Studying cell-to-cell interactions: an easy method of tethering ligands on artificial membranes

Extensive studies have been performed in order to understand the interaction of receptors with soluble ligands. However, we know very little of the parameters that regulate the interaction of receptors with membrane-bound ligands. Artificial lipid bilayers can be used to mimic cell-to-cell interactions, but a major challenge remains how to tether molecules to these membranes. We describe a simple and reliable method to tether ligands on glass-supported artificial bilayers containing biotinylated lipids. In this system, the model antigen hen egg lysozyme (HEL) is tethered through a fluorescently labeled streptavidin-monobiotinylated anti-HEL antibody bridge. This allows us to study the interaction of HEL-specific B cells with the tethered antigen by a variety of microscopy techniques. We recently used this system to study the activation of B cells by membrane antigens.