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Anjuère F, Bekri S, Bihl F, Braud VM, Cuburu N, Czerkinsky C, Hervouet C, Luci C. B cell and T cell immunity in the female genital tract: potential of distinct mucosal routes of vaccination and role of tissue-associated dendritic cells and natural killer cells. Clin Microbiol Infect 2012; 18 Suppl 5:117-22. [PMID: 22882377 DOI: 10.1111/j.1469-0691.2012.03995.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The female genital mucosa constitutes the major port of entry of sexually transmitted infections. Most genital microbial pathogens represent an enormous challenge for developing vaccines that can induce genital immunity that will prevent their transmission. It is now established that long-lasting protective immunity at mucosal surfaces has to involve local B-cell and T-cell effectors as well as local memory cells. Mucosal immunization constitutes an attractive way to generate systemic and genital B-cell and T-cell immune responses that can control early infection by sexually transmitted pathogens. Nevertheless, no mucosal vaccines against sexually transmitted infections are approved for human use. The mucosa-associated immune system is highly compartmentalized and the selection of any particular route or combinations of routes of immunization is critical when defining vaccine strategies against genital infections. Furthermore, mucosal surfaces are complex immunocompetent tissues that comprise antigen-presenting cells and also innate immune effectors and non-immune cells that can act as 'natural adjuvants' or negative immune modulators. The functions of these cells have to be taken into account when designing tissue-specific antigen-delivery systems and adjuvants. Here, we will discuss data that compare different mucosal routes of immunization to generate B-cell and T-cell responses in the genital tract, with a special emphasis on the newly described sublingual route of immunization. We will also summarize data on the understanding of the effector and induction mechanisms of genital immunity that may influence the development of vaccine strategies against genital infections.
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Affiliation(s)
- F Anjuère
- CNRS, UMR7275 CNRS/UNS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France.
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Hook CE, Telyatnikova N, Goodall JC, Braud VM, Carmichael AJ, Wills MR, Gaston JSH. Effects of Chlamydia trachomatis infection on the expression of natural killer (NK) cell ligands and susceptibility to NK cell lysis. Clin Exp Immunol 2004; 138:54-60. [PMID: 15373905 PMCID: PMC1809177 DOI: 10.1111/j.1365-2249.2004.02596.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Natural killer (NK) cells are an important component of the immediate immune response to infections, including infection by intracellular bacteria. We have investigated recognition of Chlamydia trachomatis (CT) by NK cells and show that these cells are activated to produce interferon (IFN)-gamma when peripheral blood mononuclear cells (PBMC) are stimulated with CT organisms. Furthermore, infection of epithelial cell lines with CT renders them susceptible to lysis by human NK cells. Susceptibility was observed 18-24 h following infection and required protein synthesis by the infecting chlamydiae, but not by the host cell; heat or UV inactivated chlamydiae did not induce susceptibility to NK cell lysis. CT infection was also shown to decrease the expression of classical and non-classical major histocompatibility complex (MHC) molecules on infected cells, thus allowing recognition by NK cells when combined with an activating signal. A candidate activating signal is MICA/B, which was shown to be expressed constitutively on epithelial cells.
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Affiliation(s)
- C E Hook
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge UK
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Abstract
Cytotoxic T cells are major players in the immune defence against human cytomegalovirus (HCMV). The virus has, however, developed several mechanisms to escape from this control. In particular, it down-regulates cell surface expression of HLA class I molecules. Because natural killer (NK) cells recognize and eliminate cells that lack HLA class I molecules, HCMV-infected cells could be more susceptible to NK lysis. In this review, we discuss the role played by NK cells in immune defence against HCMV and we describe potential strategies the virus has developed to escape from NK cell-mediated lysis. We focus in particular on a newly described protein, HCMV gpUL40, that induces cell surface expression of HLA-E, a non-classical class I molecule known to regulate NK cell functions.
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Affiliation(s)
- V M Braud
- Centre National de la Recherche Scientifique, CNRS UMR 6097, Institut de Pharmacologie Moleculaire et Cellulaire, 660 Route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
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Lemberg MK, Bland FA, Weihofen A, Braud VM, Martoglio B. Intramembrane proteolysis of signal peptides: an essential step in the generation of HLA-E epitopes. J Immunol 2001; 167:6441-6. [PMID: 11714810 DOI: 10.4049/jimmunol.167.11.6441] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Signal sequences of human MHC class I molecules are a unique source of epitopes for newly synthesized nonclassical HLA-E molecules. Binding of such conserved peptides to HLA-E induces its cell surface expression and protects cells from NK cell attack. After cleavage from the pre-protein, we show that the liberated MHC class I signal peptide is further processed by signal peptide peptidase in the hydrophobic, membrane-spanning region. This cut is essential for the release of the HLA-E epitope-containing fragment from the lipid bilayer and its subsequent transport into the lumen of the endoplasmic reticulum via the TAP.
