Figure 2. Construction and characterization of ROCV/WNV chimeric viruses.

(a) Schematic representation of ROCV/WNV_NSW2011 chimeric viruses. (b) Plaque morphology of parental (ROCV and WNV) and chimeric (ROCV/WNV-prME and WNV/ROCV-prME) viruses in BHK-21 cells (upper) and comparison of plaque size areas (lower). Plaque areas (mm²) for 25–40 randomly selected plaques were measured using ImageJ software (National Institutes of Health, USA) and plotted as mean ± SD. (c) Growth kinetics of parental and chimeric viruses in IFN-competent mouse embryonic fibroblasts (WT MEF) and (d) IFNAR^−/− MEF cells infected at MOI = 0.1. Viral titers were determined by plaque assay on BHK-21 cells at the indicated time points. The dashed lines represent the LOD of the assay. Parametric one-way ANOVA test was used to compare within groups. *P-value ≤ 0.05, ****P-value ≤ 0.0001.