The Role of Glycosylation in Therapeutic Antibodies

Comparison of orthogonal chromatographic and lectin-affinity microarray methods for glycan profiling of a therapeutic monoclonal antibody

“…All currently approved therapeutic mAbs are of the immunoglobulin G (IgG) isotype; glycoproteins which are Nglycosylated at a fully conserved and completely occupied site in each of the two C H 2 domains near the hinge of the Fc region [5][6][7][8][9][10][11]. Unlike the complex N-glycans of most membrane and secreted glycoproteins, those of IgG Fc are incomplete structures with varying amounts of branch N-acetylglucosamine and terminal galactose, and generally minimal sialylation.…”

“…Unlike the complex N-glycans of most membrane and secreted glycoproteins, those of IgG Fc are incomplete structures with varying amounts of branch N-acetylglucosamine and terminal galactose, and generally minimal sialylation. The glycan structures associated with this site are derived from a library of ∼35 mostly complex diantennary N-oligosaccharides, and few high-mannose or hybrid-type glycans [5][6][7][8][9][10][11][12][13][14][15][16]. The IgG glycoform portfolios of each mammalian species contain characteristic subsets/ratios of these structures [15,17,18].…”

“…These in turn are composite functions of the species, age/gender of the organism, the type of cell/tissue, individual clonal variation, the physiological state of the organism and state of differentiation of the cell, and other biological, environmental and physicochemical factors. It is the dynamic interactions of various genetic, epigenetic and other biological and environmental factors that accounts for responsive glycosylation variability [9,10,12,[23][24][25][26][27][28][29][30][31][32][33][34][35]. For example, the glycosylation of polyclonal IgG in vivo is altered during normal physiological changes such as aging [20,[36][37][38][39][40][41] and pregnancy [21,22,[42][43][44][45], and certain disease states such as rheumatoid arthritis [6,8,12,[46][47][48] and systemic inflammation [11,49,50].…”

“…IgG plays important roles in both innate and adaptive immunities, in which the state of glycosylation provides the capacity to regulate the intrinsic underlying IgG functions through glycandependent structural effects in the receptor-binding regions of the hinge/C H 2 and C H 2/C H 3 domains [6][7][8]10,11,51]. These IgG glycoform conformational variants differentially interact with the Fc␥Rs and other receptors variously expressed on immune cells and other cells throughout the body.…”

“…These IgG glycoform conformational variants differentially interact with the Fc␥Rs and other receptors variously expressed on immune cells and other cells throughout the body. Therefore, the absence or modification of Fc glycans can profoundly affect the therapeutic performance of mAbs by modulation or loss of intended functions, greater immunogenicity, and unfavourable pharmacokinetic profiles [6][7][8][9][10][11]14,[51][52][53][54].…”