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Affiliation(s)
- M K Lemberg
- Institute of Biochemistry, Swiss Federal Institute of Technology (Eidgenössiche Technische Hochschule), Zurich, Switzerland
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Lepin EJ, Bastin JM, Allan DS, Roncador G, Braud VM, Mason DY, van der Merwe PA, McMichael AJ, Bell JI, Powis SH, O'Callaghan CA. Functional characterization of HLA-F and binding of HLA-F tetramers to ILT2 and ILT4 receptors. Eur J Immunol 2000; 30:3552-61. [PMID: 11169396 DOI: 10.1002/1521-4141(200012)30:12<3552::aid-immu3552>3.0.co;2-l] [Citation(s) in RCA: 160] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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.
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Affiliation(s)
- E J Lepin
- Centre for Nephrology, Royal Free and University College Medical School, University College London, London, GB
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King A, Allan DS, Bowen M, Powis SJ, Joseph S, Verma S, Hiby SE, McMichael AJ, Loke YW, Braud VM. HLA-E is expressed on trophoblast and interacts with CD94/NKG2 receptors on decidual NK cells. Eur J Immunol 2000. [PMID: 10898498 DOI: 10.1002/1521-4141(200006)30: 6<1623: : aid-immu1623>3.0.co; 2-m] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Non-classical MHC class I molecule HLA-E is the ligand for CD94/NKG2 NK cell receptors. Surface expression of HLA-E requires binding of specific HLA class I leader sequences. The uterine mucosa in early pregnancy (decidua) is infiltrated by large numbers of NK cells, which are closely associated with placental trophoblast cells. In this study we demonstrate that trophoblast cells express HLA-E on their cell surface in addition to the previously reported expression of HLA-G and HLA-C. Furthermore, we show that the vast majority of decidual NK cells bind to HLA-E tetrameric complexes and this binding is inhibited by mAb to CD94. Thus, recognition of fetal HLA-E by decidual NK cells may play a key role in regulation of placentation. The functional consequences of decidual NK cell interaction were investigated in cytotoxicity assays using polyclonal decidual NK cells. The overall effect of CD94/NKG2 interaction with HLA-E is inhibition of cytotoxicity by decidual NK cells. However, since decidual NK cells are unable to kill trophoblast even in the presence of mAb to MHC class I molecules and NK cell receptors, HLA-E interaction with CD94/NKG2 receptors may regulate other functions besides cytolysis during implantation.
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Affiliation(s)
- A King
- Department of Pathology, University of Cambridge.
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King A, Allan DS, Bowen M, Powis SJ, Joseph S, Verma S, Hiby SE, McMichael AJ, Loke YW, Braud VM. HLA-E is expressed on trophoblast and interacts with CD94/NKG2 receptors on decidual NK cells. Eur J Immunol 2000; 30:1623-31. [PMID: 10898498 DOI: 10.1002/1521-4141(200006)30:6<1623::aid-immu1623>3.0.co;2-m] [Citation(s) in RCA: 276] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Non-classical MHC class I molecule HLA-E is the ligand for CD94/NKG2 NK cell receptors. Surface expression of HLA-E requires binding of specific HLA class I leader sequences. The uterine mucosa in early pregnancy (decidua) is infiltrated by large numbers of NK cells, which are closely associated with placental trophoblast cells. In this study we demonstrate that trophoblast cells express HLA-E on their cell surface in addition to the previously reported expression of HLA-G and HLA-C. Furthermore, we show that the vast majority of decidual NK cells bind to HLA-E tetrameric complexes and this binding is inhibited by mAb to CD94. Thus, recognition of fetal HLA-E by decidual NK cells may play a key role in regulation of placentation. The functional consequences of decidual NK cell interaction were investigated in cytotoxicity assays using polyclonal decidual NK cells. The overall effect of CD94/NKG2 interaction with HLA-E is inhibition of cytotoxicity by decidual NK cells. However, since decidual NK cells are unable to kill trophoblast even in the presence of mAb to MHC class I molecules and NK cell receptors, HLA-E interaction with CD94/NKG2 receptors may regulate other functions besides cytolysis during implantation.
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Affiliation(s)
- A King
- Department of Pathology, University of Cambridge.
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Abstract
In this short review we examine the recently identified immunoglobulin-like transcript (ILT) family of receptors (also known as LIR and MIR). ILT are expressed by many leukocyte subsets, especially monocytic cells. Expression levels of certain ILT molecules allow definition of blood monocyte and dendritic cell (DC) subsets. Two receptors, ILT2 and ILT4, recognise a broad range of MHC class I molecules and transduce an inhibitory signal. Such recognition may give many cell lineages the potential to recognise and respond to MHC class I down-regulation.
