Figure 2.

Levistolide A exhibits antiviral activity against PEDV strain DR13 and YN15 in Vero and LLC-PK1 cells. Vero cells were treated with LA at indicated concentrations and infected with PEDV at an MOI of 0.1 at the same time. DMSO served as the treatment control. Samples were collected at 36 hpi for IFA or TCID₅₀ assay analysis. (A) Immunofluorescence of PEDV-S protein (green) detected in PEDV strain DR13 infected Vero cells. (B) The viral titer determined in PEDV strain DR13 infected Vero cells. (C) Viral titer determined in PEDV strain YN15 infected Vero cells. (D,E) Vero cells were treated with LA (80 µM) or DMSO, and exposed to PEDV at 0.25 MOI or 0.5 MOI. Viral titers were assessed at 36 hpi. (F,G) Vero cells were treated with LA (80 µM) or DMSO, and exposed to PEDV (0.1 MOI). Viral titers were assessed at designed hpi. (H) Viral titer determined in the PEDV strain DR13 infected LLC-PK1 cells. (I) The viral titer determined in PEDV strain YN15 infected LLC-PK1 cells. Viral titer level was represented by the value of −lg TCID₅₀/0.1 mL. Data represent the mean ± standard deviation (SD) of three independent experiments, and error bars represent standard deviation. Asterisks indicate significant differences between mock-treated group and LA or DMSO treated group: * p $<$ 0.05; ** p $<$ 0.01; *** p $<$ 0.001; **** p ≤ 0.0001; ns, not significant.