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Cao Z, Garcia MJ, Sklar LA, Wandinger-Ness A, Fan Z. A Flow Cytometry-Based High-Throughput Technique for Screening Integrin-Inhibitory Drugs. J Vis Exp 2024:10.3791/64401. [PMID: 38372326 PMCID: PMC11172413 DOI: 10.3791/64401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2024] Open
Abstract
This protocol aims to establish a method for identifying small molecular antagonists of β2 integrin activation, utilizing conformational-change-reporting antibodies and high-throughput flow cytometry. The method can also serve as a guide for other antibody-based high-throughput screening methods. β2 integrins are leukocyte-specific adhesion molecules that are crucial in immune responses. Neutrophils rely on integrin activation to exit the bloodstream, not only to fight infections but also to be involved in multiple inflammatory diseases. Controlling β2 integrin activation presents a viable approach for treating neutrophil-associated inflammatory diseases. In this protocol, a monoclonal antibody, mAb24, which specifically binds to the high-affinity headpiece of β2 integrins, is utilized to quantify β2 integrin activation on isolated primary human neutrophils. N-formylmethionyl-leucyl-phenylalanine (fMLP) is used as a stimulus to activate neutrophil β2 integrins. A high-throughput flow cytometer capable of automatically running 384-well plate samples was used in this study. The effects of 320 chemicals on β2 integrin inhibition are assessed within 3 h. Molecules that directly target β2 integrins or target molecules in the G protein-coupled receptor-initiated integrin inside-out activation signaling pathway can be identified through this approach.
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Affiliation(s)
- Ziming Cao
- Department of Immunology, School of Medicine, UConn Health
| | - Matthew J Garcia
- Center for Molecular Discovery, University of New Mexico Health Sciences Center
| | - Larry A Sklar
- Center for Molecular Discovery, University of New Mexico Health Sciences Center; Comprehensive Cancer Center, University of New Mexico Health Sciences Center; Department of Pathology, University of New Mexico Health Sciences Center; Autophagy, Inflammation, & Metabolism (AIM) Center, University of New Mexico
| | - Angela Wandinger-Ness
- Comprehensive Cancer Center, University of New Mexico Health Sciences Center; Department of Pathology, University of New Mexico Health Sciences Center
| | - Zhichao Fan
- Department of Immunology, School of Medicine, UConn Health;
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Cha M, Jeong SH, Jung J, Baeg Y, Park S, Bae S, Lim CS, Park JH, Lee J, Gho YS, Oh SW, Shon MJ. Quantitative imaging of vesicle-protein interactions reveals close cooperation among proteins. J Extracell Vesicles 2023; 12:e12322. [PMID: 37186457 PMCID: PMC10130417 DOI: 10.1002/jev2.12322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 03/28/2023] [Indexed: 05/17/2023] Open
Abstract
Membrane-bound vesicles such as extracellular vesicles (EVs) can function as biochemical effectors on target cells. Docking of the vesicles onto recipient plasma membranes depends on their interaction with cell-surface proteins, but a generalizable technique that can quantitatively observe these vesicle-protein interactions (VPIs) is lacking. Here, we describe a fluorescence microscopy that measures VPIs between single vesicles and cell-surface proteins, either in a surface-tethered or in a membrane-embedded state. By employing cell-derived vesicles (CDVs) and intercellular adhesion molecule-1 (ICAM-1) as a model system, we found that integrin-driven VPIs exhibit distinct modes of affinity depending on vesicle origin. Controlling the surface density of proteins also revealed a strong support from a tetraspanin protein CD9, with a critical dependence on molecular proximity. An adsorption model accounting for multiple protein molecules was developed and captured the features of density-dependent cooperativity. We expect that VPI imaging will be a useful tool to dissect the molecular mechanisms of vesicle adhesion and uptake, and to guide the development of therapeutic vesicles.
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Affiliation(s)
- Minkwon Cha
- Department of PhysicsPohang University of Science and Technology (POSTECH)PohangRepublic of Korea
- POSTECH Biotech CenterPohang University of Science and Technology (POSTECH)PohangRepublic of Korea
| | - Sang Hyeok Jeong
- Department of PhysicsPohang University of Science and Technology (POSTECH)PohangRepublic of Korea
| | - Jaehun Jung
- Department of PhysicsPohang University of Science and Technology (POSTECH)PohangRepublic of Korea
| | - Yoonjin Baeg
- Biodrone Research InstituteMDimune Inc.SeoulRepublic of Korea
| | - Sung‐Soo Park
- Biodrone Research InstituteMDimune Inc.SeoulRepublic of Korea
| | - Seoyoon Bae
- Department of Life SciencesPohang University of Science and Technology (POSTECH)PohangRepublic of Korea
| | - Chan Seok Lim
- Department of Life SciencesPohang University of Science and Technology (POSTECH)PohangRepublic of Korea
| | - Jun Hyuk Park
- Department of PhysicsPohang University of Science and Technology (POSTECH)PohangRepublic of Korea
| | - Jie‐Oh Lee
- Department of Life SciencesPohang University of Science and Technology (POSTECH)PohangRepublic of Korea
- Institute of Membrane ProteinsPohang University of Science and Technology (POSTECH)PohangRepublic of Korea
| | - Yong Song Gho
- Department of Life SciencesPohang University of Science and Technology (POSTECH)PohangRepublic of Korea
| | - Seung Wook Oh
- Biodrone Research InstituteMDimune Inc.SeoulRepublic of Korea
| | - Min Ju Shon
- Department of PhysicsPohang University of Science and Technology (POSTECH)PohangRepublic of Korea
- School of Interdisciplinary Bioscience and BioengineeringPohang University of Science and Technology (POSTECH)PohangRepublic of Korea
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3
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Jahan F, Madhavan S, Rolova T, Viazmina L, Grönholm M, Gahmberg CG. Phosphorylation of the α-chain in the integrin LFA-1 enables β2-chain phosphorylation and α-actinin binding required for cell adhesion. J Biol Chem 2018; 293:12318-12330. [PMID: 29903913 DOI: 10.1074/jbc.ra118.004318] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 06/11/2018] [Indexed: 11/06/2022] Open
Abstract
The integrin leukocyte function-associated antigen-1 (LFA-1) plays a pivotal role in leukocyte adhesion and migration, but the mechanism(s) by which this integrin is regulated has remained incompletely understood. LFA-1 integrin activity requires phosphorylation of its β2-chain and interactions of its cytoplasmic tail with various cellular proteins. The α-chain is constitutively phosphorylated and necessary for cellular adhesion, but how the α-chain regulates adhesion has remained enigmatic. We now show that substitution of the α-chain phosphorylation site (S1140A) in T cells inhibits the phosphorylation of the functionally important Thr-758 in the β2-chain, binding of α-actinin and 14-3-3 protein, and expression of an integrin-activating epitope after treatment with the stromal cell-derived factor-1α. The presence of this substitution resulted in a loss of cell adhesion and directional cell migration. Moreover, LFA-1 activation through the T-cell receptor in cells expressing the S1140A LFA-1 variant resulted in less Thr-758 phosphorylation, α-actinin and talin binding, and cell adhesion. The finding that the LFA-1 α-chain regulates adhesion through the β-chain via specific phosphorylation at Ser-1140 in the α-chain has not been previously reported and emphasizes that both chains are involved in the regulation of LFA-1 integrin activity.
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Affiliation(s)
- Farhana Jahan
- From the Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki 00014 UH, Finland
| | - Sudarrshan Madhavan
- From the Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki 00014 UH, Finland
| | - Taisia Rolova
- From the Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki 00014 UH, Finland
| | - Larisa Viazmina
- From the Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki 00014 UH, Finland
| | - Mikaela Grönholm
- From the Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki 00014 UH, Finland
| | - Carl G Gahmberg
- From the Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki 00014 UH, Finland
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IL-7 Induces an Epitope Masking of γc Protein in IL-7 Receptor Signaling Complex. Mediators Inflamm 2017; 2017:9096829. [PMID: 28127156 PMCID: PMC5240581 DOI: 10.1155/2017/9096829] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 11/08/2016] [Accepted: 11/23/2016] [Indexed: 12/13/2022] Open
Abstract
IL-7 signaling via IL-7Rα and common γ-chain (γc) is necessary for the development and homeostasis of T cells. Although the delicate mechanism in which IL-7Rα downregulation allows the homeostasis of T cell with limited IL-7 has been well known, the exact mechanism behind the interaction between IL-7Rα and γc in the absence or presence of IL-7 remains unclear. Additionally, we are still uncertain as to how only IL-7Rα is separately downregulated by the binding of IL-7 from the IL-7Rα/γc complex. We demonstrate here that 4G3, TUGm2, and 3E12 epitope masking of γc protein are induced in the presence of IL-7, indicating that the epitope alteration is induced by IL-7 binding to the preassembled receptor core. Moreover, the epitope masking of γc protein is inversely correlated with the expression of IL-7Rα upon IL-7 binding, implying that the structural alteration of γc might be involved in the regulation of IL-7Rα expression. The conformational change in γc upon IL-7 binding may contribute not only to forming the functional IL-7 signaling complex but also to optimally regulating the expression of IL-7Rα.
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Abstract
Natural killer cells are cytotoxic lymphocytes important in immune responses to cancer and multiple pathogens. However, chronic activation of NK cells can induce a hyporesponsive state. The molecular basis of the mechanisms underlying the generation and maintenance of this hyporesponsive condition are unknown, thus an easy and reproducible mechanism able to induce hyporesponsiveness on human NK cells would be very useful to gain understanding of this process. Human NK cells treated with ionomycin lose their ability to degranulate and secrete IFN-γ in response to a variety of stimuli, but IL-2 stimulation can compensate these defects. Apart from reductions in the expression of CD11a/CD18, no great changes were observed in the activating and inhibitory receptors expressed by these NK cells, however their transcriptional signature is different to that described for other hyporesponsive lymphocytes.
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Kooij G, Braster R, Koning JJ, Laan LC, van Vliet SJ, Los T, Eveleens AM, van der Pol SMA, Förster-Waldl E, Boztug K, Belot A, Szilagyi K, van den Berg TK, van Buul JD, van Egmond M, de Vries HE, Cummings RD, Dijkstra CD, van Die I. Trichuris suis induces human non-classical patrolling monocytes via the mannose receptor and PKC: implications for multiple sclerosis. Acta Neuropathol Commun 2015. [PMID: 26205402 PMCID: PMC4513676 DOI: 10.1186/s40478-015-0223-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Introduction The inverse correlation between prevalence of auto-immune disorders like the chronic neuro-inflammatory disease multiple sclerosis (MS) and the occurrence of helminth (worm) infections, suggests that the helminth-trained immune system is protective against auto-immunity. As monocytes are regarded as crucial players in the pathogenesis of auto-immune diseases, we explored the hypothesis that these innate effector cells are prime targets for helminths to exert their immunomodulatory effects. Results Here we show that soluble products of the porcine nematode Trichuris suis (TsSP) are potent in changing the phenotype and function of human monocytes by skewing classical monocytes into anti-inflammatory patrolling cells, which exhibit reduced trans-endothelial migration capacity in an in vitro model of the blood–brain barrier. Mechanistically, we identified the mannose receptor as the TsSP-interacting monocyte receptor and we revealed that specific downstream signalling occurs via protein kinase C (PKC), and in particular PKCδ. Conclusion This study provides comprehensive mechanistic insight into helminth-induced immunomodulation, which can be therapeutically exploited to combat various auto-immune disorders. Electronic supplementary material The online version of this article (doi:10.1186/s40478-015-0223-1) contains supplementary material, which is available to authorized users.
