Ultra-Dilute Developability Analysis of Antibody Self-Association and Non-Specific Binding

Early-stage screening of antibody developability properties is important for identifying monoclonal antibody (mAb) candidates with favorable biophysical properties in addition to potent biological activities. Nevertheless, this process is challenging given the large numbers of mAb candidates, as well as their low quantities, concentrations, and purities. Here, we report methods for assessing the developability of mAbs in terms of their levels of self-association and non-specific binding at ultra-dilute concentrations (~0.01-0.05 mg/ml). The self-association measurements using the AC-SINS and CS-SINS assays are performed by capturing mAbs on immunogold conjugates and evaluating their plasmon shifts in either formulation (CS-SINS) or physiological (AC-SINS) solution conditions. The non-specific binding measurements using the PSP assay are performed by capturing mAbs on Protein A-functionalized magnetic beads and evaluating their interactions with protein reagents in physiological solution conditions using flow cytometry. Using these methods in concert enables the identification of mAbs with reduced risk for development challenges associated with high self-association (e.g., high viscosity or low solubility) and high non-specific binding (e.g., fast antibody clearance).