FIG 5.

Prophylactic antiviral activity. Confluent monolayers (96-well plate format; 5 × 10⁴ cells/well; quadruplicates) of MDCK cells were pretreated with the indicated 3-fold serial dilutions of the indicated compounds (starting concentration of 50 μM) or with 0.1% DMSO vehicle control for 24 h before infection with 200 FFU of BIRFLU. At 48 hpi, tissue culture supernatants from infected cells were collected and used to measure Nluc expression. Images of Venus expression were taken using a fluorescence microscope. Percent viral infection and the EC₅₀ were calculated based on Nluc expression. Dotted lines indicate 50% viral inhibition. Data are expressed as mean and SD from three independent experiments conducted in quadruplicates. Bar, 50 μm.