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Biassoni R, Malnati MS. Human Natural Killer Receptors, Co-Receptors, and Their Ligands. ACTA ACUST UNITED AC 2019; 121:e47. [PMID: 30040219 DOI: 10.1002/cpim.47] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In the last 20 years, the study of human natural killer (NK) cells has moved from the first molecular characterizations of very few receptor molecules to the identification of a plethora of receptors displaying surprisingly divergent functions. We have contributed to the description of inhibitory receptors and their signaling pathways, important in fine regulation in many cell types, but unknown until their discovery in the NK cells. Inhibitory function is central to regulating NK-mediated cytolysis, with different molecular structures evolving during speciation to assure its persistence. More recently, it has become possible to characterize the NK triggering receptors mediating natural cytotoxicity, unveiling the existence of a network of cellular interactions between effectors of both natural and adaptive immunity. This unit reviews the contemporary history of molecular studies of receptors and ligands involved in NK cell function, characterizing the ligands of the triggering receptor and the mechanisms for finely regulating their expression in pathogen-infected or tumor cells. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Roberto Biassoni
- IRCCS Istituto Giannina Gaslini, Laboratory of Molecular Medicine, Genova, Italy
| | - Mauro S Malnati
- IRCCS Ospedale San Raffaele, Unit of Human Virology, Division of Immunology, Transplantation and Infectious Diseases, Milan, Italy
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2
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He Y, Peng H, Sun R, Wei H, Ljunggren HG, Yokoyama WM, Tian Z. Contribution of inhibitory receptor TIGIT to NK cell education. J Autoimmun 2017; 81:1-12. [PMID: 28438433 DOI: 10.1016/j.jaut.2017.04.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 04/01/2017] [Accepted: 04/03/2017] [Indexed: 01/20/2023]
Abstract
Engagement of inhibitory receptors by cognate host MHC-I molecules triggers NK cell education, resulting in functional maturation and allowing NK cells to sense missing-self. However, NK cells also express inhibitory receptors for non-MHC-I ligands and their role in NK cell education is poorly understood. TIGIT is a recently identified inhibitory receptor that recognizes a non-MHC-I ligand CD155. Here, we demonstrated that TIGIT+ NK cells from wild-type mice exerted augmented responsiveness to various stimuli, including targets that lacked expression of CD155 ligand. TIGIT+ NK cells derived from CD155-deficient hosts, however, exhibited functional impairment, indicating that the engagement of TIGIT receptor by host CD155 promoted NK cell functional maturation. Furthermore, TIGIT deficiency impaired NK cell-mediated missing-self recognition and rejection of CD155- targets, such as allogenic splenocytes and certain tumor cells, in an MHC-I-independent and CD226-unrelated manner. Thus, TIGIT-CD155 pathway is also involved in the acquisition of optimal NK cell effector function, representing a novel MHC-I-independent education mechanism for NK cell tolerance and activation.
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Affiliation(s)
- Yuke He
- Institute of Immunology, Key Laboratory of Innate Immunity and Chronic Disease of Chinese Academy of Science, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, 230027, China
| | - Hui Peng
- Institute of Immunology, Key Laboratory of Innate Immunity and Chronic Disease of Chinese Academy of Science, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, 230027, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Rui Sun
- Institute of Immunology, Key Laboratory of Innate Immunity and Chronic Disease of Chinese Academy of Science, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, 230027, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, 310003, China.
| | - Haiming Wei
- Institute of Immunology, Key Laboratory of Innate Immunity and Chronic Disease of Chinese Academy of Science, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, 230027, China
| | - Hans-Gustaf Ljunggren
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, 16451, Sweden
| | - Wayne M Yokoyama
- Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, Missouri, 63123, USA
| | - Zhigang Tian
- Institute of Immunology, Key Laboratory of Innate Immunity and Chronic Disease of Chinese Academy of Science, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, 230027, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, 310003, China.
