IgG

Jamshed Arslan, Pharm D, PhD

By Jamshed Arslan, Pharm D, PhD

CD16 is a lymphocyte Fc gamma type III low-affinity receptor for IgG and is represented by two similar genes, CD16A (Fc gamma RIII A) and CD16B (Fc gamma RIIIB). CD16A exists as a heterooligomeric polypeptide-anchored form in macrophages and NK cells. CD16B exists as a monomeric glycosylphosphatidylinositol (GPI)-anchored form in neutrophils. CD16 binds IgG in the form of immune complexes or free antibody. It exhibits preferential binding to IgG1 and IgG3 isotypes, with minimal binding of IgG2 and IgG4.

Human IgG is a component of the immune system that protects the body from infection. It is the most abundantly found antibody isotype within the circulatory system of the human body. All antibody isotypes contain two heavy chains and two light chains that are arranged in a Y-shape.