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Albrecht-Schgoer K, Lackner P, Schmutzhard E, Baier G. Cerebral Malaria: Current Clinical and Immunological Aspects. Front Immunol 2022; 13:863568. [PMID: 35514965 PMCID: PMC9067128 DOI: 10.3389/fimmu.2022.863568] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/21/2022] [Indexed: 11/23/2022] Open
Abstract
This review focuses on current clinical and immunological aspects of cerebral malaria induced by Plasmodium falciparum infection. Albeit many issues concerning the inflammatory responses remain unresolved and need further investigations, current knowledge of the underlying molecular mechanisms is highlighted. Furthermore, and in the light of significant limitations in preventative diagnosis and treatment of cerebral malaria, this review mainly discusses our understanding of immune mechanisms in the light of the most recent research findings. Remarkably, the newly proposed CD8+ T cell-driven pathophysiological aspects within the central nervous system are summarized, giving first rational insights into encouraging studies with immune-modulating adjunctive therapies that protect from symptomatic cerebral participation of Plasmodium falciparum infection.
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Affiliation(s)
- Karin Albrecht-Schgoer
- Division of Translational Cell Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Peter Lackner
- Department of Neurology, Klinik Floridsdorf, Wien, Austria
| | - Erich Schmutzhard
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Gottfried Baier
- Division of Translational Cell Genetics, Medical University of Innsbruck, Innsbruck, Austria
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2
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Kuehlwein JM, Borsche M, Korir PJ, Risch F, Mueller A, Hübner MP, Hildner K, Hoerauf A, Dunay IR, Schumak B. Protection of Batf3-deficient mice from experimental cerebral malaria correlates with impaired cytotoxic T-cell responses and immune regulation. Immunology 2020; 159:193-204. [PMID: 31631339 PMCID: PMC6954726 DOI: 10.1111/imm.13137] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 09/30/2019] [Accepted: 10/14/2019] [Indexed: 12/28/2022] Open
Abstract
Excessive inflammatory immune responses during infections with Plasmodium parasites are responsible for severe complications such as cerebral malaria (CM) that can be studied experimentally in mice. Dendritic cells (DCs) activate cytotoxic CD8+ T-cells and initiate immune responses against the parasites. Batf3-/- mice lack a DC subset, which efficiently induces strong CD8 T-cell responses by cross-presentation of exogenous antigens. Here we show that Batf3-/- mice infected with Plasmodium berghei ANKA (PbA) were protected from experimental CM (ECM), characterized by a stable blood-brain barrier (BBB) and significantly less infiltrated peripheral immune cells in the brain. Importantly, the absence of ECM in Batf3-/- mice correlated with attenuated responses of cytotoxic T-cells, as their parasite-specific lytic activity as well as the production of interferon gamma and granzyme B were significantly decreased. Remarkably, spleens of ECM-protected Batf3-/- mice had elevated levels of regulatory immune cells and interleukin 10. Thus, protection from ECM in PbA-infected Batf3-/- mice was associated with the absence of strong CD8+ T-cell activity and induction of immunoregulatory mediators and cells.
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MESH Headings
- Animals
- Basic-Leucine Zipper Transcription Factors/deficiency
- Basic-Leucine Zipper Transcription Factors/genetics
- Blood-Brain Barrier/immunology
- Blood-Brain Barrier/parasitology
- Brain/immunology
- Brain/metabolism
- Brain/parasitology
- Cells, Cultured
- Dendritic Cells/immunology
- Dendritic Cells/metabolism
- Dendritic Cells/parasitology
- Disease Models, Animal
- Female
- Granzymes/immunology
- Granzymes/metabolism
- Host-Parasite Interactions
- Interferon-gamma/immunology
- Interferon-gamma/metabolism
- Interleukin-10/immunology
- Interleukin-10/metabolism
- Malaria, Cerebral/immunology
- Malaria, Cerebral/metabolism
- Malaria, Cerebral/parasitology
- Malaria, Cerebral/prevention & control
- Mice, Inbred C57BL
- Mice, Knockout
- Plasmodium berghei/immunology
- Plasmodium berghei/pathogenicity
- Repressor Proteins/deficiency
- Repressor Proteins/genetics
- Spleen/immunology
- Spleen/metabolism
- Spleen/parasitology
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/metabolism
- T-Lymphocytes, Cytotoxic/parasitology
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Affiliation(s)
- Janina M. Kuehlwein
- Institute of Medical Microbiology, Immunology and ParasitologyUniversity Hospital BonnBonnGermany
| | - Max Borsche
- Institute of Medical Microbiology, Immunology and ParasitologyUniversity Hospital BonnBonnGermany
| | - Patricia J. Korir
- Institute of Medical Microbiology, Immunology and ParasitologyUniversity Hospital BonnBonnGermany
| | - Frederic Risch
- Institute of Medical Microbiology, Immunology and ParasitologyUniversity Hospital BonnBonnGermany
| | - Ann‐Kristin Mueller
- Parasitology UnitCentre for Infectious DiseasesHeidelberg University HospitalHeidelbergGermany
- DZIF German Center for Infection ResearchPartner Site HeidelbergHeidelbergGermany
| | - Marc P. Hübner
- Institute of Medical Microbiology, Immunology and ParasitologyUniversity Hospital BonnBonnGermany
| | - Kai Hildner
- Medical Department 1University Hospital ErlangenErlangenGermany
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and ParasitologyUniversity Hospital BonnBonnGermany
- DZIF German Center for Infection ResearchPartner Site Bonn‐CologneBonnGermany
