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癌胚抗原(CEA)是一种非特异性肿瘤标记(TW).在结肠癌,胃癌,肺癌,乳腺癌,宫颈癌等许多恶性肿瘤中均有较高表达.利用抗CEA单克隆抗体进行放免显像研究近年来发展较快,但都存在着放射性本底较高的问题,影响了显像结果.F(ab’)_2.由于分子量小,没有Fc段,从血液中清除较快,可减少非特异结合,而因显像效果较好,但仍然受HAMA反应的影响.为此,本研究利用昆虫杆状病毒表达系统在SF9细胞中表达了抗CEA人鼠嵌合F(ah’)_2,以利于临床肿瘤的放免显像.提取一株表达完整抗CEA嵌合抗体的CHO细胞的总RNA,分别用与人轻链k恒区基因及α1重链CH2基因互补的3’引物进行反转录,再以CDNA为模板,5’引物相同,都与鼠重链前导肽互补,3’引物与反转录相同分别进行PCR扩增,得到含有鼠重链前导肽,轻链可变区,完整的k恒区的680bp的轻链基因和含有鼠重链前导肽,重链可变区,
Carcinoembryonic antigen (CEA) is a nonspecific tumor marker (TW). It is highly expressed in many malignant tumors such as colon cancer, gastric cancer, lung cancer, breast cancer, cervical cancer, etc. Anti-CEA monoclonal antibody is used for radioimmunoimaging. For example, research has developed rapidly in recent years, but there are problems with a high radioactive background, affecting the imaging results. F(ab’)_2. Due to the small molecular weight, there is no Fc segment, and the removal from the blood is faster and can be reduced. Non-specific binding, but because of the better imaging results, but still affected by the HAMA reaction. To this end, the present study used an insect baculovirus expression system to express anti-CEA human murine chimeric F(ah’)_2 in SF9 cells. In order to facilitate clinical tumor radioimmunoassay, extract total RNA of a CHO cell expressing intact anti-CEA chimeric antibody, and use the 3′ primers complementary to human light chain k constant region gene and α1 heavy chain CH2 gene respectively. Transcription, using CDNA as a template, 5′ primers are the same, both are complementary to the mouse heavy chain leader peptide, 3′ primers and reverse transcription are the same for PCR amplification, and the mouse heavy chain leader peptide is contained, and the light chain variable region is obtained. , the complete 680 bp light chain gene in the k constant region and contains the mouse heavy chain leader peptide, the heavy chain variable region,