Micropatterned Ligand Arrays to Study Spatial Regulation in Fc Receptor Signaling

Abstract

Fc receptor signaling plays a fundamental role in immune responses. A plethora of Fc ­receptors (e.g., Fc gamma, Fc-alpha, and Fc-epsilon) are expressed on different immune cells, including natural killer cells, macrophages, mast cells, and neutrophils. Receptor clustering and activation by multivalent ligands or opsonized particles induce a signaling cascade that leads to targeted secretion of chemical mediators (i.e., histamine, cytokines, and chemokines) and phagocytosis, among other responses. Spatial targeting and compartmentalization are common mechanisms of regulation in Fc receptor signaling. However, the tools for studying these dynamic interactions have been limited. To overcome these limitations in our model system, microfabricated surfaces containing spatially defined ligands are used to cluster­ and activate IgE receptors (FcεRI), involved in allergic responses by mast cells. Micron-scale control of cell activation allows investigation of spatially regulated mechanisms for intracellular signaling with ­fluorescence microscopy. This approach in conjunction with biochemical techniques has proven to be valuable for investigating immune receptor signaling.