DI-244 produced in PB2opt expressing cell lines exerts anti-IAV activity.

(A) Undiluted or 10-fold serially diluted DIP supernatants harvested from transfected 293T-PB2opt/MDCK-PB2opt cells or supernatants from transfected 293T/MDCK control cells were co-inoculated with A/PR/8/34 (H1N1) onto MDCK cells. Fresh medium was added at 1 h post infection and infectivity present in supernatants harvested at 72 h post infection was analyzed by focus formation assay. The average of three (MOI 0.1, MOI 0.01) and six (MOI 0.001), respectively, independent experiments is shown. Infection in the absence of supernatants was set as 100%. Error bars indicate standard error of the mean (SEM). Two tailed paired students t-test was used to assess statistical significance. (B) The experiment was carried out as described for panel A but A/Panama/2007/99 (H3N2) was used for infection. The average of three independent experiments is shown. Infection in the absence of supernatants was set as 100%. Error bars indicate SEM. Two tailed paired students t-test was used to assess statistical significance. (C) The experiment was carried out as for panel A but cells were infected with GFP-encoding VSV and supernatants were harvested for titration at 24 h post infection. The results of a single representative experiment conducted with triplicate samples are shown and were confirmed in two separate experiments.