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Amiot L, Ferrone S, Grosse-Wilde H, Seliger B. Biology of HLA-G in cancer: a candidate molecule for therapeutic intervention? Cell Mol Life Sci 2010; 68:417-31. [PMID: 21063893 DOI: 10.1007/s00018-010-0583-4] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Accepted: 10/22/2010] [Indexed: 01/13/2023]
Abstract
Although the expression of the non-classical HLA class I molecule HLA-G was first reported to be restricted to the fetal-maternal interface on the extravillous cytotrophoblasts, the distribution of HLA-G in normal tissues appears broader than originally described. HLA-G expression was found in embryonic tissues, in adult immune privileged organs, and in cells of the hematopoietic lineage. More interestingly, under pathophysiological conditions HLA-G antigens may be expressed on various types of malignant cells suggesting that HLA-G antigen expression is one strategy used by tumor cells to escape immune surveillance. In this article, we will focus on HLA-G expression in cancers of distinct histology and its association with the clinical course of diseases, on the underlying molecular mechanisms of impaired HLA-G expression, on the immune tolerant function of HLA-G in tumors, and on the use of membrane-bound and soluble HLA-G as a diagnostic or prognostic biomarker to identify tumors and to monitor disease stage, as well as on the use of HLA-G as a novel therapeutic target in cancer.
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Affiliation(s)
- Laurence Amiot
- UPRES EA 4427 SeRAIC, University of Rennes 1, 2 av Prof Léon Bernard, 35043 RENNES Cedex, France
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2
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Sebti Y, Le Maux A, Gros F, De Guibert S, Pangault C, Rouas-Freiss N, Bernard M, Amiot L. Expression of functional soluble human leucocyte antigen-G molecules in lymphoproliferative disorders. Br J Haematol 2007; 138:202-12. [PMID: 17593027 DOI: 10.1111/j.1365-2141.2007.06647.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Membrane-bound and soluble human leucocyte antigen-G (sHLA-G) molecules display immunotolerant properties favouring tumour cell escape from immune surveillance. sHLA-G molecules have been detected in several tumour pathologies; this study aimed to evaluate sHLA-G expression in lymphoproliferative disorders. sHLA-G plasma level was significantly increased in 110 of 178 newly diagnosed lymphoid proliferations cases i.e. 59% of chronic lymphocytic leukaemia, 65% of B non-Hodgkin lymphomas (NHL) and 58% of T-NHL. To assess the mechanisms involved in this secretion, the differential effect of cytokines was tested in in vitro cultures of NHL cells. A significant induction of sHLA-G level was shown in T-NHL in contrast with B-NHL and normal equivalent cells, after cytokine stimulation with (i) interferongamma (IFNgamma), interleukin-2 (IL-2) and granulocyte-macrophage colony-stimulating factor, (ii) IL-10 and (iii) transforming growth factor beta. An impact of microenvironment on sHLA-G expression was found in B-NHL as shown by the in vitro effect of addition of normal monocytes. Finally, a functional effect of sHLA-G molecules purified from pathologic plasma was demonstrated by their strong capacity to inhibit T-cell proliferation at concentrations currently observed during these disorders. These results suggest that functional sHLA-G molecules are upregulated in lymphoproliferative disorders which can support their potential immunomodulatory role during this pathology.
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Affiliation(s)
- Yasmine Sebti
- UPRES Immunologie Hématologie, Université de Rennes 1, Rennes, France
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3
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Rebmann V, Nückel H, Dührsen U, Grosse-Wilde H. HLA-G in B-chronic lymphocytic leukaemia: clinical relevance and functional implications. Semin Cancer Biol 2007; 17:430-5. [PMID: 17683947 DOI: 10.1016/j.semcancer.2007.06.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Accepted: 06/19/2007] [Indexed: 11/28/2022]
Abstract
HLA-G appears to be involved in regulatory functions counteracting the cellular immune response of T and NK cells by several pathways. We here summarize the HLA-G expression patterns in leukaemia with emphasis on the clinical relevance of this expression for disease progression. Especially in patients with B-chronic lymphocytic leukaemia (B-CLL) the HLA-G expression on B-CLL cells was strongly associated with a reduced treatment-free survival. The corresponding immunological parameters point to a broad immunosuppression in these patients. Thus, HLA-G seems to contribute to the impaired immune response in B-CLL supporting disease progression.
