Cellular distribution, regulation, and biochemical nature of an Fcα receptor in humans

• Published in: The Journal of experimental medicine Vol. 171; no. 3; pp. 597 - 613
• Main Authors: MONTEIRO, R. C, KUBAGAWA, H, COOPER, M. D
• Format: Journal Article
• Language: English
• Published: New York, NY Rockefeller University Press 01.03.1990; The Rockefeller University Press
• Subjects: Antigens, CD; Antigens, Differentiation - analysis; Biological and medical sciences; Cell Line; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Granulocytes - analysis; Humans; Immunobiology; Immunoglobulin A - metabolism; Immunoglobulin A - pharmacology; Monocytes - analysis; Myeloid cells: ontogeny, maturation, markers, receptors; Receptors, Fc - analysis; Receptors, Fc - metabolism; Receptors, IgG; Tetradecanoylphorbol Acetate - pharmacology; Human; Flow cytometry; IgA; Immunoglobulins; Monocyte; Molecular weight determination; Gel electrophoresis; Granulocyte; Glycoproteins; Immunoprecipitation reaction; Membrane receptor; Isoelectrical focusing; Fc-Fragment; Cell population; Distribution; Immunofluorescence; Macrophage
• ISSN: 0022-1007; 1540-9538
• DOI: 10.1084/jem.171.3.597

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.