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Zalli A, Bosch JA, Goodyear O, Riddell N, McGettrick HM, Moss P, Wallace GR. Targeting ß2 adrenergic receptors regulate human T cell function directly and indirectly. Brain Behav Immun 2015; 45:211-8. [PMID: 25526818 DOI: 10.1016/j.bbi.2014.12.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 11/30/2014] [Accepted: 12/01/2014] [Indexed: 01/28/2023] Open
Abstract
It is well-established that central nervous system activation affects peripheral blood mononuclear cell (PBMCs) function through the release of the catecholamines (Epi) and norepinephrine (NE), which act on ß2-adrenergic receptors (ß2AR). However, most studies have used non-specific stimulation of cells rather than antigen-specific responses. Likewise, few studies have parsed out the direct effects of ß2AR stimulation on T cells versus indirect effects via adrenergic stimulation of antigen presenting cells (APC). Here we report the effect of salmeterol (Sal), a selective ß2AR agonist, on IFN-γ(+) CD4 and IFN-γ(+) CD8 T cells following stimulation with Cytomegalovirus lysate (CMVL-strain AD169) or individual peptides spanning the entire region of the HCMV pp65 protein (pp65). Cells were also stimulated with Staphylococcal enterotoxin B. Additionally, we investigated the effect of Epi and Sal on cytotoxic cell killing of transfected target cells at the single cell level using the CD107a assay. The results show that Sal reduced the percentage of IFN-γ(+) CD4 and IFN-γ(+) CD8 T cells both when applied directly to isolated T cells, and indirectly via treatment of APC. These inhibitory effects were mediated via a ß2 adrenergic-dependent pathway and were stronger for CD8 as compared to CD4 T cells. Similarly, the results show that Sal suppressed cytotoxicity of both CD8 T and NK cells in vitro following stimulation with Chinese hamster ovary cell line transfected with MICA(*009) (T-CHO) and the human erythromyeloblastoid leukemic (K562) cell line. The inhibitory effect on cytotoxicity following stimulation with T-CHO was stronger in NK cells compared with CD8 T cells. Thus, targeting the ß2AR on lymphocytes and on APC leads to inhibition of inflammatory cytokine production and target cell killing. Moreover, there is a hierarchy of responses, with CD8 T cells and NK cells inhibited more effectively than CD4 T cells.
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Affiliation(s)
- A Zalli
- School of Sports and Exercise, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
| | - J A Bosch
- Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands.
| | - O Goodyear
- School of Cancer Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - N Riddell
- School of Sports and Exercise, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - H M McGettrick
- School of Immunity and Infection, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - P Moss
- School of Cancer Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - G R Wallace
- School of Immunity and Infection, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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Parasa VRR, Sikhamani R, Raja A. Effect of recombinant cytokines on the expression of natural killer cell receptors from patients with TB or/and HIV infection. PLoS One 2012; 7:e37448. [PMID: 22715368 PMCID: PMC3371021 DOI: 10.1371/journal.pone.0037448] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2010] [Accepted: 04/19/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND NK cells express several specialized receptors through which they recognize and discriminate virally-infected/tumor cells efficiently from healthy cells and kill them. This ability to lyse is regulated by an array of inhibitory or activating receptors. The present study investigated the frequency of various NK receptors expressed by NK cell subsets from HIV-infected TB patients. The effect of IL-15+IL-12 stimulation on the expression of NK receptors was also studied. METHODOLOGY/PRINCIPAL FINDINGS The study included 15 individuals each from normal healthy subjects, pulmonary tuberculosis patients, HIV-infected individuals and patients with HIV and tuberculosis co-infection. The expression of NK cell receptors was analyzed on two NK cell subsets within the peripheral blood: CD16+CD3- and CD56+CD3- using flow cytometry. The expression of inhibitory receptors (CD158a, CD158b, KIRp70, CD85j and NKG2A) on NK subsets was increased in HIV, when compared to NHS. But the response in HIV-TB was not uniform. Stimulation with IL-15+IL-12 dropped (p<0.05) the expression of CD85j and NKG2A in HIV. The basal expression of natural cytotoxicity receptors (NKp30 and NKp46) on NK cell subsets was lowered (p<0.05) in HIV and HIV-TB as compared to NHS. However, the expression of NKp44 and NKG2D was elevated in HIV. Enhanced NKp46 and NKG2D expression was observed in HIV with IL-15+IL-12 stimulation. The coreceptor NKp80 was found to be expressed in higher numbers on NK subsets from HIV compared to NHS, which elevated with IL-15+IL-12 stimulation. The expression of NK receptors and response to stimulation was primarily on CD56+CD3- subset. CONCLUSIONS/SIGNIFICANCE IL-15+IL-12 has an immunomodulatory effect on NK cell subsets from HIV-infected individuals viz down-regulation of iNKRs, elevation of activatory receptors NKp46 and NKG2D, and induction of coreceptor NKp80. IL-15+IL-12 is not likely to be of value when co-infected with TB probably due to the influence of tuberculosis.
