Mammalian cell-based expression is the dominant system for the production of therapeutic recombinant proteins. Their capacity to handle complex post-translational modifications, folding and assembly of recombinant proteins and protein complexes is superior to other systems. Mammalian expression vectors have been engineered to contain elements that improve expression and are generally more complex than vectors from other systems.
There are two main methods for recombinant protein production in mammalian cells i.e. stably transfected and transiently transfected cell lines. Stably transfected cell lines enable continuous expression of the recombinant protein and have been shown to produce high yields. The creation of a stable cell line can take up to several months to complete.
A transient transfection can be used for small- to large-scale expression cultures. Recent improvements to the method have been able to increase yields from milligram to gram quantities. The advantages of a transient transfection method lie in the shorter timeframe from DNA delivery to protein harvest.
Transient expression and purification
Stable expression cell lines
Figure 1. Mammalian cell expression systems – HEK293 and CHO
See Creative Biostructure’s cell-free and cell-based expression services.