FIG. 4.

Growth curves of chimeric viruses in cell culture. Cells were infected at a multiplicity of 0.5 PFU/cell, and media were collected at 12- or 24-h intervals, followed by plaque titration on LLC-MK₂ cells. (A) YF/JE-S compared to its parental viruses on LLC-MK₂ cells. (B) YF/JE-N compared to its parental viruses on LLC-MK₂ cells. The titers represent averages of triplicate samples for both experiments. (C) Chimeric virus growth on C6/36 cells, with values representing an average of two samples for each virus. (D) Growth of YF/JE-S and YF/JE-N viruses on SW-13 cells. (E) Growth of YF5.2iv, YF/JE-S, and YF/JE-N on NB41A3 cells. The titers represent averages of triplicate samples, except for the last time point, which was determined in duplicate.