title: Enhanced productivity during controlled proliferation of BHK cells in continuously perfused bioreactors.
abstract: A perfused cell-culture process was developed to investigate the stability of IRF-1-mediated proliferation control in BHK cells and to evaluate the efficacy of a novel promoter in these cells. The cell density of proliferation-controlled producer cells was effectively regulated for over 7 weeks in a microcarrier-based continuously perfused bioreactor. An IRF-1-inducible promoter was employed to express a heterodimeric IgG antibody as a relevant model protein. Basal expression levels were equivalent to that of a highly active viral promoter, while productivity increased up to sixfold during growth arrest. However, no stably expressing clone was isolated in this study. Protein expression decreased gradually with time and could not be induced further in subsequent growth-repression cycles. The results demonstrate that the regulatory system is sufficiently stable to allow controlled growth in a continuous scalable reactor system and that productivity increases can be achieved in a proliferation controlled microcarrier culture.
authors.affiliation: Department of Gene Regulation and Differentiation, GBF, National Research Center for Biotechnology, Braunschweig, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Geserick
authors.forename: H P
authors.initials: HP
authors.lastname: Bonarius
authors.forename: L
authors.initials: L
authors.lastname: Kongerslev
authors.forename: H
authors.initials: H
authors.lastname: Hauser
authors.forename: P P
authors.initials: PP
authors.lastname: Mueller
mesh_terms: D000818:Animals; D019149:Bioreactors; D002452:Cell Count; D002455:Cell Division; D002460:Cell Line; D002470:Cell Survival; D002999:Clone Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006224:Cricetinae; D046508:Culture Techniques / Q000379:methods*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D004967:Estrogens / Q000494:pharmacology; D005814:Genes, Viral / Q000235:genetics; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D050856:Interferon Regulatory Factor-1; D008863:Microspheres; D010477:Perfusion; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D015533:Transcriptional Activation / Q000187:drug effects
chemical_list: D004268:DNA-Binding Proteins; D004967:Estrogens; D007074:Immunoglobulin G; D050856:Interferon Regulatory Factor-1; D010750:Phosphoproteins; D011960:Receptors, Estrogen; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins