The construct with a double C deletion, dC24-59;76-96, produces a larger amount of SVPs than other C-deletion constructs. (A) Cells transfected with each plasmid were stained for KUNV E. Culture fluid derived from this transfection was diluted 1:10 and inoculated onto Vero cells for analysis of infectious particle content via KUNV E staining. Nuclei were counterstained using DAPI. (B) Western blot detection of KUNV E and C protein expression in transfected cell lysate and E secretion into culture fluid. Blots were stained using antibodies specific for WNV C and KUNV E. Detection of GAPDH was utilized as a lysate loading control. (C) Capture ELISA to quantitatively compare E/SVP secretion into culture fluid. As all samples were assayed in parallel, controls are the same for Fig. 2 and 3. Results shown in panels A and B are representative of those of at least three independent experiments, while results shown in panel C are averages from at least three independent experiments. *, significant (P = 0.01 to 0.05); **, very significant (P = 0.001 to 0.01); ***, highly significant (P < 0.001).