At 72 hrs post infection, infectious PRRSV particles were also detected from the supernatant samples from MARC-145, PK-15CD163, or COS-7CD163+MYH9 cells, but not in PK-15puro, COS-7puro, or COS-7CD163 cell supernatant samples (Fig. 4b). This evidence concerns the gene MYH9 and infection.