Fused expression of anti-CEA single-chain antibody gene with core-streptavidin gene in insect cells

A fused construct formed by an anti-CEA single-chain antibody gene with a core-streptavidin gene (ScFv-CS)was inserted into the donor plasmids pFastBacHTa and expressed in Tn-5B1-4 cells. SDS-PAGE analysis revealed that the molecular weight expressed product of ScFv-CS were 41 kD, Using horseradish peroxidase (HRP) labeled biotin as antibody product Western blot, one band of 41 kD only was detected. It was also shown by RIA that the expression product possessed the ability to bind to its specific antigen of CEA. These results showed that the fusion protein not only had the ability to bind CEA, but also could bind biotin specifically.