Lombes M, Desfosses B, Cittanova N, Erlanger B F
Department of Microbiology, Columbia University, New York 10032.
J Immunol. 1989 Dec 15;143(12):4078-83.
Immunization with a murine anti-aldosterone mAb (AAC) resulted in the isolation of a syngeneic monoclonal anti-idiotypic antibody, LH9G4. LH9G4 bound to Fab fragments of AAC and was affinity-purified on an AAC column. LH9G4 inhibited the binding of aldosterone to AAC in a dose-dependent manner with an apparent dissociation constant of 0.5 nM as determined by competitive inhibition assays in ELISA and RIA. LH9G4 and aldosterone have similar relative affinities for AAC. Kinetic studies and Scatchard plot analysis support a reversible and reciprocal competitive inhibition mechanism between LH9G4 and aldosterone for the paratope of AAC. The possibility of a steric hindrance mechanism was eliminated. No cross-reactivity was seen with six other murine anti-aldosterone mAb, with a rabbit polyclonal antibody or with aldosterone receptor. The anti-idiotypic antibody, defined as a "restricted" internal image of aldosterone, is apparently directed at a private idiotope present in the paratope of AAC but not in binding sites of other aldosterone-binding proteins. Biophysical considerations involving characteristics of nonbonded attractive forces can explain these findings. An advantage of the one-step auto-anti-idiotypic procedure for the generation of Ab2-beta or internal image antibodies is discussed.
用鼠抗醛固酮单克隆抗体（AAC）进行免疫后，分离出了一种同基因抗独特型单克隆抗体LH9G4。LH9G4与AAC的Fab片段结合，并在AAC柱上进行亲和纯化。通过ELISA和RIA中的竞争性抑制试验测定，LH9G4以剂量依赖方式抑制醛固酮与AAC的结合，其表观解离常数为0.5 nM。LH9G4和醛固酮对AAC具有相似的相对亲和力。动力学研究和Scatchard图分析支持LH9G4和醛固酮之间针对AAC互补位的可逆和相互竞争性抑制机制。空间位阻机制的可能性被排除。与其他六种鼠抗醛固酮单克隆抗体、兔多克隆抗体或醛固酮受体均未观察到交叉反应。这种抗独特型抗体被定义为醛固酮的“受限”内影像，显然针对的是AAC互补位中存在但其他醛固酮结合蛋白结合位点中不存在的一个独特型表位。涉及非键合吸引力特征的生物物理因素可以解释这些发现。讨论了一步法自身抗独特型程序在产生Ab2-β或内影像抗体方面的优势。
