The Influence of Charge Distribution on Self-Association and Viscosity Behavior of Monoclonal Antibody Solutions

Abstract

The present work investigates the influence of electrostatic surface potential distribution of monoclonal antibodies (MAbs) on intermolecular interactions and viscosity. Electrostatic models suggest MAb-1 has a less uniform surface charge distribution than MAb-2. The patches of positive and negative potential on MAb-1 are predicted to favor intermolecular attraction, even in the presence of a small net positive charge. Consistent with this expectation, MAb-1 exhibits a negative second virial coefficient (B₂₂), an increase in static structure factor, S((q→0)), and a decrease in hydrodynamic interaction parameter, H((q→0)), with increase in MAb-1 concentration. Conversely, MAb-2 did not show such heterogeneous charge distribution as MAb-1 and hence favors intermolecular repulsion (positive B₂₂), lower static structure factor, S((q→0)), and repulsion induced increase in momentum transfer, H((q→0)), to result in lower viscosity of MAb-2. Charge swap mutants of MAb-1, M-5 and M-7, showed a decrease in charge asymmetry and concomitantly a loss in self-associating behavior and lower viscosity than MAb-1. However, replacement of charge residues in the sequence of MAb-2, M-10, did not invoke charge distribution to the same extent as MAb-1 and hence exhibited a similar viscosity and self-association profile as MAb-2.

Hydrogen exchange mass spectrometry reveals protein interfaces and distant dynamic coupling effects during the reversible self-association of an IgG1 monoclonal antibody

“…Increases in intermolecular associations between antibody molecules at high protein concentrations have been previously correlated to elevated solution viscosity values. 5,51 This effect can be attributed to the antibody network formation at high protein concentration, which affects the packing volume fraction of the antibody and ultimately results in an increase in solution viscosity. 10 For example, Pathak et al demonstrated that the presence of reversibly associated clusters at high protein concentrations contributed to an increase in solution viscosity.…”

Assessment and significance of protein–protein interactions during development of protein biopharmaceuticals

“…This network is hypothesized to consist of a transient formation of protein clusters whereby the interactions result in short lifetimes for rearrangement. In the case of MAb 1 and MAb 2, these interactions appeared to be dominated by electrostatics as suggested by the studies by Yadav et al (2012a). Molecular dynamics simulations can be useful in gaining additional insights into which specific regions of the MAbs are involved in network formation.…”

“…The influence of surface charge distribution in governing the different high concentration solution behavior of MAbs 1 and 2 was assessed in recent work by studying the chargeswap mutants of MAb 1 and MAb 2 (Yadav et al 2011c(Yadav et al , 2012a. The details of these charge-swap mutants, including specific amino acid changes, are discussed in Yadav et al (2011c).…”

“…The red and blue contours indicate −1 and +1 KT/e isosurface potential. Reproduced from Yadav et al (2012a) charge asymmetry (Fig. 6e vs. a) favoring intermolecular repulsions (positive B 22 ; Fig.…”

“…In order to investigate the role of electrostatic interactions in MAb The viscosity was measured using a cone/plate measuring system at a shear rate of 1,000/s. Reproduced from Yadav et al (2012a). b The corrected weight average molecular weights (M wc ) for MAb 1 and Mutants, using the non-ideality corrections for MAb 2 (Eq.…”