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Antohe I, Dǎscǎlescu A, Dǎnǎilǎ C, Titieanu A, Zlei M, Ivanov I, Sireteanu A, Pavel M, Cianga P. B7-Positive and B7-Negative Acute Myeloid Leukemias Display Distinct T Cell Maturation Profiles, Immune Checkpoint Receptor Expression, and European Leukemia Net Risk Profiles. Front Oncol 2020; 10:264. [PMID: 32231996 PMCID: PMC7082324 DOI: 10.3389/fonc.2020.00264] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 02/14/2020] [Indexed: 01/24/2023] Open
Abstract
Acute myeloid leukemia (AML) is generally considered a poorly immunogenic malignancy, displaying a “non-inflamed” leukemia microenvironment (LME), leading to T cell tolerance. However, the immune landscape of AML is much more heterogeneous. Since B7 expression is regarded as a consequence of an interferon-mediated “inflammatory” phenotype, we have investigated by flow cytometry the B7 checkpoint ligands B7.1, B7.2, programmed death ligand 1 (PD-L1), PD-L2, ICOS-L, B7-H3, and B7-H4 on the AML blasts of 30 newly diagnosed patients and their corresponding receptors [cytotoxic T lymphocyte-associated protein 4 (CTLA-4), programmed death 1 (PD-1), and inducible T cell costimulator (ICOS)] on bone marrow (BM) T cell maturation populations. We could thus evidence B7-negative and B7-positive leukemias either with an isolated expression or part of eight different checkpoint ligand “signatures” that always included an inhibitory B7 molecule. B7-positive AMLs encompassed intermediate and adverse European Leukemia Net (ELN) risk cases and displayed mainly central memory CD4+ T cells with high ICOS levels and effector CD8+ T cells with high PD-1 expression. B7-negative cases were rather classified as AML with recurrent genetic anomalies and displayed predominantly naive T cells, with the exception of NPM1 mutated AMLs, which expressed B7-H3. These different B7 immune profiles suggest that specific immunotherapies are required to target the distinct immune evasion strategies of this genetically heterogeneous disease.
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Affiliation(s)
- Ion Antohe
- Hematology Department, Grigore T. Popa University of Medicine and Pharmacy, Iaşi, Romania.,Hematology Department, Regional Oncology Institute, Iaşi, Romania
| | - Angela Dǎscǎlescu
- Hematology Department, Grigore T. Popa University of Medicine and Pharmacy, Iaşi, Romania.,Hematology Department, Regional Oncology Institute, Iaşi, Romania
| | - Cǎtǎlin Dǎnǎilǎ
- Hematology Department, Grigore T. Popa University of Medicine and Pharmacy, Iaşi, Romania.,Hematology Department, Regional Oncology Institute, Iaşi, Romania
| | - Amalia Titieanu
- Hematology Department, Grigore T. Popa University of Medicine and Pharmacy, Iaşi, Romania.,Hematology Department, Regional Oncology Institute, Iaşi, Romania
| | - Mihaela Zlei
- Immunophenotyping Department, Regional Oncology Institute, Iaşi, Romania
| | - Iuliu Ivanov
- Molecular Diagnostic Department, Regional Oncology Institute, Iaşi, Romania
| | - Adriana Sireteanu
- Molecular Diagnostic Department, Regional Oncology Institute, Iaşi, Romania
| | - Mariana Pavel
- Immunology Department, Grigore T. Popa University of Medicine and Pharmacy, Iaşi, Romania
| | - Petru Cianga
- Immunology Department, Grigore T. Popa University of Medicine and Pharmacy, Iaşi, Romania
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Bakela K, Athanassakis I. Soluble major histocompatibility complex molecules in immune regulation: highlighting class II antigens. Immunology 2018; 153:315-324. [PMID: 29159903 PMCID: PMC5795187 DOI: 10.1111/imm.12868] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 11/09/2017] [Accepted: 11/14/2017] [Indexed: 01/10/2023] Open
Abstract
The involvement of major histocompatibility complex (MHC) antigens in the development and regulation of immune response has been well defined over the years, starting from maturation, antigenic peptide loading, migration to the cell membrane for recognition by the T-cell receptor and recycling for immune response cessation. During this intracellular trafficking, MHC antigens find a way to be excreted by the cells, because they can be found as soluble MHC class I (sMHC-I) and class II (sMHC-II) molecules in all body fluids. Although secretion mechanisms have not been sufficiently studied, sMHC molecules have been shown to display important immunoregulatory properties. Their levels in the serum have been shown to be altered in a variety of diseases, including viral infections, inflammation, autoimmunities and cancer, etc. while they seem to be involved in a number of physiological reactions, including maintenance of tolerance, reproduction, as well as mate choice vis-à-vis species evolution. The present review aims to present the thus far existing literature on sMHC molecules and point out the importance of these molecules in the maintenance of immune homeostasis.
