Fig. 4

The inhibitory effect of anidulafungin on SFTSV fusion with the cell membrane. A SFTSV NP and Gn expression both on the cell surface and in cells were detected by IFAs. Vero cells were treated with anidulafungin (20 μM for 1 h and then incubated with SFTSV (MOI = 100) at 4 °C for 1 h, or infected with SFTSV (MOI = 25)) and maintained at 37 °C for 48 h. After washes, IFAs were performed to detect viral protein on the cell surface without treatment of 0.2% Triton X-100 (non-permeabilized) and in cells with treatment of 0.2% Triton X-100 (Permeabilized). Bars, 50 μm. B Western blot was performed to analyze SFTSV NP, Gn, and Gc expression in Vero cells incubated with SFTSV (MOI = 100) at 4 °C for 1 h or cells infected with SFTSV (MOI = 5) at 37 °C for 48 h. Mock, healthy cells. C Syncytia formation assays were performed to investigate the inhibitory effects of anidulafungin on SFTSV fusion ability triggered by acidic conditional. The infected Vero cells were indicated by immunostaining SFTSV NP expression, and cells were indicated by staining nuclei. Bars, 200 μm. D The fusion ability of SFTSV in the presence or absence of anidulafungin was expressed by the number of cells that form syncytium over the number of SFTSV-infected cells from three images of each test. h p.i., hours post-incubation. The significant difference was determined using Student’s t-test. *P < 0.05; **P< 0.01; ***P < 0.001; ****P < 0.0001