Seeing the Unseen: Revealing Immune Complex Formation and Antibody Aggregation with Mass Photometry

Fabian Soltermann and Brenda Watt examine mass photometry as a complementary method for measuring therapeutic-antibody aggregates and immune complexes. The programme compares automated mass photometry with SEC-MALS and sedimentation-velocity analytical ultracentrifugation, including quantification of monomers, dimers and larger aggregates. An IL-17A/anti-IL-17 antibody study illustrates heterogeneous target-related complexes and possible implications for immunogenicity. The discussion also considers how binding geometry and target valency influence complex formation and where a rapid, low-sample, column-free assay adds useful information.