| | - Ildiko Rita Dunay
- Institute of Inflammation and NeurodegenerationUniversity of MagdeburgMagdeburgGermany
| | - Beatrix Schumak
- Institute of Medical Microbiology, Immunology and ParasitologyUniversity Hospital BonnBonnGermany
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3
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Gbedande K, Carpio VH, Stephens R. Using two phases of the CD4 T cell response to blood-stage murine malaria to understand regulation of systemic immunity and placental pathology in Plasmodium falciparum infection. Immunol Rev 2020; 293:88-114. [PMID: 31903675 PMCID: PMC7540220 DOI: 10.1111/imr.12835] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 12/08/2019] [Accepted: 12/09/2019] [Indexed: 02/06/2023]
Abstract
Plasmodium falciparum infection and malaria remain a risk for millions of children and pregnant women. Here, we seek to integrate knowledge of mouse and human T helper cell (Th) responses to blood-stage Plasmodium infection to understand their contribution to protection and pathology. Although there is no complete Th subset differentiation, the adaptive response occurs in two phases in non-lethal rodent Plasmodium infection, coordinated by Th cells. In short, cellular immune responses limit the peak of parasitemia during the first phase; in the second phase, humoral immunity from T cell-dependent germinal centers is critical for complete clearance of rapidly changing parasite. A strong IFN-γ response kills parasite, but an excess of TNF compared with regulatory cytokines (IL-10, TGF-β) can cause immunopathology. This common pathway for pathology is associated with anemia, cerebral malaria, and placental malaria. These two phases can be used to both understand how the host responds to rapidly growing parasite and how it attempts to control immunopathology and variation. This dual nature of T cell immunity to Plasmodium is discussed, with particular reference to the protective nature of the continuous generation of effector T cells, and the unique contribution of effector memory T cells.
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Affiliation(s)
- Komi Gbedande
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas
| | - Victor H Carpio
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas
| | - Robin Stephens
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas
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4
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Faleiro R, Karunarathne DS, Horne-Debets JM, Wykes M. The Contribution of Co-signaling Pathways to Anti-malarial T Cell Immunity. Front Immunol 2018; 9:2926. [PMID: 30631323 PMCID: PMC6315188 DOI: 10.3389/fimmu.2018.02926] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 11/29/2018] [Indexed: 12/30/2022] Open
Abstract
Plasmodium spp., the causative agent of malaria, caused 212 million infections in 2016 with 445,000 deaths, mostly in children. Adults acquire enough immunity to prevent clinical symptoms but never develop sterile immunity. The only vaccine for malaria, RTS,S, shows promising protection of a limited duration against clinical malaria in infants but no significant protection against severe disease. There is now abundant evidence that T cell functions are inhibited during malaria, which may explain why vaccine are not efficacious. Studies have now clearly shown that T cell immunity against malaria is subdued by multiple the immune regulatory receptors, in particular, by programmed cell-death-1 (PD-1). Given there is an urgent need for an efficacious malarial treatment, compounded with growing drug resistance, a better understanding of malarial immunity is essential. This review will examine molecular signals that affect T cell-mediated immunity against malaria.
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Affiliation(s)
- Rebecca Faleiro
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | | | | | - Michelle Wykes
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
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Muscate F, Stetter N, Schramm C, Schulze Zur Wiesch J, Bosurgi L, Jacobs T. HVEM and CD160: Regulators of Immunopathology During Malaria Blood-Stage. Front Immunol 2018; 9:2611. [PMID: 30483269 PMCID: PMC6243049 DOI: 10.3389/fimmu.2018.02611] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 10/23/2018] [Indexed: 12/29/2022] Open
Abstract
CD8+ T cells are key players during infection with the malaria parasite Plasmodium berghei ANKA (PbA). While they cannot provide protection against blood-stage parasites, they can cause immunopathology, thus leading to the severe manifestation of cerebral malaria. Hence, the tight control of CD8+ T cell function is key in order to prevent fatal outcomes. One major mechanism to control CD8+ T cell activation, proliferation and effector function is the integration of co-inhibitory and co-stimulatory signals. In this study, we show that one such pathway, the HVEM-CD160 axis, significantly impacts CD8+ T cell regulation and thereby the incidence of cerebral malaria. Here, we show that the co-stimulatory molecule HVEM is indeed required to maintain CD8+ T effector populations during infection. Additionally, by generating a CD160-/- mouse line, we observe that the HVEM ligand CD160 counterbalances stimulatory signals in highly activated and cytotoxic CD8+ T effector cells, thereby restricting immunopathology. Importantly, CD160 is also induced on cytotoxic CD8+ T cells during acute Plasmodium falciparum malaria in humans. In conclusion, CD160 is specifically expressed on highly activated CD8+ T effector cells that are harmful during the blood-stage of malaria.
