Coated Latex Beads as Artificial Cells for Quantitative Investigations of Receptor/Ligand Interactions

Abstract Cellular interactions are often essential to regulate immune cell activities during an immune response. To understand the details of this process, it is necessary to study individual receptor/ligand interactions in a quantitative fashion. However, this is often very difficult or even impossible when using real cells for stimulation. Here, we present a method to use cell‐sized latex beads for such studies. These beads can be coated with agonistic antibodies or specific ligands in a defined and quantifiable fashion. This creates the possibility of titrating the strength of the stimulation for a specific receptor in a three‐dimensional system. Using natural killer (NK) cells as an example, we demonstrate how these beads can be used to stimulate NK cell responses. © 2020 The Authors. Basic Protocol 1 : Covalent coating of latex beads with antibodies Basic Protocol 2 : Quantification of the amount of antibodies on the beads with the QIFIKIT ® Alternate Protocol 1 : Covalent coating of latex beads with streptavidin to bind biotinylated proteins Alternate Protocol 2 : Quantification of the amount of protein on the beads with the QIFIKIT ® Support Protocol : Functional testing of the beads in a natural killer cell degranulation assay