ExpiCHO-S™ Cells, 6 Vial Cell Bank Pack
ExpiCHO-S™ Cells, 6 Vial Cell Bank Pack
Gibco™

ExpiCHO-S™ Cells, 6 Vial Cell Bank Pack

ExpiCHO-S™ Cells are derived from a non-engineered subclone that has been screened and isolated from CHO-S Chinese hamster ovary (CHO)Read more
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Catalog number A29132
Price (USD)
5,030.00
Each
Add to cart
Price (USD)
5,030.00
Each
Add to cart
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 over 30 passages after thaw
• Maintain high cell viability and productivity for greater than 10 days post-transfection as part of the ExpiCHO expression system

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.
For Research Use Only. Not for use in diagnostic procedures.
Specifications
Cell LineCHO-S, SFM Adapted
Culture TypeSuspension Cell Culture
FormCryopreserved
SpeciesHamster
Format6-vial pack
For Use With (Application)Expression
No. of Cells1 x 107 cells
Product LineExpiCHO™
Product TypeCHO-S Cell
Quantity6 x 1 mL
Shipping ConditionDry Ice
Unit SizeEach
Contents & Storage
1 x 107 cells/mL

Store in liquid nitrogen.

Frequently asked questions (FAQs)

When subculturing ExpiCHO the day before a transfection to 3-4 x 10E6/mL, would you recommend pelleting the cells and resuspending them in completely fresh media, or simply replacing some of the media to split them down to the desired cell density?

Before transfecting ExpiCHO cells, there is no need to change out the media during the subculturing. This would become expensive and the conditioned media is not necessary.

Find additional tips, troubleshooting help, and resources within our Cell Culture Support Center.

For how many passages would you recommend using ExpiCHO cells before replacing them with new cells that were frozen at earlier passages?

For optimal performance with respect to protein production, we recommend thawing ExpiCHO cells and letting them grow for 2-3 passages prior to transfection. Overall, we do not recommend using the cells beyond ˜20 passages.

Find additional tips, troubleshooting help, and resources within our Cell Culture Support Center.

Sometimes in the high-titer or max-titer ExpiCHO Expression System protocols, I see a drop in viability on or about day 7-8 posttransfection. How can I fix this?

This drop in viability tends to indicate that some aspect of the cell culture conditions are not optimal during the expression run. If this is observed, the shaking speed of the flasks should be verified to be within protocol specifications; the volume and size of the flask should be appropriate; and care should be taken when handling the ExpiCHO-S Cells ahead of the expression run to ensure that cells are not stressed by vigorous mixing, etc.

In some instances, flask-to-flask variability has been observed using the high- and max-titer protocols at the 125 mL flask scale. Here, it is recommended to increase the shaking speed to 130 rpm for 25 mm shakers and 140 rpm for 19 mm shakers.

Alternatively, we have found that baffled flasks work well for the 125 mL scale to correct any flask-to-flask variability—in such an instance, to account for the baffles, the volume of cells to be transfected should be increased from 25 mL to 35-40 mL to allow for optimal flow over the baffles, and the volumes of other reagents should be scaled accordingly.

Lower transfection volumes (i.e., 30-35 mL) can also be used with baffled flasks; however, shaking speeds must be reduced slightly to account for the baffles (i.e., 115 rpm for 19 mm shakers and 110 rpm for 25 mm shakers). We have not found baffled flasks to be necessary or beneficial at other flask sizes.

Can an ExpiCHO expression run be scaled down to smaller volumes than that in shake flasks?

Yes. For expression in 24- and 96-deep well blocks and 50 mL mini bioreactor tubes, please refer to the online protocol (https://www.thermofisher.com/content/dam/LifeTech/global/life-sciences/Protein%20Bio%20-%20Thermo/pdf/ExpiCHO-Protocols-Deep-Well-Blocks-Mini-Bioreactor-Tubes.pdf)

Find additional tips, troubleshooting help, and resources within our Protein Expression Support Center.

Sometimes the ExpiCHO cell supernatant is difficult to filter during clarification. How can I overcome this?

Because the ExpiCHO system uses components that differ from that of HEK 293-based expression systems such as the Gibco Expi293 system, the supernatant may be more difficult to process through standard bottle top filters in some instances. To remedy this, we recommend centrifuging the supernatant first at ~5,000 x g for 30 minutes followed by filtration using a 0.22 µm filter. Alternative filters (such as depth filters) provide superior filtration for supernatants, especially at larger scales, as these filters are specifically designed to handle supernatant from CHO-derived expressions.

Find additional tips, troubleshooting help, and resources within our Protein Expression Support Center.