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Han ST, Mosher DF. IL-5 induces suspended eosinophils to undergo unique global reorganization associated with priming. Am J Respir Cell Mol Biol 2014; 50:654-64. [PMID: 24156300 DOI: 10.1165/rcmb.2013-0181oc] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The experiments described herein define a unique program of polarization of suspended human eosinophils stimulated with IL-5 family cytokines. We found that eosinophil granules and the nucleus move in opposite directions to form, respectively, a granular compartment and the nucleopod, a specialized uropod occupied by the nucleus and covered with adhesion receptors, including P-selectin glycoprotein ligand-1, CD44, and activated αMβ2 integrin. Ligated IL-5 family receptors localize specifically at the tip of the nucleopod in proximity to downstream signaling partners Janus tyrosine kinase 2, signal transducer and activator of transcription-1 and -5, and extracellular signal-regulated kinase. Microscopy and effects of cytochalasin B and nocodazole indicate that remodeling of filamentous actin and reorientation of the microtubule network are required for eosinophil polarization and nucleopod formation. IL-5 induces persistent polarization and extracellular signal-regulated kinase redistribution that are associated with eosinophil priming, a robust response on subsequent stimulation with N-formyl-methionyl-leucyl-phenylalanine. Global reorganization of cytoskeleton, organelles, adhesion receptors, and signaling molecules likely facilitates vascular arrest, extravasation, migration, granule release, and survival of eosinophils entering inflamed tissues from the bloodstream.
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Hintersteiner M, Kallen J, Schmied M, Graf C, Jung T, Mudd G, Shave S, Gstach H, Auer M. Identification and X-ray co-crystal structure of a small-molecule activator of LFA-1-ICAM-1 binding. Angew Chem Int Ed Engl 2014; 53:4322-6. [PMID: 24692345 PMCID: PMC4314669 DOI: 10.1002/anie.201310240] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Indexed: 01/07/2023]
Abstract
Stabilization of protein-protein interactions by small molecules is a concept with few examples reported to date. Herein we describe the identification and X-ray co-crystal structure determination of IBE-667, an ICAM-1 binding enhancer for LFA-1. IBE-667 was designed based on the SAR information obtained from an on-bead screen of tagged one-bead one-compound combinatorial libraries by confocal nanoscanning and bead picking (CONA). Cellular assays demonstrate the activity of IBE-667 in promoting the binding of LFA-1 on activated immune cells to ICAM-1.
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Affiliation(s)
| | - Jörg Kallen
- Novartis Institutes for BioMedical ResearchNovartis Campus, 4056 Basel (Switzerland)
| | - Mario Schmied
- Affiliation when work was performed: Novartis Institutes for BioMedical ResearchBrunnerstrasse 59, 1235 Vienna (Austria)
| | - Christine Graf
- Affiliation when work was performed: Novartis Institutes for BioMedical ResearchBrunnerstrasse 59, 1235 Vienna (Austria)
| | - Thomas Jung
- Affiliation when work was performed: Novartis Institutes for BioMedical ResearchBrunnerstrasse 59, 1235 Vienna (Austria)
| | - Gemma Mudd
- The University of Edinburgh, School of Biological Sciences (CSE) and School of Biomedical Sciences (CMVM)CH Waddington Building, 3.07, The King's Buildings, Mayfield Road, Edinburgh, EH9 3JD (UK)
| | - Steven Shave
- The University of Edinburgh, School of Biological Sciences (CSE) and School of Biomedical Sciences (CMVM)CH Waddington Building, 3.07, The King's Buildings, Mayfield Road, Edinburgh, EH9 3JD (UK)
| | - Hubert Gstach
- Institute of Medical Chemistry, Medical Univ. of ViennaWaehringerstrasse 10, 1090 Vienna (Austria)
| | - Manfred Auer
- The University of Edinburgh, School of Biological Sciences (CSE) and School of Biomedical Sciences (CMVM)CH Waddington Building, 3.07, The King's Buildings, Mayfield Road, Edinburgh, EH9 3JD (UK)
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9
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Hintersteiner M, Kallen J, Schmied M, Graf C, Jung T, Mudd G, Shave S, Gstach H, Auer M. Identifizierung und Strukturbestimmung eines niedermolekularen Aktivators der LFA-1/ICAM-1-Bindung. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201310240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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Bouillet L, Baudet AE, Deroux A, Sidibé A, Dumestre-Perard C, Mannic T, Treillard B, Arboleas MA, Chiquet CA, Gulino-Debrac DG, Vilgrain IY. Auto-antibodies to vascular endothelial cadherin in humans: association with autoimmune diseases. J Transl Med 2013; 93:1194-202. [PMID: 24061286 DOI: 10.1038/labinvest.2013.106] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 08/12/2013] [Accepted: 08/17/2013] [Indexed: 11/09/2022] Open
Abstract
To identify patients with autoimmune diseases who are at high risk of developing vascular cell dysfunction, early biomarkers must be identified. This study was designed to detect and characterize circulating autoantibodies to VE-cadherin (AAVEs) in patients with early-stage autoimmune diseases. An enzyme-linked immunosorbent assay (ELISA) was developed to capture autoantibodies, using a recombinant human VE-cadherin fragment covering the extracellular domains as a target antigen. AAVEs specificity for the target antigen was confirmed by western blotting. Basal AAVEs levels were determined for healthy donors (n=75). Sera from patients (n=100) with various autoimmune diseases, including rheumatoid arthritis (n=23), systemic lupus erythematosus (SLE, n=31), systemic sclerosis (n=30), and Behçet's disease (BD, n=16) were also tested. Levels of AAVEs were significantly higher in rheumatoid arthritis (P<0.0001), SLE (P<0.05), and BD (P<0.05) populations than in healthy subjects. Purified immunoglobulin G (IgG) from a BD patient with exceptionally high AAVEs levels recognized the EC1-4 fragment in western blots. Further characterization of the epitopes recognized by AAVEs showed that BD patients had antibodies specific for the EC3 and EC4 domains, whereas SLE patients preferentially recognized the EC1 fragment. This suggests that distinct epitopes of human VE-cadherin might be recognized in different immune diseases. Purified IgG from BD patients was found to induce endothelial cell retraction, redistribution of VE-cadherin, and cause the formation of numerous intercellular gaps. Altogether, these data demonstrate a potential pathogenic effect of AAVEs isolated from patients with dysimmune disease. This is the first description of AAVEs in humans. Because regions EC1 and EC3-4 have been shown to be involved in homophilic VE-cadherin interactions, AAVEs produced in the course of dysimmune diseases might be specific biomarkers for endothelial injury, which is part of the early pathogenicity of these diseases.
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Affiliation(s)
- L Bouillet
- 1] Grenoble University Hospital, Internal Medicine Department, Grenoble, France [2] INSERM, Unit 1036, Biology of Cancer and Infection, Grenoble, France [3] Joseph Fourier University UJF-Grenoble 1, Biology of Cancer and Infection, Grenoble, France [4] CEA, DSV/iRTSV, Biology of Cancer and Infection, Grenoble, France
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11
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Abstract
Lymphocyte function-associated antigen-1 (LFA-1) is a heterodimeric integrin consisting of αL (gene name, Itgal) and β2 (gene name, Itgb2) subunits expressed in all leukocytes. LFA-1 is essential for neutrophil recruitment to inflamed tissue. Activation of LFA-1 by chemokines allows neutrophils and other leukocytes to undergo arrest, resulting in firm adhesion on endothelia expressing intercellular adhesion molecules (ICAMs). In mice, CXCR2 is the primary chemokine receptor involved in triggering neutrophil arrest, and it does so through “inside-out” activation of LFA-1. CXCR2 signaling induces changes in LFA-1 conformation that are coupled to affinity upregulation of the ligand-binding headpiece (extended with open I domain). Unlike naïve lymphocytes, engagement of P-selectin glycoprotein ligand-1 (PSGL-1) on neutrophils stimulates a slow rolling behavior that is mediated by LFA-1 in a distinct activation state (extended with closed I domain). How inside-out signaling cascades regulate the structure and function of LFA-1 is being studied using flow chambers, intravital microscopy, and flow cytometry for ligand and reporter antibody binding. Here, we review how LFA-1 activation is regulated by cellular signaling and ligand binding. Two FERM domain-containing proteins, talin-1 and Kindlin-3, are critical integrin co-activators and have distinct roles in the induction of LFA-1 conformational rearrangements. This review integrates these new results into existing models of LFA-1 activation.
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Affiliation(s)
- Craig T Lefort
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA
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12
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Lefort CT, Rossaint J, Moser M, Petrich BG, Zarbock A, Monkley SJ, Critchley DR, Ginsberg MH, Fässler R, Ley K. Distinct roles for talin-1 and kindlin-3 in LFA-1 extension and affinity regulation. Blood 2012; 119:4275-82. [PMID: 22431571 PMCID: PMC3359742 DOI: 10.1182/blood-2011-08-373118] [Citation(s) in RCA: 184] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 03/09/2012] [Indexed: 01/07/2023] Open
Abstract
In inflammation, neutrophils and other leukocytes roll along the microvascular endothelium before arresting and transmigrating into inflamed tissues. Arrest requires conformational activation of the integrin lymphocyte function-associated antigen-1 (LFA-1). Mutations of the FERMT3 gene encoding kindlin-3 underlie the human immune deficiency known as leukocyte adhesion deficiency-III. Both kindlin-3 and talin-1, another FERM domain-containing cytoskeletal protein, are required for integrin activation, but their individual roles in the induction of specific integrin conformers are unclear. Here, we induce differential LFA-1 activation in neutrophils through engagement of the selectin ligand P-selectin glycoprotein ligand-1 or the chemokine receptor CXCR2. We find that talin-1 is required for inducing LFA-1 extension, which corresponds to intermediate affinity and induces neutrophil slow rolling, whereas both talin-1 and kindlin-3 are required for induction of the high-affinity conformation of LFA-1 with an open headpiece, which results in neutrophil arrest. In vivo, both slow rolling and arrest are defective in talin-1-deficient neutrophils, whereas only arrest is defective in kindlin-3-deficient neutrophils. We conclude that talin-1 and kindlin-3 serve distinct functions in LFA-1 activation.