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MESH Headings
- HLA Antigens/chemistry
- HLA Antigens/immunology
- HLA Antigens/metabolism
- HLA-G Antigens
- Histocompatibility Antigens Class I/chemistry
- Histocompatibility Antigens Class I/immunology
- Histocompatibility Antigens Class I/metabolism
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/immunology
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Leukemia, Lymphocytic, Chronic, B-Cell/physiopathology
- Prognosis
- Receptors, Immunologic/immunology
- Receptors, Immunologic/metabolism
- Tumor Escape
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Affiliation(s)
- Vera Rebmann
- Institut für Immunologie, Universitätsklinikum Essen, Virchowstr. 171, D-45122 Essen, Germany
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4
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Sebti Y, Le Friec G, Pangault C, Gros F, Drénou B, Guilloux V, Bernard M, Lamy T, Fauchet R, Amiot L. Soluble HLA-G molecules are increased in lymphoproliferative disorders. Hum Immunol 2004; 64:1093-101. [PMID: 14602240 DOI: 10.1016/j.humimm.2003.08.345] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The immunomodulatory properties of soluble human leukocyte antigen G (sHLA-G) explain its potential interest in malignancies. HLA-G frequently transcribed in lymphoproliferative disorders is rarely expressed at cell surface. In this article, we will demonstrate that the plasmatic level of soluble HLA-G was significantly increased in 70% of B chronic lymphocytic leukemia, 53% of non-Hodgkin B lymphoma (B-NHL), and 45% of T-NHL. To explain this variable secretion, the HLA-G secreting cell was searched and was identified as tumoral T4 lymphocytes only in one patient with Sezary syndrome. To approach the mechanisms involved in sHLA-G secretion, the potential role of cytokines has been studied in vitro on T lymphomas. A significant increase of sHLA-G level is observed after activation by cytokines associated with a small increase in the quantity of transcripts using real-time polymerase chain reaction, suggesting an involvement of both transcriptional and post-transcriptional mechanisms. Western Blot analysis reveals no evident variation of the protein expression whatever the conditions, suggesting a continuous secretion and a low intracellular storage. The frequency of the sHLA-G secretion associated to its inhibiting role on T cells and natural killer cells during tumoral lymphoid malignancies suggests a potential role of these molecules as escape mechanism from antitumoral response.
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MESH Headings
- Antibodies, Monoclonal
- Blotting, Western
- Cytokines/immunology
- Cytokines/pharmacology
- Cytotoxicity, Immunologic
- Enzyme-Linked Immunosorbent Assay
- Flow Cytometry
- HLA Antigens/blood
- HLA Antigens/genetics
- HLA Antigens/immunology
- HLA-G Antigens
- Histocompatibility Antigens Class I/blood
- Histocompatibility Antigens Class I/genetics
- Histocompatibility Antigens Class I/immunology
- Humans
- Killer Cells, Natural/immunology
- Leukemia, Lymphocytic, Chronic, B-Cell/immunology
- Lymphocyte Activation
- Lymphoma, B-Cell/immunology
- Lymphoma, T-Cell/immunology
- RNA, Messenger/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sezary Syndrome/immunology
- Solubility
- T-Lymphocytes/immunology
- Transcription, Genetic
- Tumor Escape
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Affiliation(s)
- Yasmine Sebti
- Laboratoire Universitaire d'Hématologie et la Biologie des Cellules Sanguines, UPRES EA 22 33, Faculté de Médecine, Université de Rennes 1, Rennes, France
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5
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Abstract
Soluble human leukocyte antigen-G molecules (HLA-G5) can be found in the peripheral blood of healthy females and males, and in other body fluids. To identify cells secreting HLA-G5 we generated a rabbit antiserum against a peptide motif encoded by intron-4 of HLA-G (RaHLA-G/I-4). Utilizing this antiserum as capture and antihuman beta 2-microglobulin as detection reagent, an enzyme-linked immunospot assay specific for HLA-G5 was developed. The results of this enzyme-linked immunospot assay format were proven by the HLA-G1 and soluble HLA-G5 (sHLA-G5) specific mAb MEM/G9 used in parallel as capture reagent. For the choriocarcinoma cell line JEG3 the number of HLA-G5 specific spots was found to be increased after stimulation with IFN-alpha, IFN-beta, and IFN-gamma at various concentrations. In contrast to this, no substantial variation of HLA-G5 specific spots was observed after incubation with lymphokines such as leukemia inhibitory factor, interleukin-10 (IL-10), IL-2, IL-4, and granulocyte-colony-stimulating factor. To clarify the cellular source of secreted HLA-G5 molecules, peripheral blood monocytes, CD4 and CD8 positive T and B cells from healthy donors (n = 14) were tested at a fixed cell number (5000/well) in the absence and presence of IFN-gamma (500 U/ml, 24 hours). In all experiments the number of HLA-G5 specific spots was significantly (p < 0.001) increased primarily in monocytes compared with T and B cells, which suggests that peripheral blood monocytes are the predominant cells secreting HLA-G5.