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Affiliation(s)
- Venkata Ramana Rao Parasa
- Department of Immunology, National Institute for Research in Tuberculosis (ICMR), Formerly Tuberculosis Research Centre, Chetput, Chennai, India
| | | | - Alamelu Raja
- Department of Immunology, National Institute for Research in Tuberculosis (ICMR), Formerly Tuberculosis Research Centre, Chetput, Chennai, India
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Chauhan M, Balakrishnan M, Yallampalli U, Endsley J, Hankins GDV, Theiler R, Yallampalli C. Adrenomedullin 2/intermedin regulates HLA-G in human trophoblasts. Biol Reprod 2011; 85:1232-9. [PMID: 21816853 DOI: 10.1095/biolreprod.110.086835] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Adrenomedullin 2 (ADM2), also referred to as intermedin (IMD), is expressed in trophoblast cells in human placenta and enhances the invasion and migration of first-trimester HTR-8SV/neo cells. Further infusion of ADM2 antagonist in pregnant rat causes fetoplacental growth restriction, suggesting a role for ADM2 in maintaining a successful pregnancy. This study was undertaken to assess whether ADM2 protein is present in decidual tissue and colocalized with HLA-G-positive cytotrophoblast cells and natural killer cells; to assess whether ADM2 regulates expression of HLA-G in trophoblast cells; and to identify whether mitogen-activated protein kinase (MAPK) signaling pathway is involved in ADM2-induced trophoblast cell invasion and migration. Using immunohistochemical methods and RT-PCR, this study shows that ADM2 protein is colocalized with HLA-G-expressing cytotrophoblast cells as well as with NCAM1 (CD56) immunoreactivity in human first-trimester decidual tissue, and that ADM2 mRNA is expressed in peripheral blood natural killer cells. Further, ADM2 dose dependently increases the expression of HLA-G antigen in HTR-8SV/neo cells as well as in term placental villi explants, suggesting involvement of ADM2 in the regulation of HLA-G in trophoblast cells. In addition, interference with the activity of RAF and MAPK3/1 by their inhibitors, manumycin and U0126, respectively, reduces ADM2-induced HTR-8SV/neo cell invasion and migration. In summary, this study suggests a potential involvement for ADM2 in regulating HLA-G antigen at the maternal-fetal interface in human pregnancy and facilitating trophoblast invasion and migration via MAPK3/1 phosphorylation.
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Affiliation(s)
- Madhu Chauhan
- Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, Texas 77555-1062, USA.
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Biassoni R. Human natural killer receptors, co-receptors, and their ligands. CURRENT PROTOCOLS IN IMMUNOLOGY 2009; Chapter 14:14.10.1-14.10.40. [PMID: 19235767 DOI: 10.1002/0471142735.im1410s84] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In the last 20 years, the study of human natural killer (NK) cells has moved from the first molecular characterizations of very few receptor molecules to the identification of a plethora of receptors displaying surprisingly divergent functions. Our laboratory has contributed to the description of inhibitory receptors and their signaling pathways, important in fine regulation in many cell types, but unknown until their discovery in the NK cells. Inhibitory function is central to regulating NK-mediated cytolysis, with different molecular structures evolving during speciation to assure its persistence. Only in the last ten years has it become possible to characterize the NK triggering receptors mediating natural cytotoxicity, leading to an appreciation of the existence of a cellular interaction network between effectors of both natural and adaptive immunity. This report reviews the contemporary history of molecular studies of receptors and ligands involved in NK cell function, characterizing the ligands of the triggering receptor and the mechanisms for finely regulating their expression in pathogen-infected or tumor cells.
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Affiliation(s)
- Roberto Biassoni
- Instituto Giannina Gaslini, Laboratory of Molecular Medicine, Genova, Italy
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Abstract
As natural killer (NK) cells were first described more than 30 years ago--a lifetime in recent immunological history--this is a good time to reflect on their transition from outcasts of mainstream immunology to prominent players in innate immunity. Whereas much of our existing knowledge about NK cells is taken as longstanding fact, it may be surprising to immunologists of a younger vintage, particularly those working on NK cells today, that some of this knowledge was, at least initially, unexpected. In this Perspective, I take an unconventional approach to discussing our progress in understanding NK cells.