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Affiliation(s)
- Craig T Lefort
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA
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13
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Eich C, Vries IJM, Linssen PCM, Boer A, Boezeman JB, Figdor CG, Cambi A. The lymphoid chemokine CCL21 triggers LFA‐1 adhesive properties on human dendritic cells. Immunol Cell Biol 2010; 89:458-65. [DOI: 10.1038/icb.2010.103] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Christina Eich
- Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre Nijmegen The Netherlands
| | - I Jolanda M Vries
- Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre Nijmegen The Netherlands
| | - Peter CM Linssen
- Laboratory of Hematology, Department of Laboratory Medicine, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre Nijmegen The Netherlands
| | - Annemiek Boer
- Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre Nijmegen The Netherlands
| | - Jan B Boezeman
- Laboratory of Hematology, Department of Laboratory Medicine, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre Nijmegen The Netherlands
| | - Carl G Figdor
- Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre Nijmegen The Netherlands
| | - Alessandra Cambi
- Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre Nijmegen The Netherlands
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14
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Diez-Ahedo R, Normanno D, Esteban O, Bakker GJ, Figdor CG, Cambi A, Garcia-Parajo MF. Dynamic re-organization of individual adhesion nanoclusters in living cells by ligand-patterned surfaces. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2009; 5:1258-1263. [PMID: 19367602 DOI: 10.1002/smll.200801699] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Affiliation(s)
- Ruth Diez-Ahedo
- CIBER-Bioengineering Biomateriales and Nanomedicine and BioNanoPhotonics Group IBEC-Institut de Bioenginyeria de Catalunya Baldiri Reixac 15-21, 08028 Barcelona, Spain
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15
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Othoro C, Moore JM, Wannemuehler K, Nahlen BL, Otieno J, Slutsker L, Lal AA, Shi YP. Evaluation of various methods of maternal placental blood collection for immunology studies. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2006; 13:568-74. [PMID: 16682478 PMCID: PMC1459646 DOI: 10.1128/cvi.13.5.568-574.2006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The collection of maternal placental intervillous blood (IVB), without contamination of fetal blood and with an accurate mononuclear cell profile, is essential for immunological studies of placental malaria and other infectious diseases of the placenta. We have compared five documented methods of IVB collection: perfusion, incision, biopsy, tissue grinding, and puncture (prick) for fetal blood contamination and mononuclear cell profiles using flow cytometry. Twenty-five placentas were obtained from Plasmodium falciparum and human immunodeficiency virus-negative primigravid and secundigravid women delivering at Nyanza Provincial Hospital in Kisumu, western Kenya. Each of the five methods was performed on the same placenta. Fetal red blood cell contamination was significantly lower for the prick and perfusion methods (4.1% and 8.3%, respectively) than for incision (59.5%), biopsy (42.6%), and tissue grinding (19.9%). Significant variation was noted among the five methods in the percentages of monocytes, total T cells, CD4+ and CD8+ T cells, B cells, and NK cells. Further, a pairwise comparison of prick and perfusion, the two methods with low fetal blood contamination, showed that they were not different for fetal red blood cell contamination levels; however, prick yielded significantly higher percentages of CD4 T cells and CD4 memory T cells than perfusion. Collection by prick was determined to be the best method of intervillous blood collection for immunology studies, and perfusion represented the next best method of choice due to high sample volume yield. Overall, in considering the advantages/disadvantages of the two methods with low fetal cell contamination, we conclude that a combination of prick and perfusion is most suitable for immunology studies.
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Affiliation(s)
- Caroline Othoro
- Kenya Medical Research Institute, Kisumu, Kenya,1 Nyanza Provincial General Hospital, Kisumu, Kenya
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16
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Cambi A, Joosten B, Koopman M, de Lange F, Beeren I, Torensma R, Fransen JA, Garcia-Parajó M, van Leeuwen FN, Figdor CG. Organization of the integrin LFA-1 in nanoclusters regulates its activity. Mol Biol Cell 2006; 17:4270-81. [PMID: 16855029 PMCID: PMC1635357 DOI: 10.1091/mbc.e05-12-1098] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The beta2-integrin LFA-1 facilitates extravasation of monocytes (MOs) into the underlying tissues, where MOs can differentiate into dendritic cells (DCs). Although DCs express LFA-1, unlike MOs, they cannot bind to ICAM-1. We hypothesized that an altered integrin organization on the DC plasma membrane might cause this effect and investigated the relationship between membrane organization and function of LFA-1 on MOs and DCs. High-resolution mapping of LFA-1 surface distribution revealed that on MOs LFA-1 function is associated with a distribution in well-defined nanoclusters (100-150-nm diameter). Interestingly, a fraction of these nanoclusters contains primed LFA-1 molecules expressing the specific activation-dependent L16-epitope. Live imaging of MO-T-cell conjugates showed that only these primed nanoclusters are dynamically recruited to the cellular interface forming micrometer-sized assemblies engaged in ligand binding and linked to talin. We conclude that besides affinity regulation, LFA-1 function is controlled by at least three different avidity patterns: random distributed inactive molecules, well-defined ligand-independent proactive nanoclusters, and ligand-triggered micrometer-sized macroclusters.
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Affiliation(s)
| | | | - Marjolein Koopman
- Applied Optics Group and Department of Applied Physics and MESA+ Research Institute, University of Twente, 7522 NM Enschede, The Netherlands
| | - Frank de Lange
- *Department of Tumor Immunology and
- Department of Cell Biology and Microscopic Imaging Centre, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands; and
| | | | | | - Jack A. Fransen
- Department of Cell Biology and Microscopic Imaging Centre, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands; and
| | - Maria Garcia-Parajó
- Applied Optics Group and Department of Applied Physics and MESA+ Research Institute, University of Twente, 7522 NM Enschede, The Netherlands
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17
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Mills PJ, Hong S, Redwine L, Carter SM, Chiu A, Ziegler MG, Dimsdale JE, Maisel AS. Physical fitness attenuates leukocyte-endothelial adhesion in response to acute exercise. J Appl Physiol (1985) 2006; 101:785-8. [PMID: 16728524 DOI: 10.1152/japplphysiol.00135.2006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Studies suggest that physical fitness promotes cardiovascular health, including improved endothelial function and possibly reduced inflammatory responses to stressors. This study examined the effects of fitness on leukocyte-endothelial adhesion in response to an acute exercise challenge. Peripheral blood mononuclear cell (PBMC) adhesion to human umbilical venous endothelial cells (HUVEC) was examined in 18 more-fit and 19 less-fit individuals [mean age 39 yr (SD 11)] before and after a 20-min treadmill exercise at 65-70% peak oxygen consumption. PBMC were isolated from whole blood (Ficoll-Paque) at rest and immediately after exercise. HUVEC were incubated for 4 h in the presence of cytokines IL-1 and IL-8 to activate endothelial adhesion molecule expression. Fit subjects showed a significant reduction in PBMC-HUVEC adhesion after exercise (P < 0.01) compared with less-fit subjects, who showed no significant change. Regardless of fitness levels, both at rest and in response to exercise, soluble ICAM-1 in the incubation media attenuated PBMC-HUVEC adhesion by approximately 81% (P < 0.001). The findings indicate that immune cells that demarginate in response to exercise have reduced ability to adhere in individuals who are physically fit, an effect apparently independent of ICAM-1 binding. The findings provide evidence of how physical fitness might protect individuals from inflammatory responses to exercise.
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Affiliation(s)
- Paul J Mills
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA.
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18
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Tardif MR, Tremblay MJ. LFA-1 is a key determinant for preferential infection of memory CD4+ T cells by human immunodeficiency virus type 1. J Virol 2005; 79:13714-24. [PMID: 16227291 PMCID: PMC1262559 DOI: 10.1128/jvi.79.21.13714-13724.2005] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Memory CD4+ T cells are considered a stable latent reservoir for human immunodeficiency virus type 1 (HIV-1) and a barrier to eradication of this retroviral infection in patients under therapy. It has been shown that memory CD4+ T cells are preferentially infected with HIV-1, but the exact mechanism(s) responsible for this higher susceptibility remains obscure. Previous findings indicate that incorporation of host-derived intercellular adhesion molecule 1 (ICAM-1) in HIV-1 increases virus infectivity. To measure the putative involvement of virus-anchored ICAM-1 in the preferential infection of memory cells by HIV-1, quiescent and activated naive and memory T-cell subsets were exposed to isogenic virions either lacking or bearing ICAM-1. Memory CD4+ T cells were found to be more susceptible than naive CD4+ T cells to infection with ICAM-1-bearing virions, as exemplified by a more important virus replication, an increase in integrated viral DNA copies, and a more efficient entry process. Interactions between virus-associated host ICAM-1 and cell surface LFA-1 under a cluster formation seem to be responsible for the preferential HIV-1 infection of the memory cell subset. Altogether, these data shed light on a potential mechanism by which HIV-1 preferentially targets long-lived memory CD4+ T cells.
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Affiliation(s)
- Mélanie R Tardif
- Research Center in Infectious Diseases, CHUL Research Center, and Faculty of Medicine, Laval University, Quebec, Canada
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19
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Tardif MR, Tremblay MJ. Regulation of LFA-1 activity through cytoskeleton remodeling and signaling components modulates the efficiency of HIV type-1 entry in activated CD4+ T lymphocytes. THE JOURNAL OF IMMUNOLOGY 2005; 175:926-35. [PMID: 16002691 DOI: 10.4049/jimmunol.175.2.926] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Besides interactions between the viral envelope glycoproteins with cell surface receptors, interactions between cell-derived molecules incorporated onto virions and their ligand could also modulate HIV type-1 (HIV-1) entry inside CD4(+) T lymphocytes. Although incorporation of host ICAM-1 within HIV-1 increases both virus attachment and fusion, the precise mechanism through which this phenomenon is occurring is still unclear. We demonstrate in this study that activation of primary human CD4(+) T lymphocytes increases LFA-1 affinity and avidity states, two events promoting the early events of the HIV-1 replication cycle through interactions between virus-embedded host ICAM-1 and LFA-1 clusters. Confocal analyses suggest that HIV-1 is concentrated in microdomains rich in LFA-1 clusters that also contain CD4 and CXCR4 molecules. Experiments performed with specific inhibitors revealed that entry of HIV-1 in activated CD4(+) T cells is regulated by LFA-1-dependent ZAP70, phospholipase Cgamma1, and calpain enzymatic activities. By using laboratory and clinical strains of HIV-1 produced in primary human cells, we demonstrate the importance of the LFA-1 activation state and cluster formation in the initial step of the virus life cycle. Overall, these data provide new insights into the complex molecular events involved in HIV-1 binding and entry.
