Mammalian cells, primarily Chinese hamster ovary (CHO), are often used as an expression system for synthesis of protein that needs post-translation modification, such as glycosylation. The following table summarizes the advantages and disadvantages of mammalian cells as an expression system.

Advantages Disadvantages
Capable of post-translation modification, including phosphorylation and glycosylation Expensive
Protein produced is properly folded Poor secretion

Figure 1. Mammalian expression system.