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Affiliation(s)
- Katerina Bakela
- Laboratory of ImmunologyDepartment of BiologyUniversity of CreteHeraklion, CreteGreece
| | - Irene Athanassakis
- Laboratory of ImmunologyDepartment of BiologyUniversity of CreteHeraklion, CreteGreece
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ICOS, SLAM and PD-1 expression and regulation on T lymphocytes reflect the immune dysregulation in patients with HIV-related illness with pulmonary tuberculosis. J Int AIDS Soc 2012; 15:17428. [PMID: 22713261 PMCID: PMC3499801 DOI: 10.7448/ias.15.2.17428] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 05/15/2012] [Accepted: 03/15/2012] [Indexed: 12/11/2022] Open
Abstract
Background Tuberculosis (TB) continues to be the most frequent cause of illness and death from an infectious agent globally, and its interaction with HIV is having devastating effects. To investigate how HIV alters the immune response to Mycobacterium tuberculosis (Mtb), we assessed basal and Mtb-induced proliferation, cytokine production, and expression of signalling lymphocytic activation molecule (SLAM), inducible costimulator (ICOS) and programmed death-1 (PD-1) on T lymphocytes from HIV-positive individuals coinfected with TB, HIV-positive subjects, TB patients and healthy donors (HD). Findings HIV-TB patients showed increased ICOS, SLAM and PD-1 basal levels on T lymphocytes, whereas HIV-positive individuals displayed elevated levels of SLAM and PD-1, TB patients high levels of SLAM, and HD low levels of the three proteins. Mtb-stimulation enhanced ICOS expression in the four groups, but only TB and HD increased SLAM and PD-1 levels. Conclusions These data show the immune deregulation that takes place during the immune response against TB in different study populations.
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Srinivasan M, Dunker AK. Proline rich motifs as drug targets in immune mediated disorders. INTERNATIONAL JOURNAL OF PEPTIDES 2012; 2012:634769. [PMID: 22666276 PMCID: PMC3362030 DOI: 10.1155/2012/634769] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 02/15/2012] [Indexed: 12/26/2022]
Abstract
The current version of the human immunome network consists of nearly 1400 interactions involving approximately 600 proteins. Intermolecular interactions mediated by proline-rich motifs (PRMs) are observed in many facets of the immune response. The proline-rich regions are known to preferentially adopt a polyproline type II helical conformation, an extended structure that facilitates transient intermolecular interactions such as signal transduction, antigen recognition, cell-cell communication and cytoskeletal organization. The propensity of both the side chain and the backbone carbonyls of the polyproline type II helix to participate in the interface interaction makes it an excellent recognition motif. An advantage of such distinct chemical features is that the interactions can be discriminatory even in the absence of high affinities. Indeed, the immune response is mediated by well-orchestrated low-affinity short-duration intermolecular interactions. The proline-rich regions are predominantly localized in the solvent-exposed regions such as the loops, intrinsically disordered regions, or between domains that constitute the intermolecular interface. Peptide mimics of the PRM have been suggested as potential antagonists of intermolecular interactions. In this paper, we discuss novel PRM-mediated interactions in the human immunome that potentially serve as attractive targets for immunomodulation and drug development for inflammatory and autoimmune pathologies.