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Affiliation(s)
- Vera Rebmann
- Institute of Immunology, University Hospital of Essen, Essen, Germany
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6
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Abstract
Despite well-defined and immunogenic tumor antigens, and even in the presence of tumor antigen-specific cytotoxic cells, the immune system does not appear to be very effective in eradicating cells that have undergone malignant transformation. Tumor cells, even though invading and representing a threat, are not truly "foreign" but autologous cells that have become transformed in a subtle way, enabling them to escape the host immune system. Melanoma, and to less extent nonmelanoma, skin cancers have developed different strategies to circumvent host immunosurveillance. HLA-G is one of the molecules implicated in cancer immunescape. This review will concentrate on induction and expression of this nonclassical class I molecule in different skin cancer types presenting existing experimental evidence on this topic.
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Affiliation(s)
- Mirjana Urosevic
- Department of Dermatology, University Hospital Zurich, Zurich, Switzerland.
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7
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Wiendl H, Mitsdoerffer M, Weller M. Hide-and-seek in the brain: a role for HLA-G mediating immune privilege for glioma cells. Semin Cancer Biol 2003; 13:343-51. [PMID: 14708714 DOI: 10.1016/s1044-579x(03)00025-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This review summarizes the current knowledge on the expression and functional role of HLA-G in normal CNS cells and brain tumor cells in vitro and in vivo. The CNS has classically been viewed as an immune-privileged organ. Here we discuss some of the particularities of anti-tumoral responses within this compartment. Special emphasis is dedicated to the possible role of the non-classical MHC molecule HLA-G as an alternative mechanism of immune escape. We review the mechanisms how glioma cell-derived HLA-G may paralyze the immune system and which cellular subsets of the immune system are affected. Possible therapeutic implications derived from these observations include the targeting of HLA-G expression within the framework of inducing glioma-specific immunity.
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Affiliation(s)
- Heinz Wiendl
- Department of Neurology, University of Tübingen, Hoppe-Seyler-Strasse 3, D-72076 Tübingen, Germany.
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8
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Amiot L, Le Friec G, Sebti Y, Drénou B, Pangault C, Guilloux V, Leleu X, Bernard M, Facon T, Fauchet R. HLA-G and lymphoproliferative disorders. Semin Cancer Biol 2003; 13:379-85. [PMID: 14708718 DOI: 10.1016/s1044-579x(03)00029-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The immunomodulatory properties of the HLA-G molecule explain its relevance in malignancies. Our investigations in lymphoproliferative disorders show (i) a frequent and variable distribution of alternatively spliced HLA-G mRNA isoforms, (ii) a rare cell surface expression in diffuse large cell lymphomas with HLA class I loss in half of cases, and (iii) an increased serum level of sHLA-G in half of cases. The potential role of the microenvironment and/or tumoral process in HLA-G expression is discussed in the light of these data. HLA-G rather through its soluble isoform might provide a new way of immune evasion for lymphoid proliferations.
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Affiliation(s)
- Laurence Amiot
- Laboratoire Universitaire d'Hématologie et de la Biologie des Cellules Sanguines, UPRES EA 22-33, Faculté de Médecine, Université de Rennes 1, Rennes, France.
