Screening Strategies for the Discovery of Ion Channel Monoclonal Antibodies

Abstract

Ion channels play crucial roles in physiology by modulation of cellular functions that include electrical excitability, secretion, cell migration, and gene transcription. They are an important target class for drug discovery and have historically been targeted using small molecule approaches. A significant opportunity exists to target these channels with antibodies and alternative forms of biologics. Antibodies display high specificity, selectivity, and affinity for their target antigen, thus having the potential to target ion channels very precisely. Nonetheless, isolating antibodies to ion channels is challenging due to the difficulties in expression and purification of ion channels in a format suitable for antibody drug discovery and due to the complexities of screening for function. In this overview, we focus on an array of screening methods, ranging from direct antibody binding screens to complex electrophysiological assays, and describe how these assays can be used to identify functional monoclonal antibodies. We also provide some insights into specific considerations which are required to enable these screens to be used for antibody drug discovery. © 2018 by John Wiley & Sons, Inc.

TRPV6 Calcium Channel Targeting by Antibodies Raised against Extracellular Epitopes Induces Prostate Cancer Cell Apoptosis

“…Indeed, antibodies, as protein entities, are known to be capable of changing protein conformation upon binding. A large amount of data exist showing that binding of IgGs to the protein can modify the conformation/structure of a protein [ 25 , 26 , 27 ]. Since an ion channel’s function depends directly on its spatial conformation, its interaction/insertion into lipid bilayer, its thermodynamic state, mono/tetrameric structure, and many more parameters/criteria, any binding to the protein channel in its natural, functional conformation will definitely induce a switch in ion channel conformation and thus activity [ 27 , 28 , 29 ].…”

Ion channels as therapeutic antibody targets

“…These include flux-based assays that measure the cellular influx or efflux of radioactive Na + , Ca 2+ and Rb + for studying sodium, calcium and potassium channels, respectively, and fluorescence-based assays that utilize either voltage-sensitive dyes that measure cell membrane voltage changes or ion-specific fluorescent probes that measure changes in intracellular ion concentrations. 101 A recent and more detailed review of ion channel antibody screening strategies can be found in Colley et al 102…”