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Affiliation(s)
- Mythily Srinivasan
- Department of Oral Pathology, Medicine and Radiology, Indiana University School of Dentistry, Indiana University Purdue University at Indianapolis 1121 West Michigan Street, DS290, Indianapolis, IN 46268, USA
| | - A. Keith Dunker
- Department of Biochemistry and Molecular Biology and School of Informatics, Indiana University School of Medicine, Indiana University Purdue University at Indianapolis, Indianapolis, IN, USA
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5
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DNA demethylation in PD-1 gene promoter induced by 5-azacytidine activates PD-1 expression on Molt-4 cells. Cell Immunol 2011; 271:450-4. [PMID: 21907333 DOI: 10.1016/j.cellimm.2011.08.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 08/15/2011] [Accepted: 08/17/2011] [Indexed: 01/20/2023]
Abstract
The expression of the programmed death 1 (PD-1) gene is an indicator of exhausted T-cells with decreased activation and function. It remains unknown, however, whether the methylation status of the PD-1 gene promoter is associated with PD-1 expression level. This study shows the changes of PD-1 expression levels and the demethylation status of the PD-1 promoter region in Molt-4 cells under different concentrations of 5-azacytidine (5-Zac). The result demonstrated that DNA demethylation at PD-1 promoter may contribute to PD-1 overexpression.
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Kyvelidou C, Chatzi K, Semitekolou M, Papathanassiou X, Vassiliadis S, Athanassakis I. Characterization of CD25-Positive T Cells During Syngeneic Pregnancy: Production of Stimulatory Class II MHC Molecules. Scand J Immunol 2009; 70:584-95. [DOI: 10.1111/j.1365-3083.2009.02342.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Galustian C, Meyer B, Labarthe MC, Dredge K, Klaschka D, Henry J, Todryk S, Chen R, Muller G, Stirling D, Schafer P, Bartlett JB, Dalgleish AG. The anti-cancer agents lenalidomide and pomalidomide inhibit the proliferation and function of T regulatory cells. Cancer Immunol Immunother 2009; 58:1033-45. [PMID: 19009291 PMCID: PMC11030759 DOI: 10.1007/s00262-008-0620-4] [Citation(s) in RCA: 313] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Accepted: 10/22/2008] [Indexed: 01/23/2023]
Abstract
Lenalidomide (Revlimid; CC-5013) and pomalidomide (CC-4047) are IMiDs proprietary drugs having immunomodulatory properties that have both shown activity in cancer clinical trials; lenalidomide is approved in the United States for a subset of MDS patients and for treatment of patients with multiple myeloma when used in combination with dexamethasone. These drugs exhibit a range of interesting clinical properties, including anti-angiogenic, anti-proliferative, and pro-erythropoietic activities although exact cellular target(s) remain unclear. Also, anti-inflammatory effects on LPS-stimulated monocytes (TNF-alpha is decreased) and costimulatory effects on anti-CD3 stimulated T cells, (enhanced T cell proliferation and proinflammatory cytokine production) are observed. These drugs also cause augmentation of NK-cell cytotoxic activity against tumour-cell targets. Having shown that pomalidomide confers T cell-dependent adjuvant-like protection in a preclinical whole tumour-cell vaccine-model, we now show that lenalidomide and pomalidomide strongly inhibit T-regulatory cell proliferation and suppressor-function. Both drugs inhibit IL-2-mediated generation of FOXP3 positive CTLA-4 positive CD25high CD4+ T regulatory cells from PBMCs by upto 50%. Furthermore, suppressor function of pre-treated T regulatory cells against autologous responder-cells is abolished or markedly inhibited without drug related cytotoxicity. Also, Balb/C mice exhibit 25% reduction of lymph-node T regulatory cells after pomalidomide treatment. Inhibition of T regulatory cell function was not due to changes in TGF-beta or IL-10 production but was associated with decreased T regulatory cell FOXP3 expression. In conclusion, our data provide one explanation for adjuvant properties of lenalidomide and pomalidomide and suggest that they may help overcome an important barrier to tumour-specific immunity in cancer patients.