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9
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Cardoso CS, de Sousa M. HFE, the MHC and hemochromatosis: paradigm for an extended function for MHC class I. TISSUE ANTIGENS 2003; 61:263-75. [PMID: 12753664 DOI: 10.1034/j.1399-0039.2003.00065.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
HFE was discovered as the hereditary hemochromatosis (HH) gene. It is located on chromosome 6 (6p21.3), 4Mb telomeric to the HLA-A locus, and its product has a structure similar to MHC class I molecules. HFE encodes two frequent mutations: C282Y and H63D. One of these (C282Y) is present in a large proportion of Caucasian HH patients. HFE has a tissue distribution compatible with a role in iron absorption (intestine), recycling (macrophages) and transport to the fetus (placenta).
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Affiliation(s)
- C S Cardoso
- Molecular Immunology, Institute for Molecular and Cell Biology, Oporto, Portugal Molecular Pathology and Immunology, Instituto de Ciências Biomédicas Abel Salazar, OPorto, Portugal
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10
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Abstract
Non-classical MHC class Ib molecules have attracted growing interest in recent years, especially because they interact with non-T-cell inhibitory or triggering receptors expressed on natural killer (NK) and T cells, suggesting that they have a role in immune recognition. Abnormalities in MHC class Ib expression are frequently found in human tumors of various histologies and might be associated with poor clinical outcome despite the local accumulation of immune competent cells. Available data suggest that the balance between activating and suppressing signals significantly influences the efficacy of the immune response and consequently of tumor progression.
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Affiliation(s)
- Barbara Seliger
- Johannes Gutenberg University, IIIrd Department of Internal Medicine, Johannes Gutenberg Universität, Langenbeckstr. 1D-55101 Mainz, Germany.
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11
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Urosevic M, Willers J, Mueller B, Kempf W, Burg G, Dummer R. HLA-G protein up-regulation in primary cutaneous lymphomas is associated with interleukin-10 expression in large cell T-cell lymphomas and indolent B-cell lymphomas. Blood 2002; 99:609-17. [PMID: 11781245 DOI: 10.1182/blood.v99.2.609] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Primary cutaneous lymphomas (CLs) constitute a spectrum of diseases characterized by a clonal accumulation of lymphocytes in the skin. Most CLs display a T(h)2 cytokine profile, including expression of interleukin-10 (IL-10). Because the up-regulation of HLA-G, a nonclassical class Ib molecule inducible by IL-10, might account for the immunescape of the malignant clone, HLA-G and IL-10 expression has been investigated in 45 cases of primary CL (10 of B-cell and 35 of T-cell origin) with quantitative polymerase chain reaction (PCR) and immunohistochemistry. HLA-G message was present in all cutaneous B-cell (CBCL) and T-cell (CTCL) lymphomas evaluated. Immunohistochemistry revealed HLA-G protein expression in 23 (51%) of 45 cases (7 of 10 CBCL, 16 of 35 CTCL). While in CBCL mostly indolent types displayed HLA-G positivity, in CTCL HLA-G expression was associated with high-grade histology and advanced stage of the disease. Except for neoplastic and infiltrating lymphocytes, other cells such as macrophages and dendritic cells showed HLA-G immunoreactivity. Furthermore, IL-10 protein expression was demonstrated in 16 (73%) of 22 HLA-G(+) cases, which correlated with HLA-G protein presence (P <.001). HLA-G up-regulation together with IL-10 expression in CL might additionally contribute to the evasion of immunosurveillance and facilitate the transition from low- to high-grade lymphomas.
