Bcl-x(L) mediates increased production of humanized monoclonal antibodies in Chinese hamster ovary cells.
Enhanced product yields, reduction in throughput time, improved cost-effectiveness and product quality are examples of benefits gained by delaying apoptotic cell death in bioreactors. To examine the effect on recombinant protein production, bcl-x(L) was overexpressed in a CHO cell line secreting humanized monoclonal antibody directed against the alpha1beta1 integrin. When cell lines overexpressing bcl-x(L) were compared to the parent, cell viability was increased by 20% and titers by 80%. Total viable cell densities were similar and specific productivities were enhanced by almost two-fold on scale-up to bioreactors. Comparison in a chemically defined media demonstrated an even greater sustained viability in bcl-x(L) expressing cells by 50% and up to 90% increase in titer with no impact on product quality. Caspase 3 activities were monitored as a marker for apoptotic cell death. In the presence of Bcl-x(L), caspase activities were reduced to background levels. The role of Bcl-x(L) in protecting cells from premature death was further examined in studies performed in the presence of NaBu, at concentrations known to trigger cell death. Results demonstrated that cells expressing bcl-x(L) retained 88% cell viability with >2 fold increase in titer. Bcl-x(L) was similarly overexpressed in a different CHO cell line producing a humanized mAb against the chemokine MCP1. Once again, production titer was increased by 80% and viability by 75%. Together the studies have shown that overexpression of bcl-x(L) in production cell lines was able to significantly increase the titer by enhancing both the specific activity and total cell viability while maintaining product quality.
Chiang
Gisela G
GG
Cellular Engineering Technology Group, Biogen Idec, Inc., 14 Cambridge Center, Cambridge, Massachusetts 02142, USA. Gisela.Chiang@biogenidec.com
Sisk
William P
WP
D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D017209:Apoptosis; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods*; D016466:CHO Cells / Q000378:metabolism*; D053148:Caspase 3; D020169:Caspases / Q000032:analysis; D002452:Cell Count; D018929:Cell Culture Techniques; D002470:Cell Survival; D018932:Chemokine CCL2 / Q000276:immunology; D006224:Cricetinae; D003470:Culture Media / Q000737:chemistry; D005285:Fermentation; D006801:Humans; D039222:Integrin alpha1beta1 / Q000276:immunology; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D051020:bcl-X Protein / Q000235:genetics* / Q000276:immunology
D000911:Antibodies, Monoclonal; C111835:CCL2 protein, human; D018932:Chemokine CCL2; D003470:Culture Media; D039222:Integrin alpha1beta1; D011994:Recombinant Proteins; D051020:bcl-X Protein; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases