Thermodynamic Unfolding and Aggregation Fingerprints of Monoclonal Antibodies Using Thermal Profiling.

purposePredicting thermal protein stability is of major interest in the development of protein-based biopharmaceuticals. Therefore, this study provides a predictive tool for determining transition enthalpies, which can be used for ranking different proteins according to their thermal stability.

methodsUnfolding and aggregation profiles of eight different therapeutic monoclonal antibodies (mAbs) of type G, isotype 1 were investigated. The unfolding profiles were determined by intrinsic fluorescence (IF) spectroscopy and differential scanning calorimetry (DSC). A three-state unfolding fitting model was used to determine thermodynamic parameters for macromolecular multi-domain mAbs in IF experiments, like the van't Hoff enthalpy change (∆H

resultsComparing the thermodynamic parameters derived from IF spectroscopy and DSC resulted in similar values. Data generated by thermal-induced stress at 40°C show similar stability ranking as postulated through the Fab enthalpies for mAbs in two different formulations, while at 25°C a meaningful ranking is not possible, because distinct differences in the thermal stability cannot be observed. The additional consideration of Fab enthalpies to predict the 40 °C SEC ranking seems to be more reliable compared to the use of exclusively the melting temperatures or aggregation onset temperatures and times.

conclusionWe show that thermodynamic profiling can help predicting unfolding and aggregation properties of therapeutic mAbs at 40°C. Therefore, analyzing thermodynamic unfolding parameters is a useful and supportive tool discriminating thermal stability profiles of mAbs for further pharmaceutical development and clinical studies.