Use of High Throughput SPR to Characterize Antibodies To Common Cancer Biomarkers

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As a disease of misregulation, cancer is characterized both genetically and proteomically, requiring high quality tools to dissect the change difference between cell states. Among the reagents used to characterize biological systems at the protein level, antibodies are routinely applied, and engineered versions have proven useful for treating multiple therapeutic indications. We have generated a human proteome wide toolbox of polyclonal antibodies, identifying three antigenic 14mer sequences within each of the 20,000+ open reading frames at N-terminal, middle and C-terminal regions. Using a high throughput SPR system, Carterra® LSA®, we are able to define average on-rates, off-rates, and KD’s for pAb’s generated to important cancer regulators and biomarkers, including KRAS, STAT3, and Gli1. Due to the small size of the peptide targets, the kinetics of the observed interactions with polyclonal antibodies exhibit remarkable 1:1 fit typically observed when measuring monoclonal antibody affinities. The platform is a sensitive system capable of both identifying multiple antibody-antigen interactions with KD in the nanomolar to picomolar range, but also as a mass screening tool for developing de novo antibody pairs. We define the kinetic characteristics of these antibody reagents relative to performance in western blotting specifically. Improving the characterization of such widely used tools is critical for advancing translational opportunities into use in the clinic.