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Loebbermann J, Thornton H, Durant L, Sparwasser T, Webster KE, Sprent J, Culley FJ, Johansson C, Openshaw PJ. Regulatory T cells expressing granzyme B play a critical role in controlling lung inflammation during acute viral infection. Mucosal Immunol 2012; 5:161-72. [PMID: 22236998 PMCID: PMC3282434 DOI: 10.1038/mi.2011.62] [Citation(s) in RCA: 142] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The inflammatory response to lung infections must be tightly regulated, enabling pathogen elimination while maintaining crucial gas exchange. Using recently described "depletion of regulatory T cell" (DEREG) mice, we found that selective depletion of regulatory T cells (Tregs) during acute respiratory syncytial virus (RSV) infection enhanced viral clearance but increased weight loss, local cytokine and chemokine release, and T-cell activation and cellular influx into the lungs. Conversely, inflammation was decreased when Treg numbers and activity were boosted using interleukin-2 immune complexes. Unexpectedly, lung (but not draining lymph node) Tregs from RSV-infected mice expressed granzyme B (GzmB), and bone marrow chimeric mice with selective loss of GzmB in the Treg compartment displayed markedly enhanced cellular infiltration into the lung after infection. A crucial role for GzmB-expressing Tregs has not hitherto been described in the lung or during acute infections, but may explain the inability of children with perforin/GzmB defects to regulate immune responses to infection. The effects of RSV infection in mice with defective immune regulation closely parallel the observed effects of RSV in children with bronchiolitis, suggesting that the pathogenesis of bronchiolitis may involve an inability to regulate virus-induced inflammation.
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Affiliation(s)
- J Loebbermann
- Department of Medicine, Centre for Respiratory Infection/MRC and Asthma UK Centre, National Heart and Lung Institute, Imperial College, London, UK
| | - H Thornton
- Department of Medicine, Centre for Respiratory Infection/MRC and Asthma UK Centre, National Heart and Lung Institute, Imperial College, London, UK
| | - L Durant
- Department of Medicine, Centre for Respiratory Infection/MRC and Asthma UK Centre, National Heart and Lung Institute, Imperial College, London, UK
| | - T Sparwasser
- Institute of Infection Immunology, TWINCORE, Center for Experimental and Clinical Infection Research, Hannover, Germany
| | - K E Webster
- Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - J Sprent
- Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - F J Culley
- Department of Medicine, Centre for Respiratory Infection/MRC and Asthma UK Centre, National Heart and Lung Institute, Imperial College, London, UK
| | - C Johansson
- Department of Medicine, Centre for Respiratory Infection/MRC and Asthma UK Centre, National Heart and Lung Institute, Imperial College, London, UK,() or ()
| | - P J Openshaw
- Department of Medicine, Centre for Respiratory Infection/MRC and Asthma UK Centre, National Heart and Lung Institute, Imperial College, London, UK,() or ()
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Abstract
Inducing a strong immune response is an essential aim of vaccination. Although immune responses to virus infections are usually protective, they can also be harmful. The best-documented examples of an immune response increasing disease severity are with dengue, measles and respiratory syncytial virus infections. In the 1960s, administration of formalin-inactivated, tissue culture grown RSV (FI-RSV) was found to induce strong ELISA binding but poor virus-neutralising antibody. Infants given this 'lot 100' vaccine appeared to exhibit an increased rate of RSV infection during subsequent natural RSV outbreaks. Although it has not been possible to exactly delineate the cause of disease enhancement in man, animal models strongly suggest that it was due to strong (and perhaps unbalanced) T cell priming rather than infection-enhancing or sensitising antibody. In animal models, enhanced disease can result from over-exuberant T cell priming which recruits an abundant inflammatory infiltrate in the lung (the nature of which depends on the patterns of cytokines and chemokines produced). Formalin-treated RSV vaccination has been linked specifically to the induction of Th2 cells, which make IL-4 and IL-5 and induce a strong pulmonary eosinophilic response. The vaccine dosing regime and the interval between vaccination and challenge can be critical to the induction of protection or pathology. Defining the correlates of protection and disease enhancement in man is critical to the rational development of effective and protective vaccines against RSV.
