Production of recombinant proteins in Chinese hamster ovary cells using a protein-free cell culture medium.
The growth-factor prototrophic Chinese hamster ovary (CHO) SSF3 cell line was previously adapted for growth in serum-free media. Here we present a newly designed medium which allows these cells to grow in the absence of any exogenously added growth factors. To investigate the capacity of CHO SSF3 cells for the efficient production of recombinant proteins in protein-free media, expression plasmids containing either a human single chain urokinase-type plasminogen activator (uPA)-encoding cDNA or a humanized immunoglobulin G (IgG) kappa light chain cDNA were introduced by transfection. The tryptophan synthase (trpB) gene of Escherichia coli was used as a dominantly acting selection marker allowing the cells to survive in a medium containing indole in place of tryptophan. Some of the clones obtained exhibited a stable uPA expression over a period of several months under selective conditions and the yields were up to 74 mg of uPA/l in a bioreactor and the productivity was around 40 mg/day per 10(9) cells. The yields of IgG light chains were up to 118 mg/l and the productivity was in the order of 56 mg/day per 10(9) cells in a bioreactor. These results demonstrate the potential of CHO SSF3 cells for the efficient production of recombinant proteins under protein-free conditions.
Zang
M
M
Institute of Biotechnology, Swiss Federal Institute of Technology, ETH-Hönggerberg, Zürich, Switzerland.
Trautmann
H
H
Gandor
C
C
Messi
F
F
Asselbergs
F
F
Leist
C
C
Fiechter
A
A
Reiser
J
J
D000818:Animals; D016466:CHO Cells / Q000378:metabolism*; D006224:Cricetinae; D003470:Culture Media; D016895:Culture Media, Serum-Free; D018076:DNA, Complementary; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression; D005819:Genetic Markers; D006801:Humans; D007074:Immunoglobulin G / Q000235:genetics; D007145:Immunoglobulin kappa-Chains / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011506:Proteins / Q000008:administration & dosage*; D011994:Recombinant Proteins / Q000096:biosynthesis; D014162:Transfection; D014367:Tryptophan Synthase / Q000235:genetics; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics
D003470:Culture Media; D016895:Culture Media, Serum-Free; D018076:DNA, Complementary; D005819:Genetic Markers; D007074:Immunoglobulin G; D007145:Immunoglobulin kappa-Chains; D011506:Proteins; D011994:Recombinant Proteins; D014568:Urokinase-Type Plasminogen Activator; D014367:Tryptophan Synthase