Figure 1.

Human umbilical cord derived mesenchymal stem cells (hUCMSCs) are highly permissive to ZIKV infection (A) Confocal images of hUCMSCs infected with PRVABC59 (Asian lineage) at 24 hpi. ZIKV envelope (E) protein (Red), DAPI (blue), and CD73 (green) are shown. Scale bar = 20 μm. (B) hUCMSCs and JAR choriocarcinoma cells were infected with ZIKV at a multiplicity of infection (MOI) of 1 and RNA was collected at different time points. qRT-PCR was performed to determine the ZIKV NS5 transcript levels. Data are representative of three independent experiments (mean ± SD). *p < 0.05; **p < 0.01; ***p < 0.001, versus mock-infected cells. (C) Cells were infected with ZIKV (MR766 or PRVABC59) at a MOI of 1 for 72 h. Cells were fixed with paraformaldehyde and permeabilized with 0.5% Triton X-100. ZIKV E protein was immunostained with anti-pan-flavivirus envelope monoclonal antibody. ZIKV E and cell nuclei are stained red and blue, respectively. The images are representative of three independent experiments. Scale bar = 20 μm. (D) Viral titers were measured by TCID50 assay. Supernatant were collected from hUCMSCs infected with ZIKV (MR766 or PRVABC59) at a MOI of 1 for various timepoints. TCID50 was calculated using the Spearman-Kärber method. Results represent means ± SD of two independent experiments.