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Affiliation(s)
- D S Allan
- Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK
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Tomasec P, Braud VM, Rickards C, Powell MB, McSharry BP, Gadola S, Cerundolo V, Borysiewicz LK, McMichael AJ, Wilkinson GW. Surface expression of HLA-E, an inhibitor of natural killer cells, enhanced by human cytomegalovirus gpUL40. Science 2000; 287:1031. [PMID: 10669413 DOI: 10.1126/science.287.5455.1031] [Citation(s) in RCA: 457] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The nonclassical major histocompatibility complex (MHC) class I molecule HLA-E inhibits natural killer (NK) cell-mediated lysis by interacting with CD94/NKG2A receptors. Surface expression of HLA-E depends on binding of conserved peptides derived from MHC class I molecules. The same peptide is present in the leader sequence of the human cytomegalovirus (HCMV) glycoprotein UL40 (gpUL40). It is shown that, independently of the transporter associated with antigen processing, gpUL40 can up-regulate expression of HLA-E, which protects targets from NK cell lysis. While classical MHC class I molecules are down-regulated, HLA-E is up-regulated by HCMV. Induction of HLA-E surface expression by gpUL40 may represent an escape route for HCMV.
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Affiliation(s)
- P Tomasec
- Department of Medicine, University of Wales College of Medicine, Cardiff CF14 4XN, UK
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Allan DS, Colonna M, Lanier LL, Churakova TD, Abrams JS, Ellis SA, McMichael AJ, Braud VM. Tetrameric complexes of human histocompatibility leukocyte antigen (HLA)-G bind to peripheral blood myelomonocytic cells. J Exp Med 1999; 189:1149-56. [PMID: 10190906 PMCID: PMC2193000 DOI: 10.1084/jem.189.7.1149] [Citation(s) in RCA: 205] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The nonclassical MHC class I molecule human histocompatibility leukocyte antigen (HLA)-G is selectively expressed on fetal trophoblast tissue at the maternal-fetal interface in pregnancy. It has long been suggested that HLA-G may inhibit maternal natural killer (NK) cells through interaction with particular NK cell receptors (KIRs). To investigate interactions of HLA-G, we constructed phycoerythrin-labeled tetrameric complexes of HLA-G refolded with a self-peptide. These HLA-G tetramers failed to bind to NK cells and cells transfected with CD94/NKG2 and killer immunoglobulin-like NK receptors. In contrast, HLA-G tetramers did bind to peripheral blood monocytes, staining a CD16(+)CD14(mid) subset with greater intensity. On transfectants, HLA-G tetramers bound to inhibitory immunoglobulin-like transcript (ILT)2 and ILT4 receptors. However, staining in the presence of antibodies reactive with ILT receptors revealed that the interaction of HLA-G tetramers with blood monocytes was largely due to binding to ILT4. These results suggest that the primary role of HLA-G may be the modulation of myelomonocytic cell behavior in pregnancy.
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Affiliation(s)
- D S Allan
- Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
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11
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Abstract
Fascinating recent discoveries have focused attention on the nonclassical class I molecules. They can exert their function at most levels of the immune response, being part of both innate and adaptive immune systems. They not only have specialized antigen-presentation functions but also play important immunoregulatory roles: HLA-E regulates natural killer cells by interacting with CD94/NKG2 receptors; the MIC (MHC class I chain related) glycoproteins appear crucial to the activation of gammadelta T cells in the gastrointestinal epithelium; HLA-G may play a role in controlling the immune response to the fetus; and CD1 molecules are important in defense against bacterial infections, as well as in the development and regulation of a subset of NKT cells expressing a highly restricted TCR repertoire; however not all nonclassical class I molecules have an immunological function, as demonstrated by HFE which is implicated in iron metabolism.
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Affiliation(s)
- V M Braud
- Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK.
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Braud VM, McMichael AJ. Regulation of NK cell functions through interaction of the CD94/NKG2 receptors with the nonclassical class I molecule HLA-E. Curr Top Microbiol Immunol 1999; 244:85-95. [PMID: 10453651 DOI: 10.1007/978-3-642-58537-1_7] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- V M Braud
- Institute of Molecular Medicine, Headington, Oxford, UK
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O'Callaghan CA, Tormo J, Willcox BE, Braud VM, Jakobsen BK, Stuart DI, McMichael AJ, Bell JI, Jones EY. Structural features impose tight peptide binding specificity in the nonclassical MHC molecule HLA-E. Mol Cell 1998; 1:531-41. [PMID: 9660937 DOI: 10.1016/s1097-2765(00)80053-2] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The crystal structure of the nonclassical human class lb MHC molecule HLA-E has been determined in complex with a prototypic ligand, the nonamer peptide (VMAPRTVLL), derived from the highly conserved residues 3-11 of the human MHC class la leader sequence. The mode of peptide binding retains some of the standard features observed in MHC class la complexes, but novel features imply that HLA-E has evolved to mediate specific binding to a tightly defined set of almost identical hydrophobic peptides from the highly conserved class l leader sequences. These molecular adaptations make HLA-E a rigorous checkpoint at the cell surface reporting on the integrity of the antigen processing pathway to CD94/NKG2 receptor-bearing natural killer cells.
