Kavli Affiliate: Thomas P. Sakmar
| Authors: Leo Dahl, Ilana Kotliar, Annika Bendes, Tea Dodig-Crnkovic, Samuel Fromm, Arne Elofsson, Mathias Uhlen, Thomas P Sakmar and Jochen Schwenk
| Summary:
Abstract G protein-coupled receptors (GPCRs) control critical cellular signaling pathways. Therapeutic agents, such as antibodies (Abs), are being developed to modulate GPCR signaling pathways. However, validating the selectivity of anti-GPCR Abs is challenging due to sequence similarities of individual receptors within GPCR subfamilies. To address this, we developed a multiplexed immunoassay to test >400 anti-GPCR Abs from the Human Protein Atlas targeting a customized library of 215 expressed and solubilized GPCRs representing all GPCR subfamilies. We found that ~61% of Abs were selective for their intended target, ~11% to bind off-target, and ~28% not to bind any GPCR. Antigens of on-target Abs were, on average, significantly longer, more disordered, and less likely to be buried in the interior of the GPCR protein than the other Abs. These results provide important insights into the immunogenicity of GPCR epitopes and form a basis for the design of therapeutic Abs and the detection of pathological auto-antibodies. Competing Interest Statement M.U. is a cofounder of Atlas Antibodies AB, the commercial distributor of some of the Abs used in this study. J.M.S. acknowledges a relationship with Atlas Antibodies AB. J.M.S. has, unrelated to this study, conducted contract research with Luminex Corp. and received speaker fees from Roche Diagnostics. The other authors declare that they have no competing interests. All other authors declare they have no competing interests.