Glycosylation of IgG-Fc antibodies determines biologic functions mediated through cellular Fc receptors (FcγR), the C1q component of the classical pathway of complement, mannan binding ligand (MBL) and the mannose receptor (MR). FcγR and C1 binding are dependent on core oligosaccharide structure, MBL and MR by terminal sugar residues (glycoforms).