IgG Subclass-independent Improvement of Antibody-dependent Cellular Cytotoxicity by Fucose Removal from Asn297-linked Oligosaccharides

Fucose depletion from oligosaccharides of human IgG1-type antibodies results in a great enhancement of antibody-dependent cellular cytotoxicity (ADCC). The aim of this study was to clarify the effect of fucose removal on effector functions of all human IgG subclasses. A panel of anti-CD20 chimeric antibodies having a matched set of human heavy chain subclasses with different fucose contents in their oligosaccharides was constructed using wild-type and fucosyltransferase-knockout Chinese hamster ovary cells as host cells. As found previously for IgG1, fucose-negative variant of IgG2, IgG3, and IgG4 exhibited enhanced ADCC and FcgammaRIIIa binding compared with their highly fucosylated counterparts. In contrast, fucose removal did not affect complement-dependent cytotoxicity (CDC) of any IgGs. Consequently, fucose removal from IgG2 and IgG4 resulted in a unique effector function profile; they had potent ADCC and no CDC. In conclusion fucose depletion can provide a panel of IgGs with enhanced ADCC without an impact on other inherent properties specific for each IgG subclass, such as CDC.