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Affiliation(s)
- Franziska Muscate
- Protozoa Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Nadine Stetter
- Protozoa Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Christoph Schramm
- 1st Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.,Martin Zeitz Centre for Rare Diseases, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | | | - Lidia Bosurgi
- Protozoa Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,1st Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Thomas Jacobs
- Protozoa Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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The Lymphotoxin β Receptor Is Essential for Upregulation of IFN-Induced Guanylate-Binding Proteins and Survival after Toxoplasma gondii Infection. Mediators Inflamm 2017; 2017:7375818. [PMID: 28845089 PMCID: PMC5563413 DOI: 10.1155/2017/7375818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 05/23/2017] [Accepted: 06/07/2017] [Indexed: 12/22/2022] Open
Abstract
Lymphotoxin β receptor (LTβR) signaling plays an important role in efficient initiation of host responses to a variety of pathogens, encompassing viruses, bacteria, and protozoans via induction of the type I interferon response. The present study reveals that after Toxoplasma gondii infection, LTβR−/− mice show a substantially reduced survival rate when compared to wild-type mice. LTβR−/− mice exhibit an increased parasite load and a more pronounced organ pathology. Also, a delayed increase of serum IL-12p40 and a failure of the protective IFNγ response in LTβR−/− mice were observed. Serum NO levels in LTβR−/− animals rose later and were markedly decreased compared to wild-type animals. At the transcriptional level, LTβR−/− animals exhibited a deregulated expression profile of several cytokines known to play a role in activation of innate immunity in T. gondii infection. Importantly, expression of the IFNγ-regulated murine guanylate-binding protein (mGBP) genes was virtually absent in the lungs of LTβR−/− mice. This demonstrates clearly that the LTβR is essential for the induction of a type II IFN-mediated immune response against T. gondii. The pronounced inability to effectively upregulate host defense effector molecules such as GBPs explains the high mortality rates of LTβR−/− animals after T. gondii infection.
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Cai H, Chen S, Xu S, Sun Y, Bai Q, Lu C, Chen Y, Fu X, Xu G, Chen L. Deficiency of LIGHT signaling pathway exacerbates Chlamydia psittaci respiratory tract infection in mice. Microb Pathog 2016; 100:250-256. [PMID: 27725282 DOI: 10.1016/j.micpath.2016.10.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 09/27/2016] [Accepted: 10/06/2016] [Indexed: 11/28/2022]
Abstract
LIGHT, a costimulatory member of the immunoglobulin superfamily (Ig SF), can greatly impact T cell activation. The role of the LIGHT signaling pathway in chlamydial infection was evaluated in mice following respiratory tract infection with Chlamydia psittaci. Compared with wild type (WT) mice, LIGHT knockout (KO) mice showed significant reduction of body weight, much lower survival rate, higher bacterial burden, prolonged infection time courses and more severe pathological changes in lung tissue. The mRNA levels of IFN-γ, TNF-α, IL-17 and IL-12 in the lung tissue of LIGHT KO mice were significantly lower than those in WT mice. While there was no obvious difference in the percentages of CD4+ and CD8+ T cells in the spleens of the two groups of mice, there was a markedly elevated percentage of CD4+ CD25+ FoxP3+ Treg cells in LIGHT KO mice. Together, these results demonstrate that the LIGHT signaling pathway is not only required for inflammatory cytokine production as part of the host response to chlamydial infection, but also influences the differentiation of CD4+ CD25+ FoxP3+ Treg cells, both of which may be essential for control of C. psittaci respiratory tract infection.
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Affiliation(s)
- Hengling Cai
- College of Public Health, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China; Medical College, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China
| | - Shenghua Chen
- Medical College, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China
| | - Sha Xu
- College of Public Health, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China
| | - Yuanbin Sun
- College of Public Health, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China
| | - Qinqin Bai
- College of Public Health, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China
| | - Chunxue Lu
- Medical College, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China
| | - Yuyu Chen
- Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 421000, China
| | - Xizong Fu
- College of Public Health, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China
| | - Guilian Xu
- Institute of Immunology, The Third Military Medical University, Chongqing 400038, China.
| | - Lili Chen
- College of Public Health, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China.
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8
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Seleznik G, Seeger H, Bauer J, Fu K, Czerkowicz J, Papandile A, Poreci U, Rabah D, Ranger A, Cohen CD, Lindenmeyer M, Chen J, Edenhofer I, Anders HJ, Lech M, Wüthrich RP, Ruddle NH, Moeller MJ, Kozakowski N, Regele H, Browning JL, Heikenwalder M, Segerer S. The lymphotoxin β receptor is a potential therapeutic target in renal inflammation. Kidney Int 2016; 89:113-26. [PMID: 26398497 DOI: 10.1038/ki.2015.280] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 07/14/2015] [Accepted: 07/16/2015] [Indexed: 02/07/2023]
Abstract
Accumulation of inflammatory cells in different renal compartments is a hallmark of progressive kidney diseases including glomerulonephritis (GN). Lymphotoxin β receptor (LTβR) signaling is crucial for the formation of lymphoid tissue, and inhibition of LTβR signaling has ameliorated several non-renal inflammatory models. Therefore, we tested whether LTβR signaling could also have a role in renal injury. Renal biopsies from patients with GN were found to express both LTα and LTβ ligands, as well as LTβR. The LTβR protein and mRNA were localized to tubular epithelial cells, parietal epithelial cells, crescents, and cells of the glomerular tuft, whereas LTβ was found on lymphocytes and tubular epithelial cells. Human tubular epithelial cells, mesangial cells, and mouse parietal epithelial cells expressed both LTα and LTβ mRNA upon stimulation with TNF in vitro. Several chemokine mRNAs and proteins were expressed in response to LTβR signaling. Importantly, in a murine lupus model, LTβR blockade improved renal function without the reduction of serum autoantibody titers or glomerular immune complex deposition. Thus, a preclinical mouse model and human studies strongly suggest that LTβR signaling is involved in renal injury and may be a suitable therapeutic target in renal diseases.
