>95%, by SDS-PAGE under reducing conditions
Fc γ RIV (Low affinity immunoglobulin gamma Fc region receptor IV), also known as CD16-2 (Fc γ RIV), belongs to the Fc γ receptor family. Fc γ receptors can be divided into three types: Fc γ RI (CD64), Fc γ RII (CD32) and Fc γ RIII (CD16). Fc γ RI (CD64) has a high affinity for IgG monomers, while Fc γ RII (CD32) and Fc γ RIII (CD16) have relatively low affinity for IgG. Human CD16 is encoded by two genes, Fc γ RIIIA and Fc γ RIIIB. The gene sequence of CD16-2 is more similar to human Fc γ RIIIA protein. Fc γ RIV binding with IgG2a can promote osteocyte differentiation, while binding with IgE can promote macrophage-mediated phagocytosis, antigen presentation and pro-inflammatory cytokines production.