Fig. 4.

Flow cytometric analysis of cell-surface envelope glycoprotein. Vero cells expressing the envelope glycoproteins were stained using the G1-specific neutralizing MAb BE08 (Sanchez et al., 1989) and subsequently stained using propidium iodide (1 μg/ml) to exclude dead cells in the population. Cells were fixed using 2% formaldehyde and analyzed using a FACSCalibur flow cytometer (BD Biosciences). Background staining of mock-transfected cells is shown in the first panel; the non-expressing cell population within the GP-C transfected cultures (other panels) tend to pick up additional staining, possibly due to membrane exchange within the culture. The expressing cell populations were defined using a gate of ≥30 that included <0.1% of the mock-transfected population (arrow).