Adaptation Of An Adherent hCK (MDCK) Cell Line To A Serum-Free Suspension RCB For MCB Production

An engineered Madin-Darby canine kidney (MDCK) cell line was developed and optimized for isolating and propagating human influenza viruses by modifying the host cell's α-2, 6-sialoglycan and α-2, 3-sialoglycan expression levels. However, the adherent nature of this humanized MDCK (hCK) cell line posed challenges for large-scale influenza vaccine production relating to scalability. Over a period of ten months, this serum-dependent hCK cell line was adapted into a serum-free suspension cell line while preserving its engineered characteristics. The adaptation process involved three phases: transitioning from serum-containing media to serum-free media in flatware, then from adherent serum-free to suspension serum-free in shake flasks, and finally establishing a stable progenitor cell bank optimized for growth.

Through extensive testing of various serum-free media and agitation methods for suspension growth, a Research Cell Bank was established with greater than or equal to 80% viability, less than or equal to 20% aggregation, and less than or equal to a 30-hour doubling time. Subsequently, this process was successfully transferred to manufacturing to produce a GMP Master Cell Bank. This modified serum-free suspension MDCK cell line now serves as an optimal platform for isolating human influenza viruses from clinical samples and scaling up influenza vaccine production to an industrial scale.