No abstract

Analytical methods founded upon whole cell-based assays are of importance in early stage drug development and in fundamental studies of biomolecular recognition. Here we have studied the binding of the monoclonal antibody trastuzumab to human epidermal growth factor receptor 2 (HER2) on human ovary adenocarcinoma epithelial cancer cells (SKOV3) using quartz crystal microbalance (QCM) technology. An optimized procedure for immobilizing the cells on the chip surface was established with respect to fixation procedure and seeding density. Trastuzumab binding to the cell decorated sensor surface was studied, revealing a mean dissociation constant, KD, value of 7 ± 1 nM (standard error of the mean). This study provides a new perspective on the affinity of the antibody-receptor complex presented a more natural context compared to purified receptors. These results demonstrate the potential for using whole cell-based QCM assay in drug development, the screening of HER2 selective antibody-based drug candidates, and for the study of biomolecular recognition. This real time, label free approach for studying interactions with target receptors present in their natural environment afforded sensitive and detailed kinetic information about the binding of the analyte to the target.

We present a method to study the interaction between biomolecules and receptors present on the cell surface. This enables studies of molecular interactions in a natural biological context. As the analyte interacts with the receptors still intact on the cell surface, the experimental data provides complete dynamics and complexity of the interaction, thereby generating highly informative data. Attana's cell-based biosensor platform can be used to obtain this information from a diverse range of interactions as described in these protocols, which detail how to grow or capture cells on a surface, how to stabilize and visualize the cells on the surface, and how to set up assays to measure detailed interaction kinetics directly on the cell surface.