OK

The OK cell line is a permanent epithelial-like cell culture derived from kidney tissue of an adult female American opossum (Didelphis virginiana). Established in vitro, this cell line is notable for its non-diploid chromosomal modal number of 23 and its adaptability to tissue culture conditions. Initially derived from mixed cell types, the culture evolved into predominantly epithelial cells after eight passages. The OK cell line has been extensively characterized in terms of morphology, chromosomal constitution, and growth dynamics, making it a robust model for cytogenetic and chromosome isolation studies.

One of the key features of the OK cell line is its utility in chromosome studies, especially for isolating the mammalian X chromosome. The opossum X chromosome is significantly smaller (approximately 30% smaller than the smallest autosomes) and does not contain large blocks of constitutive heterochromatin, facilitating separation from autosomes through techniques like flow microfluorometry and gradient centrifugation. The stable karyotype of the OK cells, with the presence of a distinctive metacentric marker chromosome, enhances their application in genomic and chromosomal studies. The paternal X chromosome's preferential inactivation in this marsupial provides a comparative model for studying mechanisms underlying X-chromosome inactivation in mammals.

OK cells have also demonstrated resilience and adaptability in various culture conditions, including serum variations and different mitotic-arresting agents like Velban (vinblastine sulfate), which is particularly effective for achieving high mitotic indices for chromosome isolation. The cell line's ability to synchronize and produce high yields of metaphase cells further underscores its suitability for detailed chromosomal analyses, including DNA content quantification and high-resolution imaging of chromosomal spreads.

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.