Fig. 6.

CCHFV-infected dendritic cells activate ECs by a TNF-α-dependent mechanism. Conditioned medium from CCHFV-infected (MOI, 10) moDCs or noninfected MODCs was incubated with or without neutralizing antibody (5 μg/ml) targeting TNF-α for 1 h, followed by addition to confluent endothelial cells for 6 h. Control treatments included incubating TNF-α (2 ng/ml) or cell medium with or without neutralizing antibody. The moDCs were derived from four individual donors. The ECs were fixed and stained for cell surface-bound ICAM1. Background ICAM1 levels derived from ECs exposed to only cell culture medium were subtracted. The values displayed are the averages of triplicates, with the error bars indicating standard deviations. Activation of ECs by conditioned medium from infected moDCs is reduced upon preincubation with neutralizing antibody against TNF-α. The results are expressed as means and SD; ns, not significant; *, P < 0.05; ***, P < 0.001. The treated cells were compared to the respective control, and statistical significance was tested by the Wilcoxon signed-rank test.