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Affiliation(s)
- C A O'Callaghan
- Nuffield Department of Clinical Medicine, University of Oxford, John Radcliffe Hospital, United Kingdom
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Braud VM, Allan DS, O'Callaghan CA, Söderström K, D'Andrea A, Ogg GS, Lazetic S, Young NT, Bell JI, Phillips JH, Lanier LL, McMichael AJ. HLA-E binds to natural killer cell receptors CD94/NKG2A, B and C. Nature 1998; 391:795-9. [PMID: 9486650 DOI: 10.1038/35869] [Citation(s) in RCA: 1610] [Impact Index Per Article: 61.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The protein HLA-E is a non-classical major histocompatibility complex (MHC) molecule of limited sequence variability. Its expression on the cell surface is regulated by the binding of peptides derived from the signal sequence of some other MHC class I molecules. Here we report the identification of ligands for HLA-E. We constructed tetramers in which recombinant HLA-E and beta2-microglobulin were refolded with an MHC leader-sequence peptide, biotinylated, and conjugated to phycoerythrin-labelled Extravidin. This HLA-E tetramer bound to natural killer (NK) cells and a small subset of T cells from peripheral blood. On transfectants, the tetramer bound to the CD94/NKG2A, CD94/NKGK2B and CD94/NKG2C NK cell receptors, but did not bind to the immunoglobulin family of NK cell receptors (KIR). Surface expression of HLA-E was enough to protect target cells from lysis by CD94/NKG2A+ NK-cell clones. A subset of HLA class I alleles has been shown to inhibit killing by CD94/NKG2A+ NK-cell clones. Only the HLA alleles that possess a leader peptide capable of upregulating HLA-E surface expression confer resistance to NK-cell-mediated lysis, implying that their action is mediated by HLA-E, the predominant ligand for the NK cell inhibitory receptor CD94/NKG2A.
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Affiliation(s)
- V M Braud
- Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK.
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Abstract
To investigate how early events in antigen processing affect the repertoire of peptides presented by MHC class I molecules, we compared the presentation of the influenza A nucleoprotein epitope 265-273 by HLA-A3 class I molecules in human and mouse cells. Mouse cells that express HLA-A3 failed to present the NP265-273 peptide when contained within the full-length nucleoprotein, to HLA-A3-restricted human cytotoxic T lymphocytes. However, when the epitope was generated directly in the cytosol using a recombinant vaccinia virus that expressed the nonamer peptide, mouse cells were recognized by HLA-A3-restricted CTL. Poor transport of the peptide by mouse TAP was not responsible for the defect as co-infection of mouse cells with recombinant vaccinia viruses encoding the full-length nucleoprotein and the human TAP1 and TAP2 peptide transporter complex failed to restore presentation. These results therefore demonstrate a differential processing of the influenza nucleoprotein in mouse and human cells. This polymorphism influences the repertoire of peptides presented by MHC class I molecules at the cell surface.
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Affiliation(s)
- V M Braud
- Molecular Immunology Group, Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, GB.
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Abstract
BACKGROUND The human major histocompatibility complex (MHC) class lb molecule HLA-E is transcribed in most tissues but little is known about its localisation within the cell. We have recently shown that HLA-E binds signal-sequence-derived peptides from human MHC class I molecules in vitro. RESULTS Using a newly characterised antibody recognising HLA-E, we show that HLA-E is expressed at the cell surface. We demonstrate that HLA-E surface expression is correlated with the presence of MHC class I molecules which provide suitable leader sequence peptides capable of binding to HLA-E. Further studies on the interaction of HLA-E with molecules in the endoplasmic reticulum revealed that HLA-E associates with the transporter associated with antigen processing (TAP) and calreticulin, and that HLA-E expression is TAP-dependent and tapasin-dependent. In addition, HLA-E dissociates from TAP upon binding of MHC class I leader sequence peptides. CONCLUSION These experiments establish that surface expression of HLA-E is regulated by the binding of a restricted pool of peptides from the leader sequence of MHC class I molecules. The correlation between HLA-E and MHC class I surface expression might be relevant to the function of HLA-E. Our results also show that, although these HLA-E binding peptides are derived from signal sequences, they may be released back into the cytosol and subsequently translocated by the TAP complex and loaded onto HLA-E molecules.
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Affiliation(s)
- V M Braud
- Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, OX3 9DS, UK.
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