title: Structure and function of purified monoclonal antibody dimers induced by different stress conditions.
abstract: OBJECTIVE
  To investigate structure and function of different monoclonal antibody (MAb) dimers.
  
  
  METHODS
  MAb dimers were induced by process-related, low pH and UV light stress. Dimers were isolated and purified by chromatography and extensively characterized by biochemical, structural and functional methods.
  
  
  RESULTS
  Highly purified dimer forms were obtained which enabled detailed characterization. Dimers induced by process stress were associated by a single non-covalent interaction site between two Fab domains in a characteristic "bone-like" structure observed in Transmission Electron Microscopy (TEM). These dimers showed reduced potency and antigen binding affinity. Low pH stress generated more stable but also non-covalently associated dimers without chemical alterations in a typical "closed" conformation according to TEM. These dimer species were more compact and more hydrophobic as dimers induced by process stress. They showed bioactivity and antigen binding affinity similar to the native monomer. Light-induced dimers, exhibiting various different conformations, were the most stable dimers with various chemical modifications leading to a broad range in size, charge and hydrophobicity. These dimers fully lost bioactivity and antigen binding affinity.
  
  
  CONCLUSIONS
  The use of highly purified MAb dimers and a panel of characterizations methods enabled to obtain a clear picture about molecular architecture and function of dimers.
authors.affiliation: Pharma Technical Development Europe (Biologics) Analytics, F. Hoffmann-La Roche Ltd., 4070, Basel, Switzerland.
authors.forename: Rajsekhar
authors.initials: R
authors.lastname: Paul
authors.forename: Alexandra
authors.initials: A
authors.lastname: Graff-Meyer
authors.forename: Henning
authors.initials: H
authors.lastname: Stahlberg
authors.forename: Matthias E
authors.initials: ME
authors.lastname: Lauer
authors.forename: Arne C
authors.initials: AC
authors.lastname: Rufer
authors.forename: Hermann
authors.initials: H
authors.lastname: Beck
authors.forename: Alexandre
authors.initials: A
authors.lastname: Briguet
authors.forename: Volker
authors.initials: V
authors.lastname: Schnaible
authors.forename: Thomas
authors.initials: T
authors.lastname: Buckel
authors.forename: Sabine
authors.initials: S
authors.lastname: Boeckle
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification; D002850:Chromatography, Gel; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007074:Immunoglobulin G / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification; D011487:Protein Conformation; D055503:Protein Multimerization; D017452:Receptors, IgG / Q000276:immunology; D014466:Ultraviolet Rays
chemical_list: D000911:Antibodies, Monoclonal; C496124:FCGR3A protein, human; D007074:Immunoglobulin G; D017452:Receptors, IgG