title: Intermolecular interactions and conformation of antibody dimers present in IgG1 biopharmaceuticals.
abstract: Intermolecular interactions and conformation in dimer species of Palivizumab, a monoclonal antibody (IgG1), were investigated to elucidate the physical and chemical properties of the dimerized antibody. Palivizumab solution contains ∼1% dimer and 99% monomer. The dimer species was isolated by size-exclusion chromatography and analysed by a number of methods including analytical ultracentrifugation-sedimantetion velocity (AUC-SV). AUC-SV in the presence of sodium dodecyl sulphate indicated that approximately half of the dimer fraction was non-covalently associated, whereas the other half was dimerized by covalent bond. Disulphide bond and dityrosine formation were likely to be involved in the covalent dimerization. Limited proteolysis of the isolated dimer by Lys-C and mass spectrometry for the resultant products indicated that the dimer species were formed by Fab-Fc or Fab-Fab interactions, whereas Fc-Fc interactions were not found. It is thus likely that the dimerization occurs mainly via the Fab region. With regard to the conformation of the dimer species, the secondary and tertiary structures were shown to be almost identical to those of the monomer. Furthermore, the thermal stability turned out also to be very similar between the dimer and monomer.
authors.affiliation: Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 B-9 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501; and Bio Process Research and Development Laboratories, Production Division, Kyowa Hakko Kirin Co., Ltd.; 100-1 Hagiwara-machi, Takasaki, Gunma 370-0013, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Iwura
authors.forename: Jun
authors.initials: J
authors.lastname: Fukuda
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Yamazaki
authors.forename: Shuji
authors.initials: S
authors.lastname: Kanamaru
authors.forename: Fumio
authors.initials: F
authors.lastname: Arisaka
mesh_terms: D000906:Antibodies / Q000737:chemistry / Q000378:metabolism*; D002850:Chromatography, Gel; D002942:Circular Dichroism; D019281:Dimerization; D004591:Electrophoresis, Polyacrylamide Gel; D005453:Fluorescence; D007074:Immunoglobulin G / Q000378:metabolism*; D013058:Mass Spectrometry; D011487:Protein Conformation; D014461:Ultracentrifugation
chemical_list: D000906:Antibodies; D007074:Immunoglobulin G
keywords: aggregation; analytical ultracentrifugation; conformation; immunoglobulin G; intermolecular interaction