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MESH Headings
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- Computer Systems
- Female
- Gene Expression Regulation, Neoplastic
- HLA Antigens/biosynthesis
- HLA Antigens/genetics
- HLA-G Antigens
- Histocompatibility Antigens Class I/biosynthesis
- Histocompatibility Antigens Class I/genetics
- Humans
- Immunoenzyme Techniques
- Immunologic Surveillance
- Interleukin-10/biosynthesis
- Interleukin-10/genetics
- Lymphoma, B-Cell/genetics
- Lymphoma, B-Cell/immunology
- Lymphoma, B-Cell/metabolism
- Lymphoma, Large-Cell, Anaplastic/genetics
- Lymphoma, Large-Cell, Anaplastic/immunology
- Lymphoma, Large-Cell, Anaplastic/metabolism
- Lymphoma, Non-Hodgkin/genetics
- Lymphoma, Non-Hodgkin/immunology
- Lymphoma, Non-Hodgkin/metabolism
- Lymphoma, T-Cell, Cutaneous/genetics
- Lymphoma, T-Cell, Cutaneous/immunology
- Lymphoma, T-Cell, Cutaneous/metabolism
- Male
- Middle Aged
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/genetics
- Polymerase Chain Reaction
- RNA, Messenger/biosynthesis
- RNA, Neoplasm/biosynthesis
- Skin/metabolism
- Skin Neoplasms/genetics
- Skin Neoplasms/immunology
- Skin Neoplasms/metabolism
- Transcription, Genetic
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Affiliation(s)
- Mirjana Urosevic
- Department of Dermatology, University Hospital Zurich, Switzerland
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12
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Wiendl H, Behrens L, Maier S, Johnson MA, Weiss EH, Hohlfeld R. Muscle fibers in inflammatory myopathies and cultured myoblasts express the nonclassical major histocompatibility antigen HLA-G. Ann Neurol 2001. [DOI: 10.1002/1531-8249(200010)48:4<679::aid-ana19>3.0.co;2-v] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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13
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Fournel S, Huc X, Aguerre-Girr M, Solier C, Legros M, Praud-Brethenou C, Moussa M, Chaouat G, Berrebi A, Bensussan A, Lenfant F, Le Bouteiller P. Comparative reactivity of different HLA-G monoclonal antibodies to soluble HLA-G molecules. TISSUE ANTIGENS 2000; 55:510-8. [PMID: 10902607 DOI: 10.1034/j.1399-0039.2000.550602.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Different HLA-G monoclonal antibodies (mAbs) were first evaluated for their capability to identify soluble HLA-G (sHLA-G) in ELISA. Three of them, namely 87G, BFL.1 and MEM-G/9, when used as coating mAbs together with W6/32 capture mAb, identified beta2-microglobulin (beta2m)-associated-sHLA-G but not soluble HLA-B7 (sHLA-B7) in cell culture supernatants from transfected cells. By comparison, the anti-HLA class I mAb 90 did recognize both sHLA-G and sHLA-B7. By using these HLA-G mAbs, sHLA-G was identified in amniotic fluids as well as in culture supernatants of first trimester and term placental explants but not in cord blood. Intron 4-retaining sHLA-G isoforms were identified in some amniotic fluids by the use of an intron 4-specific mAb (16G1). Reactivity of these different HLA-G mAbs was then compared to determine their respective binding sites on soluble and membrane-bound HLA-G. Using both ELISA and flow cytometry analysis, we showed that they did not compete with each other, which suggested that they did not recognize the same determinants. Finally, we report that two mAbs directed against the alpha1 domain of HLA class I heavy chain (mAb 90 and YTH 862) did compete with 87G, therefore demonstrating that this latter mAb recognized an epitope localized on this external domain of HLA-G.
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Affiliation(s)
- S Fournel
- Institut National de la Santé et de la Recherche Médicale U395, Hôpital de Purpan, Toulouse, France
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14
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Slukvin II, Watkins DI, Golos TG. Tissue distribution of the mRNA for a rhesus monkey major histocompatibility class Ib molecule, Mamu-AG. TISSUE ANTIGENS 1999; 53:282-91. [PMID: 10203022 DOI: 10.1034/j.1399-0039.1999.530309.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We identified recently a novel major histocompatibility complex (MHC) class I locus in the rhesus monkey, Mamu-AG, which is expressed in the placenta and encodes molecules that share unique characteristics of human HL4-G. We established locus-specific reverse transcription-polymerase chain reaction (RT-PCR) and ribonuclease protection assays to determine whether Mamu-AG is expressed in other rhesus monkey tissues. With an RT-PCR assay, Mamu-AG mRNA was detected in placenta, amniotic membranes, kidney, spleen, eye, brain, lung, spinal cord, liver and occasionally heart, but was undetectable in lymph nodes, salivary glands, peripheral blood lymphocytes (PBL), large and small intestine, skeletal muscle or skin. Examination of endocrine organs demonstrated the presence of Mamu-AG transcripts in pituitary, testes, ovary and adrenal glands but not in pancreas or thyroid. Quantitative analysis using a ribonuclease protection assay demonstrated that the highest level of Mamu-AG mRNA expression was consistently in the placenta and amniotic membranes, while expression was moderate in a few tissues (testis, adrenal) and low to undetectable in all other tissues. These results suggest that the Mamu-AG mRNA, like the mRNA for the human MHC class Ib gene HLA-G, is expressed at high levels in the placenta, but also has restricted low-level expression in other tissues.
