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Multilevel Characterization of Antibody-Ligand Conjugates by CESI-MS

Author(s):

Bryan Fonslow, Gabor Jarvas*, Marton Szigeti and Andras Guttman   Pages 1 - 9 ( 9 )

Abstract:


Aims: Demonstrating the capabilities of our new capillary electrophoresis – mass spectrometry method, which facilitates highly accurate relative quantitation of modification site occupancy of antibody-ligand (e.g., antibody-drug) conjugates.

Background: Antibody-drug conjugates play important roles in medical discovery for imaging and therapeutic intervention. The localization and stoichiometry of the conjugation can affect the orientation, selectivity, specificity, and strength of molecular interactions, influencing biochemical function.

Objective: To demonstrate the option to analyze the localization and stoichiometry of antibody-ligand conjugates by using essentially the same method at all levels including ligand infusion, peptide mapping, as well as reduced and intact protein analysis.

Materials and Methods: Capillary electrophoresis coupled to electrospray ionization mass spectrometry was used to analyze the antibodyligand conjugates.

Results: We identified three prevalent ligand conjugation sites with estimated stoichiometries of 73, 14, and 6% and an average ligand-antibody ratio of 1.37, illustrating the capabilities of CE-ESI-MS for rapid and efficient characterization of antibody-drug conjugates.

Conclusion: The developed multilevel analytical method offers a comprehensive way to determine the localization and stoichiometry of antibody-drug conjugates for molecular medicinal applications. In addition, a significant advantage of the reported approach is that small, hydrophilic, unmodified peptides well separated from the neutrals, which is not common with other liquid phase separation methods such as LC.

Keywords:

antibody-drug conjugates, protein small molecule conjugates, CE-MS, stoichiometry, characterization, unmodified peptides.

Affiliation:

The Scripps Research Institute, La Jolla, CA, Translational Glycomics Group, Research Institute of Biomolecular and Chemical Engineering, University of Pannonia, Veszprem, Translational Glycomics Group, Research Institute of Biomolecular and Chemical Engineering, University of Pannonia, Veszprem, Horváth Csaba Memorial Laboratory of Bioseparation Sciences, Research Centre for Molecular Medicine, Doctoral School of Molecular Medicine, Faculty of Medicine, University of Debrecen, Debrecen



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