High affinity immunoglobulin gamma Fc receptor I (CD64) (CD64)

High affinity immunoglobulin gamma Fc receptor I (CD64) is a 72 kDa transmembrane glycoprotein that serves as the only high-affinity receptor for the Fc portion of IgG in humans (UniProt: P12314). It is constitutively expressed on monocytes and macrophages and can be induced on neutrophils by pro-inflammatory cytokines like interferon-gamma (PubMed: 25535381). The CD64–antibody-coated tumor cell interface is a critical site for therapeutic intervention, where CD64-expressing myeloid cells recognize tumor cells opsonized by monoclonal antibodies (PubMed: 10449301). This interaction facilitates antibody-dependent cellular phagocytosis (ADCP) and the subsequent presentation of tumor-derived antigens to T cells, thereby linking innate and adaptive immunity (PubMed: 15549731). In oncology, bispecific antibodies like MDX-H210 have been developed to bridge CD64 directly to tumor antigens, bypassing the need for natural antibody opsonization to enhance anti-tumor efficacy (PubMed: 9212098). Beyond cancer, CD64 serves as a highly sensitive biomarker for systemic inflammation and bacterial infection, particularly when expressed on neutrophils (StatPearls: NBK554562).

Other names

Fc-gamma RIFCGR1AFCGR1CD64 antigenIgG Fc receptor I

Binding of the Fc region of IgG antibodies to CD64 on effector cells (macrophages/monocytes) triggers intracellular signaling via the common gamma chain ITAM, leading to the phagocytosis or lysis of antibody-coated tumor cells.