A substantial number of recombinant monoclonal antibodies (mAbs) are produced by Chinese Hamster Ovary (CHO) cells. CHO cells are normally counted in industry by automated cell counters. Cell count and viability are two of the most important parameters in cell culture production. By means of digital image recognition, automated cell counters measure cell density and viability, as well as additional parameters using Trypan Blue exclusion method.Prior to Phase III development, CHO cells were grown in a complex media containing yeast and plant extracts. To develop a chemically defined and animal component free Phase III process, cells were adapted to in-house proprietary media. Post adaptation, cells exhibited self adherence or clumping. The clumpy nature of cells reduced the ability to accurately measure cell density and viability using conventional automated cell counter counting methodologies. The self adherence progressed with culture age, during a given preculture step, and was substantial at the production bioreactor scale. A Trypsin treatment was developed to reduce the excessive clumping and obtain a more accurate cell count. Development of Trypsin method required evaluating time of digestion and incubation, protease activity, and source. The cell counting method enabled us to develop a robust and reproducible upstream process for production of this mAb.

Development of an optimized cell counting method for self adherent CHO cells in phase 3 cell culture process

245th National Meeting (2013)

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