Poly(I:C) mediated reduction in preOL viability is dose-dependent. Rat mixed glial cultures were stimulated with vehicle (sterile PBS; 5 μl/ml), poly(I:C) (5 and 50 μg/ml), or LPS (positive control; 0.1 and 1.0 μg/ml) for 48 h. A, B: Poly(I:C) dose-dependently increased TNFα levels as measured by ELISA (A) and reduced preOL viability at 50 μg/ml but not 5 μg/ml (B). C, D:Stimulation of mixed glia with 0.1 and 1.0 μg/ml of LPS induced similar levels of TNFα production (C) and loss of preOL viability (D). Results are combined means ± SEM from 3 independent experiments. *, p < 0.05, **, p < 0.01.