Figure 1.

Cell adaptation of A/SKR/Yeoncheon/2017 over serial passages. Foot-and-mouth disease virus (FMDV) A/SKR/Yeoncheon/2017 was serially passaged as follows for adaptation to the cells: five times in porcine kidney (LFBK) cells and three times in baby hamster kidney (BHK)-21 adherent cells (L5B3); five times in LFBK cells, four times in BHK-21 adherent cells, and one time in BHK-21 suspension cells (L5B4S1); five times in LFBK cells, four times in BHK-21 adherent cells, and four times in BHK-21 suspension cells (L5B4S4); five times in LFBK cells, four times in BHK-21 adherent cells, and six times in BHK-21 suspension cells (L5B4S6); five times in LFBK cells, four times in BHK-21 adherent cells, and seven times in BHK-21 suspension cells (L5B4S7). The 50% tissue culture infective dose (TCID₅₀) of the virus during passaging was measured in BHK-21 adherent cells expressing the integrin receptor and in CHO-K1 cells expressing the heparan sulfate (HS) receptor. Error bars indicate standard deviations (SDs) from the mean.