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Affiliation(s)
- Gitta Seleznik
- Division of Visceral & Transplantation Surgery, Swiss Hepato-Pancreato-Biliary Center, Zurich, Switzerland; Division of Nephrology, University Hospital, Zurich, Switzerland
| | - Harald Seeger
- Division of Nephrology, University Hospital, Zurich, Switzerland; Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Judith Bauer
- Institute of Virology, Technische Universität München, Helmholz Zentrum, Munich, Germany
| | - Kai Fu
- Department of Immunobiology, Biogen, Cambridge, Massachusetts, USA
| | - Julie Czerkowicz
- Department of Immunobiology, Biogen, Cambridge, Massachusetts, USA
| | - Adrian Papandile
- Department of Immunobiology, Biogen, Cambridge, Massachusetts, USA
| | - Uriana Poreci
- Department of Immunobiology, Biogen, Cambridge, Massachusetts, USA
| | - Dania Rabah
- Department of Immunobiology, Biogen, Cambridge, Massachusetts, USA
| | - Ann Ranger
- Department of Immunobiology, Biogen, Cambridge, Massachusetts, USA
| | - Clemens D Cohen
- Division of Nephrology, University Hospital, Zurich, Switzerland; Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Maja Lindenmeyer
- Division of Nephrology, University Hospital, Zurich, Switzerland; Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Jin Chen
- Division of Nephrology, University Hospital, Zurich, Switzerland; Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Ilka Edenhofer
- Division of Nephrology, University Hospital, Zurich, Switzerland; Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Hans J Anders
- Division of Nephrology, Medizinische Klinik und Poliklinik IV, Campus Innenstadt, University of Munich-LMU, Munich, Germany
| | - Maciej Lech
- Division of Nephrology, Medizinische Klinik und Poliklinik IV, Campus Innenstadt, University of Munich-LMU, Munich, Germany
| | - Rudolf P Wüthrich
- Division of Nephrology, University Hospital, Zurich, Switzerland; Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Nancy H Ruddle
- Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, USA
| | - Marcus J Moeller
- Department of Nephrology and Clinical Immunology, Rheinisch-Westfälische Technische Hochschule (RWTH) University Hospital Aachen, Aachen, Germany
| | | | - Heinz Regele
- Clinical Institute of Pathology, University of Vienna, Vienna, Austria
| | - Jeffrey L Browning
- Department of Immunobiology, Biogen, Cambridge, Massachusetts, USA; Department of Microbiology and Section of Rheumatology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Mathias Heikenwalder
- Institute of Virology, Technische Universität München, Helmholz Zentrum, Munich, Germany; Institute of Surgical Pathology, University Hospital, Zurich, Switzerland
| | - Stephan Segerer
- Division of Nephrology, University Hospital, Zurich, Switzerland; Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.
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Pai S, Qin J, Cavanagh L, Mitchell A, El-Assaad F, Jain R, Combes V, Hunt NH, Grau GER, Weninger W. Real-time imaging reveals the dynamics of leukocyte behaviour during experimental cerebral malaria pathogenesis. PLoS Pathog 2014; 10:e1004236. [PMID: 25033406 PMCID: PMC4102563 DOI: 10.1371/journal.ppat.1004236] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 05/23/2014] [Indexed: 02/02/2023] Open
Abstract
During experimental cerebral malaria (ECM) mice develop a lethal neuropathological syndrome associated with microcirculatory dysfunction and intravascular leukocyte sequestration. The precise spatio-temporal context in which the intravascular immune response unfolds is incompletely understood. We developed a 2-photon intravital microscopy (2P-IVM)-based brain-imaging model to monitor the real-time behaviour of leukocytes directly within the brain vasculature during ECM. Ly6Chi monocytes, but not neutrophils, started to accumulate in the blood vessels of Plasmodium berghei ANKA (PbA)-infected MacGreen mice, in which myeloid cells express GFP, one to two days prior to the onset of the neurological signs (NS). A decrease in the rolling speed of monocytes, a measure of endothelial cell activation, was associated with progressive worsening of clinical symptoms. Adoptive transfer experiments with defined immune cell subsets in recombinase activating gene (RAG)-1-deficient mice showed that these changes were mediated by Plasmodium-specific CD8+ T lymphocytes. A critical number of CD8+ T effectors was required to induce disease and monocyte adherence to the vasculature. Depletion of monocytes at the onset of disease symptoms resulted in decreased lymphocyte accumulation, suggesting reciprocal effects of monocytes and T cells on their recruitment within the brain. Together, our studies define the real-time kinetics of leukocyte behaviour in the central nervous system during ECM, and reveal a significant role for Plasmodium-specific CD8+ T lymphocytes in regulating vascular pathology in this disease. Cerebral malaria (CM) is a severe complication of Plasmodium falciparum infection that takes a significant toll on human life. Blockage of the brain blood vessels contributes to the clinical signs of CM, however we know little about the precise pathological events that lead to this disease. To this end, studies in Plasmodium-infected mice, that also develop a similar fatal disease, have proven useful. These studies have revealed an important role for leukocytes not so much in protecting but rather promoting pathology in the brain. To better understand leukocyte behaviour during experimental CM, we established a brain-imaging model that allows us to ‘peek’ into the brain of living mice and watch immunological events as they unfold. We found that worsening of disease was accompanied by an accumulation of monocytes in the blood vessels. Monocyte accumulation was regulated by activated CD8+ T cells but only when present in critical numbers. Monocyte depletion resulted in reduced T cell trafficking to the brain, but this did not result in improved disease outcome. Our studies reveal the orchestration of leukocyte accumulation in real time during CM, and demonstrate that CD8+ T cells play a crucial role in promoting clinical signs in this disease.
