Construction and expression of pGEX-e23 (scFv) PE40 in Escherichia coli

AIM To express a immunotoxin consisting of a single chain variable fragment (scFv) specific for human oncogene c- erb B-2 product, p185 and Pseudomonas exotoxin (PE40), named e23 (scFv) PE40, in Escherichia coli which could be used as an adjuvant therapy agent in breast cancer, gastric cancer and other malignant tumor overexpressing c- erb B-2. METHODS e23 (scFv) PE40 fusion gene for prokaryotic expression was constructed and inserted into a prokaryotic fusion protein expression vector pGEX-4T and expressed in Escherichia coli DH5α. RESULTS The DNA sequence of e23 (scfv) PE40 fusion gene was correct. A new anticipated M r 90 000-protein band appeared on SDS-PAGE gel induced by IPTG and amounted to 15% of the total bacterial protein. CONCLUSION Fusion gene of e23 (scFv) PE40 has been successfully constructed and expressed in Escherichia coli DH5α.