Cellular cholesterol is not required for BRV attachment. (A) Cell viability after treatment with various concentrations of MβCD for 30 min was determined with CCK-8 Kit. (B) The cellular cholesterol levels were measured by Amplex Red cholesterol assay kit. (C) Cholesterol depletion had no effect on BRV attachment. Cells were mock treated or treated with indicated concentrations of MβCD for 30 min, then infected with BRV at 4°C. At 1 h later, cell lysates were prepared by freeze-thaw and virus titers were measured.