Ultra-LEAF™ Purified anti-mouse CD64 (FcγRI) Antibody, CD64, W18349F,BioLegend,941904

FcγRI, also known as CD64 and FcR I, is a type I transmembrane protein, belonging to the immunoglobulin superfamily. FcγRI is an Fc receptor that binds to monomeric IgG with high affinity. Human FcγRI binds to human IgG1, IgG3 and IgG4 with higher affinity, but no affinity for IgG2. However, murine FcγRI only binds to mouse IgG2a with high affinity, but it binds to mouse IgG2b and IgG3 with low affinity and no affinity for mouse IgG1. Upon binding to IgG, FcγRI associates with signal-transducing FcR common γ chain, and in turn conducts downstream signaling. Though Fc γ chain is dispensable to FcγRI ligand-binding capacity, the surface expression of FcγRI and signaling are impaired in Fc γ chain-deficient cells. FcγRI is exclusively expressed on myeloid cells, including monocytes/macrophages, dendritic cells, and inducible on neutrophils and mast cells. The expression can be upregulated by IFN-γ, IL-10 and G-CSF stimulation. Several studies demonstrated that FcγRI plays a role in antigen capture, IgG-induced cellular phagocytosis and antibody-dependent cellular cytotoxicity (ADCC). In FcγRI-deficient mouse macrophages, the IgG2a-induced phagocytosis and antibody-mediated killing were impaired. In addition, acute and chronic inflammatory responses and immune complex-dependent antigen presentation to primed T cells were disturbed in FcγRI-deficient mice.