N-glycosylation, as one of the most complex post-translational modification, influences the structural characteristics of the antibody Fc part, thereby potentially modulating effector function and pharmacokinetics. As the long-term pioneer as well as market leader in the field of therapeutic antibody development, Creative Biolabs has successfully established and commercialized a wide spectrum of functional assays to illustrate antibody bioactivity and its mechanism of action. Particularly, we offer this unique opportunity for our worldwide customers to adopt impeccable Fc engineering services.
Glycosylation, the attachment of a sugar moiety to a given protein backbone, is a largely conservative post-translational modification in multicellular organisms. In humans, it is estimated that more than 50% of proteins are glycosylated. In particular, serum glycoproteins form a heterogeneous glycosylation mixture of other homologous protein backbones. The Fc region of IgG1 contains a conserved N-glycosylation site at Asn297 of each CH2 domain. Variations in the structure of these glycans lead to subtle changes in structure that have a significant impact on the interaction of IgG with the immune system. The remarkable success of therapeutic applications of IgG in the form of monoclonal antibodies and pooled IgG formulations has raised concerns about such glycoproteins. It is generally believed that oligosaccharides attached to the Fc region play a key role in the biological activity of IgG. Therefore, glycosylation has become a focus of great interest in many fields which has been designed to optimize antibody products.
Fig.1 Types of N-glycans.1
Primarily mammalian cell lines have been used for the production of glycoengineered antibodies, but non-mammalian expression hosts such as yeast and plants genetically modified to allow for the production of antibodies with defined carbohydrate structures may be an option. In order to fully understand the different IgG activities, more than protein-protein interactions alone have to be considered. A single N-glycan residue significantly affects the biological activity of the mAb. Due to cost effectiveness, some non-mammalian cell lines have been used to produce therapeutic antibodies and they are highly tolerant of glycosylation engineering.
Creative Biolabs aims to humanize immunogenic glycoforms by eliminating enzymes responsible for the addition of non-mammalian glycans and subsequent introduction of mammalian glycan processing enzymes. Like mammalian cells, N-glycosylation of newly synthesized proteins in insects, yeasts, and plant cells is initiated by the oligosaccharyltransferase complex in the endoplasmic reticulum (ER), which transfers the oligosaccharide precursor Glc3Man9GlcNAc2 onto the growing polypeptide chain, more specifically, onto a suitable asparagine residue within the N-glycosylation consensus sequence (Asn-Xaa-Ser/Thr). Yeast- and plant-derived mAbs exhibit most of the uniform N-glycosylation profiles. Engineering of the respective pathways in non-mammalian expression hosts yielded significant results.
Creative Biolabs has professional teams and labs for conducting Fc engineering services. The efficiency and quality of our exhaustive service have always been satisfying, with highly reproducible and reliable results obtained at the most competitive prices. Besides, we can provide immunogenicity detection service and Fc-mediated effector functional assays using our elegant Antibody GlycoOpitimize™ Platform. For more detailed information, please feel free to contact us or directly send us an inquiry.
Reference
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