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Affiliation(s)
- Wayne M Yokoyama
- Howard Hughes Medical Institute, Rheumatology Division, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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Nguyen S, Dhedin N, Vernant JP, Kuentz M, Al Jijakli A, Rouas-Freiss N, Carosella ED, Boudifa A, Debré P, Vieillard V. NK-cell reconstitution after haploidentical hematopoietic stem-cell transplantations: immaturity of NK cells and inhibitory effect of NKG2A override GvL effect. Blood 2005; 105:4135-42. [PMID: 15687235 DOI: 10.1182/blood-2004-10-4113] [Citation(s) in RCA: 202] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Natural killer (NK) cell alloreactivity is reported to mediate strong GvL (graft versus leukemia) effect in patients after haploidentical stem-cell transplantation (SCT) for acute myeloid leukemia (AML). Because subsequent immune reconstitution remains a major concern, we studied NK-cell recovery in 10 patients with AML who received haplomismatched SC transplants, among whom no GvL effect was observed, despite the mismatched immunoglobulin-like receptor (KIR) ligand in the GvH direction for 8 of 10 patients. NK cells generated after SCT exhibited an immature phenotype: the cytotoxic CD3- CD56(dim) subset was small, expression of KIRs and NKp30 was reduced, while CD94/NKG2A expression was increased. This phenotype was associated to in vitro lower levels of cytotoxicity against a K562 cell line and against primary mismatched AML blasts than donor samples. This impaired lysis was correlated with CD94/NKG2A expression in NK cells. Blockading CD94/NKG2A restored lysis against the AML blasts, which all expressed HLA-E, the ligand for CD94/NKG2A. Our present study allows a better understanding of the NK-cell differentiation after SCT. These results revealed that the NK cells generated after haplomismatched SCT are blocked at an immature state characterized by specific phenotypic features and impaired functioning, having potential impact for immune responsiveness and transplantation outcome.
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MESH Headings
- Adolescent
- Adult
- CD56 Antigen/immunology
- Cell Differentiation
- Female
- Graft vs Leukemia Effect/immunology
- Haploidy
- Hematopoietic Stem Cell Transplantation
- Humans
- Killer Cells, Natural/cytology
- Killer Cells, Natural/physiology
- Leukemia, Myeloid, Acute/immunology
- Leukemia, Myeloid, Acute/metabolism
- Leukemia, Myeloid, Acute/pathology
- Leukemia, Myeloid, Acute/therapy
- Male
- NK Cell Lectin-Like Receptor Subfamily C
- Phenotype
- Receptors, Immunologic/immunology
- Receptors, Immunologic/metabolism
- Receptors, Natural Killer Cell
- Treatment Outcome
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Affiliation(s)
- Stephanie Nguyen
- Laboratoire d'Immunologie Cellulaire et Tissulaire INSERM U543, Hôpital Pitié-Salpêtrière, 83 Bvd de l'Hôpital 75013 Paris, France.
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Moreau P, Faure O, Lefebvre S, Ibrahim EC, O'Brien M, Gourand L, Dausset J, Carosella ED, Paul P. Glucocorticoid hormones upregulate levels of HLA-G transcripts in trophoblasts. Transplant Proc 2001; 33:2277-80. [PMID: 11377528 DOI: 10.1016/s0041-1345(01)01990-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- P Moreau
- CEA, Service de Recherches en Hémato-immunologie, DSV/DRM, Institut d'Hematologie, Hôpital Saint-Louis, Paris, France.
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Dukers DF, Vermeer MH, Jaspars LH, Sander CA, Flaig MJ, Vos W, Willemze R, Meijer CJ. Expression of killer cell inhibitory receptors is restricted to true NK cell lymphomas and a subset of intestinal enteropathy-type T cell lymphomas with a cytotoxic phenotype. J Clin Pathol 2001; 54:224-8. [PMID: 11253136 PMCID: PMC1731389 DOI: 10.1136/jcp.54.3.224] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS Killer inhibitory receptors (KIR) have a modulating effect on the cytotoxic functions of natural killer (NK) cells and T cells. Because lymphoma cells often have the same receptors as their non-neoplastic counterparts, this study investigated the expression of KIR on well defined groups of NK and T cell lymphomas, with and without a cytotoxic phenotype, from different sites of origin. METHODS Nine CD56+/CD3- NK cell lymphomas, 29 CD3+/CD56- T cell lymphomas with a cytotoxic phenotype, and 19 T cell lymphomas without a cytotoxic phenotype were stained for KIR using monoclonal antibodies specific for CD94, CD158a, and CD158b. In addition, the expression of KIR was studied on normal lymphoid tissues. RESULTS KIR expression was seen in five of nine true NK cell lymphomas including three of four nasal, one of four cutaneous, and one of one intestinal lymphoma nasal type. Double staining for CD56 and CD94 in normal lymphoid tissues revealed that KIR was predominantly expressed by CD56+ NK cells and sporadically on CD8+ T cells. Moreover, enteropathy-type T cell lymphomas with a cytotoxic phenotype showed KIR expression (three cases expressing CD94 and one case expressing CD158a). All nodal and extranodal nonintestinal T cell lymphomas with or without a cytotoxic phenotype lacked expression of KIR. CONCLUSIONS These results show that KIR expression is restricted to CD56+/CD3- true NK cell lymphomas originating from the nose, gut, and skin, as well as in a subset of extranodal T cell lymphomas originating from the small intestine, which possessed a cytotoxic phenotype. Thus, the presence of KIR on NK/T cell lymphomas seems to mimic the distribution of KIR found on NK and T cells in normal lymphoid tissue.
