title: Fc alpha/mu receptor mediates endocytosis of IgM-coated microbes.
abstract: IgM is the first antibody to be produced in a humoral immune response and plays an important role in the primary stages of immunity. Here we describe a mouse Fc receptor, designated Fc alpha/microR, and its human homolog, that bind both IgM and IgA with intermediate or high affinity. Fc alpha/microR is constitutively expressed on the majority of B lymphocytes and macrophages. Cross-linking Fc alpha/microR expressed on a pro-B cell line Ba/F3 transfectant with soluble IgM or IgM-coated microparticles induced internalization of the receptor. Fc alpha/microR also mediated primary B lymphocyte endocytosis of IgM-coated Staphylococcus aureus. Thus, Fc alpha/microR is involved in the primary stages of the immune response to microbes.
authors.affiliation: Department of Immunology, Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, Japan. ashibuya@md.tsukuba.ac.jp
authors.forename: A
authors.initials: A
authors.lastname: Shibuya
authors.forename: N
authors.initials: N
authors.lastname: Sakamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Shimizu
authors.forename: K
authors.initials: K
authors.lastname: Shibuya
authors.forename: M
authors.initials: M
authors.lastname: Osawa
authors.forename: T
authors.initials: T
authors.lastname: Hiroyama
authors.forename: H J
authors.initials: HJ
authors.lastname: Eyre
authors.forename: G R
authors.initials: GR
authors.lastname: Sutherland
authors.forename: Y
authors.initials: Y
authors.lastname: Endo
authors.forename: T
authors.initials: T
authors.lastname: Fujita
authors.forename: T
authors.initials: T
authors.lastname: Miyabayashi
authors.forename: S
authors.initials: S
authors.lastname: Sakano
authors.forename: T
authors.initials: T
authors.lastname: Tsuji
authors.forename: E
authors.initials: E
authors.lastname: Nakayama
authors.forename: J H
authors.initials: JH
authors.lastname: Phillips
authors.forename: L L
authors.initials: LL
authors.lastname: Lanier
authors.forename: H
authors.initials: H
authors.lastname: Nakauchi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D001402:B-Lymphocytes / Q000276:immunology; D001483:Base Sequence; D019556:COS Cells; D002417:Cattle; D002460:Cell Line; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D004705:Endocytosis; D006801:Humans; D007070:Immunoglobulin A / Q000378:metabolism; D007075:Immunoglobulin M / Q000378:metabolism*; D066298:In Vitro Techniques; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D051381:Rats; D011961:Receptors, Fc / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013211:Staphylococcus aureus / Q000276:immunology; D014162:Transfection
chemical_list: D015703:Antigens, CD; D017931:DNA Primers; C036832:Fc(alpha) receptor; D007070:Immunoglobulin A; D007075:Immunoglobulin M; D011961:Receptors, Fc; C035311:immunoglobulin M receptor