hCG单克隆抗体特性的研究

用hCG 免疫BALB/C 小鼠,取其脾细胞和NS1骨髓瘤细胞融合,得到二株能分泌识别hCG 和hCG-β亚单位的单克隆抗体的杂交细胞株。其抗体A_(46)和A_(24)对hCG 的亲和力用Scatchard 法测得平衡常数分别为1.60×10~9M~(-1)和2.33×10~9M~(-1),对hCG-β的平衡常数为0.62×10~9M~(-1)和2.50×10~9M~(-1)。A_(46)抗体还能识别hLH,和hCG-α、hFSH 和hTSH 的交叉反应很小。而A_(24)抗体和hLH 只有2%的交叉反应,和其它几种激素几乎无交叉反应。这两种单克隆抗体都能阻断hCG 在雄小鼠体内刺激睾酮产生的作用。实验结果还提示A_(46)和A_(24)抗体在hCG 分子上所识别的抗原决定簇很接近,并可能都和hCG 分子的生物学活性的表达有关。

CHARACTERIZATION OF MONOCLONAL ANTIBODIES AGAINST HUMAN CHORIONIC GONADOTROPIN

Two hybridomas which secrete monoclonal antibodies against hCG and hCG-β subunitwere obtained by fusion of the spleen cells of BALB/C mice previously immunized withpurified hCG with NS1 myeloma cells.By Scatchard plot analysis,the equilibrium constantsof these two monoclonal antibodies(A46 and A24)to hCG were shown to be 1.60×10~9M~(-1)and 2.33×10~9M~(-1),and to hCG-β subunit,0.62×10~9M~(-1) and 2.50×10~9M~(-1),respectively.The monoclonal antibody A46 could also recognize hLH,but possessed very low cross reacti-vity with hCG-α,hFSH and hTSH.Monoclonal antibody A24,on the other hand,had a 2% cross reactivity with hLH and no detectable cross reactivity with hFSH.Both A46 and A24 monoclonal antibodies could in vivo neutralize the biological activityof hCG and block testosterone production induced by hCG in young male mice.Ourexperiments further demonstrated that the binding of hCG to monoclonal antibody A46 couldbe blocked by the pretreatment of hCG with monoclonal antibody A24.The results of thisstudy suggest that the immunological determinants of hCG recognized by A24 and A46 mon-oclonal antibodies are located very close to each other on the surface of hCG molecule,andare very likely to be responsible for the expression of the biological activity of hCG.