STING1 and infection: The rPRRSV-dsRed infection of GFP-STING and GFP control stable Marc-145 cells were quantified by flow cytometry, and the results show that either dsRed signal or dsRed/GFP double signals were decreased in GFP-STING cells relative to GFP vector control cells, in particular at 48 h post infection (hpi), indicating the antiviral role of STING (Figure 2A).