ExpiCHO-S™ Cells are derived from a non-engineered subclone that has been screened and isolated from CHO-S Chinese hamster ovary (CHO) cells (1). They are a core component of the ExpiCHO™ Expression System Kit (Cat. No. A29133). ExpiCHO-S Cells are maintained in suspension culture, have minimal tendency to clump, and grow to high density in ExpiCHO™ Expression Medium (Cat. No. A2910001). As part of the ExpiCHO Expression System Kit, the cells generate superior protein yields by transient transfection compared to standard CHO, 293, and high-density Expi293F™ cells.

ExpiCHO-S™ Cells:
• Allow you to attain yields of up to 3 g of protein per L of transfected culture as part of the ExpiCHO expression system
• Enable rapid, high-yield transient protein production, allowing labs developing protein biotherapeutics to work with CHO-expressed proteins from start to finish in the drug development process
• Are adapted to high-density suspension growth in ExpiCHO Expression Medium
• Exhibit rapid doubling times of approximately 17 hours
• Enable consistent transient expression performance for 20 passages after thaw
• Maintain high cell viability and productivity for greater than 10 days post-transfection as part of the ExpiCHO expression system
• Also available from a cGMP bank (Cat. No. A37785)

Frozen cells are supplied in a vial containing 1 mL of cells at 1 x 10⁷ viable cells per mL in ExpiCHO Expression Medium and 10% DMSO. The cells should be thawed directly into ExpiCHO Expression Medium. The 6-vial multipack eliminates the need to expand and bank the cells in the lab.

Cells are typically grown in flasks on a shaker platform in a humidified, CO₂ cell culture incubator. However, cultures are scalable from volumes of <1 mL in multi-well plates to >10 L in bioreactors. Protein harvest can be performed at 5 to 14 days post-transfection, depending on the protein expressed.

References
1. Wurm, FM. CHO Quasispecies—Implications for Manufacturing Processes (2013) Processes 1:296-311.