Fig. 3.

Surface expression of full-length membrane-associated S protein demonstrated by flow cytometry using the rabbit polyclonal antibody P540. Full-length S glycoprotein was used to transfect 293 cells, which were then infected with VTF7.3. Cells were collected and incubated with P540 polyclonal antibody plus anti-rabbit secondary antibody conjugated with FITC, washed, and subjected to flow cytometry analysis. The same plasmid used to express S but without the gene for S was used to transfect cells in a control experiment denoted as negative control (NC); the full-length S glycoprotein is denoted as S.