Figure 2.

Early cytokine markers of PRRSV infection. Two groups of weaned pigs were intranasally infected with virulent BSAL/2011 and attenuated BS114/2002 PRRSV strains, respectively [45]. Blood serum samples were collected at the indicated days post infection (DPI). Swine IFN-α was measured in serum samples by a cpe-inhibition assay on MDBK cells with vesicular stomatitis virus (VSV); the test was calibrated with a preparation of porcine recombinant IFN-α1 (PBL Biomedical Laboratories, cat. 17100-1) [50]. Porcine IFN-γ was measured by ELISA with a pair of catcher and biotinylated tracer monoclonal antibodies, as previously described [27].