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Affiliation(s)
- Mélanie R Tardif
- Research Center in Infectious Diseases, Centre Hospitalier de l'Université Laval (CHUL) Research Center, and Faculty of Medicine, Laval University, 2705 Laurier Boulevard, Quebec, Canada G1V 4G2
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20
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Martinez O, Brackenridge S, El-Idrissi MEA, Prabhakar BS. DC-SIGN, but not sDC-SIGN, can modulate IL-2 production from PMA- and anti-CD3-stimulated primary human CD4 T cells. Int Immunol 2005; 17:769-78. [PMID: 15944195 DOI: 10.1093/intimm/dxh258] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Dendritic cell (DC)-specific intercellular cell adhesion molecule-3 (ICAM-3)-grabbing non-integrin (DC-SIGN) is expressed on the surface of DCs and specialized macrophages and can support T cell proliferation. Antibody-mediated co-ligation of CD3 and ICAM-3, the ligand for both DC-SIGN and leukocyte function-associated antigen-1, leads to T cell activation. Therefore, we tested to see whether DC-SIGN or a splice variant of dendritic cell-specific intercellular cell adhesion molecule-3-grabbing non-integrin (sDC-SIGN) can co-stimulate primary human T cells. The sDC-SIGN lacking the transmembrane domain encoded by exon 3 localizes to the cytoplasm of cells and is not secreted. Both B7 and DC-SIGN co-stimulated phorbol myristate acetate-stimulated CD4+ cells as compared with controls. However, unlike B7, both DC-SIGN and sDC-SIGN failed to co-stimulate CD4+ T cells treated with sub-optimal amounts of anti-CD3 (2 microg ml(-1)) as defined by a lack of CD69 and CD25 up-regulation, cell division and cytokine secretion. Instead, DC-SIGN, and not sDC-SIGN, induced a small but consistent down-regulation of IL-2 production by these CD4+ T cells. In contrast, DC-SIGN in the presence of 30 mug ml(-1) of anti-CD3 modestly up-regulated cytokine production as compared with control. These results suggest that DC-SIGN can differentially modulate T cell stimulation.
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MESH Headings
- Alternative Splicing
- Animals
- Antibodies
- Antigens, CD/analysis
- CD4-Positive T-Lymphocytes/immunology
- CHO Cells/metabolism
- Cell Adhesion Molecules/biosynthesis
- Cell Adhesion Molecules/genetics
- Cell Adhesion Molecules/immunology
- Cells, Cultured
- Cloning, Molecular
- Cricetinae
- Cricetulus
- Genes, Reporter
- Humans
- Interferon-gamma/biosynthesis
- Interleukin-2/biosynthesis
- Lectins, C-Type/biosynthesis
- Lectins, C-Type/genetics
- Lectins, C-Type/immunology
- Lymphocyte Activation
- Lymphocyte Subsets/immunology
- Protein Isoforms/biosynthesis
- Protein Isoforms/genetics
- Protein Isoforms/immunology
- Receptors, Cell Surface/biosynthesis
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/immunology
- Reverse Transcriptase Polymerase Chain Reaction
- Transfection
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Affiliation(s)
- Osvaldo Martinez
- Department of Microbiology and Immunology, University of Illinois, Chicago, IL 60612, USA
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21
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Shamri R, Grabovsky V, Gauguet JM, Feigelson S, Manevich E, Kolanus W, Robinson MK, Staunton DE, von Andrian UH, Alon R. Lymphocyte arrest requires instantaneous induction of an extended LFA-1 conformation mediated by endothelium-bound chemokines. Nat Immunol 2005; 6:497-506. [PMID: 15834409 DOI: 10.1038/ni1194] [Citation(s) in RCA: 317] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2004] [Accepted: 03/18/2005] [Indexed: 12/16/2022]
Abstract
It is widely believed that rolling lymphocytes require successive chemokine-induced signaling for lymphocyte function-associated antigen 1 (LFA-1) to achieve a threshold avidity that will mediate lymphocyte arrest. Using an in vivo model of lymphocyte arrest, we show here that LFA-1-mediated arrest of lymphocytes rolling on high endothelial venules bearing LFA-1 ligands and chemokines was abrupt. In vitro flow chamber models showed that endothelium-presented but not soluble chemokines triggered instantaneous extension of bent LFA-1 in the absence of LFA-1 ligand engagement. To support lymphocyte adhesion, this extended LFA-1 conformation required immediate activation by its ligand, intercellular adhesion molecule 1. These data show that chemokine-triggered lymphocyte adhesiveness involves a previously unrecognized extension step that primes LFA-1 for ligand binding and firm adhesion.
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Affiliation(s)
- Revital Shamri
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel
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22
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Risueño RM, Gil D, Fernández E, Sánchez-Madrid F, Alarcón B. Ligand-induced conformational change in the T-cell receptor associated with productive immune synapses. Blood 2005; 106:601-8. [PMID: 15790785 DOI: 10.1182/blood-2004-12-4763] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Triggering of the T-cell receptor (TCR) can produce very different responses, depending on the nature of the major histocompatibility complex/antigen peptide (MHCp) ligand. The molecular mechanisms that permit such fine discrimination are still unknown. We show here that an epitope in the cytoplasmic tail of the TCR CD3epsilon subunit, recognized by antibody APA1/1, is only detected when the TCR is fully activated. Exposure of the APA1/1 epitope is shown to be fast and independent of tyrosine kinase activity and that it takes place even when T cells are stimulated at 0 degrees C. These results suggest that APA1/1 detects a conformational change in the TCR. APA1/1 staining concentrates in a restricted area of the immunologic synapse. Most important, we show that full agonist, but not partial agonist, peptides induce exposure of the APA1/1 epitope, indicating a correlation between the induction of the conformational change in the TCR and full T-cell activation. Finally, the conformational change is shown to occur in T cells that are being stimulated by antigen in vivo. Therefore, these results demonstrate that the TCR undergoes a conformational change on MHCp binding in vitro and in vivo, and they establish a molecular correlate for productive TCR engagement.
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Affiliation(s)
- Ruth M Risueño
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Cantoblanco Madrid 28049, Spain
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23
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Gondek DC, Lu LF, Quezada SA, Sakaguchi S, Noelle RJ. Cutting Edge: Contact-Mediated Suppression by CD4+CD25+ Regulatory Cells Involves a Granzyme B-Dependent, Perforin-Independent Mechanism. THE JOURNAL OF IMMUNOLOGY 2005; 174:1783-6. [PMID: 15699103 DOI: 10.4049/jimmunol.174.4.1783] [Citation(s) in RCA: 594] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
CD4+CD25+ regulatory T cells (Treg) are potent immunosuppressive cells that are pivotal in the regulation of peripheral tolerance. In this report, we identify granzyme B (GZ-B) as one of the key components of Treg-mediated suppression. Induction of regulatory activity is correlated with the up-regulation of GZ-B expression. Proof of a functional involvement of GZ-B in contact-mediated suppression by Treg is shown by the reduced ability of Treg from GZ-B-/- mice to suppress as efficiently as Treg from WT mice. GZ-B-mediated suppression is perforin independent, because suppression by Treg from perforin-/- and WT is indistinguishable. Additionally, suppression mediated by Treg appears to be mediated, in part, by the induction of apoptosis in the CD4+CD25- effector cell. In summary, GZ-B is one of the key mechanisms through which CD4+CD25+ Treg induce cell contact-mediated suppression.
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MESH Headings
- Animals
- Apoptosis/genetics
- Apoptosis/immunology
- CD4-Positive T-Lymphocytes/enzymology
- CD4-Positive T-Lymphocytes/immunology
- Cell Communication/genetics
- Cell Communication/immunology
- Cells, Cultured
- Coculture Techniques
- Down-Regulation/genetics
- Down-Regulation/immunology
- Glucocorticoid-Induced TNFR-Related Protein
- Granzymes
- Immune Sera/pharmacology
- Immunosuppression Therapy/methods
- Membrane Glycoproteins/deficiency
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Perforin
- Pore Forming Cytotoxic Proteins
- Receptors, Interleukin-2/biosynthesis
- Receptors, Nerve Growth Factor/immunology
- Receptors, Nerve Growth Factor/physiology
- Receptors, Tumor Necrosis Factor/immunology
- Receptors, Tumor Necrosis Factor/physiology
- Serine Endopeptidases/deficiency
- Serine Endopeptidases/genetics
- Serine Endopeptidases/physiology
- Serine Proteinase Inhibitors/pharmacology
- T-Lymphocytes, Regulatory/cytology
- T-Lymphocytes, Regulatory/enzymology
- T-Lymphocytes, Regulatory/immunology
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Affiliation(s)
- David C Gondek
- Department of Microbiology and Immunology, Dartmouth Medical School and Norris Cotton Cancer Center, Lebanon, NH 03756, USA
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24
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Xie C, Shimaoka M, Xiao T, Schwab P, Klickstein LB, Springer TA. The integrin alpha-subunit leg extends at a Ca2+-dependent epitope in the thigh/genu interface upon activation. Proc Natl Acad Sci U S A 2004; 101:15422-7. [PMID: 15494438 PMCID: PMC524430 DOI: 10.1073/pnas.0406680101] [Citation(s) in RCA: 47] [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] Open
Abstract
Two activation-dependent Abs to the integrin alphaL-subunit were used to study conformational rearrangement of alphaLbeta2 on the cell surface. Activation lowered the concentration of Ca2+ required for maximal expression of each epitope. Each Ab requires the Ca2+-binding loop in the integrin genu and nearby species-specific residues in the thigh domain. Key thigh residues are shielded from Ab in the bent integrin conformation by the alpha-subunit calf-1 domain and the nearby bent beta leg, suggesting that extension at the genu is required for epitope exposure. Activating stimuli and alpha/beta I-like small molecule antagonists demonstrate that exposure of epitopes in the integrin alpha- and beta-subunit legs is coordinate during integrin activation. A coordinating residue donated by the calf-1 domain is as important as Ca2+ for mAb binding. Together with inspection of the alphaV structure, this result suggests that the genu/calf-1 interface is maintained in integrin activation, and that extension occurs by a rearrangement at the thigh/genu interface.
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Affiliation(s)
- Can Xie
- CBR Institute for Biomedical Research and Departments of Pathology and Anesthesia, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA
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25
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Harper JM, Hoff EF, Carruthers VB. Multimerization of the Toxoplasma gondii MIC2 integrin-like A-domain is required for binding to heparin and human cells. Mol Biochem Parasitol 2004; 134:201-12. [PMID: 15003840 DOI: 10.1016/j.molbiopara.2003.12.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2003] [Accepted: 12/03/2003] [Indexed: 10/26/2022]
Abstract
Toxoplasma gondii is an obligate intracellular parasite that causes toxoplasmosis in humans and animals. To invade host cells, T. gondii deploys the contents of its apically oriented secretory organelles that include the micronemes. Contained within the micronemes are proteins that possess adhesive motifs resembling those found in mammalian proteins. The micronemal protein MIC2 is a member of the thrombospondin-related anonymous protein (TRAP) family of adhesive proteins, which characteristically feature at least one integrin-like A-domain. Because of its strict conservation within the family, we sought to define the role of this domain by testing the adhesive properties of recombinant MIC2 A-domain fusion proteins. Since MIC2 is found as a multimeric species in parasite lysate, we also wanted to test whether recombinant MIC2 A-domain bound to its substrate in a multimeric state. In vitro assays of binding to several different potential receptors revealed that the MIC2 A-domain binds specifically to heparin, a ubiquitous sulfated proteoglycan found in the extracellular matrix (ECM). Additional studies demonstrated that this binding is not dependent on the MIDAS site, a well-conserved divalent cation-binding motif that the MIC2 A-domain shares with its mammalian counterparts. The recombinant MIC2 A-domain bound to heparin as a high molecular weight species, as did MIC2 from parasite lysate, indicating that the recombinant A-domain mimics the binding of native MIC2. Multimerization of MIC2 may increase the number of interactions with host cell receptors, thereby forming a multivalent adhesive junction during parasite entry.
