FIG 3.

PSV binding and infection are blocked by N-acetylneuraminic acid (NANA). (A) The effect of a soluble form of NANA on the binding of AF-594-labeled PSV (MOI, 1,000 PFU/cell) to LLC-PK cells was examined by confocal microscopy. (B) The effect of soluble NANA, Gal, or 6′-SL on the binding of [³⁵S]methionine-cysteine-labeled PSV, EV70, FCV, or CVB3 (50,000 cpm) to each corresponding cell was measured by liquid scintillation and expressed as a percentage of the value for the mock-treated, virus-infected control. (C) The effect of NANA of permissive cells on the infectivity of PSV (MOI, 1 PFU/cell) was assessed by immunofluorescence using monoclonal antibody specific for PSV capsid protein at 15 h postinfection. (D) The levels of PSV, EV70, FCV, or CVB3 antigen-positive cells expressed as percentages of the mock-treated, virus-infected control were quantified from three independent fields of view. All experiments were performed three independent times. Panels A and C show representative sets of results. Scale bars corresponded to 20 μm. Error bars indicate SD from triplicate experiments. *, P < 0.05; **, P < 0.005.