Energetic Dissection of Mab-Specific Reversible Self-Association Reveals Unique Thermodynamic Signatures



Reversible self-association (RSA) remains a challenge in the development of therapeutic monoclonal antibodies (mAbs). We recently analyzed the energetics of RSA for five IgG mAbs (designated as A-E) under matched conditions and using orthogonal methods. Here we examine the thermodynamics of RSA for two of the mAbs that showed the strongest evidence of RSA (mAbs C and E) to identify underlying mechanisms.


Concentration-dependent dynamic light scattering and sedimentation velocity (SV) studies were carried out for each mAb over a range of temperatures. Because self-association was weak, the SV data were globally analyzed via direct boundary fitting to identify best-fit models, accurately determine interaction energetics, and account for the confounding effects of thermodynamic and hydrodynamic nonideality.


mAb C undergoes isodesmic self-association at all temperatures examined, with the energetics indicative of an enthalpically-driven reaction offset by a significant entropic penalty. By contrast, mAb E undergoes monomer-dimer self-association, with the reaction being entropically-driven and comprised of only a small enthalpic contribution.


Classical interpretations implicate van der Waals interactions and H-bond formation for mAb C RSA, and electrostatic interactions for mAb E. However, noting that RSA is likely coupled to additional equilibria, we also discuss the limitations of such interpretations.

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analytical ultracentrifugation


dynamic light scattering


monoclonal antibody;


phosphate buffered saline


root-mean-square deviation


reversible self-association


sedimentation velocity


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This work was supported by MedImmune, LLC, now a member of AstraZeneca.

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Correspondence to David L. Bain.

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Hopkins, M.M., Parupudi, A., Bee, J.S. et al. Energetic Dissection of Mab-Specific Reversible Self-Association Reveals Unique Thermodynamic Signatures. Pharm Res 38, 243–255 (2021). https://doi.org/10.1007/s11095-021-02987-0

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Key words

  • analytical ultracentrifugation
  • dynamic light scattering
  • interacting systems
  • monoclonal antibody
  • nonideality
  • sedimentation velocity