ExpiCHO™ Stable Production AGT Medium, 100 L - FAQs

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.

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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.

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Yes, ExpiCHO Stable Production Medium (SPM) is compatible with the GS/MSX (Glutamine Synthetase Expression Technology) selection.

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After having obtained best expressing clones, a stability study is done. The time for a stability study varies (it depends how fast the cells double). It takes 60 generations or two months (whichever comes first).

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A stability study involves testing of ExpiCHO-S clones for 60 generations (60 population doublings) to see if high protein expression is maintained.

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Yes, when stable selection is desired, transfection takes place in the presence of ExpiCHO Expression Medium but in the absence of the enhancer and feed. About 48 hours post-transfection, stable selection starts by addition of the appropriate selection antibiotics.

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We don't recommend using ExpiCHO SPM when you have an existing platform cell-line or feeds and are looking for a broadly usable medium, or when you need a transfection medium. We recommend using ExpiCHO Expression Medium for transfection.

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We recommend using ExpiCHO SPM when transfection of ExpiCHO-S cells has been already completed with ExpiCHO Expression Medium, and you want to develop stable clones and scale up protein production.

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We recommend using our pcDNA3.3-TOPO TA and pcDNA3.4-TOPO TA vectors. These vectors have only a single gene integration site so some modification will be necessary for antibody applications. You can use our GeneArt Express Cloning Service (https://www.thermofisher.com/us/en/home/life-science/cloning/gene-synthesis/geneart-plasmid-services/geneart-subcloning-service.html#express) to create a modification that will allow you to clone both the heavy and light chains into the vector (ideally joined by an IRES site). Please note that other vectors may also be used, and that you may want to test initially with 2-3 vectors for best results.

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In our initial work, we used a proprietary vector that cannot be disclosed.

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Both products are similar, however, formulation changes had to be made to make the ExpiCHO Stable Production Medium (SPM) scalable to AGT format. One such change is that it requires the addition of Glutamax whereas ExpiCHO Expression Medium does not. Additionally, ExpiCHO SPM is not compatible with transfection whereas ExpiCHO Expression Medium is compatible with transfection.

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The intended use statement for ExpiCHO Stable Production Medium (SPM) is as foll:
For Research Use or Further Manufacturing. Not for diagnostic use or direct administration into humans or animals.

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No. ExpiCHO Stable Production Medium (SPM) needs to be supplemented with Glutamax or Glutamine.

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No. Unlike ExpiCHO Expression Medium, ExpiCHO Stable Production Medium (SPM) is not recommended for transfection as it does not support high transient transfection efficiency.

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ExpiCHO Stable Production Medium (SPM) is a chemically defined protein-free, animal origin component-free medium developed specifically to support high titer expression of stable ExpiCHO-S clones in suspension. The medium is designed to provide a seamless scale-up solution for customers using the ExpiCHO Expression System for transient production looking to transition to the development of stable ExpiCHO clones. The medium is formulated without hypoxanthine and thymidine for use in dihydrofolate reductase (DHFR)-amplified systems, without L-glutamine or GlutaMAX I Supplement for use in glutamine synthetase systems, and without phenol red in order to minimize the estrogen-like effects of phenol red.

ExpiCHO SPM allows for direct transition from transient expression to the large scale production of stable clones with no adaptation. You can start process development faster, and streamline or simplify transfer to manufacturing scale. ExpiCHO SPM is available in liquid format (Cat. No. A3711001) or in dry AGT format (Cat. Nos. A3711101, A3711102, and A3711103)

Note: ExpiCHO SPM is not compatible for use as a medium during the transfection step.

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