Multiple antigens and Fc receptors

Multiple antigens and Fc receptors refers to the collective set of molecular entities targeted by intravenous immunoglobulin (IVIG) and other polyclonal antibody preparations (DrugBank DB00073). The multiple antigens component represents the diverse array of pathogens, toxins, and autoantigens recognized by the variable regions (Fab) of the pooled antibodies, providing broad-spectrum neutralization and opsonization (StatPearls, IVIG). The Fc receptors component includes the family of cell surface proteins, such as FcγRI (CD64), FcγRII (CD32), and FcγRIII (CD16), as well as the neonatal Fc receptor (FcRn), which bind the constant region (Fc) of the antibodies (UniProt). These interactions mediate critical immunomodulatory effects, including the blockade of activating receptors on macrophages, the induction of inhibitory signaling through FcγRIIB, and the regulation of IgG half-life via FcRn saturation. This multi-faceted targeting is essential for the treatment of primary immunodeficiencies and various autoimmune and inflammatory conditions, such as immune thrombocytopenic purpura (ITP) and chronic inflammatory demyelinating polyneuropathy (CIDP).

Other names

IVIG targetsImmune globulin targetsPolyclonal immunoglobulin targetsFc gamma receptors and diverse antigens

The mechanism involves the neutralization of pathogens and toxins by Fab regions and the modulation of immune responses via Fc region binding to Fc receptors (FcγRs) and the neonatal Fc receptor (FcRn). This includes blocking activating Fc receptors on macrophages to prevent cell destruction, inducing inhibitory signaling through FcγRIIB, and accelerating the clearance of pathogenic autoantibodies by saturating FcRn.