“…TBEV titer was determined by 50% tissue culture infective dose (TCID50) assay with 10-fold serial dilutions in BHK-21 cells as described ( Yang et al., 2021 ; Tang et al., 2023 ). Briefly, BHK-21 cells were seeded in 96-well plates at a density of 2 × 10 4 /well and inoculated with serially diluted serum samples and tissue homogenate.…”