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Affiliation(s)
- I I Slukvin
- Wisconsin Regional Primate Research Center, University of Wisconsin, Madison 53715-1299, USA
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15
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Amiot L, Onno M, Drénou B, Monvoisin C, Fauchet R. HLA-G class I gene expression in normal and malignant hematopoietic cells. Hum Immunol 1998; 59:524-8. [PMID: 9712358 DOI: 10.1016/s0198-8859(98)00041-x] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The class Ib HLA-G gene encodes for a molecule which is selectively expressed in fetal placental cells. Fetomaternal tolerance could be partially explained by the interactions between HLA-G molecules and KIR receptors of decidual NK cells. To determine whether the presence of HLA-G antigens might constitute a factor of immune tolerance during the tumoral process, we compared the expression of the HLA-G gene in normal and malignant hematopoietic cells. Despite a HLA-G transcriptional activity in several lymphocytes and monocytes, no antigens are found at the cell surface or in the cytosol using the specific HLA-G mAb, 87G. This lack of expression does not appear modified in malignant hematopoietic cells. However, treatment of the monohistiocytic cell line U937 with different cytokines enabled the expression of HLA-G antigens to be induced. We suggest that the potential induction of HLA-G molecules in monocytic malignant cells following secretion of cytokines may constitute a factor of immune tolerance in patients.
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Affiliation(s)
- L Amiot
- Laboratoire Universitaire d'Hématologie et de la Biologie des Cellules Sanguines, Faculté de Médecine, Université de Rennes, I, France
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16
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Zhai Y, Knechtle S. Two distinct forms of soluble MHC class I molecules synthesized by different mechanisms in normal rat cells in vitro. Hum Immunol 1998; 59:404-14. [PMID: 9684990 DOI: 10.1016/s0198-8859(98)00039-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Rat soluble MHC class I synthesis was studied at both RNA and protein levels to determine whether multiple forms of soluble MHC class I molecules are produced by different mechanisms. RT-PCR and sequencing of MHC class I transcripts identified an alternatively spliced nonclassical MHC class I gene product, lacking both exon 5 and 6, in both spleen and liver. Immunoprecipitation and SDS-PAGE identified two distinct soluble MHC class I proteins in both splenocyte- and hepatocyte-culture supernatants. The 36Kd classical soluble MHC class I protein (RT1.Aa) was precipitated by both allele-specific (MN4.91.6, R3/13, R2/15S) and pan-reactive (OX18) mAbs. The 39Kd non-RT1.A soluble MHC class I protein was precipitated only by OX18. The production of soluble RT1.Aa was inhibited by a metalloproteinase inhibitor, but not by serine/thiol protease inhibitors. None of these protease inhibitors interfered with the soluble non-RT1.A production, suggesting that it might be derived from an alternatively spliced MHC class I transcript. The soluble non-RT1.A was always associated with beta2m. However, soluble RT1.Aa molecule was cleaved in beta2m-free form and was reassociated with beta2m in culture supernatants. Thus two soluble MHC class I molecules, classical (36Kd RT1.Aa) and nonclassical (the alternatively spliced transcript), were produced from rat cells. Alternative splicing led to the nonclassical soluble MHC class I synthesis. Proteolytic cleavage by metalloproteinase led to the classical soluble MHC class I synthesis.