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MESH Headings
- Animals
- Antineoplastic Agents/pharmacology
- Cell Line, Tumor
- Colonic Neoplasms/immunology
- Colonic Neoplasms/metabolism
- Female
- Forkhead Transcription Factors/antagonists & inhibitors
- Forkhead Transcription Factors/immunology
- Forkhead Transcription Factors/metabolism
- Glucocorticoid-Induced TNFR-Related Protein
- Humans
- Immunosuppressive Agents/pharmacology
- Interleukin-10/immunology
- Interleukin-10/metabolism
- Lenalidomide
- Mice
- Mice, Inbred BALB C
- Receptors, Nerve Growth Factor/drug effects
- Receptors, Nerve Growth Factor/immunology
- Receptors, Nerve Growth Factor/metabolism
- Receptors, OX40/antagonists & inhibitors
- Receptors, OX40/immunology
- Receptors, OX40/metabolism
- Receptors, Transforming Growth Factor beta/drug effects
- Receptors, Transforming Growth Factor beta/immunology
- Receptors, Transforming Growth Factor beta/metabolism
- Receptors, Tumor Necrosis Factor/drug effects
- Receptors, Tumor Necrosis Factor/immunology
- Receptors, Tumor Necrosis Factor/metabolism
- T-Lymphocytes, Regulatory/drug effects
- T-Lymphocytes, Regulatory/immunology
- Thalidomide/analogs & derivatives
- Thalidomide/pharmacology
- Transforming Growth Factor beta/drug effects
- Transforming Growth Factor beta/immunology
- Transforming Growth Factor beta/metabolism
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Affiliation(s)
- Christine Galustian
- Department of Oncology, St Georges University of London, Cranmer Terrace, Tooting, London, UK.
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Abstract
T-cell activation and differentiation depend on the signal strength received by the T-cell receptor and on signals provided by co-stimulatory molecules. The most prominent co-stimulatory molecule is CD28, which controls the activation of naïve and memory T cells by antigen presented on professional antigen-presenting cells. Blocking of the CD28-CD80/86 pathway has been an appealing strategy for inducing tolerance in autoimmune diseases where the disease-inducing autoantigens are not known. Although CD28 has maintained its unique position, the past decade has witnessed the recognition that a large number of regulatory molecules on T cells must be stimulated to generate a fully protective immune response. These regulatory receptors differ in their preferential expression on T-cell subsets, in the ligands that they recognize, and in the signaling pathways that they trigger. They have in common the fact that they provide information on the cellular environment in which the T-cell response occurs. By intercepting these signals, we may be able to influence disease-relevant T-cell responses in autoimmune diseases while potentially minimizing broad immunosuppression.
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Affiliation(s)
- Jörg J Goronzy
- Kathleen B and Mason I Lowance Center for Human Immunology and Rheumatology, Emory University, Woodruff Circle, Atlanta, Georgia 30322, USA.
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9
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Jurado JO, Alvarez IB, Pasquinelli V, Martínez GJ, Quiroga MF, Abbate E, Musella RM, Chuluyan HE, García VE. Programmed death (PD)-1:PD-ligand 1/PD-ligand 2 pathway inhibits T cell effector functions during human tuberculosis. THE JOURNAL OF IMMUNOLOGY 2008; 181:116-25. [PMID: 18566376 DOI: 10.4049/jimmunol.181.1.116] [Citation(s) in RCA: 201] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Protective immunity against Mycobacterium tuberculosis requires the generation of cell-mediated immunity. We investigated the expression and role of programmed death 1 (PD-1) and its ligands, molecules known to modulate T cell activation, in the regulation of IFN-gamma production and lytic degranulation during human tuberculosis. We demonstrated that specific Ag-stimulation increased CD3+PD-1+ lymphocytes in peripheral blood and pleural fluid from tuberculosis patients in direct correlation with IFN-gamma production from these individuals. Moreover, M. tuberculosis-induced IFN-gamma participated in the up-regulation of PD-1 expression. Blockage of PD-1 or PD-1 and its ligands (PD-Ls: PD-L1, PD-L2) enhanced the specific degranulation of CD8+ T cells and the percentage of specific IFN-gamma-producing lymphocytes against the pathogen, demonstrating that the PD-1:PD-Ls pathway inhibits T cell effector functions during active M. tuberculosis infection. Furthermore, the simultaneous blockage of the inhibitory receptor PD-1 together with the activation of the costimulatory protein signaling lymphocytic activation molecule led to the promotion of protective IFN-gamma responses to M. tuberculosis, even in patients with weak cell-mediated immunity against the bacteria. Together, we demonstrated that PD-1 interferes with T cell effector functions against M. tuberculosis, suggesting that PD-1 has a key regulatory role during the immune response of the host to the pathogen.
