A. Human cells were pretreated with a recombinant hybrid type-I interferon, IFN-α A/D (Sigma-Aldrich I4401), at different concentrations (0, 1 and 10 IU/ml) for 12 h prior to infection with VSVΔG-CHIKV at an MOI of 0.02. Despite IFN-α treatment, strong viral infection was seen in glioma cells at 24 hpi. Infected cells were visualized by immunofluorescent labeling with VSV immunostaining. Scale bar 0.1 mm. B. The same experiment was also performed with mouse CT-2A cells compared with primary mouse glia. C. and D. The bar graph shows the percentage of infected cells. Values are reported as the mean ± SEM; n = 6. ns, not significant, * *p < 0.01, * **p < 0.001 vs. control; ANOVA with repeated measures.