title: Establishing a link between amino acid sequences and self-associating and viscoelastic behavior of two closely related monoclonal antibodies.
abstract: OBJECTIVE
  To investigate the underlying cause for the observed differences in self-associating and viscoelastic behavior between two monoclonal antibodies, MAb1, and MAb2.
  
  
  METHODS
  Several mutants were designed by swapping charged residues in MAb1 with those present in MAb2 at their respective positions and vice versa. Rheological analysis was done at low and high shear rates. Dynamic light scattering quantified intermolecular interactions in dilute solutions; sedimentation equilibrium analysis determined the corrected weight average molecular weight (M (wc)) to assess the self-associating behavior in high concentration. The molecular charge was estimated from electrophoretic mobility measurements.
  
  
  RESULTS
  Replacing the charged residues in the CDR of MAb1 resulted in a lower M (wc) and solution viscosity. The corresponding changes in either just the variable light (VL) or variable heavy (VH) chain showed only a partial decrease in viscosity, whereas changes in both VL and VH chains resulted in a dramatic reduction in viscosity. The converse case where the VL and VH chains of MAb2 were made to look like MAb1 did not self-associate or show increased viscosity.
  
  
  CONCLUSIONS
  Exposed charged residues in the CDR of MAb1 are critical in determining the self-associating and highly viscous behavior observed at high concentrations.
authors.affiliation: Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut 06269, USA.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Yadav
authors.forename: Alavattam
authors.initials: A
authors.lastname: Sreedhara
authors.forename: Sonoko
authors.initials: S
authors.lastname: Kanai
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Samantha
authors.initials: S
authors.lastname: Lien
authors.forename: Henry
authors.initials: H
authors.lastname: Lowman
authors.forename: Devendra S
authors.initials: DS
authors.lastname: Kalonia
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Shire
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000235:genetics; D002942:Circular Dichroism; D006031:Glycosylation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009154:Mutation; D055682:Viscoelastic Substances
chemical_list: D000911:Antibodies, Monoclonal; D055682:Viscoelastic Substances