Fig. 6.

Effect of UV-inactivated virus and anti-IFN-α antibodies on IFN-α production. PAM cultures were infected with either PRRSV or UV-inactivated PRRSV at MOI = 1.0 for 2 h. Polyclonal antibody against porcine IFN-α (50 neutralizing units/ml) was added into cell cultures at the time of infection. At 12 h p.i. cell culture media was replaced with media containing polyI:C (20 μg/ml). After additional 6 h incubation, cell culture media was collected and analyzed for IFN-α production by using porcine specific ELISA. One unit/ml of rIFN-α is equivalent to 26 pg/ml. *, Significant difference compared to polyI:C treated and isolate 3 infected cells (P < 0.05).