【作者】 胡静平；

【导师】 朱江；

【作者基本信息】 苏州大学 ， 微生物学， 2010， 硕士

【摘要】 B7分子是一种重要的免疫细胞因子,属协同刺激分子(Costimulatory molecule)免疫球蛋白超家族(Immunoglobin superfamily, IgSF)成员,其中B7-2因其在APC上表达时间早、表达丰度高、易诱导表达,被认为是在免疫反应初期决定T细胞命运即对刺激应答或无应答的关键分子。近年来肿瘤免疫分子机理研究业已证实,抗B7单抗有望成为有效的治疗恶性肿瘤的生物制剂。另外,通过特异性阻断协同刺激信号B7/CD28以及CD40/CD40L的传导,可获得外周性免疫耐受。因此,对抗人B7-2单链抗体的表达和活性研究具有重要的应用价值。单链抗体由于分子小,减少了免疫原性,实体组织穿透力强,血浆半衰期短,因而在临床疾病的诊断和治疗中具有重要的应用价值。本研究在成功制备抗人B7-2单链抗体的基础上取得了以下成果:1.通过Bac to Bac杆状病毒表达系统,构建并筛选了含抗人B7-2单链抗体基因的重组AcBacmid和HyBacmid,并在昆虫细胞(Tn5)和BmN细胞-家蚕体内进行了表达;2.构建了含信号肽的抗人B7-2单链抗体基因的哺乳动物细胞表达载体,并在哺乳动物细胞中进行了分泌表达;3.对不同表达系统表达的抗人B7-2单链抗体进行了生物学活性的比较研究。更多还原

【Abstract】 As a member of costimulatory molecule in immunoglobin superfamily, B7 is a important cytokine.Because being expressed early , abundantly and easy to be induced in APC, B7-2 is seen as the key element which decides if immune responses happen in the initial stage. In recent years, the molecular mechanism of tumor has been confirmed and anti-B7 antibody is expected to be an effective biological agents in treating malignant tumors. In addition, peripheral immune tolerance can be obtained by blocking the conduction of B7/CD28 and CD40/CD40L specifically. Therefore, the study in expression and activity of anti-human B7-2 single chain antibody has an important value. Single chain antibody in clinical diagnostic and therapeutic applications is valuable as they have been shown to have reduced immunogenicity, easy to penetrate into a solid tumor and have a shorter half life in plasma because of its smaller size.In this research, we obtained the following results , based on the successful preparation of anti-human B7-2 single chain antibody:1. AcBacmid and HyBacmid with the anti-human B7-2 single chain antibody was constructed and screened through the Bac-to-Bac baculovirus expression system. B7-2-ScFv was expressed in Tn5 cells , BmN cells and silkworms.2. Mammalian cells’expression vector with the anti-human B7-2 single chain antibody was constructed and given a Secretory expression in mammalian cells.3. Have a comparative study about the anti-human B7-2 single chain antibody with a signal peptide in different expression systems.更多还原