FIG 3.

Plaque morphology and particle stability of chimeric viruses. (A) After 72 h of incubation, the plaque morphologies of WNV/KOUV-EIII and WNV/BAGV-EIII in Vero cells were significantly smaller than those of WNV NY99, whereas those of WNV/JEV-EIII and WNV/SLEV-EIII remained similar to those of the NY99 control. (B) Ten representative plaques were measured for each chimera, with the mean and standard deviation (Std Dev) plaque sizes being determined for each. Plaque sizes statistically significantly different from those of WNV NY99 (P < 0.05, as determined by one-way ANOVA with the Bonferroni correction) are in bold. (C) Duplicate virus (WNV NY99 and EIII chimeras) samples were held at 37°C, and aliquots were harvested at 0, 12, 24, 36, 48, and 72 h. Samples were titrated, and the values were normalized to the titer at 0 h. One-phase decay curves were fitted to the data using GraphPad Prism (v6.0g) software.