α moMΦ) or a one-way ANOVA followed by Dunn’s multiple comparison test; *** p < 0.001, ** p < 0.01, * p < 0.05.