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Keywords:

  • generic fed-batch process;
  • concentrated protein-free feed medium;
  • cell culture;
  • glucose metabolism;
  • pH;
  • humanized antibody

Abstract

A fed-batch cell culture process was developed that has general applicability to all evaluated Sp2/0 (n = 8) and NS0 (n = 1) antibody-producing cell lines. The two key elements of this generic process were a protein-free concentrated feed medium, and a robust, metabolically responsive feeding strategy based on the off-line measurement of glucose. The fed-batch process was shown to perform equivalently at the 15 L development scale and 750 L manufacturing scale. Compared to batch cultures, the fed-batch process yielded a 4.3 fold increase in the average integral of viable cell concentration and a 1.7 fold increase in average specific antibody production rate, equivalent to a 7.6 fold increase in average final antibody concentration. The highest producing cell line reached a peak viable cell concentration of 1.0 × 107 cell mL−1 and a final antibody concentration of 750 mg L−1 in a 10 day process. For all lines evaluated, reducing bioreactor pH set point from 7.2 to 7.0 resulted in an additional 2.4 fold increase in average final antibody concentration. The optimized fed-batch process consistently yielded a volumetric productivity exceeding 50 mg L−1 day−1. This generic, high-yielding fed-batch process significantly decreased development time, and increased manufacturing efficiency, thereby facilitating the clinical evaluation of numerous recombinant antibodies. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 67: 585–597, 2000.