Fc receptors and complement components

Fc receptors and complement components represent the primary effector arms of the humoral immune system. Fc receptors (FcRs) are cell-surface glycoproteins, such as FcγR and the neonatal Fc receptor (FcRn), that bind the crystallizable fragment (Fc) of antibodies to mediate processes like phagocytosis, cytokine release, and the regulation of antibody half-life (1). The complement system consists of a proteolytic cascade of plasma proteins that, when activated, lead to the formation of the membrane attack complex (MAC), opsonization of pathogens, and recruitment of inflammatory cells (2). Together, these systems are critical for clearing infections but are also implicated in the pathogenesis of autoimmune and inflammatory diseases when dysregulated (3). Therapeutic strategies include inhibiting specific complement proteins (e.g., C5) to treat hemolytic disorders or targeting Fc receptors (e.g., FcRn) to accelerate the clearance of pathogenic autoantibodies in conditions like myasthenia gravis (4).

Other names

FcRComplement systemEffector systemsHumoral effector arms

Complement C5 inhibition, Complement C3 inhibition, Neonatal Fc receptor (FcRn) antagonism, C5a receptor antagonism, and Fc-mediated effector function enhancement.