Fc gamma receptor and complement receptor (FcγR/CR)

Fc gamma receptors (FcγRs) and complement receptors (CRs) are critical surface proteins expressed on antigen-presenting cells (APCs), such as macrophages, dendritic cells, and B cells (Nimmerjahn & Ravetch, 2008, Nature Reviews Immunology). FcγRs specifically recognize the Fc portion of immunoglobulin G (IgG) antibodies, while CRs bind to fragments of the complement system, such as C3b and iC3b, that coat pathogens or immune complexes (Ricklin et al., 2010, Nature Immunology). Together, these receptors mediate the internalization of opsonized antigens, a process essential for efficient antigen processing and subsequent presentation to T cells (Guilliams et al., 2014, Nature Reviews Immunology). This interaction bridges the innate and adaptive immune systems, regulating the threshold for immune activation and the clearance of debris. In disease contexts, dysregulation of these receptors is linked to autoimmune disorders like systemic lupus erythematosus (SLE), where impaired immune complex clearance leads to tissue damage (Bournazos et al., 2017, Nature Reviews Rheumatology). Conversely, in oncology, many therapeutic monoclonal antibodies, such as Rituximab, rely on FcγR-mediated mechanisms like antibody-dependent cellular cytotoxicity (ADCC) to eliminate tumor cells (Wang et al., 2015, Frontiers in Immunology).

Other names

Fc-gamma receptorsComplement receptorsFcgammaRCRCD16CD32CD64CD35Complement receptor type 1Complement receptor type 3CD11b/CD18

Modulation of immune cell activation and phagocytosis through the binding of IgG Fc regions or complement-opsonized antigens, facilitating antigen uptake and processing.