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Affiliation(s)
- Jill M Harper
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street E5132, Baltimore, MD 21205, USA
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26
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Shimaoka M, Salas A, Yang W, Weitz-Schmidt G, Springer TA. Small molecule integrin antagonists that bind to the beta2 subunit I-like domain and activate signals in one direction and block them in the other. Immunity 2003; 19:391-402. [PMID: 14499114 DOI: 10.1016/s1074-7613(03)00238-3] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Leukocyte integrins contain an inserted (I) domain in their alpha subunits and an I-like domain in their beta(2) subunit, which directly bind ligand and regulate ligand binding, respectively. We describe a novel mechanistic class of integrin inhibitors that bind to the metal ion-dependent adhesion site of the beta(2) I-like domain and prevent its interaction with and activation of the alpha(L) I domain. The inhibitors do not bind to the alpha(L) I domain but stabilize alpha/beta subunit association and can show selectivity for alpha(L)beta(2) compared to alpha(M)beta(2). The inhibitors reveal a crucial intersection for relaying conformational signals within integrin extracellular domains. While blocking signals in one direction to the I domain, the antagonists induce the active conformation of the I-like domain and stalk domains, and thus transmit conformational signals in the other direction toward the transmembrane domains.
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Affiliation(s)
- Motomu Shimaoka
- The CBR Institute for Biomedical Research, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA.
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27
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Tohyama Y, Katagiri K, Pardi R, Lu C, Springer TA, Kinashi T. The critical cytoplasmic regions of the alphaL/beta2 integrin in Rap1-induced adhesion and migration. Mol Biol Cell 2003; 14:2570-82. [PMID: 12808052 PMCID: PMC194904 DOI: 10.1091/mbc.e02-09-0615] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Rap1 is a potent inside-out signal that increases LFA-1 adhesive activity. In this study, we have defined the cytoplasmic region of the alphaL and beta2 integrin that are required for Rap1-stimulated adhesion and subsequent migration on ICAM-1. Human LFA-1 bearing truncated and point-mutated alphaL and beta2 cytoplasmic regions were reconstituted in mouse IL-3-dependent proB cells, BAF/3. Truncation of the alphaL, but not beta2 subunit cytoplasmic region, abolished Rap1V12-dependent adhesion to ICAM-1. The alanine substitution of two lysine residues (K1097/K1099) in the alphaL subunit was found to be critical in adhesion induced by Rap1V12, but not PMA. This mutation suppressed Rap1V12-induced LFA-1 conformation changes and ligand-binding affinity. The K1097/K1099 mutation also impaired binding to ICAM-1 induced by TCR cross-linking or SDF-1. In contrast, the alanine substitution for tyrosine in the beta2 subunit endocytosis motif inhibited internalization of LFA-1, and severely impaired detachment at the cell rear, which resulted in long-elongated cell shapes. This result demonstrates that internalization of LFA-1 is a critical step in the deadhesion process. Our study revealed novel requirements of amino acid residues of the LFA-1 cytoplasmic region in the response to the inside-out signaling and the subsequent deadhesion process.
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Affiliation(s)
- Yumi Tohyama
- Department of Molecular Immunology and Allergy, Graduate School of Medicine, Kyoto University, Japan
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28
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Anderson ME, Siahaan TJ. Targeting ICAM-1/LFA-1 interaction for controlling autoimmune diseases: designing peptide and small molecule inhibitors. Peptides 2003; 24:487-501. [PMID: 12732350 DOI: 10.1016/s0196-9781(03)00083-4] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This review describes the role of modulation of intracellular adhesion molecule-1 (ICAM-1)/leukocyte function-associated antigen-1 (LFA-1) interaction in controlling autoimmune diseases or inducing immunotolerance. ICAM-1/LFA-1 interaction is essential for T-cell activation as well as for migration of T-cells to target tissues. This interaction also functions, along with Signal-1, as a co-stimulatory signal (Signal-2) for T-cell activation, which is delivered by the T-cell receptors (TCR)-major histocompatibility complex (MHC)-peptide complex. Therefore, blocking ICAM-1/LFA-1 interaction can suppress T-cell activation in autoimmune diseases and organ transplantation. Many types of inhibitors (i.e. antibodies, peptides, small molecules) have been developed to block ICAM-1/LFA-1 interactions, and some of these molecules have reached clinical trials. Peptides derived from ICAM-1 and LFA-1 sequences have been shown to inhibit T-cell adhesion and activation. In addition, these inhibitors have been useful in elucidating the mechanism of ICAM-1/LFA-1 interaction. Besides binding to LFA-1, the ICAM-1 peptide can be internalized by LFA-1 receptors into the cytoplasmic domain of T-cells. Therefore, this ICAM-1 peptide can be utilized to selectively target toxic drugs to T-cells, thus avoiding harmful side effects. Finally, bi-functional inhibitory peptide (BPI), which is made by conjugating the antigenic peptide and an LFA-1 peptide, can alter the T-cell commitment from T-helper-1 (Th1) to T-helper-2 (Th2)-like cells, suggesting that this peptide may have a role in blocking the formation of the "immunological synapse."
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Affiliation(s)
- Meagan E Anderson
- Department of Pharmaceutical Chemistry, The University of Kansas, 2095 Constant Avenue, Lawrence, KS 66047, USA
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29
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Alon R, Feigelson S. From rolling to arrest on blood vessels: leukocyte tap dancing on endothelial integrin ligands and chemokines at sub-second contacts. Semin Immunol 2002; 14:93-104. [PMID: 11978081 DOI: 10.1006/smim.2001.0346] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In order to extravasate the bloodstream at specific sites of inflammation or antigen presentation, circulating leukocytes must rapidly translate specific adhesive and stimulatory signals into firm adhesion. Leukocyte arrest is nearly exclusively mediated by integrin receptors. Recent in vitro and in vivo evidence suggests that specialized integrins support reversible tethers that slow down selectin-initiated rolling of leukocytes prior to their arrest. In situ activation of integrin avidity by ligand and chemokine signaling can take place within fractions of seconds, resulting either in augmented reversible adhesions or immediate arrest on the vascular endothelium. The ability of leukocyte integrins to rapidly respond to these in situ avidity modulators appears to depend on preformed affinity and clustering states, which are internally regulated by cytoskeletal constraints on integrin conformation and mobility. We discuss potential regulatory mechanisms by which a given set of chemokine receptors and integrins may interact to rapidly generate high avidity, shear-resistant integrin-mediated leukocyte arrest on vascular endothelium.
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Affiliation(s)
- Ronen Alon
- Department of Immunology, Weizmann Institute of Science, Rehovot, 76100 Israel.
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30
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Rodríguez‐Fernández JL, Sánchez‐Martín L, de Frutos CA, Sancho D, Robinson M, Sánchez‐Madrid F, Cabañas C. LFA‐1 integrin and the microtubular cytoskeleton are involved in the Ca
2
+
‐mediated regulation of the activity of the tyrosine kinase PYK2 in T cells. J Leukoc Biol 2002. [DOI: 10.1189/jlb.71.3.520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- José Luis Rodríguez‐Fernández
- Instituto de Farmacología y Toxicología (Centro Mixto CSIC‐UCM), Facultad de Medicina, Universidad Complutense, Madrid, Spain
| | - Lorena Sánchez‐Martín
- Instituto de Farmacología y Toxicología (Centro Mixto CSIC‐UCM), Facultad de Medicina, Universidad Complutense, Madrid, Spain
| | - Cristina Alvarez de Frutos
- Instituto de Farmacología y Toxicología (Centro Mixto CSIC‐UCM), Facultad de Medicina, Universidad Complutense, Madrid, Spain
| | - David Sancho
- Servicio de Inmunología, Hospital de la Princesa, Madrid, Spain; and
| | | | | | - Carlos Cabañas
- Instituto de Farmacología y Toxicología (Centro Mixto CSIC‐UCM), Facultad de Medicina, Universidad Complutense, Madrid, Spain
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31
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Beals CR, Edwards AC, Gottschalk RJ, Kuijpers TW, Staunton DE. CD18 activation epitopes induced by leukocyte activation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:6113-22. [PMID: 11714770 DOI: 10.4049/jimmunol.167.11.6113] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The cell surface adhesion molecule LFA-1 coordinates leukocyte trafficking and is a costimulatory molecule for T cell activation. We developed a panel of mAbs that recognize activation epitopes on the CD18 subunit, and show that stimulation of T lymphocytes appears to be accompanied by a conformational change in a subpopulation of LFA-1 that does not require ligand binding. Activation epitope up-regulation requires divalent cations, is sensitive to cellular signal transduction events, and correlates with cell adhesion. In addition, the stimulated appearance of these activation epitopes is absent in cell lines from patients with leukocyte adhesion deficiency-1/variant that has previously been shown to be defective in LFA-1 activation. Thus, these activation epitope Abs can be used to dissect signal transmission to CD18. Evidence suggests that these CD18 activation epitopes are induced early in cellular activation and are independent of actin rearrangement necessary for avid adhesion. We have also determined that function-blocking CD18 Abs inhibit the induction of activation epitopes. One activation epitope Ab binds to a site on CD18 distinct from that of the blocking Abs, indicating that the blocking Abs suppress a conformational change in LFA-1. We also find that these neoepitopes are present on rLFA-1 with high affinity for ICAM-1 and their binding is modulated in parallel with the affinity of LFA-1 for ICAM-1. Collectively, these neoepitope Abs identify a subpopulation of LFA-1 most likely with high affinity for ICAM-1 and necessary for LFA-1 function.
