CHO cells dominate biopharmaceutical manufacturing (>70% of approved biologics) because they perform N-glycosylation that is sufficiently similar to human glycans for correct protein folding, effector function, and pharmacokinetics. Incorrect glycosylation can reduce half-life, alter immunogenicity, and affect Fc receptor binding of monoclonal antibodies. CHO cells also grow in serum-free suspension, are amenable to genetic engineering, and have a long regulatory safety track record.