Fig. 2.

Analysis of the growth properties of the recombinant IBVs in Vero cells.

Growth curves for the recombinant IBVs in Vero cells. In order to determine the growth curves for the recombinant IBVs and Beaudette, Vero cells were infected and harvested at 0, 4, 8, 16, 24, and 36 h post-infection. Viral stocks were prepared by freezing/thawing the cells three times and TCID₅₀ was determined by infecting Vero cells in 96-well plates with 10-fold serial dilutions of each viral stock. The experiments were conducted based on three replicates. ANOVA followed Tukey’s multiple comparison tests were performed to compare the virus titers of different strains at the same time point, and differences were considered significant at P < 0.05.