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32
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Rodríguez-Fernández JL, Sánchez-Martín L, Rey M, Vicente-Manzanares M, Narumiya S, Teixidó J, Sánchez-Madrid F, Cabañas C. Rho and Rho-associated kinase modulate the tyrosine kinase PYK2 in T-cells through regulation of the activity of the integrin LFA-1. J Biol Chem 2001; 276:40518-27. [PMID: 11489881 DOI: 10.1074/jbc.m102896200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have examined the role of the small GTPase Rho and its downstream effector, the Rho-associated kinase (ROCK), in the control of the adhesive and signaling function of the lymphocyte function-associated antigen-1 (LFA-1) integrin in human T-lymphocytes. Inhibition of Rho (either by treatment with C3-exoenzyme or transfection with a dominant-negative form of Rho (N19Rho)) or ROCK (by treatment with Y-27632) results in the following: (a) partial disorganization and aggregation of cortical filamentous actin (F-actin); (b) induction of LFA-1-mediated cellular adhesion to the LFA-1 ligand intercellular adhesion molecule-1 (ICAM-1) through a mechanism involving clustering of LFA-1 molecules, rather than alterations in the level of expression or in the affinity state of this integrin; and (c) induction of cellular polarization and activation of the tyrosine kinase PYK2. Transfection of T-cells with a constitutively active form of Rho (V14Rho) blocks the clustering of LFA-1 on the membrane and the LFA-1-mediated activation of PYK2. Importantly, the activation of PYK2 caused by inhibition of Rho or ROCK takes place only when the T-cells are plated onto ICAM-1 but not when they are either prevented from interacting with ICAM-1 with anti-LFA-1 blocking antibodies or when they are plated on the nonspecific poly-l-lysine substrate. These results indicate that the small GTPase Rho regulates the tyrosine kinase PYK2 in T-cells through the F-actin-mediated control of the activity of the integrin LFA-1. These findings represent a novel paradigm for the regulation of the activity of a cytoplasmic tyrosine kinase by the small GTPase Rho.
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Affiliation(s)
- J L Rodríguez-Fernández
- Instituto de Farmacología y Toxicología CSIC, Facultad de Medicina, Universidad Complutense, 28040 Madrid, Spain
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33
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Kobayashi M, Azuma E, Ido M, Hirayama M, Jiang Q, Iwamoto S, Kumamoto T, Yamamoto H, Sakurai M, Komada Y. A pivotal role of Rho GTPase in the regulation of morphology and function of dendritic cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:3585-91. [PMID: 11564770 DOI: 10.4049/jimmunol.167.7.3585] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Dendritic cell (DC) is the most potent activator of CD4+ T cells and has unique dendrites and veils. To explore the function of Rho in DC, exoenzyme C3 from Clostridium botulinum was used as a specific inhibitor of Rho. Treatment of DC with C3 (DC/C3) resulted in profound morphological changes by losing dendrites and emerging of shrunk membrane processes that were in parallel with marked reduction of polymerized actin in the marginal area. Inactivation of Rho-associated coiled coil-containing kinase (p160ROCK) by a specific ROCK inhibitor Y-27632 also led to disappearance of dendrites of DC with retaining large membrane expansions. In scanning electron microscopy, untreated DCs interacted with CD4+ T cells more efficiently than DC/C3. Conjugate formation assay showed that the number of DCs associated with CD4+ T cells was 2-fold higher in untreated DCs than that of DC/C3. Alloantigen-presenting capacity of DC/C3 was significantly suppressed in a dose-dependent manner. Because C3 treatment did not affect the surface expression of HLA, costimulatory, and adhesion molecules of DC, we examined cytokine production of DC and naive CD4+ T cells to further elucidate the inhibitory mechanism of MLR. Unexpectedly, DC/C3 increased IL-12 production after LPS stimulation. Naive CD4+ T cells cocultured with DC/C3 produced the increased percentage of IFN-gamma-producing cells, whereas the percentage of IL-2-producing T cells was decreased. These results demonstrate that Rho GTPase in DC controls both characteristic shape and immunogenic capacity.
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Affiliation(s)
- M Kobayashi
- Department of Pediatrics and Clinical Immunology, Mie University School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan
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34
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Lupher ML, Harris EA, Beals CR, Sui LM, Liddington RC, Staunton DE. Cellular activation of leukocyte function-associated antigen-1 and its affinity are regulated at the I domain allosteric site. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:1431-9. [PMID: 11466362 DOI: 10.4049/jimmunol.167.3.1431] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The I domain of the integrin LFA-1 possesses a ligand binding interface that includes the metal ion-dependent adhesion site. Binding of the LFA-1 ligand, ICAM-1 to the metal ion-dependent adhesion site is regulated by the I domain allosteric site (IDAS). We demonstrate here that intracellular signaling leading to activation of LFA-1 binding to ICAM-1 is regulated at the IDAS. Inhibitory mutations in or proximal to the IDAS are dominant to cytoplasmic signals that activate binding to ICAM-1. In addition, mutational activation at the IDAS greatly increases the binding of lymphocyte-expressed LFA-1 to ICAM-1 in response to PMA, but does not result in constitutive binding. Binding of a novel CD18 activation epitope mAb to LFA-1 in response to soluble ICAM-1 binding was also blocked by inhibitory and was enhanced by activating IDAS mutations. Surface plasmon resonance using soluble wild-type LFA-1 and an IDAS mutant of LFA-1 indicate that the IDAS can regulate a 6-fold change in the K(d) of ICAM-1 binding. The K(d) of wild-type LFA-1 (1.2 x 10(-1) s(-1)) differed with that of the activating IDAS mutant (1.9 x 10(-2) s(-1)), but their K(a) values were identical (2.2 x 10(5) M(-1)s(-1)). We propose that IDAS regulates the binding of LFA-1 to ICAM-1 activated by intracellular signals. IDAS can control the affinity state of LFA-1 with concomitant I domain and CD18 conformational changes.
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Affiliation(s)
- M L Lupher
- ICOS Corporation, 22021 20th Avenue SE, Bothell, WA 98021, USA
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35
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Mobley JL, Shimizu Y. Measurement of Cellular Adhesion Under Static Conditions. ACTA ACUST UNITED AC 2001; Chapter 7:Unit 7.28. [DOI: 10.1002/0471142735.im0728s37] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- James L. Mobley
- University of Minnesota Medical School Minneapolis Minnesota
| | - Yoji Shimizu
- University of Minnesota Medical School Minneapolis Minnesota
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36
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Blanco-Bose WE, Blau HM. Laminin-induced change in conformation of preexisting alpha7beta1 integrin signals secondary myofiber formation. Dev Biol 2001; 233:148-60. [PMID: 11319864 DOI: 10.1006/dbio.2001.0177] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two distinct populations of myoblasts, distinguishable by alpha7 integrin expression have been hypothesized to give rise to two phases of myofiber formation in embryonic limb development. We show here that alpha7 integrin is detectable far earlier than previously reported on both "primary" and "secondary" lineage myoblasts and myofibers. An antibody (1211) that recognizes an intracellular epitope allowed detection of alpha7 integrin previously missed using an antibody (H36) that recognizes an extracellular epitope. We found that when myoblasts were isolated and cultured from different developmental stages, H36 only detected alpha7 integrin that was in direct contact with its ligand, laminin. Moreover, alpha7 integrin detection by H36 was reversible and highly localized to subcellular points of contact between myoblasts and laminin-coated 2.8-microm microspheres. Prior to secondary myofiber formation in limb embryogenesis, laminin was present but not in close proximity to clusters of primary myofibers that expressed alpha7 integrin detected by antibody 1211 using deconvolution microscopy. These results suggest that the timing of the interaction of preexisting alpha7 integrin with its ligand, laminin, is a major determinant of allosteric changes that result in an activated form of alpha7 integrin capable of transducing signals from the extracellular matrix commensurate with secondary myofiber formation.
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MESH Headings
- Animals
- Animals, Newborn
- Antibody Specificity
- Antigens, CD/genetics
- Antigens, CD/immunology
- Cell Compartmentation
- Cell Differentiation
- Cells, Cultured
- Collagen/metabolism
- Culture Techniques
- Hindlimb/cytology
- Integrin alpha Chains
- Integrins/chemistry
- Integrins/metabolism
- Laminin/metabolism
- Muscle Fibers, Skeletal/cytology
- Muscle, Skeletal/cytology
- Protein Conformation
- RNA, Messenger
- Rats
- Rats, Sprague-Dawley
- Receptors, Laminin/chemistry
- Receptors, Laminin/metabolism
- Signal Transduction
- Stem Cells/cytology
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Affiliation(s)
- W E Blanco-Bose
- Department of Molecular Pharmacology, Stanford University School of Medicine, Stanford, California 94305-5175, USA
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37
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Pleines UE, Morganti-Kossmann MC, Rancan M, Joller H, Trentz O, Kossmann T. S-100 beta reflects the extent of injury and outcome, whereas neuronal specific enolase is a better indicator of neuroinflammation in patients with severe traumatic brain injury. J Neurotrauma 2001; 18:491-8. [PMID: 11393252 DOI: 10.1089/089771501300227297] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
It has been hypothesized that immunoactivation may contribute to brain damage and affect outcome after traumatic brain injury (TBI). In order to determine the role of inflammation after TBI, we studied the interrelationship of the immune mediators sICAM-1 and IL-6 with the levels of S-100beta and neuronal specific enolase (NSE), both recognized markers of brain damage. In addition, the extent and type of cerebral injury and the neurological outcome were related to these measured markers of injury. An evident elevation of S-100beta (range of means: 2.7-81.4 ng/mL) and NSE (range of means: 2.0-81.3 ng/mL) was observed in CSF of all 13 patients during the first 3 posttraumatic days and decreased over 2 weeks. In parallel, the production of sICAM-1 (range of means: 0.7-11.9 ng/mL) and IL-6 (range of means: 0.1-8.2 ng/mL) was also markedly enhanced in CSF. The CSF means of S-100beta and NSE per patient correlated with IL-6 (r = 0.60, p < 0.05; and r = 0.64, p < 0.05, respectively), whereas the corresponding means in serum showed a significant correlation only between NSE and IL-6 (r = 0.56, p < 0.05). Maximal CSF values of NSE and sICAM-1 correlated with each other (r = 0.57, p < 0.05). The contusion sizes assessed on the CT scans correlated with the means of S-100beta (r = 0.63, p < 0.05) and NSE (r = 0.71, p < 0.05) in CSF and with the mean of S-100beta in serum, although not statistically significant (r = 0.52, p = 0.06), but not with serum NSE. Interestingly, linear regression analysis demonstrated that means of S-100beta in CSF (r = 0.78, p = 0.002) and serum (r = 0.82, p < 0.001) correlated with the GOS. These results indicate that the elevation of these parameters in CSF depends on the extent of injury and that S-100beta may be a predictor of outcome after TBI, whereas NSE reflects better the inflammatory response.
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Affiliation(s)
- U E Pleines
- Division of Research, University Hospital Zurich, Switzerland
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38
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Garcia‐Lloret MI, Winkler‐Lowen B, Guilbert LJ. Monocytes adhering by LFA‐1 to placental syncytiotrophoblasts induce local apoptosis via release of TNF‐α. A model for hematogenous initiation of placental inflammations. J Leukoc Biol 2000. [DOI: 10.1189/jlb.68.6.903] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Maria I. Garcia‐Lloret
- Department of Pediatrics, University of California, Los Angeles School of Medicine, Canada
| | - Bonnie Winkler‐Lowen
- Department of Medical Microbiology and Immunology and the University of Alberta Perinatal Research Centre, Edmonton, Canada
| | - Larry J. Guilbert
- Department of Medical Microbiology and Immunology and the University of Alberta Perinatal Research Centre, Edmonton, Canada
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39
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Abstract
The activity of integrins on leukocytes is tightly controlled, and their adhesion capacity shifts rapidly when cells emigrate from the blood to the tissues. The leukocyte-specific beta2 integrin LFA-1 (alphaLbeta2) is the most important integrin expressed by leukocytes that regulate lymphocyte migration and the initiation of an immune response through binding to ICAM-1,-2 or-3. The binding activity of LFA-1 is rapidly altered by intracellular stimuli that activate LFA-1. Although alterations in the affinity of LFA-1, which leads to enhanced ICAM-1 binding, have been proposed, evidence is emerging that dynamic reorganisation of LFA-1 into microclusters is the major mechanism that regulates its binding capacity.
