Antiviral Activity of Benzavir-2 against Emerging Flaviviruses

Gwon, Yong-Dae; Strand, Mårten; Lindqvist, Richard; Nilsson, Emma; Saleeb, Michael; Elofsson, Mikael; Överby, Anna K.; Evander, Magnus

To further confirm the antiviral activity of benzavir-2 and to exclude that the observed inhibition was specific against rZIKV-ZsGreen, we analyzed whether benzavir-2 inhibited wt ZIKV plaque formation. The formation of plaques corresponds to a full infection cycle, from entry to egress of newly-formed viral particles. Based on the dose-response activity against the rZIKV-ZsGreen vector ( Figure 2 and Table 1 ), we conducted a plaque formation assay in a dose-dependent manner by using benzavir-2 (from 20 to 0.6 µM) and ribavirin (from 200 to 6.3 µM) to observe plaque forming inhibition against the more clinically relevant wt ZIKV Asian lineage (BeH819015, Brazil strain). After 4 days of ZIKV infection, the Vero B4 cells were fixed and plaques were visualized by crystal violet staining and then quantified. Benzavir-2 showed significant reduction of plaque formation at all applied concentrations, while ribavirin only showed inhibition of plaque formation at 200 µM ( Figure 3A ). To further investigate benzavir-2 inhibition against other wt ZIKV lineages, we treated the African lineage (MR766, Uganda strain) with benzavir-2 at 2.5 µM. It showed a significant reduction of plaque formation, 94% reduction for the African lineage and 88% reduction for Asian lineage (Figure 3 ).