Fig 1.

Cytotoxicity and antiviral effects of five fatty acids. (A–C) Vero cells, PK-15 cells, and LLC-PK1 cells were treated with 0–200 μM of NaB, LA, PA, DHA, or EPA for 24 h. The relative cell viability was evaluated by the Cell Counting Kit-8 (CCK-8) according to the manufacturer’s instructions. (D–F) Vero cells, PK-15 cells, or LLC-PK1 cells were infected with TGEV, PEDV, or PDCoV [multiplicity of infection (MOI) = 0.01], respectively, for 1 h and treated with NaB, LA, PA, DHA, or EPA. The virus N gene load at 12 h was quantified by qRT-PCR. (G) At 24 h postinfection, TGEV, PEDV, or PDCoV (MOI = 0.1) replication in PK-15, vero, or LLC-PK1 cells was determined by IFA. Cells were fixed with 4% paraformaldehyde and stained with an anti-TGEV-N, anti-PEDV-N, or anti-PDCoV-N antibody and a fluorescein isothiocyanate (FITC)-conjugated secondary antibody (green); nuclei were stained blue with 4′,6-diamidino-2-phenylindole (DAPI). (H–J) Vero cells, PK-15 cells, or LLC-PK1 cells were infected with TGEV, PEDV, or PDCoV (MOI = 0.01), respectively, for 1 h and treated with 100 µM of fatty acids. Cells were collected after 12 h, 24 h, and 36 h for western blotting analysis. Results are presented as mean ± SD, and the asterisks indicate significance compared to dimethylsulfoxide (DMSO)-treated cells (Student’s t test, *P < 0.05; **P < 0.01).