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Affiliation(s)
- D F Dukers
- Department of Pathology, Vrije Universiteit, Amsterdam, The Netherlands.
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Ahmad R, Sindhu ST, Tran P, Toma E, Morisset R, Menezes J, Ahmad A. Modulation of expression of the MHC class I-binding natural killer cell receptors, and NK activity in relation to viral load in HIV-infected/AIDS patients. J Med Virol 2001. [DOI: 10.1002/jmv.2053] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Salcedo M. Inhibitory role of murine Ly49 lectin-like receptors on natural killer cells. Curr Top Microbiol Immunol 1999; 244:97-105. [PMID: 10453652 DOI: 10.1007/978-3-642-58537-1_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- M Salcedo
- Unité de Biologie Moléculaire du Gène, INSERM U277, Institut Pasteur, Paris, France
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13
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Lefebvre S, Moreau P, Guiard V, Ibrahim EC, Adrian-Cabestre F, Menier C, Dausset J, Carosella ED, Paul P. Molecular mechanisms controlling constitutive and IFN-gamma-inducible HLA-G expression in various cell types. J Reprod Immunol 1999; 43:213-24. [PMID: 10479057 DOI: 10.1016/s0165-0378(99)00035-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
HLA-G molecule is thought to play a major role in down-regulating the maternal immune response by inhibiting NK and T cell cytolytic activities. We examined the molecular regulatory mechanisms that may control the restricted expression pattern of the HLA-G gene. We first analyzed protein interactions between nuclear extracts from the HLA-G-positive JEG-3 choriocarcinoma and the HLA-G-negative NK-like YT2C2 cell lines to a 244 bp regulatory element located 1.2 kb from the HLA-G gene, previously shown to direct HLA-G expression in transgenic mouse placenta. This allowed characterization of cell-specific DNA-protein interactions that could account for differential cell-specific expression of the HLA-G gene. In particular two DNA-protein complexes were exclusively observed in YT2C2, suggesting that this HLA-G regulatory element is a target for putative cell-specific repressor factors. We further mapped nuclear factor binding sites to a 70 bp fragment in the upstream region of the regulatory element. We then investigated the effect of IFN-gamma on HLA-G gene expression. HLA-G cell surface expression was enhanced by IFN-gamma treatment in JEG-3 and U937 cell lines and peripheral blood monocytes while no effect was observed in tera-2 teratocarcinoma cell line. HLA-G transcriptional activity was increased only in JEG-3 and U937 cell lines. Activity of the 1.4-kb HLA-G promoter region was unchanged after IFN-gamma treatment in JEG-3 and Tera-2. These results suggest that both post-transcriptional and transcriptional mechanisms implicating IFN-responsive regulatory sequences outside the 1.4 kb-region are involved in IFN-gamma gene activation of the HLA-G gene.
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Affiliation(s)
- S Lefebvre
- CEA, Service de Recherches en Hémato-Immunologie, DSV/DRM, Hôpital Saint-Louis, Centre Hayem 1, Paris, France
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14
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Gergely J, Pecht I, Sármay G. Immunoreceptor tyrosine-based inhibition motif-bearing receptors regulate the immunoreceptor tyrosine-based activation motif-induced activation of immune competent cells. Immunol Lett 1999; 68:3-15. [PMID: 10397150 DOI: 10.1016/s0165-2478(99)00024-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
ITIM-bearing receptors, a family which only recently has been recognized, play a key role in the regulation of the ITAM-induced activation of immune competent cells. The mechanism of ITM-mediated regulation in various cells was recently clarified. The present review focuses on ITIM bearing membrane proteins that negatively regulate the activation of cells when co-crosslinked with ITAM containing receptors, illustrates the inhibitory processes by the negative regulation of B-, NK-, T-cells and mast cells and summarizes current views on the mechanism of ITIM-mediated inhibition.
