Cell Line Stability
After cells were expanded into spin tubes or shake flasks, selection pressure was removed for approximately 30 PDLs (population doubling levels) before fed-batch inoculation for the stability study.
In addition to the expression level, the single-cell qPCR method was also adopted on the candidates for top clones to probe the genetic stability as previously described (He et al., 2012).
The final cell line stability was performed with the MCB.