Detailed understanding of enhanced specific antibody productivity in NS0 myeloma cells

Abstract

The understanding of how cellular productivity is modulated in cell lines is of significant importance in the biopharmaceutical industry. Often, single molecular mechanisms fail to fully explain how specific antibody productivity is enhanced during proliferation arrest. Previously, we reported that certain physiological changes occur when proliferation is arrested by p21(CIP1) over expression. In this work, we correlate physiological and molecular factors to enhance antibody productivity. Using biomass, cell volume and total cellular protein content as a basis for determining specific productivity, it was found that total cellular protein correlated best with cellular productivity. This meant that there was no preferential increase in antibody production relative to cellular proteins in arrested cultures. However, molecular analysis of mRNA transcription and stability indicated that both processes were altered in arrested cultures resulting in up to threefold increased heavy chain mRNA levels. While flow cytometric analysis revealed that arrested cells had elevated translational capacity for both heavy and light chains, the heavy to light chain polypeptide ratio was 10-50% higher than in the control. This resulted in a lower extracellular accumulation of light chains and a better utilization of cellular resources for the formation of complete antibodies. Active transcriptional regulation of heavy and light chain mRNA and the modulation of translational activities play a vital role in the modulation of overall antibody productivity of these cells. The combined effect of heavy chain mRNA enhancement and the increased cellular assembly capacity was determined to effectively increase specific productivity.

Cell line‐specific control of recombinant monoclonal antibody production by CHO cells

“…Excess LC mRNA is also a function of the greater stability of the LC transcript, as previously observed for an NS0 cell line producing cB72.3 Mab by Khoo and Al-Rubeai (2009). However, the reason for this differential transcript stability is currently unknown.…”

“…Excess LC mRNA and polypeptide production is a feature of many Mab production systems, both recombinant and natural Dorai et al, 2006;Khoo and Al-Rubeai, 2009;Lee et al, 2009;van Anken et al, 2003). Moreover, low LC:HC mRNA ratios, below 1.5, have also been associated with increased levels of Mab aggregation, a characteristic particularly undesirable in a production cell line (Lee et al, 2009).…”

Production of anti TNF-α antibodies in eukaryotic cells using different combinations of vectors carrying heavy and light chains

“…Besides soluble TNF-a, the transmembrane form of TNF-a demonstrates some unique biologic functions, such as cytotoxic activity and polyclonal B cell activation (Utsumi et al 1989). Antibodies (Abs) to soluble or membrane-associated forms of TNF-a have provided a new possibility to treat severe forms of rheumatoid and psoriatic arthritis, cutaneous Crohn's disease, psoriasis, and possibly other inflammatory skin diseases like Behcet's disease and pyoderma gangrenosum (Baldi et al 2005;Khoo and Rubeai 2008;Kohler 1980;Schlatter et al 2005).…”

Scale-down of CHO cell fed-batch cultures

“…This is in agreement with Lloyd et al 56 , who argued that the cell size is the major cellular determinant of productivity rather than the cell cycle phase. In addition to this, Edros et al 89 and Khoo and Al-Rubeai 90 showed that the increase in specific productivity is directly related to the increase in cell volume due to increase in transcription, translation, and secretion machinery. Kim et al 58 reported that the enhancement of the specific thrombopoietin productivity is linearly correlated with the increase in cell size for nine CHO cell clones generated using the same transfection process.…”

“…Furthermore, Kim et al 58 showed that the enhancement of the qp was linearly correlated with an increase in cell size for nine CHO cell clones generated using the same transfection process. Edros et al 89 and Khoo and Al-Rubeai 90 showed that the increase in qp was directly related to the increase in cell volume due to enhancement of the transcription, translation, and secretion machinery.…”