Cyclosporin A inhibits cytopathic effects of FIPV on fcwf-4 cells. (A) WST-8 assay of fcwf-4 cells cultured with indicated concentrations of CsA. Error bars indicate means ± 2SD. *P, **P < 0.05. (B) Plaques counted in FIPV-infected fcwf-4 cells incubated with or without CsA. Cells infected with FIPV were incubated with various concentrations of CsA.