Attachment, internalization, disassembly and infection of PRRSV in PK15S1–CD163 and PK15S10–CD163 cells. Cells were inoculated with PAM-grown LV. Then, the different stages of viral replication were visualized with a staining for the nucleocapsid of PRRSV. The experiments were performed in triplicate; the numbers on the images represent mean ± SD of 3 repeats. Scale bar: 25 µm.