【摘要】 背景与目的:微型双功能抗体是基因工程抗体的一种形式,它具有两个抗原结合位点,可选择性募集效应细胞到靶细胞周围,介导特异性杀伤作用。本实验构建抗CD3/抗CD19微型双功能抗体(diabody)载体,表达纯化后测定其生物学活性。方法:用重叠PCR(overlap PCR)和PCR方法,构建抗CD3/抗CD19 diabody载体,转化感受态大肠埃希菌进行原核表达。表达产物经抗His-tag亲和层析柱分离纯化,12% SDS-PAGE电泳及Western blot鉴定。应用间接免疫荧光和竞争性免疫荧光结合流式细胞分析技术(FACS)检测生物学活性。结果:基因重组质粒经测序证实序列正确。抗CD3/抗CD19 diabody能够在原核表达系统中进行可溶性表达。12% SDS-PAGE显示28×103和26×103各有一条带,Western blot在28×103显示有条带,与预期相符。表达产物经纯化定量可达5mg/L。FACS检测抗CD3/抗CD19 diabody可与CD19+ Raji细胞和CD3+ Jurkat细胞特异结合,并能竞争性抑制HIT3a和HIT19a与上述细胞的结合活性。结论:本实验成功构建了抗CD3/抗CD19 diabody,并且能够进行可溶性表达,可与CD19+ Raji细胞和CD3+ Jurkat细胞特异结合,为以后的抗体功能实验奠定了基础。更多还原

【Abstract】 Background and purpose:Bispecific antibody is a special pattern of genetic engineering antibody.It possesses 2 antigen binding sites, one directed at the effecter cells and the other at the target cells which are always the tumor cells.This enables the effecter cells to recruit to the targets efficiently and exert cytotoxic effect.The experiment was aimed to construct the expression vector of anti-CD3×anti-CD19 bispecific antibody, purification and analyzing the activity of the diabody.Methods:Applyed PCR and overlap PCR to construct the expression vector of anti-CD3×anti-CD19 bispecific antibodies, transformed it into E.coli 16C9 for expression.Purified the diabody by His-tag affinity chromatography and confirmed by 12% SDS-PAGE and Western blot.Antigen binding activity of the diabody was analyzed by FACS.Results:The DNA sequence of the expression vector containing anti-CD3×anti-CD19 fragment was comfirmed.The yield of purified diabody was up to 5 mg/L.The molecular weight of diabody was correctly indicated by SDS-PAGE and Western blot.The diabody could specifically bind to CD19+ Raji cells and CD3+ Jurkat cells while competitively inhibit binding of HIT3a and HIT19a to the cells.Conclusion:Successfully constructed the expression vector of anti-CD3×anti-CD19 bispecific antibodies, the diabody acquired by the method could be produced with high level expression and also had high specific affinity with CD19+ Raji cells and CD3+ Jurkat cells.更多还原