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Affiliation(s)
- Saparna Pai
- Immune Imaging Laboratory, The Centenary Institute, Newtown, Sydney, New South Wales, Australia
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
- * E-mail: (SP); (WW)
| | - Jim Qin
- Immune Imaging Laboratory, The Centenary Institute, Newtown, Sydney, New South Wales, Australia
| | - Lois Cavanagh
- Immune Imaging Laboratory, The Centenary Institute, Newtown, Sydney, New South Wales, Australia
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Andrew Mitchell
- Immune Imaging Laboratory, The Centenary Institute, Newtown, Sydney, New South Wales, Australia
| | - Fatima El-Assaad
- Vascular Immunology Unit, Discipline of Pathology, Sydney Medical School, University of Sydney, Camperdown, Sydney, New South Wales, Australia
| | - Rohit Jain
- Immune Imaging Laboratory, The Centenary Institute, Newtown, Sydney, New South Wales, Australia
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Valery Combes
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
- Vascular Immunology Unit, Discipline of Pathology, Sydney Medical School, University of Sydney, Camperdown, Sydney, New South Wales, Australia
| | - Nicholas H. Hunt
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
- Molecular Immunopathology Unit, Discipline of Pathology, Sydney Medical School and Bosch Institute, University of Sydney, Camperdown, Sydney, New South Wales, Australia
| | - Georges E. R. Grau
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
- Vascular Immunology Unit, Discipline of Pathology, Sydney Medical School, University of Sydney, Camperdown, Sydney, New South Wales, Australia
| | - Wolfgang Weninger
- Immune Imaging Laboratory, The Centenary Institute, Newtown, Sydney, New South Wales, Australia
- Discipline of Dermatology, University of Sydney, Sydney, New South Wales, Australia
- Department of Dermatology, Royal Prince Alfred Hospital, Camperdown, Sydney, New South Wales, Australia
- * E-mail: (SP); (WW)
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10
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Maglinao M, Klopfleisch R, Seeberger PH, Lepenies B. The C-type lectin receptor DCIR is crucial for the development of experimental cerebral malaria. THE JOURNAL OF IMMUNOLOGY 2013; 191:2551-9. [PMID: 23918990 DOI: 10.4049/jimmunol.1203451] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cerebral malaria (CM) is the most severe complication of malaria. The murine Plasmodium berghei ANKA (PbA) infection model has helped to identify crucial players in the pathogenesis of CM. However, the role of pattern recognition receptors in innate immunity to CM induction is still poorly understood. C-type lectin receptors (CLRs) represent a family of pattern recognition receptors that recognize carbohydrate structures on pathogens and self-Ags often in a Ca(2+)-dependent manner. In this study, we investigated the role of the CLR dendritic cell immunoreceptor (DCIR) in the genesis of CM. Using the murine PbA infection, we show in this article that DCIR is essential for the development of CM. Although PbA infection led to 80% CM in wild-type C57BL/6 mice, DCIR-deficient mice were highly protected with only 15% CM development. In accordance with the reduced CM incidence in DCIR(-/-) mice, CD8(+) T cell sequestration was markedly reduced in brains of PbA-infected DCIR(-/-) mice, which was accompanied by reduced brain inflammation. Reduced T cell sequestration in the brain was caused by decreased TNF-α levels in sera, as well as a modulated activation of CD4(+) and CD8(+) T cells in spleen of PbA-infected DCIR(-/-) mice. This study indicates that DCIR is critically involved in CM induction, thus highlighting the importance of this CLR in innate immunity during malaria infection.
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Affiliation(s)
- Maha Maglinao
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
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Maña P, Liñares D, Silva DG, Fordham S, Scheu S, Pfeffer K, Staykova M, Bertram EM. LIGHT (TNFSF14/CD258) Is a Decisive Factor for Recovery from Experimental Autoimmune Encephalomyelitis. THE JOURNAL OF IMMUNOLOGY 2013; 191:154-63. [DOI: 10.4049/jimmunol.1203016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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12
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Stanley AC, de Labastida Rivera F, Haque A, Sheel M, Zhou Y, Amante FH, Bunn PT, Randall LM, Pfeffer K, Scheu S, Hickey MJ, Saunders BM, Ware C, Hill GR, Tamada K, Kaye PM, Engwerda CR. Critical roles for LIGHT and its receptors in generating T cell-mediated immunity during Leishmania donovani infection. PLoS Pathog 2011; 7:e1002279. [PMID: 21998581 PMCID: PMC3188526 DOI: 10.1371/journal.ppat.1002279] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 08/08/2011] [Indexed: 11/18/2022] Open
Abstract
LIGHT (TNFSF14) is a member of the TNF superfamily involved in inflammation and defence against infection. LIGHT signals via two cell-bound receptors; herpes virus entry mediator (HVEM) and lymphotoxin-beta receptor (LTβR). We found that LIGHT is critical for control of hepatic parasite growth in mice with visceral leishmaniasis (VL) caused by infection with the protozoan parasite Leishmania donovani. LIGHT-HVEM signalling is essential for early dendritic cell IL-12/IL-23p40 production, and the generation of IFNγ- and TNF-producing T cells that control hepatic infection. However, we also discovered that LIGHT-LTβR interactions suppress anti-parasitic immunity in the liver in the first 7 days of infection by mechanisms that restrict both CD4+ T cell function and TNF-dependent microbicidal mechanisms. Thus, we have identified distinct roles for LIGHT in infection, and show that manipulation of interactions between LIGHT and its receptors may be used for therapeutic advantage. Visceral leishmaniasis (VL) is a potentially fatal human disease caused by the intracellular protozoan parasites Leishmania donovani and L. infantum (chagasi). Parasites infect macrophages throughout the viscera, though the spleen and liver are the major sites of disease. VL is responsible for significant morbidity and mortality in the developing world, particularly in India, Sudan, Nepal, Bangladesh and Brazil. Because of the intrusive techniques required to analyse tissue in VL patients, our current understanding of the host immune response during VL largely derives from studies performed in genetically susceptible mice. We have discovered that mice which are unable to produce a cytokine called LIGHT have poor control of L. donovani infection in the liver, compared with wild-type control animals. In addition, we demonstrated that LIGHT has distinct roles during VL, depending on which of its two major cell-bound receptors it engages. Finally, we identified an antibody that stimulates the lymphotoxin β receptor (one of the LIGHT receptors), that can stimulate anti-parasitic activity during an established infection, thereby identifying this receptor as a therapeutic target during disease.
