title: Specific binding of HLA-B44 to human macrophage MHC receptor 1 on monocytes.
abstract: Allograft (H-2D(d)K(d))-induced macrophages (AIM) in C57BL/6 (H-2D(b)K(b)) mice exhibit major histocompatibility complex (MHC) haplotype-specific killing of allografts in a macrophage MHC receptor 1 (MMR1; for H-2D(d))- and MMR2 (for H-2K(d))-dependent manner. Recently, we showed HLA-B62 to be a ligand for the human homologue of mouse MMR2. In the present study, we isolated a cDNA encoding the human homologue of mouse MMR1 and found HLA-B44 to be the sole ligand specific for the human MMR1 by using beads that had been conjugated with 80 kinds of HLA proteins. Flow cytometric analyses revealed that HLA-B44-conjugated beads are specifically bound to HEK293T cells expressing human MMR1, that HLA-B44 tetramers are bound to the human MMR1-transfected HEK293T cells with a dissociation constant of 3.0×10(-9) M, and that the interaction was completely inhibited by the addition of R15 monoclonal antibody specific for mouse MMR1. The MMR1 cDNA (1537-bp) encoded a 473-amino acid polypeptide and was expressed at least in part in the brain and peripheral blood mononuclear cells (PBMCs) or monocytes, but not in granulocytes or lymphocytes. PBMCs from 7 non-H-2D(d) (non-self), but none from 5 H-2D(d) (self), in-bred mice expressed mouse MMR1 specific for H-2D(d). In contrast, PBMCs from none of the 16 human volunteers expressed HLA-B44; whereas those from only 3 of these 16 volunteers expressed human MMR1. These results reveal that human MMR1 on monocytes is a novel receptor specific for HLA-B44.
authors.affiliation: Department of Physiology, Osaka Medical College, Takatsuki, Osaka-fu 569-8686, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Tashiro-Yamaji
authors.forename: Tetsunosuke
authors.initials: T
authors.lastname: Shimizu
authors.forename: Michihiro
authors.initials: M
authors.lastname: Hayashi
authors.forename: Hidenori
authors.initials: H
authors.lastname: Yamana
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Tanigawa
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Uchiyama
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kubota
authors.forename: Ryotaro
authors.initials: R
authors.lastname: Yoshida
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000276:immunology; D057809:HEK293 Cells; D059948:HLA-B44 Antigen / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009000:Monocytes / Q000276:immunology*; D011971:Receptors, Immunologic / Q000737:chemistry / Q000235:genetics / Q000276:immunology*
chemical_list: D059948:HLA-B44 Antigen; D011971:Receptors, Immunologic; C573592:macrophage MHC receptor 1, human