FIG. 7.

Tracking cell binding with eGFP-tagged MHV-68. A. BHK-21 cells were exposed to either wild-type (WT) or gL-deficient versions of MHV-68 with eGFP-tagged gM (2 PFU/cell) and then cultured at 37°C. The cells were washed with PBS or at low pH after the time indicated and analyzed by flow cytometry for green fluorescence. B. BHK-21 fibroblasts, NMuMG epithelial cells, and MCCD epithelial cells were exposed to gL⁻ or gL⁺ versions of the gM-eGFP virus as for panel A. The cells were washed with PBS at the time indicated and then analyzed by flow cytometry for green fluorescence. The decline from maximum fluorescence with time may reflect the destruction of gM-eGFP in lysosomes following endocytosis and fusion. C. NS0 cells were analyzed for green fluorescence after exposure to gL⁻ or gL⁺ gM-eGFP MHV-68 as for panel C. A 2-h parallel infection of BHK-21 cells at the same multiplicity (2 PFU/cell) is shown.