FIG. 9.

Cell binding and penetration assay. HeLa cells were incubated with 10 PFU of purified F9⁺ virions or the same number of F9⁻ virions at 4°C for 1 h and then shifted to 37°C for 2 h. Subsequently, cells were fixed, permeabilized, and stained for indirect immunofluorescence microscopy. The L1 MV membrane protein was stained with a mouse monoclonal anti-L1 antibody and a goat anti-mouse secondary antibody conjugated to Alexa Fluor 488 (green). The A4 core protein was stained with a rabbit primary antibody and a goat anti-rabbit IgG secondary antibody conjugated to Alexa Fluor 568 (red). Cellular DNA was stained with DAPI (blue).