关键词: 单链抗体，免疫毒素，基因表达

    摘 要:目的 在大肠杆菌中表达抗原癌基因c-erbB-2表达产物p185的单链抗体e23(scFv)/假单孢菌属外毒素活性片段PE40免疫毒素的融合蛋白，为乳腺癌、胃癌等多种c-erbB-2呈过量表达的恶性肿瘤的免疫治疗奠定基础. 方法 去除克隆在真核表达载体pLNCX中的e23(scFv)PE40基因5′端编码信号肽的核苷酸序列，并将改建后的融合基因克隆到原核融合表达载体pGEX-4T中表达. 结果 序列测定表明.改建后的抗p185e23(scFv)/PE40序列正确.融合基因经IPTG诱导表达4h后，经SDS-聚丙烯酰胺凝胶电泳分析，在Mr 90000处出现一条新生蛋白带，表达量约占菌体总蛋白的15%. 结论 成功改建并在原核中表达了抗p185e23(scFv)/PE40融合蛋白.

     INTRODUCTION

    The c-erbB-2oncogene is located in17q21，and en-codes185ku(p185)transmembrane receptor(HER2)that belongs to the epidermal growth fac-tor receptor family and has intrinsic tyrosine kinase activity

    [1-4] .HER-2gene is activated by amplifica-tion and overexpression of its protein product，which leads to its constitutive activation resulting in unregulated cell growth ......