Engineering of pH-dependent antigen binding properties for toxin-targeting IgG1 antibodies using light-chain shuffling

Description

Immunoglobulin G (IgG) antibodies that bind their cognate antigen in a pH-dependent manner (acid-switched antibodies) can release their bound antigen for degradation in the acidic environment of endosomes, while the IgGs are rescued by the neonatal Fc receptor (FcRn). Thus, such IgGs can over time neutralize multiple antigens and therefore be used at lower doses than their non-pH-responsive counterparts. Here, we show that light-chain shuffling combined with phage display technology can be used to discover antibodies with increased pH-dependent antigen-binding properties, using the snake toxins, myotoxin II, and α-cobratoxin, as examples. We reveal differences in how the selected IgG1s engage their antigens and human FcRn, and how these translate into distinct cellular handling properties related to their pH-dependent antigen-binding phenotypes and Fc-engineering for improved FcRn binding. Our study showcases the complexity of engineering pH-dependent antigen-binding properties into IgG1s and demonstrates the effects on cellular antibody-antigen recycling. A data overview can be found in "Data-organization.xlsx" Provided here are the raw data for each of the figures, as well as protein and nucleotide sequences of: TPL0039_05_B04 TPL0552_02_A05 TPL0197_01_C08 TPL0544_01_B01

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