Rapid Global Characterization Of Immunoglobulin G1 Following Oxidative Stress

While peroxide and leachable metal-induced chemical modifications are among the most important quality attributes in bioprocess development, there is no mainstream characterization method covering all common modifications theoretically possible on therapeutic proteins that also gives consistent and quick results. Here, we describe a method for rapid and consistent global characterization of leachable metals- or peroxide-stressed immunoglobulin (Ig) G1 monoclonal antibodies (mAbs). Using two independent protease digestions, data-independent acquisition (DIA) and data-dependent acquisition (DDA) liquid chromatography mass spectrometry (LCMS), we monitored 55 potential chemical modification on trastuzumab, a humanized IgG1 mAb. Processing templates including all observed peptides were developed on Skyline to consistently monitor all modifications throughout the stress conditions for both enzymatic digestions. The Global Characterization Data Processing Site, a universal automated data processing application, was created to batch process data, plot modification trends for peptides, generate sortable and downloadable modification tables, and produce Jmol code for three-dimensional structural models of the analyzed protein. The combination of Skyline templates and the Global Characterization Data Processing Site results in a universally applicable assay allowing users to batch process numerous modification. Applying this new method to stability studies will promote a broader and deeper understanding of stress modifications on therapeutic proteins.