title: Cellular distribution, regulation, and biochemical nature of an Fc alpha receptor in humans.
abstract: In these studies, we characterize an Fc receptor (FcR) for IgA that is present on human granulocytes, monocyte/macrophages, and their corresponding cell lines. Receptor expression appears to be constitutive but can be selectively upregulated on monocyte cell lines by stimulation with a phorbol ester and polymeric IgA. Both the induction requirements and ligand specificity of the IgA receptor differ from the IgG receptors, Fc gamma R I, II, and III, that are also expressed on monocytes and granulocytes. IgA binding to the cell surface receptor is mediated via the Fc alpha region. The Fc alpha R is a heterogenously charged, approximately 60-kD molecule with an isoelectric point of 4.5-5.6 that binds monomeric or polymeric IgA1 and IgA2 molecules. This transmembrane glycoprotein appears to be composed of 32- and 36-kD protein cores with multiple N-linked carbohydrate moieties. We conclude that this Fc alpha R represents a novel member of the FcR family that may have a distinctive role in host defense.
authors: Department of Medicine, University of Alabama, Birmingham 35294.
authors: R C
authors: RC
authors: Monteiro
authors: H
authors: H
authors: Kubagawa
authors: M D
authors: MD
authors: Cooper
mesh_terms: D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000032:analysis; D002460:Cell Line; D006098:Granulocytes / Q000032:analysis; D006801:Humans; D007070:Immunoglobulin A / Q000378:metabolism* / Q000494:pharmacology; D009000:Monocytes / Q000032:analysis; D011961:Receptors, Fc / Q000032:analysis* / Q000378:metabolism; D017452:Receptors, IgG; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; C036832:Fc(alpha) receptor; D007070:Immunoglobulin A; D011961:Receptors, Fc; D017452:Receptors, IgG; C034639:polymeric IgA; D013755:Tetradecanoylphorbol Acetate