KB

The KB cell line is an adherent epithelial cell line initially believed to be derived from an epidermal carcinoma of the mouth. However, subsequent analyses, including isoenzyme assays, HeLa marker chromosome identification, and DNA fingerprinting, revealed that the KB cell line was actually established through contamination with HeLa cells. This misidentification underscores the importance of rigorous cell line authentication in research.

KB cells express keratin, a key structural protein in epithelial cells, as confirmed by immunoperoxidase staining. Additionally, they have been found to contain sequences from human papillomavirus 18 (HPV-18), which may be of interest in studies related to viral oncology. The isoenzyme profile of KB cells includes glucose-6-phosphate dehydrogenase (G6PD) type A, consistent with the characteristics of HeLa cells. Given these findings, it is critical to recognize that KB cells share many biological properties with HeLa cells, including the presence of HeLa-specific marker chromosomes.

As a result, KB cells should be used with caution, particularly in experiments where the exact cellular origin is crucial. Despite this, they remain a useful model for studying epithelial cell behavior, cancer biology, and the mechanisms of viral integration and expression. As with all cell lines, KB cells are intended strictly for in vitro research and are not suitable for therapeutic or in vivo applications.

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.