A New Approach to Examine Cell–Antibody Avidity with Surface Plasmon Resonance Imaging

In recent years, avidity has emerged as a critical parameter in antibody design, yet most current analytical instruments are limited to measuring affinity alone. This study aims to evaluate the capabilities and advantages of a novel surface plasmon resonance imaging instrument, CellVysion, designed to quantify cell–antibody avidity using a continuous antibody density gradient. A key feature of this approach is the identification of a “tipping point”—the specific ligand density, measured in µRIUs, at which cells remain bound to the sensor surface under defined shear flow conditions. In this paper, we present the technical principles and application of this method, demonstrating how avidity can be quantitatively assessed across different antibody–cell line combinations.