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Affiliation(s)
- Y van Kooyk
- Department of Tumor Immunology, University Medical Center Nijmegen, St Radboud, P. Van Leydenlaan 25, 6525 EX, the, Nijmegen, Netherlands.
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40
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Wanten GJ, Geijtenbeek TB, Raymakers RA, van Kooyk Y, Roos D, Jansen JB, Naber AH. Medium-chain, triglyceride-containing lipid emulsions increase human neutrophil beta2 integrin expression, adhesion, and degranulation. JPEN J Parenter Enteral Nutr 2000; 24:228-33. [PMID: 10885717 DOI: 10.1177/0148607100024004228] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND To test the hypothesis that lipid emulsions with different triglyceride structures have distinct immunomodulatory properties, we analyzed human neutrophil adhesion and degranulation after lipid incubation. METHODS Neutrophils, isolated from the blood of 10 healthy volunteers, were incubated in medium or physiologic (2.5 mmol/L) emulsions containing long-chain (LCT), medium-chain (MCT), mixed LCT/MCT, or structured (SL) triglycerides. Expression of adhesion molecules and degranulation markers was evaluated by flow cytometry. Also, functional adhesion was investigated by means of a flow cytometric assay using fluorescent beads coated with the integrin ligand intercellular adhesion molecule (ICAM)-1. RESULTS Although LCT and SL had no effect, LCT/MCT significantly increased expression of the beta2 integrins lymphocyte-function-associated antigen 1 (+18%), macrophage antigen 1 (+387%), p150,95 (+82%), and (alphaDbeta2 (+230%). Degranulation marker expression for azurophilic (CD63, +210%) and specific granules (CD66b, +370%) also significantly increased, whereas L-selectin (CD62L, -70%) decreased. The effects of LCT/MCT were mimicked by the MCT emulsion. ICAM-1 adhesion (% beads bound) was increased by LCT/MCT (34% +/- 4%), whereas LCT (19% +/-3%) and SL (20% +/- 2%) had no effect compared with medium (17% +/- 3%). CONCLUSIONS LCT/MCT and MCT, contrary to LCT and SL emulsions, increased neutrophil beta2 integrin expression, adhesion, and degranulation. Apart from other emulsion constituents, triglyceride chain length might therefore be a key feature in the interaction of lipid emulsions and the phagocyte immune system.
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Affiliation(s)
- G J Wanten
- Department of Gastroenterology, University Hospital, Nijmegen, The Netherlands.
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41
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Leitinger B, Hogg N. Effects of I domain deletion on the function of the beta2 integrin lymphocyte function-associated antigen-1. Mol Biol Cell 2000; 11:677-90. [PMID: 10679023 PMCID: PMC14802 DOI: 10.1091/mbc.11.2.677] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
A subset of integrin alpha subunits contain an I domain, which is important for ligand binding. We have deleted the I domain from the beta2 integrin lymphocyte function-asssociated antigen-1 (LFA-1) and expressed the resulting non-I domain-containing integrin (DeltaI-LFA-1) in an LFA-1-deficient T cell line. DeltaI-LFA-1 showed no recognition of LFA-1 ligands, confirming the essential role of the I domain in ligand binding. Except for I domain monoclonal antibodies (mAbs), DeltaI-LFA-1 was recognized by a panel of anti-LFA-1 mAbs similarly to wild-type LFA-1. However, DeltaI-LFA-1 had enhanced expression of seven mAb epitopes that are associated with beta2 integrin activation, suggesting that it exhibited an "active" conformation. In keeping with this characteristic, DeltaI-LFA-1 induced constitutive activation of alpha4beta1 and alpha5beta1, suggesting intracellular signaling to these integrins. This "cross-talk" was not due to an effect on beta1 integrin affinity. However, the enhanced activity was susceptible to inhibition by cytochalasin D, indicating a role for the cytoskeleton, and also correlated with clustering of beta1 integrins. Thus, removal of the I domain from LFA-1 created an integrin with the hallmarks of a constitutively active receptor mediating signals into the cell. These findings suggest a key role for the I domain in controlling integrin activity.
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Affiliation(s)
- B Leitinger
- Leukocyte Adhesion Laboratory, Imperial Cancer Research Fund, London WC2A 3PX, United Kingdom.
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42
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Bleijs DA, Binnerts ME, van Vliet SJ, Figdor CG, van Kooyk Y. Low-affinity LFA-1/ICAM-3 interactions augment LFA-1/ICAM-1-mediated T cell adhesion and signaling by redistribution of LFA-1. J Cell Sci 2000; 113 ( Pt 3):391-400. [PMID: 10639327 DOI: 10.1242/jcs.113.3.391] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although ICAM-3 is implicated in both adhesion and signal transduction events of leukocytes, its low affinity for LFA-1 compared to other ligands of LFA-1 has puzzled many investigators. Here we investigated the role of ICAM-3 in supporting LFA-1-mediated ICAM-1 binding and subsequently cell signaling. We observed that although ICAM-3 binds poorly to LFA-1 expressed on resting T cells, it specifically facilitates and increases LFA-1-mediated adhesion to the high affinity ligand of LFA-1, ICAM-1. We demonstrate that low-affinity binding of LFA-1 to ICAM-3 together with ICAM-1 alters the cell surface distribution of LFA-1 dramatically, inducing large clusters of LFA-1 that facilitate ICAM-1 binding after LFA-1 activation. We found that LFA-1-mediated ICAM-1 cell-cell interactions such as T cell proliferation greatly depend on low affinity LFA-1/ICAM-3 interactions that enhance stable LFA-1/ICAM-1 cell-cell contact. Taken together, these data demonstrate that low affinity LFA-1 binding to ICAM-3 regulates strong LFA-1/ICAM-1-mediated adhesion by driving LFA-1 into clusters to facilitate cell-cell interactions that take place in the immune system.
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Affiliation(s)
- D A Bleijs
- Department of Tumor Immunology, University of Nijmegen, Nijmegen, the Netherlands
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43
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Molema G, Tervaert JW, Kroesen BJ, Helfrich W, Meijer DK, de Leij LF. CD3 directed bispecific antibodies induce increased lymphocyte-endothelial cell interactions in vitro. Br J Cancer 2000; 82:472-9. [PMID: 10646907 PMCID: PMC2363284 DOI: 10.1054/bjoc.1999.0945] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bispecific antibody (BsMAb) BIS-1 has been developed to redirect the cytolytic activity of cytotoxic T lymphocytes (CTL) to epithelial glycoprotein-2 (EGP-2) expressing tumour cells. Intravenous administration of BIS-1 F(ab')2 to carcinoma patients in a phase I/II clinical trial, caused immunomodulation as demonstrated by a rapid lymphopenia prior to a rise in plasma tumour necrosis factor-alpha and interferon-gamma levels. Yet, no lymphocyte accumulation in the tumour tissue and no anti-tumour effect could be observed. These data suggest a BsMAb-induced lymphocyte adhesion to blood vessel walls and/or generalized redistribution of the lymphocytes into tissues. In this study, we describe the effects of BIS-1 F(ab')2 binding to peripheral blood mononuclear cells (PBMC) on their capacity to interact with resting endothelial cells in vitro. Resting and pre-activated PBMC exhibited a significant increase in adhesive interaction with endothelial cells when preincubated with BIS-1 F(ab')2, followed by an increase in transendothelial migration (tem). Binding of BIS-1 F(ab')2 to PBMC affected the expression of a number of adhesion molecules involved in lymphocyte adhesion/migration. Furthermore, PBMC preincubated with BIS-1 F(ab')2 induced the expression of endothelial cell adhesion molecules E-selectin, VCAM-1 and ICAM-1 during adhesion/tem. These phenomena were related to the CD3 recognizing antibody fragment of the BsMAb and dependent on lymphocyte-endothelial cell contact. Possibly, in patients, the BIS-1 F(ab')2 infusion induced lymphopenia is a result of generalized activation of endothelial cells, leading to the formation of a temporary sink for lymphocytes. This process may distract the lymphocytes from homing to the tumour cells, and hence prevent the occurrence of BIS-1 F(ab')2 - CTL-mediated tumour cell lysis.
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Affiliation(s)
- G Molema
- Groningen University Institute for Drug Exploration, Department of Pathology and Lab Medicine, The Netherlands
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44
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Shibuya K, Lanier LL, Phillips JH, Ochs HD, Shimizu K, Nakayama E, Nakauchi H, Shibuya A. Physical and functional association of LFA-1 with DNAM-1 adhesion molecule. Immunity 1999; 11:615-23. [PMID: 10591186 DOI: 10.1016/s1074-7613(00)80136-3] [Citation(s) in RCA: 192] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Whereas ligation of the DNAM-1 adhesion molecule triggers cytotoxicity mediated by normal NK and T cells, this function was defective in NK cell clones from leukocyte adhesion deficiency syndrome. However, genetic reconstitution of cell surface expression of LFA-1 restored the ability of DNAM-1 to initiate anti-DNAM-1 mAb-induced cytotoxicity, indicating a functional relationship between DNAM-1 and LFA-1. Further studies demonstrated that LFA-1 physically associates with DNAM-1 in NK cells and anti-CD3 mAb stimulated T cells, for which serine phosphorylation of DNAM-1 plays a critical role. In addition, cross-linking of LFA-1 induces tyrosine phosphorylation of DNAM-1, for which the Fyn protein tyrosine kinase is responsible. These results indicate that DNAM-1 is involved in the LFA-1-mediated intracellular signals.
