Figure 2.

Fludarabine inhibited infection of ZIKV. (a,b) Inhibitory effect of fludarabine on ZIKV SZ01 and MR766 infection in Vero cells. (c–e) Inhibitory effect of fludarabine against ZIKV SZ01 infection in BHK21, U251 MG and HMC3 cells, respectively. Fludarabine, diluted to 1, 0.2, 0.04, and 0.008 μM or 5, 1.25, 0.31, and 0.08 μM, was mixed with 0.1 MOI of ZIKV SZ01 or ZIKV MR766. After the mixture was inoculated to cells for 2 h, the mixture was discarded and the cells were washed twice with PBS. The cell cultures were supplemented with DMEM or MEM (2% FBS) containing fludarabine of the same concentration as mentioned above. Total RNA was prepared 24 h later to measure ZIKV E gene transcription by qRT-PCR assay. The differences between infected-groups without and with treatment of fludarabine were evaluated by two-tailed Student’s t test. Data are presented as mean ± SD; *, p < 0.05; **, p < 0.01; ***, p < 0.001; ns, no significance; ‒, no fludarabine was added. (f) Decrease of viral protein in ZIKV-infected cells treated with fludarabine. The expression of ZIKV SZ01 E protein was measured by western blot analysis after the Vero cells were treated for 36 h as mentioned above. ‒, no fludarabine was added. (g) Anti-ZIKV activity of fludarabine was tested using immunofluorescence analysis. After the Vero cells were treated for 24 h as mentioned above, ZIKV SZ01 dsRNA was detected by immunostaining with J2 anti-dsRNA monoclonal antibody (green). Cell nuclei were stained by 40, 6-diamidino-2-pheny-lindole (DAPI, blue). Scale bars, 20 μm.