title: Very high cell density perfusion of CHO cells anchored in a non-woven matrix-based bioreactor.
abstract: Recombinant Chinese Hamster Ovary (CHO) cells producing IgG monoclonal antibody were cultivated in a novel perfusion culture system CellTank, integrating the bioreactor and the cell retention function. In this system, the cells were harbored in a non-woven polyester matrix perfused by the culture medium and immersed in a reservoir. Although adapted to suspension, the CHO cells stayed entrapped in the matrix. The cell-free medium was efficiently circulated from the reservoir into- and through the matrix by a centrifugal pump placed at the bottom of the bioreactor resulting in highly homogenous concentrations of the nutrients and metabolites in the whole system as confirmed by measurements from different sampling locations. A real-time biomass sensor using the dielectric properties of living cells was used to measure the cell density. The performances of the CellTank were studied in three perfusion runs. A very high cell density measured as 200 pF/cm (where 1 pF/cm is equivalent to 1 × 10(6)viable cells/mL) was achieved at a perfusion rate of 10 reactor volumes per day (RV/day) in the first run. In the second run, the effect of cell growth arrest by hypothermia at temperatures lowered gradually from 37 °C to 29 °C was studied during 13 days at cell densities above 100 pF/cm. Finally a production run was performed at high cell densities, where a temperature shift to 31 °C was applied at cell density 100 pF/cm during a production period of 14 days in minimized feeding conditions. The IgG concentrations were comparable in the matrix and in the harvest line in all the runs, indicating no retention of the product of interest. The cell specific productivity was comparable or higher than in Erlenmeyer flask batch culture. During the production run, the final harvested IgG production was 35 times higher in the CellTank compared to a repeated batch culture in the same vessel volume during the same time period.
authors.affiliation: School of Biotechnology, Dept. Industrial Biotechnology/Bioprocess Design, Cell Technology Group (CETEG), Royal Institute of Technology, KTH, SE-10691 Stockholm, Sweden. Electronic address: yezhang@kth.se.
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: PerfuseCell, Malmmosevej 19C, DK-2840 Holte, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Stobbe
authors.affiliation: Belach Bioteknik, Dumpervägen 8, SE-14250 Skogås, Sweden(1).
authors.forename: Christian Orrego
authors.initials: CO
authors.lastname: Silvander
authors.affiliation: School of Biotechnology, Dept. Industrial Biotechnology/Bioprocess Design, Cell Technology Group (CETEG), Royal Institute of Technology, KTH, SE-10691 Stockholm, Sweden. Electronic address: chotteau@kth.se.
authors.forename: Véronique
authors.initials: V
authors.lastname: Chotteau
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis*; D019149:Bioreactors; D016466:CHO Cells; D002452:Cell Count; D003412:Cricetulus; D007074:Immunoglobulin G / Q000096:biosynthesis*; D010477:Perfusion
chemical_list: D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G
keywords: Dielectric spectroscopy; Disposable bioreactor; Hypothermia; IgG production; On-line biomass sensor