0 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 2 38
Viability
(%)
Time
in
selection
(days)
50
20
10
0
60
70
80
90
30
40
100
Ph || recovered
Ph | recovered
No DNA-10
20-50
20-30
10-50
10-30
10
20
Q:
A:
58 Life Technologies
™
| Selection and Stable Pool Considerations
How should I handle stable pools once they are recovered?
A frozen stock of each stable pool should be generated as soon as
pools recover from each selection phase.
Stable pools should not be passaged without selection pressure.
Because of pool drift, it is best to seed stable pools for limited dilution
cloning as close to stable pool recovery as possible.
Selection and Stable Pool Considerations
Figure 13. Example of Freedom
®
CHO-S
®
pool recovery profiles during selection. Blue lines:
low selection pressure in Phase I. Green lines: high selection pressure in Phase I. When the
viability of Phase I pools exceeds 85% (red line), then Phase II selection is initiated. When
the viability of Phase II pools exceeds 90% (purple line), then the stable pool is considered
recovered.