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Affiliation(s)
- P J Openshaw
- Department of Respiratory Medicine, National Heart and Lung Institute, Imperial College of Science, Technology and Medicine at St. Mary's, Norfolk Place, W2 1PG, London, UK.
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Bee A, Culley FJ, Alkhalife IS, Bodman-Smith KB, Raynes JG, Bates PA. Transformation of Leishmania mexicana metacyclic promastigotes to amastigote-like forms mediated by binding of human C-reactive protein. Parasitology 2001; 122:521-9. [PMID: 11393825 DOI: 10.1017/s0031182001007612] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Infective metacyclic promastigote forms of Leishmania mexicana are introduced by the bite of sandfly vectors into their human hosts where they transform into the amastigote form. The kinetics of this process was examined in vitro in response to different combinations of temperature (26 degrees C or 32 degrees C), pH (7.2 or 5.5), and exposure to human serum. Little transformation occurred at 26 degrees C/pH 7.2, intermediate levels at 26 degrees C/pH 5.5 and 32 degrees C/pH 7.2, and the greatest response at 32 degrees C/pH 5.5. Transformation was stimulated by exposure to normal human serum, but was markedly reduced when serum previously incubated at 56 degrees C for 1 h was used (complement heat-inactivated). This stimulatory effect was reproduced by exposure to a single purified component of human serum, C-reactive protein (CRP). Binding of CRP to the whole surface of L. mexicana metacyclic promastigotes, including the flagella, was demonstrated by an indirect fluorescent antibody test. The effect of purified CRP was dose dependent and occurred using normal serum concentrations. The stimulatory effect of whole serum was oblated by CRP depletion and restored by addition of purified CRP. The effects of cAMP analogues indicated that transformation could be mediated via an adenylate cyclase cascade.
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Affiliation(s)
- A Bee
- Division of Molecular Biology and Immunology, Liverpool School of Tropical Medicine, UK
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Culley FJ, Brown A, Conroy DM, Sabroe I, Pritchard DI, Williams TJ. Eotaxin is specifically cleaved by hookworm metalloproteases preventing its action in vitro and in vivo. J Immunol 2000; 165:6447-53. [PMID: 11086084 DOI: 10.4049/jimmunol.165.11.6447] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Eotaxin is a potent eosinophil chemoattractant that acts selectively through CCR3, which is expressed on eosinophils, basophils, mast cells, and Th2-type T cells. This arm of the immune system is believed to have evolved to control helminthic parasites. We hypothesized that helminths may employ mechanisms to inhibit eosinophil recruitment, to prolong worm survival in the host. We observed that the excretory/secretory products of the hookworm Necator americanus inhibited eosinophil recruitment in vivo in response to eotaxin, but not leukotriene B(4), a phenomenon that could be prevented by the addition of protease inhibitors. Using Western blotting, N. americanus supernatant was shown to cause rapid proteolysis of eotaxin, but not IL-8 or eotaxin-2. N. americanus homogenate was fractionated by gel filtration chromatography, and a FACS-based bioassay measured the ability of each fraction to inhibit the activity of a variety of chemokines. This resulted in two peaks of eotaxin-degrading activity, corresponding to approximately 15 and 50 kDa molecular mass. This activity was specific for eotaxin, as responses to other agonists tested were unaffected. Proteolysis of eotaxin was prevented by EDTA and phenanthroline, indicating that metalloprotease activity was involved. Production of enzymes inactivating eotaxin may be a strategy employed by helminths to prevent recruitment and activation of eosinophils at the site of infection. As such this represents a novel mechanism of regulation of chemokine function in vivo. The existence of CCR3 ligands other than eotaxin (e.g., eotaxin-2) may reflect the evolution of host counter measures to parasite defense systems.
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Affiliation(s)
- F J Culley
- Leukocyte Biology Section, Biomedical Sciences Division, Imperial College School of Medicine, South Kensington, London, United Kingdom.
