Figure 5

IRF1 and IRF8 are preferentially up-regulated in OPCs treated with IFNγ. A-C, Quantitative analysis of induction of IRF1, IRF2, IRF3, IRF6, IRF7, IRF8, and IRF9 mRNA in OPCs before (Cnt 0 h) and at 24 h after incubation with IFNγ (100 ng/ml, G 24 h), IFNβ (1 kU/ml, B 24 h), or medium alone (Cnt 24 h). Each data point was from at least 3 independent experiments. Note that the data are plotted as ratios to copy numbers of GAPDH cDNA on a logarithmic scale. ** Indicates p < 0.01 compared with control at 24 h (Cnt 24 h). D, IRF1 and IRF8 mRNA in OPCs were quantified by real-time PCR at 1, 3, 6, 12, and 24 h after addition of GM alone (control, open circle), IFNγ (100 ng/ml, closed circle) or IFNβ (1 kU/ml, closed triangle). For IRF8, basal IRF8 mRNA levels in the two RNA samples of spleen are shown as positive control (open triangles). At time 0, data from controls are only shown. E, Induction of IRF1 and IRF8 proteins in OPCs was examined at 24 h after treatment with IFNγ and IFNβ by immunoblotting.