Fig. 4

Inhibition of JAK-signalling rescues influenza A virus replication in macrophages. A OMVs activate TRIF-IRF-signalling in macrophages, which in turn induces IFN-β expression and release with subsequent IFNAR-signalling. IFNAR signals via JAK/STAT and induces the expression of ISGs, one of which is Mx1. This leads to a block of IAV replication. B–E THP-1 cells were pre-incubated for 1 h with 10 µM JAK inhibitor (JAKi) before addition of OMVs (1 µg/mL; Kp/Sal) for 20 h. B–C CXCL8 (B) and Mx1 (C) expression was determined by qPCR and results are normalized to RPS18 and depicted relative to untreated control. Bars show mean values of three to four independent experiments + SEM. D + E OMV pre-treated cells were additionally infected with IAV (MOI 0.001). D Western blot shows Mx1 protein expression at 0–3 h post infection (p.i.). E Viral replication was determined by plaque assay 24 h after infection. Bars show mean values of four independent experiments + SEM. Statistics: 1-way ANOVA (B + C + E); *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001; *compared to DMSO control, # as depicted in the graph; ns = not significant; n = 4