PNNL

Abstract

One challenge associated with the discovery and development of monoclonal antibody (mAb) therapeutics is the de-termination of heavy chain and light chain pairing. Advances in MS instrumentation and MS/MS methods have greatly enhanced capabilities for the analysis of large intact proteins yielding much more detailed and accurate proteoform characterization. Consequently, direct interrogation of intact antibodies or F(ab’)2 and Fab fragments has the poten-tial to significantly streamline therapeutic mAb discovery processes. Here, we demonstrate for the first time the abil-ity to efficiently cleave disulfide bonds linking heavy and light chains of mAbs using electron capture dissociation (ECD) and 157 nm ultraviolet photodissociation (UVPD). The combination of intact mAb, Fab, or F(ab’)2 mass, intact LC and Fd masses, and CDR3 sequence coverage yield unambiguous determination of heavy chain and light chain pair-ing from a single experiment and experimental condition. These results demonstrate the potential of top-down and middle-down proteomics to significantly streamline therapeutic antibody discovery.