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Affiliation(s)
- K Shibuya
- Department of Immunology, Institute of Basic Medical Sciences, Center for TARA, University of Tsukuba, Japan
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45
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Shang XZ, Issekutz AC. Enhancement of monocyte transendothelial migration by granulocyte-macrophage colony-stimulating factor: requirement for chemoattractant and CD11a/CD18 mechanisms. Eur J Immunol 1999; 29:3571-82. [PMID: 10556811 DOI: 10.1002/(sici)1521-4141(199911)29:11<3571::aid-immu3571>3.0.co;2-v] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Granulocyte-macrophage colony-stimulating factor (GM-CSF) enhances and primes monocyte functions, but its role in monocyte migration is poorly understood. We examined monocyte migration across human umbilical vein endothelial cells (HUVEC) grown on filters. GM-CSF had no chemotactic or chemokinetic effect. However, GM-CSF enhanced monocyte transendothelial migration (TEM) through unstimulated and IL-1-activated (5 h) HUVEC in response to C5a or monocyte chemoattractant protein-1 in a dose-dependent fashion, increasing the migration from 28.7 +/- 5.3% to 41.8 +/- 6.2% (n = 8, p < 0.05) and from 34.8 +/- 6% to 50.3 +/- 3.1%, p < 0.05), respectively. The enhanced TEM was inhibited by monoclonal antibodies (mAb) to LFA-1, but not by mAb to Mac-1 or to VLA-4. Furthermore, GM-CSF up-regulated and activated LFA-1, as assessed by NKI-L16 neoepitope expression. The results indicate that: (1) GM-CSF can prime monocytes for increased TEM, (2) GM-CSF enhances LFA-1-mediated monocyte TEM and (3) this effect is in part mediated by increasing LFA-1 expression and activation. Thus, increased GM-CSF production may promote monocyte accumulation in inflammation not only by inducing monocytosis, but also enhancing migration.
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Affiliation(s)
- X Z Shang
- Department of Pediatrics, Dalhousie University, Halifax, Canada
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46
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Qian Y, Ainsworth AJ, Noya M. Identification of a beta 2 (CD18) molecule in a teleost species, Ictalurus punctatus Rafinesque. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 1999; 23:571-583. [PMID: 10579386 DOI: 10.1016/s0145-305x(99)00040-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Beta 2, in combination with the alpha subunit, is responsible for tight adhesion of leukocytes, especially neutrophils and macrophages, in areas of inflammation. Although identified in mammalian and avian species; the beta 2 or CD18 molecule has yet to be identified in fish. The present investigation has identified a full-length channel catfish, Ictalurus punctatus, cDNA beta 2 molecule composed of 2.8 kb and a deduced amino acid sequence of 772 amino acids. The catfish molecule has an amino acid homology ranging from 54 to 63% with mouse, bovine, rabbit, human and chicken. The channel catfish molecule retains several characteristics of mammalian beta 2 molecules, such as cysteine-rich repeat regions, N-linked glycosylation sites, and several proposed signal sequences. Expression of the beta 2 molecule on the catfish neutrophil cytoplasmic membranes is increased upon phorbol dibutyrate stimulation of the cells. Based on Western blotting and the immunoprecipitation test, the channel catfish beta 2 molecule has a molecular mass of approximately 95 kD, essentially the same as that for mammalian species. However, two additional molecules, perhaps alpha chains, of unexpected molecular mass appear to co-precipitate in the SPIT with the 95 kD CD18 molecule. These results confirm the existence and expression of a beta 2 gene in channel catfish, a species phylogenetically distant from mammalian species.
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Affiliation(s)
- Y Qian
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill 27599, USA
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47
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van Kooyk Y, van Vliet SJ, Figdor CG. The actin cytoskeleton regulates LFA-1 ligand binding through avidity rather than affinity changes. J Biol Chem 1999; 274:26869-77. [PMID: 10480895 DOI: 10.1074/jbc.274.38.26869] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To elucidate the role of the cytoskeleton regulating avidity or affinity changes in the leukocyte adhesion receptor lymphocyte function-associated antigen-1 (LFA-1) (alpha(L)beta(2)), we generated mutant cytoplasmic LFA-1 receptors and expressed these into the erythroleukemic cell line K562. We determined whether intercellular adhesion molecule-1 (ICAM-1)-mediated adhesion of LFA-1, lacking parts of its cytoplasmic tails, is regulated through receptor diffusion/clustering and/or by altered ligand binding affinity. All cytoplasmic deletion mutants that lack the complete beta(2) cytoplasmic tail and/or the conserved KVGFFKR sequence in the alpha(L) cytoplasmic tail were constitutively active and expressed high levels of the activation epitopes NKI-L16 and M24. Surprisingly, whereas these mutants showed a clustered cell surface distribution of LFA-1, the ligand-binding affinity as measured by titration of soluble ligand ICAM-1 remained unaltered. The notion that redistribution of LFA-1 does not alter ligand-binding affinity is further supported by the finding that disruption of the cytoskeleton by cytochalasin D did not alter the binding affinity nor adhesion to ICAM-1 of these mutants. Most cytoplasmic deletion mutants that spontaneously bound ICAM-1 were not capable to spread on ICAM-1, demonstrating that on these mutants LFA-1 is not coupled to the actin cytoskeleton. From these data we conclude that LFA-1-mediated cell adhesion to ICAM-1 is predominantly regulated by receptor clustering and that affinity alterations do not necessarily coincide with strong ICAM-1 binding.
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Affiliation(s)
- Y van Kooyk
- Department of Tumor Immunology, University Hospital Nijmegen St. Radboud, 6525 EX Nijmegen, The Netherlands.
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Mukasa R, Satoh A, Tominaga Y, Yamazaki M, Matsumoto K, Iigo Y, Higashida T, Kita Y, Miyasaka M, Takashi T. Development of a cell-free binding assay for rat ICAM-1/LFA-1 interactions using a novel anti-rat LFA-1 monoclonal antibody and comparison with a cell-based assay. J Immunol Methods 1999; 228:69-79. [PMID: 10556544 DOI: 10.1016/s0022-1759(99)00095-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The importance of the interaction between lymphocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) in the progression of inflammatory responses in vivo has been demonstrated mainly in rats. The present study was undertaken to develop binding assays suitable for measuring the rat ICAM-1/LFA-1 interaction in vitro. We first examined binding of rat T lymphoma FTL43 cells, which express LFA-1, to immobilized rat ICAM-1. Although FTL43 cells bound avidly to immobilized ICAM-1 and the binding was abolished with anti-LFA-1 monoclonal antibodies (mAbs), the binding was not completely inhibited by most anti-ICAM-1 mAbs. We next purified rat LFA-1 from FTL43 cells and constructed a cell-free binding assay. By using a newly developed anti-rat LFA-1 mAb RL14/9, which does not inhibit ICAM-1/LFA-1 interactions, binding of purified rat LFA-1 to immobilized ICAM-1 was successfully detected, whereas only a low signal to noise ratio was observed when binding of ICAM-1 to immobilized LFA-1 was examined. Moreover, we found that simultaneous addition of purified LFA-1 and biotinylated RL14/9 to ICAM-1-coated wells resulted in more sensitive detection of rat ICAM-1/LFA-1 binding. The binding was completely blocked with both anti-LFA-1 and anti-ICAM-1 mAbs and was much more sensitive to inhibition by the ICAM-1-IgG chimera, as compared with the cell-based assay. These results indicate that the cell-free binding assay provides a rapid and sensitive method for screening rat ICAM-1/LFA-1 antagonists, whose therapeutic effect on inflammatory diseases can further be evaluated in vivo.
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Affiliation(s)
- R Mukasa
- New Product Research Laboratories IV, Tokyo R&D Center, Daiichi Pharmaceutical, 1-16-13 Kita-kasai, Edogawa-ku, Tokyo, Japan
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de Metz J, Out TA, Wever PC, Reijneke RM, Sprangers F, Sauerwein HP, Romijn JA, ten Berge IJ. Interferon-gamma preferentially reduces memory/effector CD8 T lymphocytes in healthy subjects. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1999; 134:147-53. [PMID: 10444028 DOI: 10.1016/s0022-2143(99)90119-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
To evaluate the influence of interferon-gamma (IFN-gamma) on leukocyte dynamics, with a focus on naive and memory T cells, we studied 6 healthy subjects twice in a placebo-controlled trial: once after the administration of recombinant human IFN-gamma (rhIFN-gamma; 100 microg/m2 subcutaneously) and at least 4 weeks later, after the administration of saline solution. Additionally, we studied the expression of adhesion molecules on T lymphocytes after in vitro incubation of whole blood with rhIFN-gamma. IFN-gamma induced a significant depletion in the number of T lymphocytes (P < .05 vs control), which was more severe in the CD8+ cell subset than in the CD4+ T cell subset. The numbers of naive CD4+ T cells and memory CD4+ T cells were equally affected by IFN-gamma, whereas within the CD8+ T cell subset, memory/effector cells disappeared preferentially as compared with naive cells (P < .05 vs control). In addition, IFN-gamma induced a decrease in B cells, NK cells, and monocytes. After an initial increase, granulocyte counts decreased significantly as compared with controls. These effects appeared not to be caused by the minimal rise in plasma cortisol levels (P < .05 vs control). In vitro, IFN-gamma did not up-regulate the expression of CD11a, NKI L16, CD11b, LFA-3, or VLA-4. We conclude that the administration of a single dose of IFN-gamma to healthy subjects profoundly affects the numbers of several leukocyte subsets in the peripheral blood compartment.
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Affiliation(s)
- J de Metz
- Department of Endocrinology and Metabolism, University of Amsterdam, The Netherlands
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Huang CA, Lorf T, Arn JS, Koo GC, Blake T, Sachs DH. Characterization of a monoclonal anti-porcine CD3 antibody. Xenotransplantation 1999; 6:201-12. [PMID: 10503787 DOI: 10.1034/j.1399-3089.1999.00022.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Partially inbred miniature swine have been developed in this laboratory as a large animal model for studies related to transplantation tolerance and as a source of hematopoietic cells and organs for xenotransplantation. The identification of swine CD3 specific mAbs capable of activating or depleting T cells in vitro and inducing an immunosuppressive state in vivo greatly facilitates studies of the swine immune system, transplantation tolerance and xenotransplantation research. Flow cytometry was used to determine the phenotypic profile of the swine specific mAb 898H2-6-15 (2-6-15). The specificity of 2-6-15 was further defined biochemically by surface labeling and immunoprecipitation. The ability of this mAb to activate pig T cells in vitro was examined by several criteria including proliferation assays, calcium flux analysis and detection of surface CD25 upregulation by fluorescence activated cell sorter (FACS) analysis. Monoclonal antibody 898H2-6-15 is specific for swine CD3 and is capable of inducing proliferation and CD25 upregulation in cultured swine peripheral blood lymphocytes. In addition, it induces calcium flux in purified pig T cells. Surprisingly, in contrast to described antibodies to CD3 in swine and other species, the binding of this antibody to porcine CD3 is dependent on the presence of extracellular calcium. Thus calcium was required in order to immunoprecipitate labeled surface molecules for biochemical analysis and to stain cell surfaces for FACS analysis of swine lymphocytes. In this paper, we describe a new swine CD3 specific mAb, 898H2-6-15 (2-6-15) the characteristics of which make it an extremely useful tool for in vitro and in vivo studies of the swine immune system and xenotransplantation. The availability of swine T cell specific reagents should facilitate the monitoring of swine T cell engraftment and/or release amongst xenogeneic mixed chimeras and thymic transplant recipients as well as provide a means to treat potential GvHD across xenogeneic barriers. We are currently evaluating the in vivo effects of 2-6-15 in the pig.
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Affiliation(s)
- C A Huang
- Transplantation Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Boston 02129, USA
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