Figure 6. Anti-infective activity of compound 9 against murine and human norovirus.

A. RAW264.7 cells were incubated at 37°C with DMSO (volume-matched), 2.5 µM compound 9 (right graph) or 5 µM WP1130 (left graph) for 0.5 h prior to infection. After incubation, cells were infected with MNV-1 (MOI 5) in the presence of compounds or DMSO for 1 h on ice. Cells were washed and only DMSO and WP1130 were added back to the cells. Infection proceeded for 8 h. Virus titers were determined by plaque assay. B. RAW264.7 macrophages were incubated for 0.5 h with DMSO (volume-matched), 2.5 µM compound 9 (right graph) or 5 µM WP1130 (left graph) at 37°C, followed by 1 h of incubation on ice. Cells were then washed and incubated for an additional 8 h before performing the WST-1 assay for cell viability. Results represent the percent of viability compared to the untreated cells. C. HG23-replicon cells were incubated for 24 h with DMSO or 5 µM WP1130. Alternatively, cells were incubated for 2 h with 2.5 µM compound 9 and washed. After 24 h incubation, Norwalk virus genomes were quantitated by qRT-PCR. Norwalk virus genome copy number was normalized to DMSO control. D. HG-23 replicon cells were incubated as described in C before performing the WST-1 cell viability assay. Results represent the percent of viability compared to the untreated cells. Results represent the mean of three independent experiments and significant differences were calculated using two-tailed student’s t test (A and B) or one-way ANOVA and Bonferroni’s post-test (C and D) (**p<0.01, ***p<0.001, NS, not significant).