利用单克隆抗体研究人绒毛膜促性腺激素的结构与功能关系

STUDIES ON THE RELATIONSHIP BETWEEN STRUCTURE AND FUNCTION OF hCG BY USING MONOCLONAL ANTIBODIES

利用一组抗人绒毛膜促性腺激素单克隆抗体研究它们与hCG及其亚单位结合以及在体内外中和hCG,hLH活性的能力。发现至少在hCG存在着6个抗原决定簇。其中与BAH_1,9C_2,10E_5,8B_5反应的决定簇和hCG生物活性有关,而与BAH_2和7F_3反应的决定簇与hCG生物活性无关。与抗体10E_5和8B_5反应的这两个抗原决定簇是hCGβ亚单位所特有的,它们不存在于hLH分子中。

A panel of monoclonal antibodies (McAb) were tested for binding to ^(125)I labelled hCG, hCGα, hCGβ, hLH and for blocking biological activities of hCG, hLH in vitro and in vivo.The results showed there are at least six epitopes in β subunit of hCG. McAb BAH_2 reacted with an epitope which was exposed only after hCG a and β were combined. This epitope was not responsible for the biological activities of hCG. Most of the McAbs reacted to three epitopes in hCG β subunit as well as to three epitopes in hLH β subunit. Two of the epitopes were responsible for biological activities of hCG or hLH. McAb 8B_5 and 10E_5 bound with hCG but did not bind with hLH. Both of them could neutralize the biological activities of hCG. This suggested that there are two specific epitopes which are responsible for biological activities of hCG in hCG β subunit, but it can not be found in hLH β subunit.