Specific Capture of Peptide‐Receptive Major Histocompatibility Complex Class I Molecules by Antibody Micropatterns Allows for a Novel Peptide‐Binding Assay in Live Cells

: Binding assays with fluorescently labeled ligands and recombinant receptor proteins are commonly performed in 2D arrays. But many cell surface receptors only function in their native membrane environment and/or in a specific conformation, such as they appear on the surface of live cells. Thus, receptors on live cells should be used for ligand binding assays. Here, it is shown that antibodies preprinted on a glass surface can be used to specifically array a peptide receptor of the immune system, i.e., the major histocompatibility complex class I molecule H-2Kb , into a defined pattern on the surface of live cells. Monoclonal antibodies make it feasible to capture a distinct subpopulation of H-2Kb and hold it at the cell surface. This patterned receptor enables a novel peptide-binding assay, in which the specific binding of a fluorescently labeled index peptide is visualized by microscopy. Measurements of ligand binding to captured cell surface receptors in defined confirmations apply to many problems in cell biology and thus represent a promising tool in the field of biosensors.