Primary HUVECs were isolated from human umbilical cords of 22 donors by treating the umbilical vein with 0.1% collagenase for 30 min at 37uC as described previously [47] . Cell cultures were pooled by sets of three donors for experiments. Cells were cultured in flasks coated with 0.2% gelatin in complete medium containing M199 medium (Gibco), 20% of fetal calf serum (Gibco), 100 mg/ml bovine brain extract [48] , 14 mM Hepes (Gibco), 10 UI/ml heparin (Pfizer), and a cocktail of antibiotic/antimycotic (Gibco). At passage 4, cells were seeded at 30 000 cells/cm 2 for 8 h, then serum deprived for 16 h prior to NiV-infection in complete medium. Immunofluorescent staining and analysis of HUVEC culture was performed as described in Methods S1. U373 astroglioma and Vero cells were maintained in DMEM medium (Invitrogen) supplemented with 10% fetal calf serum, 100 U/ml penicillin, 0.1 mg streptomycin, 10 mM HEPES and 2 mM L-Glutamine at 37uC in 5% CO 2 .