Engineering – Entrance into Post-Genomic Era

Chinese hamster ovary cells (CHO) cells have been the most commonly used mammalian host for the production of therapeutic proteins since the first therapeutic protein from recombinant mammalian cells, tissue plasminogen activator (tPA, Genentech, USA) synthesized in CHO cells, was approved for clinical use in 1987. Despite the availability of various mammalian cell lines (such as BHK, HEK-293, HeLa, NS0, and PerC6), nearly 70 % of all recombinant protein therapeutics produced today are made in CHO cells [1]. CHO cells have become the mammalian equivalent to E. coli in research and biotechnology today because they are a safe host with a non-replicable property for human pathogenic viruses, offer easy adaptability in a suspension culture, offer functionality with gene amplification systems for constructing high-producing cells, and have a glycosylation pattern similar to those of naive human origin. Recent achievements in CHO cell culturing at levels of more than 1