FIG 5.
Analysis of the density of purified ΔC-CHIKV virions. Shown are data for sucrose density gradient fractionation of WT and ΔC-CHIKV virions produced in BHK-21 cells. Cell-free virions were harvested, PEG 8000 concentrated, and separated on 20% to 60% linear sucrose density gradients. Ten fractions were harvested from the top (fraction 1) to the bottom (fraction 10) of the gradient. Each fraction from WT CHIKV (B and D) and ΔC-CHIKV (A and C) was subjected to qRT-PCR and E1-specific antibody-based Western blot assays to monitor the distribution of virions. ImageJ software was used to analyze the intensity of the viral E1 protein band in each fraction. The graphs (A and B) represent quantification of percent viral RNA/E1 protein in each fraction normalized to the largest amount of viral RNA/E1 protein. Three independent experiments were performed, with similar results, and one of the representative data sets is presented. CT, threshold cycle.