Objective To study the prokaryotic expression of the anti-tumor associated glycoprotein-72 (TAG-72) singlechain fragment variable (scFv) antibody and its specific affinity to hepatocellular carcinoma cell lines and tissues. Methods The cDNA of anti-TAG-72 scFv antibody was inserted into pCANTAB5E to obtain phage vector anti-TAG-72 -scFv-pCANTAB5E. Isopropyl-β-D-thiogalactoside (IPTG) was used to induce the expression of anti-TAG-72 scFv antibody. SDS-PAGE and Western blot were used to identify the anti-TAG-72 scFv antibody. Human hepatocellular carcinoma cells were cultured, and TAG-72 was determined with the obtained scFv by immunohistochemistry in the cells and paraffin-embedded hepatocellular carcinoma tissues. Results SDS-PAGE and Western blot showed that the anti-TAG-72-scFv antibody was successfully expressed. Anti-TAG-72 scFv could bind to hepatocellular carcinoma cell lines SMMC7721, HepG2, and HHCC, but not to BEL7402, suggesting that SMMC7721, HepG2, and HHCC cells expressed TAG-72. For the 40 cases of hepatocellular carcinoma tissues, the positive rate of TAG-72 in stage Ⅰ and Ⅱ-Ⅲ was 23.08% (3/13) and 62.96%(17/27), respectively. While no TAG-72 expression was found in the 10 normal cases. TAG-72 expression was significantly different between hepatocellular carcinomas and normal tissues (Plt;0.05). Conclusions The prokaryotic expression of anti-TAG-72 scFv antibody is successfully achieved, and can be used to identify TAG-72 antigen. TAG-72 is highly expressed in hepatocellular carcinoma, but not in normal liver tissue, which may be suggested as cancer marker of hepatocellular carcinoma.
