Genetically engineered antibodies targeting human liver cancer cells

Abstract

This study involves the genetic engineering of a monoclonal antibody mAb-95 and the construction of a single chain fragment (scFv) antibody molecule (scFv95), both of which target human hepatocellular carcinoma (HCC). The mAb-95 was raised with crude membrane fragments of a human liver cancer cell line. Its specificity was confirmed by solid phase ELISA analysis, indirect immunostaining and immuno-gold labeling assays. To construct the scFv95, variable regions of Immunoglobulin (IgG) genes of mAb-95 were inserted into a bacterial expression vector, then expressed and characterized. The scFv95 was shown to have a binding ability to HCC cells. Mutagenesis experiments indicated that complimentary determining region 3 (CDR3) was important in binding to HCC. In particular, position 99 in CDR3 of the heavy chain was found to be crucial for scFv95's ability to bind to HCC. All results indicate that mAb-95 itself and the genetically engineered scFv95 could potentially be used as targeting agents for HCC immunotherapy or immuno-detection