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Affiliation(s)
- J Gergely
- Research Group of the Hungarian Academy of Science at the Department of Immunology, Eötvös Loránd University, Göd
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15
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King A, Loke YW. The influence of the maternal uterine immune response on placentation in human subjects. Proc Nutr Soc 1999; 58:69-73. [PMID: 10343342 DOI: 10.1079/pns19990010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The immunological relationship between the mammalian fetus and its mother during pregnancy has been considered similar to that between a transplanted allograft and its recipient ever since Medawar (1953) first proposed the concept of the 'fetus as an allograft' in the early 1950s. Based on this analogy, it has been assumed that implantation of the fetal placenta in the uterus would be controlled similarly by a maternal immune response mediated by T-cells recognizing paternally-derived alloantigens expressed by the placenta. Surprisingly, recent evidence suggests that implantation might involve predominantly a novel allogeneic recognition system based on natural killer cells rather than T-cells (Loke & King, 1995). The cellular and molecular basis of this local immune interaction between the fetal placenta and maternal uterus is now the focus of intense research interest. Since aberrant implantation can cause a variety of clinical problems, including miscarriage, intrauterine growth retardation and pre-eclampsia, an understanding of the immunological mechanism by which this process is controlled could lead to the development of regimens to improve fetal growth and development.
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Affiliation(s)
- A King
- Department of Pathology, University of Cambridge, UK.
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Abstract
Recent studies on human NK cells have demonstrated that the NK cell CD94/NKG2 receptors bind to the nonclassical MHC class I molecule HLA-E. A functional CD94/NKG2 complex has not yet been identified in rodents, but cDNA encoding rat and mouse CD94 and NKG2 have recently been cloned, suggesting that CD94/NKG2 receptors may exist in species other than man. The mouse nonclassical MHC class I molecule Qa-1 shares several features with HLA-E. This suggests that Qa-1 may be similarly recognized by murine NK cells. To study the ability of Qa-1 to bind to murine NK cells, we have produced a soluble tetrameric form of Qa-1b. In the present study, we demonstrate that Qa-1b tetramers distinctly bind to a large subset of fresh or IL-2-activated NK1.1+/CD3- splenocytes independently of the expression of Ly49 inhibitory receptors. Binding occurs whether NK cells have evolved in an MHC class I-expressing or in an MHC class I-deficient environment. Our data suggest the existence of a Qa-1-recognizing structure on a large subpopulation of murine NK cells that may be similar to the human CD94/NKG2 heterodimeric complex.
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Affiliation(s)
- M Salcedo
- Unité de Biologie Moléculaire du Gène, INSERM U277, Institut Pasteur, Paris, France.
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17
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Moreau P, Lefebvre S, Gourand L, Dausset J, Carosella ED, Paul P. Specific binding of nuclear factors to the HLA-G gene promoter correlates with a lack of HLA-G transcripts in first trimester human fetal liver. Hum Immunol 1998; 59:751-7. [PMID: 9831130 DOI: 10.1016/s0198-8859(98)00081-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The nonclassical MHC class I HLA-G antigen is expressed in cytotrophoblasts during pregnancy and may play a role in inhibiting lysis by maternal natural killer cells. HLA-G gene transcription was analyzed in human fetal liver of 6-8 wk of gestation, a development stage where classical HLA class I expression is very reduced. We demonstrated that HLA-G transcription is undetectable in these cells and we investigated the molecular mechanisms that control the lack of HLA-G gene transcription. We compared protein interactions of nuclear extracts from first trimester fetal livers, YT2C2-PR (HLA-G negative) and JEG-3 (HLA-G positive) cell lines to a 244-bp EcoR I/Hind III DNA region located 1.2 kb from the HLA-G gene, previously shown to direct HLA-G expression in transgenic mouse placenta. A strong specific C7-factor was specifically detected in first trimester fetal liver that could account for the inhibition of HLA-G transcription. Interaction of C7-factor and cell-specific factors previously detected in YT2C2 cell line (C5, C6) with two distinct regulatory regions identify this 244-bp EcoR I/Hind III fragment as a putative target for inhibition of HLA-G transcription.
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Affiliation(s)
- P Moreau
- CEA, Service de Recherches en Hémato-immunologie, DSV, DRM, Centre Hayem, Hôpital Saint-Louis, Paris, France.
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