Genetic Divergence and Antibody Expression Influence the N-Glycomes of CHO-K1 and CHO-S Cells

While Chinese hamster ovary (CHO) cells continue to be the workhorse of recombinant therapeutic protein production, decades of genetic divergence in the industrially relevant CHO-K1 and CHO-S cell lines, are likely to have resulted in differing glycosylation capabilities. Glycosylation can influence the efficacy, serum half-life, and safety of biologics, and as a critical quality attribute of glycoprotein biopharmaceuticals, it is essential to better understand how major CHO cell manufacturing platforms diverge. We used matrix-assisted laser desorption ionization-time of flight mass spectrometry to perform N-glycomic analyses comparing CHO-K1 cells, CHO-S cells and antibody-producing daughter cell lines. The results reveal that genetic divergence in these industrially relevant cell lines, as well as the burden of antibody production, lead to significant differences in antennal branching and terminal elaboration in the cellular N-glycome. More specifically, CHO-K1 cells produce larger and more complex N-glycans with higher levels of sialylation than CHO-S cells, and antibody production was associated with increased antennal branching. Additionally, these findings were also reflected in the N-glycomic profiles of IgG1-Fc constructs produced in either CHO-K1 and CHO-S cells.