UV-inactivated supernatant from WNV-infected human neuroblastoma cell line, SK-N-SH, activates astrocytes and induces expression of pro-inflammatory cytokines. (A) FACS analysis of GFAP expression in naïve HBCA cells treated with UV-inactivated supernatant derived from mock- and WNV (MOI-1)-infected SK-N-SH cells at 48 h after treatment is shown as overlapped histograms with the mean fluorescence intensity (MFI) in arbitrary units at the right. The MFI of GFAP increased significantly in HBCA cells treated with UV-inactivated supernatant from infected SK-N-SH cells (*p < 0.05). Data are representative of three independent experiments. (B) cDNA templates synthesized from RNA extracted from HBCA cells at 6, 24 and 48 h after treatment with UV-inactivated supernatant from SK-N-SH cells were used to determine the fold-change of IL-1β, -6, -8, and TNF-α by qRT-PCR. Changes in the levels of pro-inflammatory cytokines were first normalized to the GAPDH gene and then the fold-change in infected supernatant treated cells as compared to corresponding controls was calculated. Data represents mean ± SD of five independent experiments conducted in duplicate.