title: Establishment of a signal peptide with cross-species compatibility for functional antibody expression in both Escherichia coli and Chinese hamster ovary cells.
abstract: Signal peptides are short peptides located at the N-terminus of secreted proteins. They characteristically have three domains; a basic region at the N-terminus (n-region), a central hydrophobic core (h-region) and a carboxy-terminal cleavage region (c-region). Although hundreds of different signal peptides have been identified, it has not been completely understood how their features enable signal peptides to influence protein expression. Antibody-derived signal peptides are often used to prepare recombinant antibodies expressed by eukaryotic cells, especially Chinese hamster ovary (CHO) cells. However, when prokaryotic Escherichia coli (E. coli) are utilized in drug discovery processes, such as for phage display selection or antibody humanization, signal peptides have been selected separately due to the differences in the expression systems between the species. In this study, we successfully established a signal peptide that enables a functional antibody to be expressed in both prokaryotic and eukaryotic cells by focusing on the importance of having an Ala residue in the c-region of the signal sequence. We found that changing Ser to Ala at only two positions significantly augmented the anti-HER2 antigen binding fragment (Fab) expression in E. coli. In addition, this altered signal peptide also retained the ability to express functional anti-HER2 antibody in CHO cells. Taken together, the present findings indicate that the signal peptide can promote functional antibody expression in both prokaryotic E. coli and eukaryotic CHO cells. This finding will contribute to the understanding of signal peptides and accelerate therapeutic antibody research.
authors.affiliation: Research Core Function Laboratories, Research Functions Unit, R&D Division, Kyowa Hakko Kirin Co., Ltd, 3-6-6 Asahi-machi, Machida-shi, Tokyo 194-8533, Japan.
authors.forename: Ryuma
authors.initials: R
authors.lastname: Nagano
authors.affiliation: Innovative Technology Laboratories, Research Functions Unit, R&D Division, Kyowa Hakko Kirin Co., Ltd, 3-6-6 Asahi-machi, Machida-shi, Tokyo 194-8533, Japan. Electronic address: kazuhiro.masuda@kyowa-kirin.co.jp.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Masuda
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D003429:Cross Reactions; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals / Q000235:genetics*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D013045:Species Specificity
chemical_list: D000911:Antibodies, Monoclonal; D007140:Immunoglobulin Fab Fragments; D021382:Protein Sorting Signals; D018719:Erb-b2 Receptor Tyrosine Kinases; D011994:Recombinant Proteins; C508053:ERBB2 protein, human
keywords: Antibody; CHO cells; E. coli; Fab; Protein expression; Signal peptide