Role of Domain–Domain Interactions on the Self-Association and Physical Stability of Monoclonal Antibodies: Effect of pH and Salt

Published

September 26, 2023

Author(s)

Amy Xu, Marco Blanco, Maria Castellanos, Curtis Meuse, Kevin Mattison, Ioannis Karageorgos, Harold Hatch, Vincent Shen, Joseph E. Curtis

Abstract

Monoclonal antibodies (mAbs) make up a major class of biotherapeutics with a wide range of clinical applications. Their physical stability can be affected by various environmental factors. For instance, an acidic pH can be encountered during different stages of the mAb manufacturing process, including purification and storage. Therefore, understanding the behavior of flexible mAb molecules in acidic solution environments will benefit the development of stable mAb products. This study used small-angle X-ray scattering (SAXS) and complementary biophysical characterization techniques to investigate the conformational flexibility and protein−protein interactions (PPI) of a model mAb molecule under near-neutral and acidic conditions. The study also characterized the interactions between Fab and Fc fragments under the same buffer conditions to identify domain−domain interactions. The results suggest that solution pH significantly influences mAb flexibility and thus could help mAbs remain physically stable by maximizing local electrostatic repulsions when mAbs become crowded in solution. Under acidic buffer conditions, both Fab and Fc contribute to the repulsive PPI observed among the full mAb at a low ionic strength. However, as ionic strength increases, hydrophobic interactions lead to the self-association of Fc fragments and, subsequently, could affect the aggregation state of the mAb.

Citation

Journal of Physical Chemistry B

Volume

127

Issue

39

Pub Type

Journals

Download Paper

https://doi.org/10.1021/acs.jpcb.3c03928

Local Download

Keywords

Small-angle scattering, molecular dynamics, protein, antibody

Citation

Xu, A. , Blanco, M. , Castellanos, M. , Meuse, C. , Mattison, K. , Karageorgos, I. , Hatch, H. , Shen, V. and Curtis, J. (2023), Role of Domain–Domain Interactions on the Self-Association and Physical Stability of Monoclonal Antibodies: Effect of pH and Salt, Journal of Physical Chemistry B, [online], https://doi.org/10.1021/acs.jpcb.3c03928, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=956165 (Accessed February 19, 2025)