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Abstract
C-reactive protein (CRP) is a major acute phase protein in man. In order to more fully understand the physiological role of this serum protein, we have demonstrated high avidity binding for a defined chemically synthesized carbo-hydrate ligand which represents the repeating disaccharide of lipophosphoglycan, the major surface glycoconjugate of the unicellular parasite Leishmania donovani. Increasing the number of phosphorylated disaccharides in a molecule from one up to seven did not increase the avidity for CRP, however increasing this to 10 potential CRP binding sites did. In order to define the important features of this complex and variable structure for CRP binding we competed CRP binding to whole Leishmania parasites with amino, sulfated, phosphorylated, and unsubstituted monosaccharides, of which only phosphorylated monosaccharides were able to inhibit. Both the carbohydrate and the position of phosphorylation influenced the avidity for CRP. Synthetic oligosaccharides and phospho-oligosaccharides of various lengths and conformations were used to define the structural requirements for CRP recognition. The optimum structure for recognition of a single phosphate group was between two monosaccharide pyranose rings, and within a linear rather than a cyclic molecule. This stresses the importance of the interaction of the CRP binding site with both the carbohydrate and the phosphate group. CRP function may be mediated via the recognition of large arrays of phosphorylated carbohydrates as are characteristic of the surface of microorganisms.
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Affiliation(s)
- F J Culley
- Immunology Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK and
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Affiliation(s)
- F J Culley
- Department of Clinical Sciences, London School of Hygiene and Tropical Medicine
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Culley FJ, Harris RA, Kaye PM, McAdam KP, Raynes JG. C-reactive protein binds to a novel ligand on Leishmania donovani and increases uptake into human macrophages. The Journal of Immunology 1996. [DOI: 10.4049/jimmunol.156.12.4691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
C-reactive protein (CRP) is a major acute phase protein of man, with serum concentrations increasing dramatically following stimulation of hepatocytes by inflammatory cytokines. However, the role of CRP in inflammation and resistance to infection is still poorly understood. Here, the specificity of CRP binding to the surface of Leishmania donovani, an obligate intracellular parasite of mononuclear phagocytes, is described. CRP is shown to bind to promastigotes at the infectious metacyclic stage of development, at concentrations found in normal human serum. The presence of CRP on the surface of promastigotes substantially increases uptake into human monocyte-derived macrophages. Unusually, CRP does not bind via its characteristic ligand, phosphorylcholine. We show that CRP binds to the lipophosphoglycan (LPG) component of the promastigote cell surface, a molecule implicated in both uptake and survival of these parasites within the macrophage, and also to the major secreted protein of promastigotes, secreted acid phosphatase. Using mAb to LPG with known ligand specificities, we define a novel ligand for CRP as the repeating phosphorylated disaccharide units that form the backbone of LPG.
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Affiliation(s)
- F J Culley
- Department of Clinical Sciences, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - R A Harris
- Department of Clinical Sciences, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - P M Kaye
- Department of Clinical Sciences, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - K P McAdam
- Department of Clinical Sciences, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - J G Raynes
- Department of Clinical Sciences, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Culley FJ, Harris RA, Kaye PM, McAdam KP, Raynes JG. C-reactive protein binds to a novel ligand on Leishmania donovani and increases uptake into human macrophages. J Immunol 1996; 156:4691-6. [PMID: 8648114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
C-reactive protein (CRP) is a major acute phase protein of man, with serum concentrations increasing dramatically following stimulation of hepatocytes by inflammatory cytokines. However, the role of CRP in inflammation and resistance to infection is still poorly understood. Here, the specificity of CRP binding to the surface of Leishmania donovani, an obligate intracellular parasite of mononuclear phagocytes, is described. CRP is shown to bind to promastigotes at the infectious metacyclic stage of development, at concentrations found in normal human serum. The presence of CRP on the surface of promastigotes substantially increases uptake into human monocyte-derived macrophages. Unusually, CRP does not bind via its characteristic ligand, phosphorylcholine. We show that CRP binds to the lipophosphoglycan (LPG) component of the promastigote cell surface, a molecule implicated in both uptake and survival of these parasites within the macrophage, and also to the major secreted protein of promastigotes, secreted acid phosphatase. Using mAb to LPG with known ligand specificities, we define a novel ligand for CRP as the repeating phosphorylated disaccharide units that form the backbone of LPG.
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Affiliation(s)
- F J Culley
- Department of Clinical Sciences, London School of Hygiene and Tropical Medicine, London, United Kingdom
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