The therapeutic anti-cancer potential of antibodies with decreased fucosylation has been well recognized and their power is currently being harnessed in clinical trials. As the long-term pioneer as well as market leader in the field of therapeutic antibody development, Creative Biolabs has been devoted to optimizing and maximizing the clinical efficacy of therapeutic antibodies based on multiple approaches. One of the most effective strategies is the engineering of therapeutic antibodies fully lacking core fucose residue in the Fc oligosaccharides.
Therapeutic antibody IgG1 has two N-linked oligosaccharide chains that bind to the Fc region. Oligosaccharides have a complex biantennary type composed of a trimannosyl core structure with or without the presence of core fucose, a halved N-acetylglucosamine (GlcNAc), galactose and terminal sialic acid, which gives rise to structural heterogeneity.
Antibody-dependent cellular cytotoxicity (ADCC) is a solvative attack on antibody-targeted cells that have been found to be one of the key effector functions leading to the clinical efficacy of therapeutic antibodies. ADCC is triggered after binding of the lymphocyte receptor (FcγR) to the Fc region of the antibody, after which immune effector cells are recruited to lyse target cells via release of cytotoxic factors. Decreased fucosylation or non-fucosylation of Asn-297 has been shown to increase the binding affinity of antibodies to CD16 (FcγRIIIa) on natural killer cells and ultimately increase ADCC potency. Crystal structure analysis revealed that this was attributed to a subtle conformational change in a limited region of IgG-Fc and that the high affinity of antibodies lacking fucose residues for FcγRIIIa was mediated by interactions formed between the carbohydrate at FcγRIIIa Asn-162 and regions of the Fc that are only accessible when the Fc N-glycans lack fucose residues.
Afucosylated therapeutic antibodies show more potent potency in vitro and in vivo than their fucosylated counterparts. Therefore, the use of afucosylated antibodies is expected to be a powerful and elegant method of designing next-generation therapeutic antibodies with improved efficacy. Thus, an industrially applicable antibody production method that provides consistent yields of fixed-quality, afucosylated therapeutics antibodies has been the key goal in the successful development of next-generation therapeutics.
Fig. 1 The effect of fucosylated therapeutic antibody-induced ADCC in human blood. (Yamane-Ohnuki, 2009)
Different methods have been developed to achieve the production of relatively high non-fucosylated therapeutics. These include (i) the conversion of N-glycosylation pathway of nonmammalian cells to the ‘humanized’ non-fucosylation pathway; (ii) inactivation of the fucosylation pathway of mammalian cells; and (iii) in vitro chemoenzymatic engineering. At Creative Biolabs, we offer both host cell line engineering and chemoenzymatic remodeling methods.
Especially, we recommend our Magic™ Fucose Knockout Technology Platform to produce antibodies of non-fucosylated forms. Our platform is based on the inactivation the function of the α-1, 6-fucosyltransferase (FUT8) gene. FUT8 is the only α1,6-fucosyltransferase that transfers fucose via an α1,6 linkage to the innermost N-acetylglucosamine on N-glycans for core fucosylation. FUT8 knockout cell lines exhibit similar morphology, growth kinetics, and productivity to the parental cells, and are capable of stably producing homogeneous non-fucosylated antibodies.
Besides, we have developed our powerful Antibody GlycoOpitimize™ Platform for optimization of antibody glycosylation, including fucosylation, sialylation, galactosylation, etc.
Creative Biolabs is a leader in the field of therapeutic antibody development and has focused on Fc engineering for years. We have experienced experts and advanced platforms that are able to provide excellent services. If you are interested in our services, please contact us for more details.
Reference
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