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Affiliation(s)
- Javier O Jurado
- Department of Biological Chemistry, School of Sciences, University of Buenos Aires, Buenos Aires, Argentina
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10
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Yang DF, Qiu WH, Zhu HF, Lei P, Wen X, Dai H, Zhou W, Shen GX. CTLA4-Ig-modified dendritic cells inhibit lymphocyte-mediated alloimmune responses and prolong the islet graft survival in mice. Transpl Immunol 2008; 19:197-201. [PMID: 18667318 DOI: 10.1016/j.trim.2008.05.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2008] [Revised: 04/30/2008] [Accepted: 05/02/2008] [Indexed: 11/15/2022]
Abstract
The induction of antigen specific tolerance is critical for prevention and treatment of allograft rejection. In this study, we transfected CTLA4-Ig gene into dendritic cells (DCs), and investigated their effect on inhibition of lymphocyte activity in vitro and induction of immune tolerance on pancreatic islet allograft in mice. An IDDM C57BL/6 murine model induced by streptozotocin is as model mouse. The model mice were transplanted of the islet cells isolated from the BALB/c mice to their kidney capsules, and injected of CTLA4-Ig modified DCs (mDCs). The results showed that mDCs could significantly inhibit T lymphocyte proliferation and induce its apoptosis; whereas, unmodified DCs (umDCs) promoted the murine lymphocyte proliferation. Compared with injection of umDCs and IgG1 modified DCs, the injection of mDCs prolonged IDDM mice's allograft survival, and normalized their plasma glucose (PG) levels within 3 days and maintained over 2 weeks. The level of IFN-gamma was lower and the level of IL-4 was higher in mDCs treated recipient mice than that in control mice, it indicated that mDCs led to Th1/Th2 deviation. After 7 days of islet transplantation, HE stain of the renal specimens showed that the islets and kidneys were intact in structure, and islet cells numbers are increased in mDCs treated mice. Our studies suggest that DCs expressing CTLA4-Ig fusion protein can induce the immune tolerance to islet graft and prolong the allograft survival through the inhibition of T cell proliferation in allogeneic mice.
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Affiliation(s)
- Dao-Feng Yang
- Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, China
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11
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Zang X, Loke P, Kim J, Wojnoonski K, Kusdra L, Allison JP. A genetic library screen for signaling proteins that interact with phosphorylated T cell costimulatory receptors. Genomics 2006; 88:841-845. [PMID: 17014982 DOI: 10.1016/j.ygeno.2006.08.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Revised: 08/08/2006] [Accepted: 08/23/2006] [Indexed: 10/24/2022]
Abstract
In the past decade, the fundamental importance and therapeutic potential of costimulatory signals for lymphocyte activation have spurred a large amount of work in immunology, infection, cancer, autoimmune diseases, etc. However, the mechanisms behind T cell costimulation remain unclear, partly due to the lack of suitable techniques. There is an urgent need for functional genomic research to develop comprehensive approaches to direct identification of protein-protein interactions that are dependent on the posttranslational modification of one component of the complex, particularly in the field of T cell immunology. Using inducible costimulator (ICOS) as a model, we failed to find any proteins that associated with the cytoplasmic tail of ICOS by the yeast two-hybrid approach. Therefore, we have developed a new yeast three-hybrid system that facilitates the rapid screening of cDNA libraries to find signaling molecules that interact with phosphorylated T cell costimulatory receptors. We demonstrate the utility of this technique to detect the interaction between ICOS and the p85 regulatory subunit of phosphatidylinositol 3-kinase (PI3K). The p85 unit of PI3K is the only signaling molecule identified so far that interacts with ICOS. This system may be of great help in dissecting the mechanisms of T cell costimulation and could be applied to other receptors.
