Cloning, expression and characterization of a single-chain antibody PS-9 targeted to pancreatic cancer.

Genes encoding single-chain antibodies have been first constructed, which consist of the heavy and light chain variable domains of antibody PS-9 joined together by a flexible peptide linker. The genes were cloned into coat protein g3p genes of pCANTAB5 phagemids, and expressed as fusion proteins on the phage tips. Immunological assay demonstrated that the engineered antibodies specifically bound to cancer cells LS-174-T as well as to pure bovine submaxillary gland mucin. Their specificity and affinity appeared the same as their parent antibodies. Our results supposed that the single-chain antibodies will be a target for the diagnosis and treatment of cancer.