Development of mammalian production cell lines expressing CNTO736, a glucagon like peptide‐1‐MIMETIBODYTM: Factors that influence productivity and product quality

In an attempt to develop a high producing mammalian cell line expressing CNTO736, a Glucagon like peptide-1-antibody fusion protein (also known as a Gluca- gon like peptide-1 MIMETIBODY TM ), we have noted that the N-terminal GLP-1 portion of the MIMETIBODY TM was susceptible to proteolytic degradation during cell culture, which resulted in an inactive product. Therefore, a number of parameters that had an effect on productivity as well as product quality were examined. Results suggest that the choice of the host cell line had a significant effect on the overall product quality. Product expressed in mouse mye- loma host cell lines had a lesser degree of proteolytic degradation and variability in O-linked glycosylation as compared to that expressed in CHO host cell lines. The choice of a specific CHOK1SV derived clone also had an effect on the product quality. In general, molecules that exhibited minimal N-terminal clipping had increased level of O-linked glycosylation in the linker region, giving cre- dence to the hypothesis that O-linked glycosylation acts to protect against proteolytic degradation. Moreover, products with reduced potential for N-terminal clipping had longer in vivo serum half-life. These findings suggest that early mon- itoring of product quality should be an essential part of production cell line development and therefore, has been incorporated in our process of cell line development for this class of molecules. Biotechnol. Bioeng. 2009;103: 162-176. 2008 Wiley Periodicals, Inc.