Effect of GM-CSF on poly (I:C) and R-848 induced IL-6 secretion from P815 cells. The cells were preincubated with GM-CSF for 1 h before adding poly (I:C) or R-848 for 6 h. Values shown are Mean ± SE for four separate experiments performed in duplicate. * P < 0.05 compared with the response to corresponding medium alone control. † P < 0.05 compared with the response to R-848 5.0 μg/ml alone. Poly = poly (I:C).