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.

中文翻译：

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抗 GPCR 抗体的多重选择性筛选

G 蛋白偶联受体 (GPCR) 控制着关键的细胞信号通路。正在开发治疗剂，例如抗体 (Abs) 以调节 GPCR 信号通路。然而，由于 GPCR 亚家族中单个受体的序列相似性，验证抗 GPCR 抗体的选择性具有挑战性。为了解决这个问题，我们开发了一种多重免疫测定法来测试来自人类蛋白质图谱的 >400 种抗 GPCR 抗体，目标是代表所有 GPCR 亚家族的 215 种表达和溶解的 GPCR 的定制文库。我们发现约 61% 的抗体对其预期目标具有选择性，约 11% 结合脱靶，约 28% 不结合任何 GPCR。平均而言，与其他抗体相比，靶向抗体的抗原明显更长、更无序，并且更不可能被埋在 GPCR 蛋白的内部。