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Affiliation(s)
- Xingxing Zang
- Howard Hughes Medical Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | - P'ng Loke
- Tropical Disease Research Unit, University of California at San Francisco, San Francisco, CA 94143, USA
| | - Jayon Kim
- Howard Hughes Medical Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | - Kathleen Wojnoonski
- Howard Hughes Medical Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | - Leonard Kusdra
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - James P Allison
- Howard Hughes Medical Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
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12
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Peter HH, Warnatz K. Molecules involved in T-B co-stimulation and B cell homeostasis: possible targets for an immunological intervention in autoimmunity. Expert Opin Biol Ther 2006; 5 Suppl 1:S61-71. [PMID: 16187941 DOI: 10.1517/14712598.5.1.s61] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The deepened knowledge of co-stimulatory mechanisms within the immunological synapse and the emerging biological principles governing B cell homeostasis provide a plethora of new possibilities to selectively block or enhance immune responses. These mechanisms are highly relevant to the development of new treatment modalities for autoimmune diseases. Here we review approaches to antagonise members of the CD28-B7 superfamily as well as the TNF receptor ligand superfamily members, BAFF and APRIL, and their corresponding receptors on B cells (BAFF-R, TACI and BCMA). The proof of principle that such manipulations have indeed profound consequences for the human immune response comes from genetically manipulated mouse models, and, more importantly, from human immunodeficiency syndromes. Thus, the recent discovery of deletions in the ICOS, BAFF-R and TACI genes leading to disturbances in late B cell differentiation and hypogammaglobulinaemia underline the potential impact of targeting these molecules for therapeutic strategies in autoimmune disorders.
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Affiliation(s)
- Hans H Peter
- Division of Rheumatology and Clinical Immunology, Department of Medicine, University Hospital Freiburg, Hugstetterstrasse 55, D-79106 Freiburg, Germany.
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13
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Suh WK, Wang S, Duncan GS, Miyazaki Y, Cates E, Walker T, Gajewska BU, Deenick E, Dawicki W, Okada H, Wakeham A, Itie A, Watts TH, Ohashi PS, Jordana M, Yoshida H, Mak TW. Generation and characterization of B7-H4/B7S1/B7x-deficient mice. Mol Cell Biol 2006; 26:6403-11. [PMID: 16914726 PMCID: PMC1592821 DOI: 10.1128/mcb.00755-06] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Members of the B7 family of cosignaling molecules regulate T-cell proliferation and effector functions by engaging cognate receptors on T cells. In vitro and in vivo blockade experiments indicated that B7-H4 (also known as B7S1 or B7x) inhibits proliferation, cytokine production, and cytotoxicity of T cells. B7-H4 binds to an unknown receptor(s) that is expressed on activated T cells. However, whether B7-H4 plays nonredundant immune regulatory roles in vivo has not been tested. We generated B7-H4-deficient mice to investigate the roles of B7-H4 during various immune reactions. Consistent with its inhibitory function in vitro, B7-H4-deficient mice mounted mildly augmented T-helper 1 (Th1) responses and displayed slightly lowered parasite burdens upon Leishmania major infection compared to the wild-type mice. However, the lack of B7-H4 did not affect hypersensitive inflammatory responses in the airway or skin that are induced by either Th1 or Th2 cells. Likewise, B7-H4-deficient mice developed normal cytotoxic T-lymphocyte reactions against viral infection. Thus, B7-H4 plays a negative regulatory role in vivo but the impact of B7-H4 deficiency is minimal. These results suggest that B7-H4 is one of multiple negative cosignaling molecules that collectively provide a fine-tuning mechanism for T-cell-mediated immune responses.
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Affiliation(s)
- Woong-Kyung Suh
- Campbell Family Institute for Breast Cancer Research, 620 University Ave., Suite 706, Toronto, Ontario, Canada.
