Immunoglobulin G (IgG) is one of the most abundant proteins in human serum which constitutes 75% of serum immunoglobulins. IgG is produced by B Iymphocytes as a part of our adaptive immune response.The IgG molecule has two separate functions:to bind to the pathogen that elicited the response and to recruit other cells and molecules to destroy the antigen through Antibody-dependent cell-mediated cytotoxicity (ADCC) effection.