Fig. 3.

PI inhibits RSV binding to HEp2 cells. A: Western blot analysis of RSV binding to monolayers of HEp2 cells. Monolayers of HEp2 cells were incubated with varying concentrations (MOI = 1, 2, 5, and 10) of RSV for 2 h at 18°C in either the absence (RSV) or presence (RSV + PG 200; RSV + PI 200; RSV + PC 200) of 200 μg/ml of lipid. After the binding interval, the monolayers were washed three times with PBS, and then the entire content of each well was harvested and processed by SDS-PAGE and Western blotting. Each blot contains an RSV standard (RSV ∼10⁴ PFU) and lanes corresponding to uninfected cell monolayers (UN) and to monolayers exposed to lipid but no RSV (PG, PI, PC). The location of the viral attachment glycoprotein (GP) is indicated in the left margin. The data in A show a blot from one experiment. B: Summary from three independent experiments performed as described in A and normalized to the amount of β-actin recovered from each well containing HEp2 cells. Values shown are means ± SE. C: Western blot analysis of lipid inhibition of RSV cell surface binding, comparing the activity of PI to that of PA and PS. The experiment was performed as described in A except that the lipids examined were 200 μg/ml PA, PS, or PI. D: Summary of three independent experiments performed as in C and normalized to the amount of β-actin recovered from each well containing HEp2 cells. Values shown are means ± SE.