Peter Jean-Christophe, Eftekhari Pierre, Billiald Philippe, Wallukat Gerd, Hoebeke Johan
CNRS, UPR 9021, Institut de Biologie Moléculaire et Cellulaire, Laboratory of Therapeutical Chemistry and Immunology, F-67084 Strasbourg, France.
J Biol Chem. 2003 Sep 19;278(38):36740-7. doi: 10.1074/jbc.M306877200. Epub 2003 Jul 14.
Antibodies directed against the second extracellular loop of G protein-coupled receptors were shown to possess functional activities. Using a functional monoclonal antibody against the human beta2-adrenergic receptor, a scFv fragment with high affinity for the target epitope was constructed and produced. The fragment recognized the beta2-adrenergic receptors on A431 cells, blocked cAMP accumulation induced by the beta2-agonist salbutamol, and decreased basal cAMP accumulation in the same cells. Their in vitro activity was tested on neonatal rat cardiomyocytes. The antibody fragments blocked the chronotropic activity induced by the beta2-agonist clenbuterol. They also decreased the in vivo heart beating frequency of mice pretreated with bisoprolol (a beta1-adrenergic receptor antagonist) for 4 min after injection. The immunological approach presented here may serve as a strategy for the synthesis of a new class of allosteric modulators for G protein-coupled receptors.
针对G蛋白偶联受体第二细胞外环的抗体已被证明具有功能活性。利用一种针对人β2 -肾上腺素能受体的功能性单克隆抗体，构建并产生了对目标表位具有高亲和力的单链抗体片段（scFv）。该片段识别A431细胞上的β2 -肾上腺素能受体，阻断β2 -激动剂沙丁胺醇诱导的环磷酸腺苷（cAMP）积累，并降低同一细胞中的基础cAMP积累。在新生大鼠心肌细胞上测试了它们的体外活性。抗体片段阻断了β2 -激动剂克伦特罗诱导的变时活性。它们还降低了注射后用比索洛尔（一种β1 -肾上腺素能受体拮抗剂）预处理4分钟的小鼠的体内心跳频率。本文提出的免疫方法可作为合成一类新型G蛋白偶联受体变构调节剂的策略。
