FIG. 6.

Effect of zinc salts on RSV plaque formation when added only after adsorption and/or penetration. RSV plaque counts in the presence of the indicated salts in a plaque reduction assay with approximately 90 PFU of wild-type RSV strain A2. HEp-2 cell monolayers were infected with virus, incubated at 37°C for 1 h, and then overlaid with methylcellulose containing various concentrations of zinc or control salts. Percent plaque counts were determined by adjusting the plaque count percentage for the mock-treated cultures to 100. Values are means and SEM of two independent experiments.