Biochemical nature of an Fcμ receptor on human B-lineage cells

• Type of Material: Article
• Authors: Tatsuharu Ohno, University of Alabama at Birmingham; Hiromi Kubagawa, University of Alabama at Birmingham; Sheila K. Sanders, Yale University; Max Cooper, Emory University
• Language: English
• Date: 1990-10-01
• Publisher: Rockefeller University Press
• Publication Version: Final Published Version
• Copyright Statement: © Rockefeller University Press.
• Final Published Version (URL): http://dx.doi.org/10.1084/jem.172.4.1165
• Title of Journal or Parent Work: Journal of Experimental Medicine
• ISSN: 0022-1007
• Volume: 172
• Issue: 4
• Start Page: 1165
• End Page: 1175
• Grant/Funding Information: This work was supported by grants CA-16673, CA-13148, and AI-18745 from the National Institutes of Health.
• Keywords: Research & Experimental Medicine; Life Sciences & Biomedicine; Immunology; Science & Technology
• Research Categories: Health Sciences, Immunology; Chemistry, Biochemistry; Biology, Microbiology

Abstract

An IgM-binding protein of ∼60 kD has been identified on activated B cells, but not on resting and activated T cells, monocytes, or granulocytes. Here, we characterize this IgM-binding protein as a receptor for the Fc portion (CH3 and/or CH4 domains) of IgM molecules (FcμR). The FcμR can be expressed as a cell surface activation antigen throughout the pre-B and B cell stages in differentiation. Receptor expression is not directly linked with IgM production, as both μ- preB cells and isotype-switched B cells may express the FcμR. The receptor molecules produced by both pre-B and B cells are identical in size and are characterized as an acidic sialoglycoprotein with O-linked, but no N-linked, oligosaccharide. The FcμR is anchored to the surface of B-lineage cells via a glycosyl phosphatidylinositol linkage. The FcμR is thus the third member of a family of Fc receptors expressed on B-lineage cells, and its preferential expression on activated B cells suggests a potential role in the response to antigens.