Features of the Freedom® CHO-S® Kit


Q: What titers can be achieved with the Freedom® CHO-S® Kit? 


A: Volumetric titers of >1 g/L in simple fed batch, and >3 g/L in fed batch with complex feeds have been obtained with the Freedom® CHO-S® Kit.


Q: How long does it take to obtain a lead clone?


A: It is possible to go from transfection to lead clone in as little as 4 months with the Freedom® CHO-S® Kit.


Q: What level of product quality is seen with Freedom® CHO-S® Kit?


A: Product quality depends on multiple development aspects, such as the product itself, the selected clone, and the upstream and downstream process. Freedom® CHO-S® cells offer all the typical CHO cell line benefits with respect to low protease levels and preferred glycan pattern.


Q: How successful is the Freedom® CHO-S® Kit in creating stable clones?


A: CHO-S clones producing a model IgG protein were assessed for stability by comparing volumetric productivity for over 60 generations. Four out of the five clones that were tested maintained expression levels over 60 generations. Expression levels were considered stable if the titer at the end of the stability assessment (at generation 60) was at least 70% of the titer observed at the beginning of the stability study.


Q: Can CHO-S® cells be used for the production of commercial products?


A: Yes. Freedom® CHO-S® cells are intended (with the purchase of a commercial license) for the development of biologics. They have been produced in a cGMP animal origin-free environment, and have been scaled up in a commercial setting to produce products for clinical testing.

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Q: What is included in the Freedom® CHO-S® Kit?


A: All major components to complete the cell line development workflow are included in the Freedom® CHO-S® Kit: cGMP banked CHO-S® cells, a vector for cloning one or two genes, transfection reagent, competent cells, serum-free cell culture media and reagents. A complete list of components, including additional materials required but not included, can be found in the Freedom™ CHO-S® Kit manual.


Q: Does the kit contain documentation of the CHO-S® cell line?


A: A certificate of analysis (COA) demonstrating suitability for research use is available to everyone who purchases Freedom® CHO-S® cells. A full documentation package, including the cell line's lineage, history and cGMP testing results, is offered in conjunction with a commercial use license.


Q: What are the main features of the Freedom® pCHO 1.0 Vector?


A: Freedom® pCHO 1.0 can be used to express 1 or 2 subunits and has both DHFR and Puromycin resistance as selection markers. Note: Kanamycin resistance is used to select for the vector in bacteria.


Q: What selection system is used in the Freedom® CHO-S® Kit?


A: Puromycin in combination with methotrexate (MTX) is used to select for stable pools following transfection with the Freedom™ pCHO 1.0 vector.

Recommended Methods


Q: What cell culture medium and feed do you recommend for Freedom® CHO-S® cells?


A: Freedom® CHO-S® cells have been optimized for use with Gibco® CD FortiCHO™ Medium and CD EfficientFeed™ C.


Q: What cloning methods can be used with the Freedom® CHO-S® Kit?


A: Limiting dilution cloning is recommended with the Freedom® CHO-S® Kit. An evaluation of cloning in semi-solid medium in combination with ClonePix™ FL is underway.


Q: What transfection methods can be used with the Freedom® CHO-S® Kit?


A: FreeStyle® MAX Reagent is included in the Freedom® CHO-S® Kit as the preferred transfection method. CHO-S® cells are also compatible with the Neon™ Transfection System (optimization of instrument settings is required).


Q: How many transfections are typically required to get high-expressing clones from the Freedom® CHO-S® Kit?


A: Only two transfections are recommended.


Q: What are some considerations for obtaining a high number of stable clones?


A: When using limiting dilution cloning, careful evaluation of monoclonality of a clone is required before assessing stability of expression in order to avoid heterogeneous clones that can drift into separate populations and appear unstable.


Q: What are some considerations for successful scale-up of CHO-S® cells?


A: In terms of scaling-up from shake flask into a bioreactor, initial experiments indicate that antibody-expressing CHO-S® clones readily scale-up into bioreactor vessels while maintaining growth and titer performance.

Developed in collaboration with ProBioGen AG


Q: What role did ProBioGen AG have in the development of the Freedom® CHO-S® Kit?


A: Life Technologies has an ongoing collaboration with ProBioGen AG to create robust, easy to use, cell line kits optimized for industrial use. ProBioGen specializes in cell line and process development and has extensive experience with vector construction.


Q: Does ProBioGen offer cell line development services?


A: Yes. ProBioGen offers cell line development and biomanufacturing services. To learn more, visit www.probiogen.de.

Licensing of the CHO-S® cell line


Q: When is a license required for the Freedom® CHO-S® Kit?


A: A commercial use license is required prior to the sale of expressed proteins, or when an IND submission is being prepared for first in human clinical studies.


Q: Is there a pull-through royalty on final products or an annual maintenance fee?


A: No. Only a one-time license fee is required, and it covers the commercialization of an unlimited number of molecules using the Freedom® CHO-S® cell line.


Q: How can I learn more about commercial licensing of Freedom® CHO-S® cells?


A: To inquire about a commercial license, please email: pd.direct@lifetech.comTo read the complete list of FAQs related to licensing, click here.

Technical support and cell line development services


Q: Do you offer technical support for the Freedom® CHO-S® Kit?


A: Yes. Contact our field-based Process Science Fellows (PSFs) at pd.direct@lifetech.com for technical support.


Q: Do you offer cell line development services?


A: Yes. Life Technologies’ process sciences staff can assist you with the development of a customized stable cell line development program, which allows for the rapid screening of high producing clones. To learn more, email pd.direct@lifetech.com.