Alexa Fluor® 488 Mouse Anti-Mouse CD64 Antibody (X54-5/7.1)

CD64, also known as Fc-gamma receptor I (FcγRI), is a 72-kDa type I transmembrane glycoprotein encoded by the FCGR1A gene on chromosome 1. It belongs to the immunoglobulin superfamily and is composed of three extracellular Ig-like C2-type domains, a single transmembrane region, and a short cytoplasmic tail that associates with the Fc receptor γ-chain containing an ITAM motif to mediate intracellular signaling. CD64 is constitutively expressed on monocytes, macrophages, and dendritic cells, and can be rapidly up-regulated on neutrophils by pro-inflammatory stimuli such as IFN-γ, LPS, or G-CSF. It functions as a high-affinity receptor for the Fc portion of IgG, particularly IgG1 and IgG3, enabling key immune processes including phagocytosis, antigen presentation, antibody-dependent cellular cytotoxicity (ADCC), and the release of reactive oxygen species and cytokines. Its expression is tightly linked to innate immune activation, making CD64 a sensitive biomarker for bacterial infections and inflammatory disorders such as sepsis and rheumatoid arthritis.