Fucose removal from complex-type oligosaccharide enhances the antibody-dependent cellular cytotoxicity of single-gene-encoded bispecific antibody comprising of two single-chain antibodies linked to the antibody constant region.

摘要

Bispecific antibodies (bsAbs) have the potential to extend binding selectivity, increase avidity and exert potent cytotoxicity due to the combination of dual specificities. scFv2-Fc type of single-gene-encoded bispecific antibody, composed of two different single-chain Fvs and an Fc, has been reported to be capable of binding to different antigens. The aim of this study was to determine the effect of fucose removal on effector functions of scFv2-Fc since fucose depletion from oligosaccharide of human IgG1 and scFv-Fc results in significant enhancement of ADCC. We generated novel single-gene-encoded bsAb with dual specificity against tumor associated glycoprotein (TAG)-72 and MUC1 mucin as fucose-negative scFv2-Fc from alpha-1,6-fucosyltransferase knock-out CHO cells and a highly fucosylated scFv2-Fc comparator from parental CHO cells. Expression, assembly and the antigen-binding activity of the scFv2-Fc were not influenced by removal of fucose. The fucose negative scFv2-Fc bound with higher avidity to FcgammaRIIIa and enhanced ADCC compared to the highly fucosylated scFv2-Fc. These results demonstrate that ADCC-enhancement by removal of fucose is effective in not only whole IgG1 and scFv-Fc, but also scFv2-Fc targeting two different antigens, and thus increases the potential of fucose-negative scFv2-Fcs as novel therapeutic candidates.