FK506 does not inhibit cytopathic effects of FIPV on fcwf-4 cells. (A) WST-8 assay of fcwf-4 cells cultured with various FK506 concentrations. Error bars indicate means ± 2SD. *P < 0.05. (B) The numbers of plaque were counted in FIPV-infected fcwf-4 cells incubated with or without FK506. Cells infected with FIPV were cultured with various concentrations of FK506.