Therapeutic glycoprotein production in mammalian cells

•The various mammalian and non-mammalian expression systems used for glycoprotein production are described.•We review recent cell engineering strategies developed to increase cell productivity.•The glycoengineering strategies used to reduce fucosylation and/or enhance sialylation of glycoproteins are discussed.•We provide an overview of the “Omics” technologies recently used to improve cell expression systems and how these will greatly contribute to platforms improvements. Over the last years, the biopharmaceutical industry has significantly turned its biologics production towards mammalian cell expression systems. The presence of glycosylation machineries within these systems, and the fact that monoclonal antibodies represent today the vast majority of new therapeutic candidates, has largely influenced this new direction. Recombinant glycoproteins, including monoclonal antibodies, have shown different biological properties based on their glycan profiles. Thus, the industry has developed cell engineering strategies not only to improve cell’s specific productivity, but also to adapt their glycosylation profiles for increased therapeutic activity. Additionally, the advance of “omics” technologies has recently given rise to new possibilities in improving these expression platforms and will significantly help developing new strategies, in particular for CHO (Chinese Hamster Ovary) cells.