Evaluation of Different Expression Systems for the Production of Pharmaceutical Recombinant Proteins with Emphasis on Mammalian Cells

A protein will be best expressed in its native cell type under physiological conditions, where a multitude of molecular systems work together for efficient production and quality control at various stages, including synthesis and folding, post-translational modification. However, production of proteins in appropriate quantity and quality is an essential requirement for therapeutic purposes in the present time. So, various expression systems have been developed to produce recombinant proteins: bacteria systems, yeast, baculovirus-infected insect cells, mammalian cells and, more recently, cell-free systems. In this review all of these systems were investigated in terms of capability to produce a recombinant protein with same function to their native. The advantages and disadvantages of each of these systems are also presented. When the folding and the extent of post-translational modifications of the recombinant protein are critical, expression in Eukaryotic systems and in particular the use of mammalian host cells, not only provides the optimal machinery for proper folding and post-translational modifications, but also possible the expression of large and complex proteins. However, an expression system should be capable to combine high yield, highest biological activity, ease of purification, and short timelines.