Figure 5. siRNA's are effective in reducing viral replication when applied before infection, even in the absence of a transfection reagent.
In a first experiment, Balb/c mice (groups of 12) were transfected intranasally with sigB3 and siOri2, alone or in combination, and mice were infected intranasally with 1×105 PFU of Ab4 0.5 h later (A). In a second experiment, Balb/c mice (groups of 12) were inoculated intranasally with 62.5 pmol sigB3/siOri2, complexed with lipofectamine (closed symbols) or in PBS (open symbols) 6 or 12 h before infection with 1×105 PFU of Ab4 (B). Mice transfected with 75 pmol siLuc were used as positive controls and viral titers were determined in three mice of each group on day 2 p.i. Titers in lungs and standard deviations are shown. Asterisks indicate statistically significant differences (p<0.05) between mice transfected with sigB3 and siOri2, alone or in combination, and mice transfected with the control siRNA siLuc.