PK-15 Cells

The PK(15) cell line, derived from PK-2A, a cell line established in 1955 from the kidney of an adult pig, is infected with the porcine type-C oncovirus (formerly known as porcine endogenous retrovirus, PERV), which is classified as a risk group 2 agent. The host cell genome contains 62 copies of the *pol* gene, which codes for reverse transcriptase and other proteins. Initially, the virus particles produced by the PK(15) cell line were described as defective and non-infectious for a variety of mammalian cell lines, including a human cell line, leading to its classification as a risk group 1 cell line. However, subsequent studies demonstrated that human 293 cells could be productively infected by the cell-free supernatant of PK(15) cells. This finding resulted in the reclassification of the PK(15) cell line by the German Central Commission for Biological Safety (ZKBS) in November 2018. PCR analyses revealed that the transmitted viruses belonged to the polytropic subtypes PERV-A and PERV-B. Additionally, it was observed that the virus particles produced by the 293 cells were resistant to inactivation by the human complement system. In addition to its virological significance, the PK(15) cell line also serves as a suitable host for transfection applications. Due to its adherent growth properties, it is highly valuable in various research and experimental settings.