PK-15

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.

37°C, 5% CO₂, humidified atmosphere.

1. Confirm that the vial remains deeply frozen upon delivery, as cells are shipped on dry ice to maintain optimal temperatures during transit.

2. Upon receipt, either store the cryovial immediately at temperatures below -150°C to ensure the preservation of cellular integrity, or proceed to step 3 if immediate culturing is required.

3. For immediate culturing, swiftly thaw the vial by immersing it in a 37°C water bath with clean water and an antimicrobial agent, agitating gently for 40-60 seconds until a small ice clump remains.

4. Perform all subsequent steps under sterile conditions in a flow hood, disinfecting the cryovial with 70% ethanol before opening.

5. Carefully open the disinfected vial and transfer the cell suspension into a 15 ml centrifuge tube containing 8 ml of room-temperature culture medium, mixing gently.

6. Centrifuge the mixture at 300 x g for 3 minutes to separate the cells and carefully discard the supernatant containing residual freezing medium.

7. Gently resuspend the cell pellet in 10 ml of fresh culture medium. For adherent cells, divide the suspension between two T25 culture flasks; for suspension cultures, transfer all the medium into one T25 flask to promote effective cell interaction and growth.

8. Adhere to established subculture protocols for continued growth and maintenance of the cell line, ensuring reliable experimental outcomes.

Mycoplasma contamination is excluded using both PCR-based assays and luminescence-based mycoplasma detection methods.

To ensure there is no bacterial, fungal, or yeast contamination, cell cultures are subjected to daily visual inspections.

For long-term preservation, place vials in vapor-phase liquid nitrogen at about −150 to −196 °C. Storage at −80 °C is acceptable only as a short interim step before transfer to liquid nitrogen.

Cryopreserved cell lines are shipped on dry ice in validated, insulated packaging with sufficient refrigerant to maintain approximately −78 °C throughout transit. On receipt, inspect the container immediately and transfer vials without delay to appropriate storage.

At Cytion, we stand behind the quality and viability of our products. We guarantee that our cells will be viable at the start of culture for 60 days after shipment from our facilities. We assure that all materials conform to the specifications described in the Certificate of Analysis and/or Product Sheet.

For full details, please refer to our Warranty Statement.