Extrapolating differential scanning calorimetry data for monoclonal antibodies to low temperatures

Arne Schön; Young Do Kwon; Michael F Bender; Ernesto Freire

doi:10.1016/j.ab.2024.115533

Extrapolating differential scanning calorimetry data for monoclonal antibodies to low temperatures

Anal Biochem. 2024 Apr 19:691:115533. doi: 10.1016/j.ab.2024.115533. Online ahead of print.

Authors

Arne Schön¹, Young Do Kwon², Michael F Bender², Ernesto Freire³

Affiliations

¹ Department of Biology, Johns Hopkins University, 3400 North Charles, Baltimore, MD, 21218, USA.
² Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
³ Department of Biology, Johns Hopkins University, 3400 North Charles, Baltimore, MD, 21218, USA. Electronic address: ef@jhu.edu.

PMID: 38642818
DOI: 10.1016/j.ab.2024.115533

Abstract

For irreversible denaturation transitions such as those exhibited by monoclonal antibodies, differential scanning calorimetry provides the denaturation temperature, T_m, the rate of denaturation at T_m, and the activation energy at T_m. These three quantities are essential but not sufficient for an accurate extrapolation of the rate of denaturation to temperatures of 25 °C and below. We have observed that the activation energy is not constant but temperature dependent due to the existence of an activation heat capacity, C_p,a. It is shown in this paper that a model that incorporates C_p,a is able to account for previous observations like, for example, that increasing the T_m does not always improve the stability at low temperatures; that some antibodies exhibit lower stabilities at 5 °C than at 25 °C; or that low temperature stabilities do not follow the rank order derived from T_m values. Most importantly, the activation heat capacity model is able to reproduce time dependent stabilities measured by size exclusion chromatography at low temperatures.

Keywords: Differential scanning calorimetry; Protein stability; Temperature denaturation; mAb aggregation; mAb denaturation.