Fig. 6From: In vitro immune responses of porcine alveolar macrophages reflect host immune responses against porcine reproductive and respiratory syndrome virusesType I IFN bioassay using sera from PRRSV-challenged pigs at 3 dpc. MDBK cells (n = 6) in 96-well plates were infected with VSV and incubated until a CPE was evident in mock-treated control cells. Type I IFN bioactivity in the serum was measured by performing a type I IFN bioassayBack to article page