Figure 4

Ad binds to the platelet cell surface. (a) Platelets were incubated with Ad (MOI = 10, 2-hrs) at 4°C or 37°C to compare cell surface binding (4°C) vs. potential cell entry (37°C). Alternatively, platelets were fixed in 4% paraformaldehyde and then measured for cell surface Ad binding using direct flow cytometry. (b) To qualitatively evaluate cell surface Ad binding, Mo cells and platelets were incubated with Ad (MOI = 10, 4°C for Mo cells and RT for platelets, 1-hr) or mock-infected, rinsed, mounted on a cover slip, fixed, blocked with BSA, rinsed, incubated with the FITC-anti-hexon antibody and visualized with a confocal fluorescent microscope. Ad virions adherent to the cell surface were detected as green labeling in Mo cells and orange labeling in platelets. Negative controls included omission of Ad incubation.