title: Functional characterization of HLA-F and binding of HLA-F tetramers to ILT2 and ILT4 receptors.
abstract: HLA-F is a human non-classical MHC molecule. Recombinant HLA-F heavy chain was refolded with 2-microglobulin to form a stable complex. This complex was used as an immunogen to produce a highly specific, high-affinity monoclonal antibody (FG1) that was used to study directly the cellular biology and tissue distribution of HLA-F. HLA-F has a restricted pattern of tissue expression in tonsil, spleen, and thymus. HLA-F could be immunoprecipitated from B cell lines and from HUT-78, a T cell line. HLA-F binds TAP, but unlike the classical human class I molecules, was undetected at the cell surface. HLA-F tetramers stain peripheral blood monocytes and B cells. HLA-F tetramer binding could be conferred on non-binding cells by transfection with the inhibitory receptors ILT2 and ILT4. Surface plasmon resonance studies demonstrated a direct molecular interaction of HLA-F with ILT2 and ILT4. These results, together with structural predictions based on the sequence of HLA-F, suggest that HLA-F may be a peptide binding molecule and may reach the cell surface under favorable conditions, which may include the presence of specific peptide or peptides. At the cell surface it would be capable of interacting with LIR1 (ILT2) and LIR2 (ILT4) receptors and so altering the activation threshold of immune effector cells.
authors.affiliation: Centre for Nephrology, Royal Free and University College Medical School, University College London, London, GB.
authors.forename: E J
authors.initials: EJ
authors.lastname: Lepin
authors.forename: J M
authors.initials: JM
authors.lastname: Bastin
authors.forename: D S
authors.initials: DS
authors.lastname: Allan
authors.forename: G
authors.initials: G
authors.lastname: Roncador
authors.forename: V M
authors.initials: VM
authors.lastname: Braud
authors.forename: D Y
authors.initials: DY
authors.lastname: Mason
authors.forename: P A
authors.initials: PA
authors.lastname: van der Merwe
authors.forename: A J
authors.initials: AJ
authors.lastname: McMichael
authors.forename: J I
authors.initials: JI
authors.lastname: Bell
authors.forename: S H
authors.initials: SH
authors.lastname: Powis
authors.forename: C A
authors.initials: CA
authors.lastname: O'Callaghan
mesh_terms: D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005260:Female; D006680:HLA Antigens / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D015395:Histocompatibility Antigens Class I / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D000075362:Leukocyte Immunoglobulin-like Receptor B1; D008562:Membrane Glycoproteins; D051379:Mice; D008807:Mice, Inbred BALB C; D017510:Protein Folding; D011971:Receptors, Immunologic / Q000378:metabolism*; D001613:beta 2-Microglobulin / Q000737:chemistry
chemical_list: D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters; D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D006680:HLA Antigens; C062341:HLA-F antigens; D015395:Histocompatibility Antigens Class I; C105299:LILRB1 protein, human; C491341:LILRB2 protein, human; D000075362:Leukocyte Immunoglobulin-like Receptor B1; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; C073119:TAP1 protein, human; C486171:Tap1 protein, mouse; D001613:beta 2-Microglobulin