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MESH Headings
- Animals
- Antibodies, Monoclonal/pharmacology
- Cell Proliferation/drug effects
- Dendritic Cells/immunology
- Dendritic Cells/metabolism
- Female
- Immunity, Cellular
- Interferon-gamma/immunology
- Interferon-gamma/metabolism
- Interleukin-12/biosynthesis
- Interleukin-23/biosynthesis
- Leishmania donovani/immunology
- Leishmania donovani/pathogenicity
- Leishmaniasis, Visceral/immunology
- Leishmaniasis, Visceral/parasitology
- Leishmaniasis, Visceral/pathology
- Liver/parasitology
- Liver/pathology
- Lymphotoxin beta Receptor/immunology
- Lymphotoxin beta Receptor/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Receptors, Tumor Necrosis Factor, Member 14/immunology
- Receptors, Tumor Necrosis Factor, Member 14/metabolism
- Signal Transduction
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- Tumor Necrosis Factor Ligand Superfamily Member 14/genetics
- Tumor Necrosis Factor Ligand Superfamily Member 14/metabolism
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Affiliation(s)
- Amanda C. Stanley
- Queensland Institute of Medical Research and the Australian Centre for Vaccine Development, Herston, Queensland, Australia
- Institute for Molecular Biology, University of Queensland, St Lucia, Queensland, Australia
| | - Fabian de Labastida Rivera
- Queensland Institute of Medical Research and the Australian Centre for Vaccine Development, Herston, Queensland, Australia
| | - Ashraful Haque
- Queensland Institute of Medical Research and the Australian Centre for Vaccine Development, Herston, Queensland, Australia
| | - Meru Sheel
- Queensland Institute of Medical Research and the Australian Centre for Vaccine Development, Herston, Queensland, Australia
| | - Yonghong Zhou
- Queensland Institute of Medical Research and the Australian Centre for Vaccine Development, Herston, Queensland, Australia
| | - Fiona H. Amante
- Queensland Institute of Medical Research and the Australian Centre for Vaccine Development, Herston, Queensland, Australia
| | - Patrick T. Bunn
- Queensland Institute of Medical Research and the Australian Centre for Vaccine Development, Herston, Queensland, Australia
| | - Louise M. Randall
- Queensland Institute of Medical Research and the Australian Centre for Vaccine Development, Herston, Queensland, Australia
- Department of Pathobiology, School of Veterinary Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Klaus Pfeffer
- Institute of Medical Microbiology and Hospital Hygiene, University of Duesseldorf, Duesseldorf, Germany
| | - Stefanie Scheu
- Institute of Medical Microbiology and Hospital Hygiene, University of Duesseldorf, Duesseldorf, Germany
| | - Michael J. Hickey
- Centre for Inflammatory Diseases, Monash University, Department of Medicine, Monash Medical Centre, Clayton, Victoria, Australia
| | | | - Carl Ware
- Infectious and Inflammatory Diseases Centre, Sanford|Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Geoff R. Hill
- Queensland Institute of Medical Research and the Australian Centre for Vaccine Development, Herston, Queensland, Australia
| | - Koji Tamada
- Marlene and Stewart Greenebaum Cancer Center, University of Maryland, Baltimore, Maryland, Unites States of America
| | - Paul M. Kaye
- Hull York Medical School, Department of Biology, York University, York, United Kingdom
| | - Christian R. Engwerda
- Queensland Institute of Medical Research and the Australian Centre for Vaccine Development, Herston, Queensland, Australia
- * E-mail:
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Schmidt KE, Schumak B, Specht S, Dubben B, Limmer A, Hoerauf A. Induction of pro-inflammatory mediators in Plasmodium berghei infected BALB/c mice breaks blood-brain-barrier and leads to cerebral malaria in an IL-12 dependent manner. Microbes Infect 2011; 13:828-36. [PMID: 21609776 DOI: 10.1016/j.micinf.2011.04.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 03/24/2011] [Accepted: 04/18/2011] [Indexed: 01/07/2023]
Abstract
A severe complication of Plasmodium infection is cerebral malaria, a condition mainly attributed to overwhelming inflammatory immune reactions of the host. Murine models differing in susceptibility to experimental cerebral malaria (ECM) allow detailed studies of the host response. We show that ECM- resistant BALB/c mice were driven into interferon gamma- and IL-12-dependent ECM and subsequent death if they received CpG-oligonucleotides after Plasmodium berghei ANKA (PbA) infection. CpG application triggered production of pro-inflammatory cytokines systemically as well in spleen and brain and induced neuropathological symptoms, leading to increased mortality. Experiments with genetically deficient mice confirmed the role of IFN-γ and IL-12 during CpG-triggered immunopathology. Furthermore, the application of CpG and downstream production of pro-inflammatory cytokines contributed to the break down of the blood brain barrier visualized by Evan's Blue, comparable to PbA-infected C57BL/6 mice. Taken together, resistance of BALB/c mice towards ECM development could be altered through induction of pro-inflammatory cytokines by CpG. Therefore, approaches discussed earlier to induce pro-inflammatory immune reactions for malaria protection should be considered with caution.