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14
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Abstract
CD4+CD25+ regulatory T cells (Treg) constitute an important mechanism of peripheral immune tolerance. Organ-specific autoimmune conditions, such as thyroiditis and insulin-dependent diabetes mellitus have been attributed to a breakdown of this tolerance mechanism. However, this T-cell subset has not been well studied in patients and mice with systemic lupus erythematosus (SLE; lupus). The information that has been gathered so far using new tools that discriminate Treg from activated T cells indicates that reduced numbers of Treg may exist in patients with lupus. In addition, potential defects in SLE Treg function have been documented in humans and mice. Our group has demonstrated equivalent proportions of thymic Treg in lupus prone and normal mice. We therefore propose that Treg function in SLE is the more important factor to address in future studies of murine lupus. Recent studies have shown that Toll-like receptor (TLR) ligation can result in an abrogation of Treg-mediated suppression; specifically ligation of TLR-2, -4, -8 and -9. We address this new information about TLRs and Treg and propose a model for Treg tolerance breakdown to nucleic acid-binding SLE autoantigens.
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Affiliation(s)
- P A Mudd
- Arthritis and Immunology Research Program, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, OK 73104, USA
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15
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Chakrabarti R, Zhou ZF, Chang Y, Prud'homme GJ. A mutant B7-1/Ig fusion protein that selectively binds to CTLA-4 ameliorates anti-tumor DNA vaccination and counters regulatory T cell activity. Vaccine 2005; 23:4553-64. [PMID: 15919138 DOI: 10.1016/j.vaccine.2005.05.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2005] [Accepted: 05/02/2005] [Indexed: 11/27/2022]
Abstract
We have shown that a plasmid encoding a B7-1/Ig fusion protein enhanced DNA vaccination against human carcinoembryonic antigen (CEA) more effectively than the plasmid encoding membrane-bound B7-1. However, it was not known if B7-1/Ig acted only by binding CD28 (amplifying a stimulatory signal) or by blocking CTLA-4 on T cells (removing inhibitory signals). Here, we aimed to determine this using a plasmid encoding mutant B7-1/Ig (B7-1wa/Ig), which binds only to CTLA-4 but not to CD28. Our results showed that both the B7-1/Ig and B7-1wa/Ig plasmids, when co-administered with a CEA plasmid, enhanced tumor rejection and the in vitro anti-CEA response. Therefore, B7-1wa/Ig ameliorates DNA vaccination, presumably by binding to CTLA-4. This could result from a number of non-exclusive mechanisms, such as a reduced threshold for T-cell activation, or blockade of CTLA-4/B7-mediated tolerogenic signals in DCs or T cells. We found that, in vitro, a significant fraction of CD3/CD28-activated T cells (in the absence of DCs) expressed CTLA-4 and B7-1. Primed T cells of CTLA-4(+)B7-1(+/-) phenotype acted as regulatory T cells by inhibiting IFNgamma production by re-stimulated CTLA-4(-)B7-1(-) cells, and this was reversed by antibodies against IL-10 or TGF-beta1. Both B7-1wa/Ig and CTLA-4/Ig, which bind to CTLA-4 and B7-1/B7-2 respectively, enhanced IFNgamma production, but not the proliferation or IL-4 release in mixed T-cell populations containing these two cell types. In contrast, CTLA-4(-)B7-1(-) T cells produced IFNgamma which was not affected by B7-1wa/Ig or CTLA-4/Ig. These results suggest that blocking of CTLA-4/B7-1 binding in T cell/T cell interactions blocks negative regulatory signals. This might be the mechanism, at least in part, of the enhancement of anti-tumor immunity by the B7-1wa/Ig and B7-1/Ig plasmids.
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Affiliation(s)
- Rabindranath Chakrabarti
- Department of Laboratory Medicine and Pathobiology, St. Michael's Hospital and University of Toronto, 30 Bond Street, Toronto, Ontario, Canada M5B 1W8.
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Abstract
The identification of key signalling pathways involved in immune-system regulation, along with the development of early pancreatic tumours in mouse models have provided new opportunities for pancreatic cancer treatment and prevention. Immunotherapy for pancreatic cancer is one approach that is at a crucial crossroads, as therapeutics that are designed to target pancreatic-cancer-associated antigens and regulatory signalling molecules are entering clinical trials.
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Affiliation(s)
- Dan Laheru
- Department of Medical Oncology, Room G89, Baltimore, Maryland 21231-1000, USA
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