Fig. 1: IFNβ potently restricts viral infection in P. alecto and E. fuscus cells.

A Schematic for the generation of recombinant IFNβ. Drosophila S2 cells were stably transfected to inducibly secrete human (Hu), E. fuscus (Ef), and P. alecto (Pa) IFNβ. GFP was produced in S2 cells for use as a control for vehicle treatments. Image created in BioRender [https://BioRender.com/o9oes1x]. B Detection of IFNβ by immunoblotting, where the V5-tag was probed for. C P. alecto (PaKiT03), E. fuscus (Efk3B), and human (A549, RPTEC) cells were untreated or treated with species-matched IFNβ (1 U/mL) for 6 h. The upregulation of MX1, IFIT1, and RSAD2 transcripts was assessed by qRT-PCR. Data are represented as mean ± SD, n = 4 biological replicates (Two-way ANOVA, Tukey’s range test, ****<0.0001, ***<0.001). D PaKiT03, Efk3B, A549, and RPTEC cells were untreated or treated with vehicle or species-matched IFNβ (10 U/mL) for 1 to 6 h prior to VSV-GFP infection (MOI 0.1). VSV-GFP levels were assessed by fluorescent microscopy. E VSV-GFP infection levels were quantified using ImageJ software. Data were represented as mean ± SD, n = 3 replicates/time point (One-way ANOVA, Tukey’s range test, **<0.01, *<0.05). F PaKiT03, Efk3B, Huh7, and RPTEC cells were uninfected (mock), infected with MERS-CoV (MOI 0.1), pretreated with species-matched IFNβ for 6 h prior to infection, or received IFNβ-treatment following infection for 48 h. Supernatant was collected and TCID₅₀ assay was performed to assess viral titer. Data were represented as mean ± SD, n = 3 biological replicates.