Immunoglobulin G3 (IgG3) is a member of many immunoglobulin G developed and secreted by effective B cells. In wake of cutting by pepsin, IgG is divided into two F(ab)s with one antigen binding site and a high conserved Fc segment. The Fc segment bears a highly conserved N-glycosylation site. Ig gamma-3 chain C region (IgG3-Fc / IGHG3) contains two constant regions of IgG3 H chain (CH2, CH3).