纤维蛋白单抗SZ-58嵌合Fab片段在大肠杆菌中的表达

Construction and expression of chimeric Fab fragment of anti-fibrin monoclonal antibody SZ-58 in E .coli

为减少鼠源单抗的免疫原性，降低其分子量，应用基因重组技术将纤维蛋白单抗ＳＺ－５８可变区基因与人ＩｇＧ１恒定区基因Ｃ_Ｈ１、Ｃｋ进行拼接、扩增。将扩增后的ＳＺ－５８嵌合Ｆａｂ基因克隆至噬菌体质粒，并导入大肠杆菌中进行表达。表达的嵌合Ｆａｂ片段为可溶性。放免检测其在表达上清中的含量约为２００μｇ／Ｌ，免疫印迹电泳证实ＳＺ－５８嵌合Ｆａｂ片段能特异地与纤维蛋白Ｄ－Ｄｉｍｅｒ结合。

In a previous study , an antifibrin monoclonal antibody (McAb ) SZ-58 was generated from mouse origin. Experiments showed in vitro that it had good fibrin clot binding characteristic. In order to reduce the immunogenicity of McAb and lower its molecular weight , the variable region gene of SZ-58 were fused to human IgGl - constant region gene CH1 , Ck. The constructor was cloned into phagemid vector pHEN-1-Fab/Hu for expressing the soluble form of chimeric SZ-58 Fab fragment in non-suppressor E. coli HB2151. The concentration of SZ-58 Fab fragment in expression supernatant was about 200μg/L measured by IRMA. Western blot showed that it had higher fibrin D-Dimer binding activity than its parent McAb.