Fig. 8

Type I IFN response in astrocytes protects against viral spread of TBEV and cell death. Primary astrocytes isolated from WT and IFNAR^−/− mice were infected with TBEV MOI of 0.1 and viral growth was determined at indicated time points. Two hours before infection, cells were treated with anti-IFNAR antibody or control IgG (IgC). Number of infected cells were measured by immunofluorescent staining of TBEV E antigen and DAPI (a, n = 8). Quantification of virus RNA determined by qPCR analysis (b, n = 6). Viral titers in cell culture supernatants determined by focus forming assay (c, n = 6). Cell viability after infection was measured using a resazurine viability assay (d, n = 8). Supernatants from TBEV-infected astrocytes were collected at the indicated time points and inactivated. Primary neurons were pretreated with the supernatants followed by TBEV infection, and viral infection was determined 48 h post infection by immunofluorescent staining of TBEV E antigen and DAPI (e, n = 6). Mean values and standard deviations from three independent experiments are shown. *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001