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Affiliation(s)
- Y Zhai
- Department of Surgery, and Animal Health and Biomedical Science, University of Wisconsin-Madison, USA
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17
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Chu W, Fant ME, Geraghty DE, Hunt JS. Soluble HLA-G in human placentas: synthesis in trophoblasts and interferon-gamma-activated macrophages but not placental fibroblasts. Hum Immunol 1998; 59:435-42. [PMID: 9684993 DOI: 10.1016/s0198-8859(98)00045-7] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The HLA class Ib antigen, HLA-G, is highly expressed in early gestation placentas where it is believed to modulate maternal-fetal immunological interactions. In this study, soluble isoforms (sHLA-G) encoded by intron 4-retaining transcripts were identified in first trimester placentas by immunohistochemistry using a mAb specific for the C-terminus of sHLA-G. Immunoreactive sHLA-G protein was localized to trophoblast cells and to villous mesenchymal cells with the morphological features of macrophages. Reverse transcriptase polymerase chain reaction analysis which used primers specific for intron 4 and the 3' untranslated region of the HLA-G gene showed that transcripts encoding sHLA-G were present in the trophoblast-derived Jeg-3 cells as well as interferon-gamma-activated myelomonocytic U937 cells but were absent and uninducible in placental fibroblasts. These results indicate that placental sHLA-G is synthesized in trophoblast cells and activated placental macrophages and support the postulate that placenta-derived sHLA-G modulates maternal and fetal immune cell functions during pregnancy.
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Affiliation(s)
- W Chu
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City 66160-7400, USA
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18
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Amiot L, Onno M, Lamy T, Dauriac C, Le Prise PY, Fauchet R, Drenou B. Loss of HLA molecules in B lymphomas is associated with an aggressive clinical course. Br J Haematol 1998; 100:655-63. [PMID: 9531330 DOI: 10.1046/j.1365-2141.1998.00631.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Major histocompatibility complex class I molecule expression is reduced in some malignant tumours permitting escape from immune surveillance and is therefore associated with a poor prognosis. Seven cases of non-Hodgkin lymphomas out of 300 cases of malignant lymphoproliferative disorders totally lacked expression of class I molecules as determined by flow cytometry. Clinical data confirmed a particular aggressiveness of these cases with frequent extra-nodal involvement, a poor international prognostic index, a histological high grade and a poor outcome leading to early death in five of the seven cases. A previous diagnosis of follicular lymphoma characterized by bcl-2 rearrangements was made in four of these cases. HLA-G (class Ib gene), which is reported to bind killer inhibitory receptors on NK cells, was absent from the cell surface. However, it was detected in three out of four cases at the mRNA level with transcripts encoding soluble forms. Additional analysis revealed other abnormalities: class II was negative in four out of the seven NHL cases and decreased expression of beta2 microglobulin was observed in all cases. Peptide transporter proteins (TAP1) were detected in various degrees by immunocytochemistry. These observations showed that total lack of class I or class II molecules is a rare event in NHL and is associated with a poor prognosis. This could support a role for specific autologous T cells in immune surveillance.
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Affiliation(s)
- L Amiot
- Laboratoire d'Hématologie (C.R. INSERM 4U006B; UPRES EA 22-33), Faculté de Médecine, Université de Rennes I, France
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Rouas-Freiss N, Kirszenbaum M, Dausset J, Carosella ED. [Fetomaternal tolerance: role of HLA-G molecule in the protection of the fetus against maternal natural killer activity]. COMPTES RENDUS DE L'ACADEMIE DES SCIENCES. SERIE III, SCIENCES DE LA VIE 1997; 320:385-92. [PMID: 9239324 DOI: 10.1016/s0764-4469(97)85026-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
HLA-G is a non-classical major histocompatibility complex class I molecule selectively expressed on extravillous trophoblast cells at the fetal-maternal interface. HLA-G may play an important role in maintaining maternal immune tolerance of the semi-allogenic fetus. In this study, we demonstrate for the first time the protective role of HLA-G during pregnancy. Indeed, cytotrophoblast cells of the fetus are resistant to lytic activity by maternal decidual natural killer cells. In order to precisely characterize the immunological functions of HLA-G products, we have investigated the protective role of the membrane-bound HLA-G1 and HLA-G2 isoforms against NK cell cytotoxicity. For this purpose, HLA-G1 and HLA-G2 cDNAs were transfected into the HLA-class I negative human K562 cell line. We demonstrate that both HLA-G1 and HLA-G2 transfectants inhibit NK cytolysis observed in peripheral blood from 25 donors (males and females). This led us to the conjecture that HLA-G is the public ligand for natural killer inhibitory receptors present in all individuals.
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Affiliation(s)
- N Rouas-Freiss
- Service de recherches en hémato-immunologie, hôpital Saint-Louis, Paris, France
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