PRRSV infection kinetics in CHOSn-CD163 and PK15Sn-CD163 cells. CHOSn-CD163 and PK15Sn-CD163 cells were inoculated with Marc-145 grown LV (open square), Marc-145 grown VR-2332 (black square) or macrophage grown LV (black circle). After 1, 2, 3, 5 and 7 dpi the cells were fixed and an immunoperoxidase staining was performed. The amount of infected cells were counted and expressed in the graphs as the percentage of infected cells. Values represent mean ± SD of three experiments.