介导多种胃癌杀伤效应的双功能抗体  

A BISPECIFIC MONOCLONAL ANTIBODY WITH VERSATILE ADAPTOR MEDIATINGDIFFERENT CYTOTOXICITIES

作　　者：王力民[1] 万文徽[1] 陆良军 董志伟 

机构地区：[1]北京市肿瘤防治研究所生化室

出　　处：《中华肿瘤杂志》1994年第2期83-87,共5页Chinese Journal of Oncology

基　　金："八六三"资助课题

摘　　要：作者设计了一种带有“通用接头”的ｂｓＭＡｂ，即制备抗胃癌及抗半抗原ＴＮＰ的ｂｓＭＡｂ，它可介导多种经ＴＮＰ化的肿瘤杀伤因子。采用分泌抗胃癌单克隆抗体（ＭｃＡｂ）的杂交瘤变异株３Ｈ１１—ＨＡＴｓ与经ＫＬＩ－ＴＮＰ免疫的Ｂａ１ｂ／ｃ小鼠脾细胞进行融合，经筛选及克隆化共获得１０株二次杂交瘤，它们均能分泌与胃癌靶细胞ＢＧＣ８２３及ＢＳＡ－ＴＮＰ呈双阳性反应的抗体。但桥联法测定表明，只有二次杂交瘤１Ｇ７（γ２ｂ，γ２ｂ）及６Ａ３（γ２ｂ，μ）分泌ｂｓＭＡｂ。实验表明，ｂｓＭＡｂ６Ａ３和１Ｇ７可介导不同性质的经ＴＮＰ化的肿瘤杀伤剂，如蓖麻毒素、人血清白蛋白与丝裂霉素的偶联物，及牛血清白蛋白与阿霉素的偶联物。研究结果还表明，桥联法在确认ｂｓＭＡｂ中具有重要意义。分泌双特异性抗体的二次杂交瘤上清中不一定含有ｂｓＭＡｂ。一般认为γ链与μ链不可能组合形成ｂｓＭＡｂ，但本研究通过亚类分析、桥联法测定及体外细胞毒试验证实，二次杂交瘤６Ａ３分泌的ｂｓＭＡｂ确是由μ链与γ２ｂ链组合而成，这是一个新的发现。Abstract Bispecific monoclonal antibody(bsMAb),secreted by hybrid-hybridoma,has an intact lgmolecule construction with dual antigen binding specificities. beMAb has several advantages overconventional conjugate in tumor targeting therapy:1)The damage to both antibody and tumoricidalagents due to chemical crosslink ing can be avoided.(2)The antigen modulation can be decreased due to monovalence binding of bsMAb with target antigen.(3) The binding affinity between Fc frdg-ment of beMAb with heterogenous heavy chains and Fc receptor is decreased, so that nonspecific distridution and side effects can be reduced.(4)The bsMAb can pretarget to tumor site, increasing the T/NT ratio and cytotoxicity.In the present study ,A bsMAb with versatile adaptor was designed. In this bsMAb ,one arm could react with gastric cancer-associated antigen, and the other with a hapten TNP. The bsMAbcould mediate different tumoricidal agents crosslinked to TNP. A variant hybridoma 3H11-HATs secreting McAb against gastric cancer was fused with spleen cells of mice immunized with KLH- TNP. After screening and subcloning,10 hybrid-hybridomaswere obtained,which secreted antibodies against both gastric cancer target cells BGC823 andBSA-TNP. By using special bridge method, only hybrid -hybridomas 6A3(γ2b,) and 1G7(γ2b,γ2b) were confirmed to secrete bsMAb.Further experiments showed that the bsMAb 6A3 and 1G7could mediate different cytotoxicities, for example,Ricin-TNP,MMC-HSA-TNP andADM-BSA-TNP. This system is useful for evaluating different tumoricidal agents in bsMAb tar-geting therapy ,and has potential value in clinics. In addition, the significance of special bridge method for comfirmation of bsMAb was empha-sized. In other word,supernatants secreted by hybrid-hybridomas with dual specificities may notcontain bsMAb. It is generally

关 键 词：胃肿瘤 单克隆抗体 杂交瘤 免疫 

分 类 号：R735.203[医药卫生—肿瘤]