Fig. 2

Fig. 2

Human primary monocytes are productively infected by ZIKV. a Monocytes purified from seven healthy blood donors were infected with Colombian (ZIKV^C) or Panama (ZIKV^P) ZIKV strains at MOI 1 (+) or 5 (++) for 48 h. Cells were fixed, permeabilized, and processed for flow cytometry. The percentage of ZIKV-infected cells (NS2B⁺) is plotted as a function of the strain and amount of ZIKV used. Each dot corresponds to the mean ± SD of ZIKV-infected cells for each donor and each condition in two individual samples. b Monocytes were infected for the indicated time with ZIKV (MOI 1) for 48 h. Total RNA was extracted and RT-qPCR was performed by using ZIKV and GAPDH-specific primers. The graph represents the fold change of ZIKV RNA with respect to GAPDH of a triplicate ± SD. Data from two donors are shown. No ZIKV RNA was detected in monocytes from a third donor in this experiment (data provided in the Source Data file). c Monocytes infected with ZIKV for 48 h were fixed and fluorescence in situ hybridization (FISH) was performed by using a ZIKV-specific RNA probe (magenta) and nuclei were stained with NucBlue (blue). Left and right panels are representative images from experiments done with two donors. Scale bar: 5 µm. d Monocytes purified from four healthy donors were untreated or pretreated with 50 µM ZCL278 for 30 min at 37 °C. The cells were then infected with ZIKV (MOI 1) in the presence or absence of ZCL278. The inoculum was removed at 4 h post infection, after which the cells were washed and re-incubated in complete media for 48 h. The supernatant was harvested and a plaque assay on Vero cells was performed to titrate ZIKV production. The bar graphs represent the mean + SD of two independent samples. Each dot represents the mean of a duplicate. ZCL278 treatment inhibited ZIKV infection of monocytes by 93% (±7). The letters attributed to each donor correlate with the ones in a. The two-tailed p value was <0.05 (*). Statistical significance was determined by using a t test. NI noninfected. Source data in a–d are provided as a Source Data file