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Affiliation(s)
- Kim E Schmidt
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany
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14
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Franke-Fayard B, Fonager J, Braks A, Khan SM, Janse CJ. Sequestration and tissue accumulation of human malaria parasites: can we learn anything from rodent models of malaria? PLoS Pathog 2010; 6:e1001032. [PMID: 20941396 PMCID: PMC2947991 DOI: 10.1371/journal.ppat.1001032] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The sequestration of Plasmodium falciparum–infected red blood cells (irbcs) in the microvasculature of organs is associated with severe disease; correspondingly, the molecular basis of irbc adherence is an active area of study. In contrast to P. falciparum, much less is known about sequestration in other Plasmodium parasites, including those species that are used as models to study severe malaria. Here, we review the cytoadherence properties of irbcs of the rodent parasite Plasmodium berghei ANKA, where schizonts demonstrate a clear sequestration phenotype. Real-time in vivo imaging of transgenic P. berghei parasites in rodents has revealed a CD36-dependent sequestration in lungs and adipose tissue. In the absence of direct orthologs of the P. falciparum proteins that mediate binding to human CD36, the P. berghei proteins and/or mechanisms of rodent CD36 binding are as yet unknown. In addition to CD36-dependent schizont sequestration, irbcs accumulate during severe disease in different tissues, including the brain. The role of sequestration is discussed in the context of disease as are the general (dis)similarities of P. berghei and P. falciparum sequestration.
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Affiliation(s)
- Blandine Franke-Fayard
- Leiden Malaria Research Group, Department of Parasitology, Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Jannik Fonager
- Leiden Malaria Research Group, Department of Parasitology, Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Anneke Braks
- Leiden Malaria Research Group, Department of Parasitology, Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Shahid M. Khan
- Leiden Malaria Research Group, Department of Parasitology, Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Chris J. Janse
- Leiden Malaria Research Group, Department of Parasitology, Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
- * E-mail:
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15
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Amante FH, Haque A, Stanley AC, Rivera FDL, Randall LM, Wilson YA, Yeo G, Pieper C, Crabb BS, de Koning-Ward TF, Lundie RJ, Good MF, Pinzon-Charry A, Pearson MS, Duke MG, McManus DP, Loukas A, Hill GR, Engwerda CR. Immune-mediated mechanisms of parasite tissue sequestration during experimental cerebral malaria. THE JOURNAL OF IMMUNOLOGY 2010; 185:3632-42. [PMID: 20720206 DOI: 10.4049/jimmunol.1000944] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cerebral malaria is a severe complication of malaria. Sequestration of parasitized RBCs in brain microvasculature is associated with disease pathogenesis, but our understanding of this process is incomplete. In this study, we examined parasite tissue sequestration in an experimental model of cerebral malaria (ECM). We show that a rapid increase in parasite biomass is strongly associated with the induction of ECM, mediated by IFN-gamma and lymphotoxin alpha, whereas TNF and IL-10 limit this process. Crucially, we discovered that host CD4(+) and CD8(+) T cells promote parasite accumulation in vital organs, including the brain. Modulation of CD4(+) T cell responses by helminth coinfection amplified CD4(+) T cell-mediated parasite sequestration, whereas vaccination could generate CD4(+) T cells that reduced parasite biomass and prevented ECM. These findings provide novel insights into immune-mediated mechanisms of ECM pathogenesis and highlight the potential of T cells to both prevent and promote infectious diseases.
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Affiliation(s)
- Fiona H Amante
- Australian Centre for Vaccine Development, Brisbane, Queensland, Australia
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16
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Waknine-Grinberg JH, Hunt N, Bentura-Marciano A, McQuillan JA, Chan HW, Chan WC, Barenholz Y, Haynes RK, Golenser J. Artemisone effective against murine cerebral malaria. Malar J 2010; 9:227. [PMID: 20691118 PMCID: PMC2928250 DOI: 10.1186/1475-2875-9-227] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 08/09/2010] [Indexed: 11/12/2022] Open
Abstract
Background Artemisinins are the newest class of drug approved for malaria treatment. Due to their unique mechanism of action, rapid effect on Plasmodium, and high efficacy in vivo, artemisinins have become essential components of malaria treatment. Administration of artemisinin derivatives in combination with other anti-plasmodials has become the first-line treatment for uncomplicated falciparum malaria. However, their efficiency in cases of cerebral malaria (CM) remains to be determined. Methods The efficacy of several artemisinin derivatives for treatment of experimental CM was evaluated in ICR or C57BL/6 mice infected by Plasmodium berghei ANKA. Both mouse strains serve as murine models for CM. Results Artemisone was the most efficient drug tested, and could prevent death even when administered at relatively late stages of cerebral pathogenesis. No parasite resistance to artemisone was detected in recrudescence. Co-administration of artemisone together with chloroquine was more effective than monotherapy with either drug, and led to complete cure. Artemiside was even more effective than artemisone, but this substance has yet to be submitted to preclinical toxicological evaluation. Conclusions Altogether, the results support the use of artemisone for combined therapy of CM.
