Monoclonal antibodies that display a low propensity to self-associate have a higher likelihood of displaying several drug-like properties, including high solubility and low viscosity in vitro and slow antibody clearance in vivo. Affinity capture self-interaction nanoparticle spectroscopy (AC-SINS) has emerged as a high-throughput assay for measuring antibody self-association without the need for complex instrumentation or high protein concentrations. AC-SINS is usually implemented with polyclonal anti-human IgGs conjugated to the surface of gold nanoparticles for subsequent capture and analysis of human monoclonal antibodies. Leveraging the inherent surface plasmon resonance of gold nanoparticles, the addition of monoclonal antibodies that are prone to self-associate causes particle aggregation and a shift in the wavelength of maximum absorbance. We sought to explore the potential of using polyclonal antibody fragments (Fab and Fab’2) as capture reagents in this assay to increase its sensitivity. Interestingly, gold particles coated with monovalent Fab fragments captured fewer monoclonal antibodies than bivalent capture antibodies (Fab’2 and IgG) but had the highest sensitivity for discriminating between mAbs with different levels of self-association. We also sought to improve the reproducibility of assay by exploring the use of monoclonal IgGs as capture reagents. Surprisingly, we found that most monoclonal anti-human antibodies were either unable to be stably conjugated to nanoparticles or displayed poor sensitivity for detecting antibody self-association. However, we identified a single monoclonal antibody that displayed excellent performance in our AC-SINS assay, and we are in the process of analyzing its unique molecular properties. We expect that these findings will improve the rapid screening of antibodies to identify variants with low levels of colloidal interactions and increased likelihood of displaying drug-like properties.

Improved methods for high-throughput screening of antibody colloidal interactions

2019 Spring National Meeting

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