Mammalian transient expression systems enable flexible and rapid production of proteins. They're ideal for expression of human or other mammalian proteins because these systems generate recombinant proteins with more native folding and post-translational modifications—such as glycosylation—than expression systems based on hosts such as E. coli, yeast, or insect cells.

Choose the mammalian transient system that's right for you


FreeStyle 293 System

Traditional transient 293 expression system


Highest-yield and most flexible 293-based system


Highest-yield and most cost-effective CHO-based system

Protein yield* 20–200 mg/L Up to 1 g/L Up to 3 g/L
Cells FreeStyle 293-F Expi293-F ExpiCHO-S
Media FreeStyle 293 Medium Expi293 Medium ExpiCHO Medium
Transfection reagent 293Fectin ExpiFectamine 293 Transfection Kit ExpiFectamine CHO Transfection Kit
Positive control vector pCMV•Sport-βgal Antibody-expressing vector Antibody-expressing vector
Maximum working culture Density 2 x 106/mL 6 x 106/mL 10 x 106/mL
Cell density for transfection 1 x 106/mL 2.5 x 106/mL 6 x 106/mL
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*Typical yield of human IgGs