Fig. 1

Visualization of MVA Plaques Using Immunostaining and Crystal Violet Staining in DF-1 Cells. MVA plaques were visualized in DF-1 cells using the gold standard immunostaining with anti-VACV serum and secondary antibody anti-rabbit IgG conjugated with HRP (A, B) and crystal violet staining (C, D). Following infection with MVA, the DF-1 cells were incubated in medium containing 0.5% methylcellulose for two to three days to facilitate plaque formation. Immunostaining revealed distinct brown plaques (A), while crystal violet staining provided distinguishable plaques (C). VACV-Western Reserve (WR) strain was used as a comparison. Each circle in the left of (B) and (D) indicates a single plaque view in B & D. Zoomed-in views (4x) of the plaques are shown in (B) and (D) in the right. The numbers following virus strains (MVA or WR) indicate the dilution fold of infection (logarithm). E MVA plaque assay using crystal violet staining in BHK-21 cells does not present visible and countable plaques compared to DF-1 cells