Virus Infection Assay in Mammalian Cell Lines

Virus infections were performed on Vero ATCC CCL-81 or SH-SY5Y ATCC CRL-2266 cells (ATCC, Manassas, VA). Vero cells were cultured in minimal essential medium (MEM) (Corning, Manassas, VA) supplemented with 10% fetal bovine serum (Gibco, Life Technologies, Paisley, UK), and SH-SY5Y cells were grown in Dulbecco’s modified Eagle’s medium (DMEM)–F-12 medium (Biowest, Nuaillé, France) supplemented with 10% fetal bovine serum. A penicillin-streptomycin mixture (Corning) and l-glutamine (Corning) were also added to cell cultures. WNV New York 99 (60 (link)), USUV SAAR 1776 (60 (link)), American ZIKV PA259459 (61 (link)), a cell-passaged derivative of DENV-2 16681 (16 (link)), VSV Indiana (61 (link)), and CVB5 Faulkner (62 (link)) were used. Procedures for infections in liquid medium and virus titrations in Vero cells in semisolid agar medium were previously described (62 (link), 63 (link)). WNV, USUV, ZIKV, VSV, and CVB5 titers were determined at 24 h postinfection (p.i.). DENV-2 titers were determined at 48 h p.i. A multiplicity of infection (MOI) of 1 PFU/cell was used for all experiments unless otherwise indicated.