The primary advantage of this system is that mammalian cells can efficiently recognize the signals for synthesis, processing, and secretion of eukaryotic proteins. Thus, expression systems using these cells are able to utilize proper protein folding, protein assembly, and post-translational modifications. Another advantage is that no self-produced endotoxin is generated during the experiment. Additionally, this system generates a high yield after optimization, as high as 100 mg/L. Mammalian protein expression systems are also able to use multi-cell lines, and multi-expression methods to improve protein expression success rate and yield.