Picking the Right Expression System

HEK vs CHO for Protein Production

293 cells are highly transfectable with most transfection reagents Suspension growth in serum-free media
Growth attached in basic media or suspension (requiring more expensive, protein-free media) 30-50% less protein than HEK
Protein Expression for structural studies eg X-ray crystallography Lower transfection efficiency
Choice for biopharmaceuticals = GMP validated
Attached Suspension
Limited by surface area of culture flask Use of bags
Scalable for secreted products Scalable
Requires trypsinization, inexpensive media eg DMEM Use expensive media eg (serum free)

Stable vs Transient Cell Systems

Stable Transient
Time consuming/Labour intensive due to generation of stable cell lines: 2-6 months Timeframe: 2-3 weeks
High Levels of Expression. Good for long-term production due to less variations. Can be scaled up to many litres (1-5 mg/L typical)
No flexibility Yield limited by expression levels