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Affiliation(s)
- Judith H Waknine-Grinberg
- Department of Microbiology and Molecular Genetics, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel
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Waknine-Grinberg JH, McQuillan JA, Hunt N, Ginsburg H, Golenser J. Modulation of cerebral malaria by fasudil and other immune-modifying compounds. Exp Parasitol 2010; 125:141-6. [DOI: 10.1016/j.exppara.2010.01.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Revised: 11/12/2009] [Accepted: 01/12/2010] [Indexed: 01/10/2023]
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18
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Randall LM, Engwerda CR. TNF family members and malaria: old observations, new insights and future directions. Exp Parasitol 2010; 126:326-31. [PMID: 20433831 DOI: 10.1016/j.exppara.2010.04.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 03/26/2010] [Accepted: 04/19/2010] [Indexed: 11/27/2022]
Abstract
Tumor necrosis factor (TNF) has long been recognized to promote malaria parasite killing, but also to contribute to the development of severe malaria disease. The precise molecular mechanisms that influence these different outcomes in malaria patients are not well understood, but the virulence and drug-resistance phenotype of malaria parasites and the genetic background and age of patients are likely to be important determinants. In the past few years, important roles for other TNF family members in host immune responses to malaria parasites and the induction of disease pathology have been discovered. In this review, we will summarize these more recent findings and highlight major gaps in our current knowledge. We will also discuss future research strategies that may allow us to better understand the sometimes subtle and intricate effects of TNF family molecules during malaria infection.
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Affiliation(s)
- Louise M Randall
- Immunology and Infection Laboratory, Queensland Institute of Medical Research and The Australian Centre for Vaccine Development, 300 Herston Road, Herston, Brisbane, Queensland, Qld 4006, Australia
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19
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Cerebral malaria: why experimental murine models are required to understand the pathogenesis of disease. Parasitology 2009; 137:755-72. [PMID: 20028608 DOI: 10.1017/s0031182009991715] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cerebral malaria is a life-threatening complication of malaria infection. The pathogenesis of cerebral malaria is poorly defined and progress in understanding the condition is severely hampered by the inability to study in detail, ante-mortem, the parasitological and immunological events within the brain that lead to the onset of clinical symptoms. Experimental murine models have been used to investigate the sequence of events that lead to cerebral malaria, but there is significant debate on the merits of these models and whether their study is relevant to human disease. Here we review the current understanding of the parasitological and immunological events leading to human and experimental cerebral malaria, and explain why we believe that studies with experimental models of CM are crucial to define the pathogenesis of the condition.
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Abstract
PURPOSE OF REVIEW Cerebral malaria continues to be a substantial cause of death and disability worldwide. Although many studies deal with cerebral malaria in children, only very few pertain to adults. Presence of multiorgan failure makes the prognosis poor. Various mechanisms in the pathogenesis of cerebral malaria and the role of adjuvant therapy will be discussed. RECENT FINDINGS Artemisinin-based therapies have improved antiparasitic treatment, but in-hospital mortality still remains high, as do neurological sequelae. Several recent studies have given new insights in the pathophysiology of cerebral malaria particularly the role of immune mechanisms in disease progression. Recent findings have identified several potential candidates for adjuvant neuroprotective treatment. Recombinant human erythropoietin has shown beneficial effect in experimental cerebral malaria and will soon enter into large clinical trials. SUMMARY Advances have been made in terms of antiparasitic treatment, but the identification of a well tolerated and effective adjuvant treatment to increase survival and reduce brain damage is still pending. The search for new approaches is a major challenge, not least of which is that mechanisms of malaria pathogenesis remain incompletely understood. The paper reviews newer information on pathogenesis and strategies in the management of cerebral malaria in adults.
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Clark IA, Alleva LM. Is human malarial coma caused, or merely deepened, by sequestration? Trends Parasitol 2009; 25:314-8. [PMID: 19541540 DOI: 10.1016/j.pt.2009.04.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 03/26/2009] [Accepted: 04/20/2009] [Indexed: 10/20/2022]
Abstract
Much research into falciparum malaria coma assumes the primary event to be vascular obstruction by parasitized red blood cells. Recent evidence that vivax malaria, caused by a parasite traditionally thought not to block blood flow, seems to alter brain function to the same degree as falciparum malaria has seriously questioned this. These data are a timely call to reassess whether vascular obstruction should still be considered the primary cause of the coma of falciparum disease. They add to a growing literature that suggests that enhancement of brain-origin cytokines, such as tumour necrosis factor, by non-brain systemic inflammation and an appreciation of the degree to which neuronal homeostasis depends on them provide a more fruitful research direction.
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Affiliation(s)
- Ian A Clark
- School of Biochemistry and Molecular Biology, Australian National University, Canberra, ACT 0200, Australia.
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