Immunoglobulin G (IgG)'s a monomeric immunoglobulin, built of two heavy chains γ and two light chains. Each IgG has two antigen binding sites. It's the most abundant immunoglobulin and's approximately equally distributed in blood and in tissue liquids, constituting 75% of serum immunoglobulins in humans. IgG molecules are synthesised and secreted by plasma B cells. Functions IgG antibodies are predominately involved in the secondary antibody response, (the main antibody involved in primary… (More on Igg)