FIG 6.

Maraba G-pseudotyped VSV escapes serum neutralization. VSV-GFP or VSV/Maraba G (5-μl volume with 1 × 10⁸ TCID₅₀) was incubated with 100 μl undiluted nonimmune human serum that contained 10% standard guinea pig complement (Cedarlane) or heat-inactivated VSV-immune serum at 37°C for 1 h, followed by determination of the virus titer (TCID₅₀/ml) on Vero cells (1 × 10⁴ cells/well). As a control, virus was incubated with medium only and plated on Vero cells. The neutralization assay result was read at 48 h after infection with virus that was treated or not with serum. Alternatively, virus treated in the presence or absence of serum was plated on 12-well plates of Vero cells (1 × 10⁵ cells/well) and fluorescence images were taken at 24 h postinfection for each condition. All virus neutralization assay experiments were conducted in triplicate. The error bars represent standard deviations.