Figure 2

Permissivity of equine neural progenitor cells and neurons to WNV. A–D Equine NPCs and equine neural cells differentiated for 14 days from eNPCs (eDNCs) were infected with WNV_NY99 at MOI 10^–1. A Immunofluorescence labeling with antibodies against WNV-E3 (red) and βIII-Tubulin (green). B Immunofluorescence labeling with WNV-E3 antibody (red) shows virus spreading in eNPCs. Cells were stained with DAPI (blue). C Viral RNA from supernatant was analyzed by RT-qPCR. D Virus in supernatant was titrated by end-point dilution (TCID₅₀). E, F Equine NPC were infected at MOI from 10^–4 to 1 and enumerated automatically based on fluorescent staining using an OPERA instrument. Enumeration of E the percentage of WNV-infected eNPCs (immunostaining with WNV-E3 antibody) and F total eNPCs number (DAPI staining). Normalization was to non-infected eNPCs at 24 h (F). Results are pooled from 3 independent experiments performed in duplicate (C, D) or representative of 3 independent experiments performed in 6 replicates (E, F). Data are expressed as the mean ± SD. Comparison between cells infected for 48/72 h and cells infected for 24 h (C–E) and comparison between infected cells (at MOI from 10^–4 to 1) and non-infected cells at the same time post-infection (F) were performed with a two-tailed unpaired Mann–Whitney test with p-values significant when *p < 0.05, **p < 0.01.