抗人肺癌单链抗体噬菌体库的构建及特异性单链抗体的鉴定

目的 构建人源噬菌体抗体库,并从中筛选出抗肺癌人源单链抗体。方法 提取肺癌患者癌旁淋巴结组织,通过RT-PCR扩增出重链可变区基因（VH）和轻链可变区基因（VL）,再经剪切-重叠-延伸PCR(SOE-PCR)将VH 和VL连接得到单链抗体（ScFv）。将双酶切后的ScFv基因片段克隆入噬菌体表达载体pCANTAB5E,得到初级噬菌体抗体库。以肺腺癌细胞株A549为抗原对抗体库进行4轮筛选富集,鉴定抗体库性能。将得到的阳性克隆用IPTG诱导表达并进行检测。结果 成功构建噬菌体单链抗体库。经筛选富集,噬菌体收获率得到增加,第4轮是第1轮的115倍。随机选取10个克隆,通过ELISA法检测到其中7个与A549细胞呈阳性反应,阳性率为70%。SDS-PAGE及ELISA检测证实得到人源抗肺癌单链抗体。结论 成功构建人源单链抗体噬菌体库,从中获得具有较高特异性的抗人肺癌单链抗体。

Construction of human phage display antibody ScFv library and identification of antibody ScFv against lung adenocarcinoma

Objective To construct a human phage single chain-antibody library, and to sieve out the antibody ScFv against lung cancer from the library. Methods Total RNA was abstracted from lymph node tissue of the lung cancer, and was used to amplify V_H and V_L gene by RT-PCR. V_H and V_L were joined by a DNA linker by SOE-PCR to form the single chain variable fragment ( ScFv) gene. ScFv gene was coloned into the phage vector pCANT-AB5E. Panning against lung cancer cell line A549 was performed and positive clones were chosen for soluble expression. Results A recombination phage single chain-antibody library was constructed. After 4 rounds panning, the number of eluted phages increased by 115 times. Positive reactions to A549 were detected in 7 of 10 random clones. The human ScFvs against lung cancer were produced and confirmed by SDS-PAGE and ELISA analysis. Conclusion ScFvs against lung cancer were acquired by the construction of phage single chain-antibody library. The soluble ScFvs has specificall avidity to human lung cancer cells.