Figure 4.

MDBK cells are permissive for ZIKV RNA replication but are not susceptible to infection with the virus. MDBK cells were mock-infected or infected with rMR-766, rP6-740, or rPRVABC-59 at an MOI of 3 (for virus infection experiments), or mock-transfected or transfected with 3 µg of synthetic RNAs transcribed in vitro from their respective infectious cDNAs (for RNA transfection experiments). At the indicated time points, the expression of three ZIKV proteins (E, NS1, and NS4A) within the cells was analyzed by confocal microscopy for E (A), flow cytometry for NS4A (B), and immunoblotting for NS1 (C). The insets in panel A show enlarged views of the boxed areas with the fluorescence of propidium iodide (PI)-stained nuclei excluded. In all experiments, ZIKV-susceptible Vero cells were included in parallel. hpi, hours post-infection; hpt, hours post-transfection.