Fig. 2.

Indirect immunofluorescence assay showed that the rescued viruses are PRRSV-specific. The supernatant of the transfected cells was collected and aliquoted as virus stock P0, of which 0.01 MOI was inoculated on Marc-145 cells of cell dishes, and incubated at 37 °C for 72 hpi. The infected cells were fixed and then stained with anti-Nsp2 monoclonal antibody of PRRSV (Kindly provided by Dr. Ying Fang at South Dakota State University) at 1:800 dilution in phosphate-buffered saline (PBS), followed by incubation with fluorescein isothiocyanate-conjugated (FITC) secondary goat anti-mouse antibody, and visualized under Olympus inverted fluorescence microscopy. Panel (A) vORF12, (B) v5ND7, (C) vORF56c, (D) vORF673, (E) vORF7Ua, and (F) negative control.