FIGURE 1.
The porcine reproductive and respiratory syndrome virus (PRRSV) Lena strain induces IFN-α in infected animals but cannot directly activate pDC in vitro. (A) Serum IFN-α responses of pigs infected oronasally with PRRSV Lena (5 × 105 TCID50 per animal), as determined by ELISA. (B) Viral RNA loads in the serum. The data was obtained using RT-qPCR for PRRSV ORF7 and is represented as the total number of cycles minus the quantification cycle (Cq)-value. (C) Comparative analysis of IFN-α production by enriched pDC in response to PRRSV-1 (LVP-23 and Lena) and PRRSV-2 strains (VR-2332 and RVB-581) after stimulation with a MOI of 0.1 TCID50/cell. CpG D32 was included as control. The supernatants were harvested after 20 h of incubation and IFN-α was quantified by ELISA. The data represent the mean IFN-α (U/ml) of triplicate cultures, with error bars representing the standard deviation. These results are representative of at least three independent experiments.