Molecular mimicry by antiidiotypic monoclonal antibody to gonadotropin releasing hormone

Antipeptide and antiidiotypic antibodies to several receptors are known to mimic their respective ligands in transducing signals on binding their rece ptors. In our attempts to study gonadotropin releasing hormone receptor, an tipeptide and antiidiotypic monoclonal antibodies specific to the receptor were established earlier. The antipeptide mAb F1G4 was to a synthetic pepti de corresponding to the extracellular domain of human GnRH receptor and the antiidiotypic mAb 4D10C1 was to the idiotype of a GnRH specific mAb. Here we report the physiological effects of the two mAbs on binding the receptor , as investigated using in vitro cultures of(a) human term placental villi and (b) rat pituitaries. The mAb 4D10C1 exerted a dose-dependent release of human chorionic gonadonopin in cultures of human term placental villi as w ell as luteinising and follicle stimulating hormones in cultures of rat pit uitaries.