Expression of Recombinant Antibodies in Mammalian Cell Lines

Since the advent of hybridoma technology, mammalian-cell culture has been employed for the expression and high-level production of monoclonal antibodies (MAbs). Recent adaptations in recombinant technology have developed the use of numerous prokaryotic and eukaryotic systems for the expression of heterologous molecules. The major systems used for MAb expression have been reviewed and compared (1 ,2 ), and a number of the key methodologies are detailed within this series. Prokaryotic expression systems offer the potential of high production yields at a substantial reduced cost of goods (see Chapter 14 ). However, because of the complexity of the protein-folding pathway, bacterial expression has been limited to small antibody fragments, and in some cases may require refolding to produce a biologically active product. Another limitation is that recombinant MAbs expressed in bacteria are aglycosylated and can result in the reduction or loss of biological effector functions (3 ). For large, multidomain molecules such as full-length MAbs or complex recombinant antibody fragments, eukaryotic systems such as mammalian or yeast expression have been utilized. Currently, nine USFDA-licensed Mabs for in vivo human use have been expressed from mammalian-cell culture for commercial production.