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56 Life Technologies
™
| Selection and Stable Pool Considerations
Don't store media prepared with puromycin and methotrexate.
Don't proceed with cultures that have not recovered by day 25 of a
given selection phase.
Do you have any data on gene copy number?
Gene copy number in CHO-S
®
cells is significantly lower than a DG44
clone with equivalent expression levels of the same molecule.
What titers can I expect after Phase I and Phase II of selection with
puromycin and methotrexate?
Although titers will vary depending on the molecule being expressed,
in general, titers increase from Phase I to Phase II selection. Typically,
Phase I pool titers are in the range of 20-50 mg/L when measured
using a 5-day assay, and Phase II pool titers are in the range of 400-
800 mg/L when measured on day 14 in a shake flask simple fed-batch
assay (glucose-only feeding, see Figures 11 and 12).
Selection and Stable Pool Considerations
Don't:
