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Deng S, Graham ML, Chen XM. The Complexity of Interferon Signaling in Host Defense against Protozoan Parasite Infection. Pathogens 2023; 12:pathogens12020319. [PMID: 36839591 PMCID: PMC9962834 DOI: 10.3390/pathogens12020319] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/11/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023] Open
Abstract
Protozoan parasites, such as Plasmodium, Leishmania, Toxoplasma, Cryptosporidium, and Trypanosoma, are causative agents of health-threatening diseases in both humans and animals, leading to significant health risks and socioeconomic losses globally. The development of effective therapeutic and prevention strategies for protozoan-caused diseases requires a full understanding of the pathogenesis and protective events occurring in infected hosts. Interferons (IFNs) are a family of cytokines with diverse biological effects in host antimicrobial defense and disease pathogenesis, including protozoan parasite infection. Type II IFN (IFN-γ) has been widely recognized as the essential defense cytokine in intracellular protozoan parasite infection, whereas recent studies also revealed the production and distinct function of type I and III IFNs in host defense against these parasites. Decoding the complex network of the IFN family in host-parasite interaction is critical for exploring potential new therapeutic strategies against intracellular protozoan parasite infection. Here, we review the complex effects of IFNs on the host defense against intracellular protozoan parasites and the crosstalk between distinct types of IFN signaling during infections.
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Affiliation(s)
- Silu Deng
- Department of Microbial Pathogens and Immunity, Rush University Medical Center, Chicago, IL 60612, USA
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Marion L. Graham
- Department of Microbial Pathogens and Immunity, Rush University Medical Center, Chicago, IL 60612, USA
| | - Xian-Ming Chen
- Department of Microbial Pathogens and Immunity, Rush University Medical Center, Chicago, IL 60612, USA
- Correspondence:
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Stijlemans B, Schoovaerts M, De Baetselier P, Magez S, De Trez C. The Role of MIF and IL-10 as Molecular Yin-Yang in the Modulation of the Host Immune Microenvironment During Infections: African Trypanosome Infections as a Paradigm. Front Immunol 2022; 13:865395. [PMID: 35464430 PMCID: PMC9022210 DOI: 10.3389/fimmu.2022.865395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 03/14/2022] [Indexed: 11/13/2022] Open
Abstract
African trypanosomes are extracellular flagellated unicellular protozoan parasites transmitted by tsetse flies and causing Sleeping Sickness disease in humans and Nagana disease in cattle and other livestock. These diseases are usually characterized by the development of a fatal chronic inflammatory disease if left untreated. During African trypanosome infection and many other infectious diseases, the immune response is mediating a see-saw balance between effective/protective immunity and excessive infection-induced inflammation that can cause collateral tissue damage. African trypanosomes are known to trigger a strong type I pro-inflammatory response, which contributes to peak parasitaemia control, but this can culminate into the development of immunopathologies, such as anaemia and liver injury, if not tightly controlled. In this context, the macrophage migration inhibitory factor (MIF) and the interleukin-10 (IL-10) cytokines may operate as a molecular “Yin-Yang” in the modulation of the host immune microenvironment during African trypanosome infection, and possibly other infectious diseases. MIF is a pleiotropic pro-inflammatory cytokine and critical upstream mediator of immune and inflammatory responses, associated with exaggerated inflammation and immunopathology. For example, it plays a crucial role in the pro-inflammatory response against African trypanosomes and other pathogens, thereby promoting the development of immunopathologies. On the other hand, IL-10 is an anti-inflammatory cytokine, acting as a master regulator of inflammation during both African trypanosomiasis and other diseases. IL-10 is crucial to counteract the strong MIF-induced pro-inflammatory response, leading to pathology control. Hence, novel strategies capable of blocking MIF and/or promoting IL-10 receptor signaling pathways, could potentially be used as therapy to counteract immunopathology development during African trypanosome infection, as well as during other infectious conditions. Together, this review aims at summarizing the current knowledge on the opposite immunopathological molecular “Yin-Yang” switch roles of MIF and IL-10 in the modulation of the host immune microenvironment during infection, and more particularly during African trypanosomiasis as a paradigm.
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Affiliation(s)
- Benoit Stijlemans
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Myeloid Cell Immunology Laboratory, Vlaams Instituut voor Biotechnologie (VIB) Centre for Inflammation Research, Brussels, Belgium
| | - Maxime Schoovaerts
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Patrick De Baetselier
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Myeloid Cell Immunology Laboratory, Vlaams Instituut voor Biotechnologie (VIB) Centre for Inflammation Research, Brussels, Belgium
| | - Stefan Magez
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Laboratory of Biomedical Research, Ghent University Global Campus, Incheon, South Korea
| | - Carl De Trez
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium
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3
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Magez S, Pinto Torres JE, Obishakin E, Radwanska M. Infections With Extracellular Trypanosomes Require Control by Efficient Innate Immune Mechanisms and Can Result in the Destruction of the Mammalian Humoral Immune System. Front Immunol 2020; 11:382. [PMID: 32218784 PMCID: PMC7078162 DOI: 10.3389/fimmu.2020.00382] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 02/18/2020] [Indexed: 12/17/2022] Open
Abstract
Salivarian trypanosomes are extracellular parasites that affect humans, livestock, and game animals around the world. Through co-evolution with the mammalian immune system, trypanosomes have developed defense mechanisms that allow them to thrive in blood, lymphoid vessels, and tissue environments such as the brain, the fat tissue, and testes. Trypanosomes have developed ways to circumvent antibody-mediated killing and block the activation of the lytic arm of the complement pathway. Hence, this makes the innate immune control of the infection a crucial part of the host-parasite interaction, determining infection susceptibility, and parasitemia control. Indeed, trypanosomes use a combination of several independent mechanisms to avoid clearance by the humoral immune system. First, perpetuated antigenic variation of the surface coat allows to escape antibody-mediated elimination. Secondly, when antibodies bind to the coat, they are efficiently transported toward the endocytosis pathway, where they are removed from the coat proteins. Finally, trypanosomes engage in the active destruction of the mammalian humoral immune response. This provides them with a rescue solution in case antigenic variation does not confer total immunological invisibility. Both antigenic variation and B cell destruction pose significant hurdles for the development of anti-trypanosome vaccine strategies. However, developing total immune escape capacity and unlimited growth capabilities within a mammalian host is not beneficial for any parasite, as it will result in the accelerated death of the host itself. Hence, trypanosomes have acquired a system of quorum sensing that results in density-dependent population growth arrest in order to prevent overpopulating the host. The same system could possibly sense the infection-associated host tissue damage resulting from inflammatory innate immune responses, in which case the quorum sensing serves to prevent excessive immunopathology and as such also promotes host survival. In order to put these concepts together, this review summarizes current knowledge on the interaction between trypanosomes and the mammalian innate immune system, the mechanisms involved in population growth regulation, antigenic variation and the immuno-destructive effect of trypanosomes on the humoral immune system. Vaccine trials and a discussion on the role of innate immune modulation in these trials are discussed at the end.
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Affiliation(s)
- Stefan Magez
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea.,Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium.,Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
| | | | - Emmanuel Obishakin
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea.,Biotechnology Division, National Veterinary Research Institute, Vom, Nigeria
| | - Magdalena Radwanska
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
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4
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Onyilagha C, Kuriakose S, Ikeogu N, Kung SKP, Uzonna JE. NK Cells Are Critical for Optimal Immunity to Experimental Trypanosoma congolense Infection. THE JOURNAL OF IMMUNOLOGY 2019; 203:964-971. [PMID: 31243088 DOI: 10.4049/jimmunol.1900103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 06/10/2019] [Indexed: 02/07/2023]
Abstract
NK cells are key innate immune cells that play critical roles in host defense. Although NK cells have been shown to regulate immunity to some infectious diseases, their role in immunity to Trypanosoma congolense has not been investigated. NK cells are vital sources of IFN-γ and TNF-α; two key cytokines that are known to play important roles in resistance to African trypanosomes. In this article, we show that infection with T. congolense leads to increased levels of activated and functional NK cells in multiple tissue compartments. Systemic depletion of NK cells with anti-NK1.1 mAb led to increased parasitemia, which was accompanied by significant reduction in IFN-γ production by immune cells in the spleens and liver of infected mice. Strikingly, infected NFIL3-/- mice (which genetically lack NK cell development and function) on the normally resistant background were highly susceptible to T. congolense infection. These mice developed fulminating and uncontrolled parasitemia and died significantly earlier (13 ± 1 d) than their wild-type control mice (106 ± 26 d). The enhanced susceptibility of NFIL3-/- mice to infection was accompanied by significantly impaired cytokine (IFN-γ and TNF-α) response by CD3+ T cells in the spleens and liver. Adoptive transfer of NK cells into NFIL3-/- mice before infection rescued them from acute death in a perforin-dependent manner. Collectively, these studies show that NK cells are critical for optimal resistance to T. congolense, and its deficiency leads to enhanced susceptibility in infected mice.
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Affiliation(s)
- Chukwunonso Onyilagha
- Department of Immunology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba R3E 0T5, Canada; and
| | - Shiby Kuriakose
- Department of Immunology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba R3E 0T5, Canada; and
| | - Nnamdi Ikeogu
- Department of Immunology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba R3E 0T5, Canada; and
| | - Sam K P Kung
- Department of Immunology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba R3E 0T5, Canada; and
| | - Jude E Uzonna
- Department of Immunology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba R3E 0T5, Canada; and .,Department of Medical Microbiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada
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5
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Van den Kerkhof M, Van Bockstal L, Gielis JF, Delputte P, Cos P, Maes L, Caljon G, Hendrickx S. Impact of primary mouse macrophage cell types on Leishmania infection and in vitro drug susceptibility. Parasitol Res 2018; 117:3601-3612. [PMID: 30141075 DOI: 10.1007/s00436-018-6059-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/15/2018] [Indexed: 01/16/2023]
Abstract
Primary mouse macrophages are frequently used to provide an in vitro intracellular model to evaluate antileishmanial drug efficacy. The present study compared the phenotypic characteristics of Swiss, BALB/c, and C57BL/6 mouse bone marrow-derived macrophages and peritoneal exudate cells using different stimulation and adherence protocols upon infection with a Leishmania infantum laboratory strain and two clinical isolates. Evaluation parameters were susceptibility to infection, permissiveness to amastigote multiplication, and impact on drug efficacy. Observed variations in infection of peritoneal exudate cells can mostly be linked to changes in the inflammatory cytokine profiles (IL-6, TNF-α, KC/GRO) rather than to differences in initial production of nitric oxide and reactive oxygen species. Optimization of the cell stimulation and adherence conditions resulted in comparable infection indices among peritoneal exudate cells and the various types of bone marrow-derived macrophages. BALB/c-derived bone marrow-derived macrophages were slightly more permissive to intracellular amastigote replication. Evaluation of antileishmanial drug potency in the various cell systems revealed minimal variation for antimonials and paromomycin, and no differences for miltefosine and amphotericin B. The study results allow to conclude that drug evaluation can be performed in all tested primary macrophages as only marginal differences are observed in terms of susceptibility to infection and impact of drug exposure. Combined with some practical considerations, the use of 24-h starch-stimulated, 48-h adhered, Swiss-derived peritoneal exudate cells can be advocated as an efficient, reliable, relatively quick, and cost-effective tool for routine drug susceptibility testing in vitro whenever the use of primary cells is feasible.
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Affiliation(s)
- M Van den Kerkhof
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Laboratory of Microbiology, Parasitology and Hygiene, University of Antwerp, Wilrijk, Belgium
| | - L Van Bockstal
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Laboratory of Microbiology, Parasitology and Hygiene, University of Antwerp, Wilrijk, Belgium
| | - J F Gielis
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Laboratory of Microbiology, Parasitology and Hygiene, University of Antwerp, Wilrijk, Belgium
- Antwerp Surgical Training, Anatomy & Research Center, Department of Medicine, University of Antwerp, Wilrijk, Belgium
| | - P Delputte
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Laboratory of Microbiology, Parasitology and Hygiene, University of Antwerp, Wilrijk, Belgium
| | - P Cos
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Laboratory of Microbiology, Parasitology and Hygiene, University of Antwerp, Wilrijk, Belgium
| | - L Maes
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Laboratory of Microbiology, Parasitology and Hygiene, University of Antwerp, Wilrijk, Belgium
| | - Guy Caljon
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Laboratory of Microbiology, Parasitology and Hygiene, University of Antwerp, Wilrijk, Belgium.
| | - Sarah Hendrickx
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Laboratory of Microbiology, Parasitology and Hygiene, University of Antwerp, Wilrijk, Belgium.
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Wu H, Liu G, Shi M. Interferon Gamma in African Trypanosome Infections: Friends or Foes? Front Immunol 2017; 8:1105. [PMID: 28936213 PMCID: PMC5594077 DOI: 10.3389/fimmu.2017.01105] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 08/23/2017] [Indexed: 12/24/2022] Open
Abstract
African trypanosomes cause fatal infections in both humans and livestock. Interferon gamma (IFN-γ) plays an essential role in resistance to African trypanosomes. However, increasing evidence suggests that IFN-γ, when excessively synthesized, also induces immunopathology, enhancing susceptibility to the infection. Thus, production of IFN-γ must be tightly regulated during infections with African trypanosomes to ensure that a robust immune response is elicited without tissue destruction. Early studies have shown that secretion of IFN-γ is downregulated by interleukin 10 (IL-10). More recently, IL-27 has been identified as a negative regulator of IFN-γ production during African trypanosome infections. In this review, we discuss the current state of our understanding of the role of IFN-γ in African trypanosome infections. We have focused on the cellular source of IFN-γ, its beneficial and detrimental effects, and mechanisms involved in regulation of its production, highlighting some recent advances and offering some perspectives on future directions.
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Affiliation(s)
- Hui Wu
- Department of Obstetrics and Gynecology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China.,Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, United States
| | - Gongguan Liu
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, United States
| | - Meiqing Shi
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, United States
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Bearss JJ, Hunter M, Dankmeyer JL, Fritts KA, Klimko CP, Weaver CH, Shoe JL, Quirk AV, Toothman RG, Webster WM, Fetterer DP, Bozue JA, Worsham PL, Welkos SL, Amemiya K, Cote CK. Characterization of pathogenesis of and immune response to Burkholderia pseudomallei K96243 using both inhalational and intraperitoneal infection models in BALB/c and C57BL/6 mice. PLoS One 2017; 12:e0172627. [PMID: 28235018 PMCID: PMC5325312 DOI: 10.1371/journal.pone.0172627] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 02/07/2017] [Indexed: 01/02/2023] Open
Abstract
Burkholderia pseudomallei, the etiologic agent of melioidosis, is a Gram negative bacterium designated as a Tier 1 threat. This bacterium is known to be endemic in Southeast Asia and Northern Australia and can infect humans and animals by several routes. Inhalational melioidosis has been associated with monsoonal rains in endemic areas and is also a significant concern in the biodefense community. There are currently no effective vaccines for B. pseudomallei and antibiotic treatment can be hampered by non-specific symptomology and also the high rate of naturally occurring antibiotic resistant strains. Well-characterized animal models will be essential when selecting novel medical countermeasures for evaluation prior to human clinical trials. Here, we further characterize differences between the responses of BALB/c and C57BL/6 mice when challenged with low doses of a low-passage and well-defined stock of B. pseudomallei K96243 via either intraperitoneal or aerosol routes of exposure. Before challenge, mice were implanted with a transponder to collect body temperature readings, and daily body weights were also recorded. Mice were euthanized on select days for pathological analyses and determination of the bacterial burden in selected tissues (blood, lungs, liver, and spleen). Additionally, spleen homogenate and sera samples were analyzed to better characterize the host immune response after infection with aerosolized bacteria. These clinical, pathological, and immunological data highlighted and confirmed important similarities and differences between these murine models and exposure routes.
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Affiliation(s)
- Jeremy J. Bearss
- Pathology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD, United States of America
| | - Melissa Hunter
- Bacteriology Division, USAMRIID, Fort Detrick, Frederick, MD, United States of America
| | - Jennifer L. Dankmeyer
- Bacteriology Division, USAMRIID, Fort Detrick, Frederick, MD, United States of America
| | - Kristen A. Fritts
- Bacteriology Division, USAMRIID, Fort Detrick, Frederick, MD, United States of America
| | - Christopher P. Klimko
- Bacteriology Division, USAMRIID, Fort Detrick, Frederick, MD, United States of America
| | - Chris H. Weaver
- Bacteriology Division, USAMRIID, Fort Detrick, Frederick, MD, United States of America
| | - Jennifer L. Shoe
- Bacteriology Division, USAMRIID, Fort Detrick, Frederick, MD, United States of America
| | - Avery V. Quirk
- Bacteriology Division, USAMRIID, Fort Detrick, Frederick, MD, United States of America
| | - Ronald G. Toothman
- Bacteriology Division, USAMRIID, Fort Detrick, Frederick, MD, United States of America
| | - Wendy M. Webster
- Bacteriology Division, USAMRIID, Fort Detrick, Frederick, MD, United States of America
| | - David P. Fetterer
- BioStatisitics Division, USAMRIID, Fort Detrick, Frederick, MD, United States of America
| | - Joel A. Bozue
- Bacteriology Division, USAMRIID, Fort Detrick, Frederick, MD, United States of America
| | - Patricia L. Worsham
- Bacteriology Division, USAMRIID, Fort Detrick, Frederick, MD, United States of America
| | - Susan L. Welkos
- Bacteriology Division, USAMRIID, Fort Detrick, Frederick, MD, United States of America
| | - Kei Amemiya
- Bacteriology Division, USAMRIID, Fort Detrick, Frederick, MD, United States of America
| | - Christopher K. Cote
- Bacteriology Division, USAMRIID, Fort Detrick, Frederick, MD, United States of America
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MIF-Mediated Hemodilution Promotes Pathogenic Anemia in Experimental African Trypanosomosis. PLoS Pathog 2016; 12:e1005862. [PMID: 27632207 PMCID: PMC5025191 DOI: 10.1371/journal.ppat.1005862] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 08/11/2016] [Indexed: 12/31/2022] Open
Abstract
Animal African trypanosomosis is a major threat to the economic development and human health in sub-Saharan Africa. Trypanosoma congolense infections represent the major constraint in livestock production, with anemia as the major pathogenic lethal feature. The mechanisms underlying anemia development are ill defined, which hampers the development of an effective therapy. Here, the contribution of the erythropoietic and erythrophagocytic potential as well as of hemodilution to the development of T. congolense-induced anemia were addressed in a mouse model of low virulence relevant for bovine trypanosomosis. We show that in infected mice, splenic extramedullary erythropoiesis could compensate for the chronic low-grade type I inflammation-induced phagocytosis of senescent red blood cells (RBCs) in spleen and liver myeloid cells, as well as for the impaired maturation of RBCs occurring in the bone marrow and spleen. Rather, anemia resulted from hemodilution. Our data also suggest that the heme catabolism subsequent to sustained erythrophagocytosis resulted in iron accumulation in tissue and hyperbilirubinemia. Moreover, hypoalbuminemia, potentially resulting from hemodilution and liver injury in infected mice, impaired the elimination of toxic circulating molecules like bilirubin. Hemodilutional thrombocytopenia also coincided with impaired coagulation. Combined, these effects could elicit multiple organ failure and uncontrolled bleeding thus reduce the survival of infected mice. MIF (macrophage migrating inhibitory factor), a potential pathogenic molecule in African trypanosomosis, was found herein to promote erythrophagocytosis, to block extramedullary erythropoiesis and RBC maturation, and to trigger hemodilution. Hence, these data prompt considering MIF as a potential target for treatment of natural bovine trypanosomosis. Bovine African trypanosomosis is a parasitic disease of veterinary importance that adversely affects the public health and economic development of sub-Saharan Africa. Anemia is a major cause of death associated with this disease. Yet, the mechanisms underlying anemia development are not elucidated, which hampers the design of effective therapeutic strategies. We show here that in a Trypanosoma congolense infection mouse model relevant for bovine trypanosomosis, red blood cells (RBCs) are generated in the spleen. This compensates for the impaired maturation of RBCs occurring in the bone marrow, the normal site of RBC generation, and for the destruction of RBCs taking place in the liver and the spleen. Instead, anemia results from an increase in blood volume (hemodilution). The immune molecule Macrophage Migration Inhibitory Factor (MIF) was found to drive RBC destruction, to block RBC maturation, as well as to trigger hemodilution. Iron accumulation in tissue due to sustained RBC destruction and hemodilution causes tissue damage, which culminates in the release of toxic molecules like bilirubin, in impaired production of blood detoxifying molecules like albumin, and in defective coagulation. Combined, these effects initiate multiple organ failure that can reduce the survival of infected mice. Given the unmet medical need for this parasite infection, our findings offer promise for improved treatment protocols in the field.
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9
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Distinct Contributions of CD4+ and CD8+ T Cells to Pathogenesis of Trypanosoma brucei Infection in the Context of Gamma Interferon and Interleukin-10. Infect Immun 2015; 83:2785-95. [PMID: 25916989 DOI: 10.1128/iai.00357-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 04/20/2015] [Indexed: 12/21/2022] Open
Abstract
Although gamma interferon (IFN-γ) and interleukin-10 (IL-10) have been shown to be critically involved in the pathogenesis of African trypanosomiasis, the contributions to this disease of CD4(+) and CD8(+) T cells, the major potential producers of the two cytokines, are incompletely understood. Here we show that, in contrast to previous findings, IFN-γ was produced by CD4(+), but not CD8(+), T cells in mice infected with Trypanosoma brucei. Without any impairment in the secretion of IFN-γ, infected CD8(-/-) mice survived significantly longer than infected wild-type mice, suggesting that CD8(+) T cells mediated mortality in an IFN-γ-independent manner. The increased survival of infected CD8(-/-) mice was significantly reduced in the absence of IL-10 signaling. Interestingly, IL-10 was also secreted mainly by CD4(+) T cells. Strikingly, depletion of CD4(+) T cells abrogated the prolonged survival of infected CD8(-/-) mice, demonstrating that CD4(+) T cells mediated protection. Infected wild-type mice and CD8(-/-) mice depleted of CD4(+) T cells had equal survival times, suggesting that the protection mediated by CD4(+) T cells was counteracted by the detrimental effects of CD8(+) T cells in infected wild-type mice. Interestingly, CD4(+) T cells also mediated the mortality of infected mice in the absence of IL-10 signaling, probably via excessive secretion of IFN-γ. Finally, CD4(+), but not CD8(+), T cells were critically involved in the synthesis of IgG antibodies during T. brucei infections. Collectively, these results highlight distinct roles of CD4(+) and CD8(+) T cells in the context of IFN-γ and IL-10 during T. brucei infections.
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10
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Onyilagha C, Jia P, Jayachandran N, Hou S, Okwor I, Kuriakose S, Marshall A, Uzonna JE. The B cell adaptor molecule Bam32 is critically important for optimal antibody response and resistance to Trypanosoma congolense infection in mice. PLoS Negl Trop Dis 2015; 9:e0003716. [PMID: 25875604 PMCID: PMC4395458 DOI: 10.1371/journal.pntd.0003716] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 03/21/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Bam32, a 32 kDa adaptor molecule, plays important role in B cell receptor signalling, T cell receptor signalling and antibody affinity maturation in germinal centres. Since antibodies against trypanosome variant surface glycoproteins (VSG) are critically important for control of parasitemia, we hypothesized that Bam32 deficient (Bam32-/-) mice would be susceptible to T. congolense infection. METHODOLOGY/PRINCIPAL FINDINGS We found that T. congolense-infected Bam32-/- mice successfully control the first wave of parasitemia but then fail to control subsequent waves and ultimately succumb to their infection unlike wild type (WT) C57BL6 mice which are relatively resistant. Although infected Bam32-/- mice had significantly higher hepatomegaly and splenomegaly, their serum AST and ALT levels were not different, suggesting that increased liver pathology may not be responsible for the increased susceptibility of Bam32-/- mice to T. congolense. Using direct ex vivo flow cytometry and ELISA, we show that CD4+ T cells from infected Bam32-/- mice produced significantly increased amounts of disease-exacerbating proinflammatory cytokines (including IFN-γ, TNF-α and IL-6). However, the percentages of regulatory T cells and IL-10-producing CD4+ cells were similar in infected WT and Bam32-/- mice. While serum levels of parasite-specific IgM antibodies were normal, the levels of parasite-specific IgG, (particularly IgG1 and IgG2a) were significantly lower in Bam32-/- mice throughout infection. This was associated with impaired germinal centre response in Bam32-/- mice despite increased numbers of T follicular helper (Tfh) cells. Adoptive transfer studies indicate that intrinsic B cell defect was responsible for the enhanced susceptibility of Bam32-/- mice to T. congolense infection. CONCLUSIONS/SIGNIFICANCE Collectively, our data show that Bam32 is important for optimal anti-trypanosome IgG antibody response and suppression of disease-promoting proinflammatory cytokines and its deficiency leads to inability to control T. congolense infection in mice.
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Affiliation(s)
- Chukwunonso Onyilagha
- Department of Immunology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Ping Jia
- Department of Immunology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Nipun Jayachandran
- Department of Immunology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Sen Hou
- Department of Immunology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Ifeoma Okwor
- Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Shiby Kuriakose
- Department of Immunology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Aaron Marshall
- Department of Immunology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Jude E. Uzonna
- Department of Immunology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
- Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
- * E-mail:
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11
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Depke M, Breitbach K, Dinh Hoang Dang K, Brinkmann L, Salazar MG, Dhople VM, Bast A, Steil L, Schmidt F, Steinmetz I, Völker U. Bone marrow-derived macrophages from BALB/c and C57BL/6 mice fundamentally differ in their respiratory chain complex proteins, lysosomal enzymes and components of antioxidant stress systems. J Proteomics 2014; 103:72-86. [PMID: 24704164 DOI: 10.1016/j.jprot.2014.03.027] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 03/05/2014] [Accepted: 03/18/2014] [Indexed: 11/27/2022]
Abstract
UNLABELLED Macrophages are essential components of the innate immune system and crucial for pathogen elimination in early stages of infection. We previously observed that bone marrow-derived macrophages (BMMs) from C57BL/6 mice exhibited increased killing activity against Burkholderia pseudomallei compared to BMMs from BALB/c mice. This effect was particularly pronounced when cells were treated with IFN-γ. To unravel mechanisms that could explain these distinct bactericidal effects, a comparative combined proteome and transcriptome analysis of untreated and IFN-γ treated BALB/c and C57BL/6 BMMs under standardized serum-free conditions was carried out. We found differences in gene expression/protein abundance belonging to cellular oxidative and antioxidative stress systems. Genes/proteins involved in the generation of oxidant molecules and the function of phagosomes (respiratory chain ATPase, lysosomal enzymes, cathepsins) were predominantly higher expressed/more abundant in C57BL/6 BMMs. Components involved in alleviation of oxidative stress (peroxiredoxin, mitochondrial superoxide dismutase) were more abundant in C57BL/6 BMMs as well. Thus, C57BL/6 BMMs seemed to be better equipped with cellular systems that may be advantageous in combating engulfed pathogens. Simultaneously, C57BL/6 BMMs were well protected from oxidative burst. We assume that these variations co-determine differences in resistance between BALB/c and C57BL/6 mice observed in many infection models. BIOLOGICAL SIGNIFICANCE In this study we performed combined transcriptome and proteome analyses on BMMs derived from two inbred mouse strains that are frequently used for studies in the field of host-pathogen interaction research. Strain differences between BALB/c and C57BL/6 BMMs were found to originate mainly from different protein abundance levels rather than from different gene expression. Differences in abundance of respiratory chain complexes and lysosomal proteins as well as differential regulation of components belonging to various antioxidant stress systems help to explain long-known differences between the mouse strains concerning their different susceptibility in several infection models.
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Affiliation(s)
- Maren Depke
- ZIK-FunGene Junior Research Group "Applied Proteomics", Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany; Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Katrin Breitbach
- Friedrich Loeffler Institute for Medical Microbiology, University Medicine Greifswald, Greifswald, Germany
| | - Khoa Dinh Hoang Dang
- Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Lars Brinkmann
- Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Manuela Gesell Salazar
- ZIK-FunGene Junior Research Group "Applied Proteomics", Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany; Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Vishnu Mukund Dhople
- Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Antje Bast
- Friedrich Loeffler Institute for Medical Microbiology, University Medicine Greifswald, Greifswald, Germany
| | - Leif Steil
- Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Frank Schmidt
- ZIK-FunGene Junior Research Group "Applied Proteomics", Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Ivo Steinmetz
- Friedrich Loeffler Institute for Medical Microbiology, University Medicine Greifswald, Greifswald, Germany
| | - Uwe Völker
- Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany.
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12
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Low-dose intradermal infection with trypanosoma congolense leads to expansion of regulatory T cells and enhanced susceptibility to reinfection. Infect Immun 2013; 82:1074-83. [PMID: 24343657 DOI: 10.1128/iai.01028-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
BALB/c mice are highly susceptible to experimental intraperitoneal Trypanosoma congolense infection. However, a recent report showed that these mice are relatively resistant to primary intradermal low-dose infection. Paradoxically, repeated low-dose intradermal infections predispose mice to enhanced susceptibility to an otherwise noninfectious dose challenge. Here, we explored the mechanisms responsible for this low-dose-induced susceptibility to subsequent low-dose challenge infection. We found that akin to intraperitoneal infection, low-dose intradermal infection led to production of interleukin-10 (IL-10), IL-6, IL-12, tumor necrosis factor alpha (TNF-α), transforming growth factor β (TGF-β), and gamma interferon (IFN-γ) by spleen and draining lymph node cells. Interestingly, despite the absence of parasitemia, low-dose intradermal infection led to expansion of CD4+ CD25+ Foxp3+ cells (T regulatory cells [Tregs]) in both the spleens and lymph nodes draining the infection site. Depletion of Tregs by anti-CD25 monoclonal antibody (MAb) treatment during primary infection or before challenge infection following repeated low-dose infection completely abolished the low-dose-induced enhanced susceptibility. In addition, Treg depletion was associated with dramatic reduction in serum levels of TGF-β and IL-10. Collectively, these findings show that low-dose intradermal infection leads to rapid expansion of Tregs, and these cells mediate enhanced susceptibility to subsequent infection.
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13
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Kuriakose S, Muleme HM, Onyilagha C, Singh R, Jia P, Uzonna JE. Diminazene aceturate (Berenil) modulates the host cellular and inflammatory responses to Trypanosoma congolense infection. PLoS One 2012; 7:e48696. [PMID: 23144931 PMCID: PMC3492428 DOI: 10.1371/journal.pone.0048696] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 09/27/2012] [Indexed: 11/18/2022] Open
Abstract
Background Trypanosoma congolense are extracellular and intravascular blood parasites that cause debilitating acute or chronic disease in cattle and other domestic animals. Diminazene aceturate (Berenil) has been widely used as a chemotherapeutic agent for trypanosomiasis in livestock since 1955. As in livestock, treatment of infected highly susceptible BALB/c mice with Berenil leads to rapid control of parasitemia and survival from an otherwise lethal infection. The molecular and biochemical mechanisms of action of Berenil are still not very well defined and its effect on the host immune system has remained relatively unstudied. Here, we investigated whether Berenil has, in addition to its trypanolytic effect, a modulatory effect on the host immune response to Trypanosoma congolense. Methodology/Principal Findings BALB/c and C57BL/6 mice were infected intraperitoneally with T. congolense, treated with Berenil and the expression of CD25 and FoxP3 on splenic cells was assessed directly ex vivo. In addition, serum levels and spontaneous and LPS-induced production of pro-inflammatory cytokines by splenic and hepatic CD11b+ cells were determined by ELISA. Berenil treatment significantly reduced the percentages of CD25+ cells, a concomitant reduction in the percentage of regulatory (CD4+Foxp3+) T cells and a striking reduction in serum levels of disease exacerbating pro-inflammatory cytokines including IL-6, IL-12, TNF and IFN-γ. Furthermore, Berenil treatment significantly suppressed spontaneous and LPS-induced production of inflammatory cytokines by splenic and liver macrophages and significantly ameliorated LPS-induced septic shock and the associated cytokine storm. Conclusions/Significance Collectively, these results provide evidence that in addition to its direct trypanolytic effect, Berenil also modulates the host immune response to the parasite in a manner that dampen excessive immune activation and production of pathology-promoting pro-inflammatory cytokines, suggesting that this drug may also be beneficial for treatment of disease conditions caused by excessive production of inflammatory cytokines.
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Affiliation(s)
- Shiby Kuriakose
- Department of Immunology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Helen M. Muleme
- Department of Immunology, University of Manitoba, Winnipeg, Manitoba, Canada
| | | | - Rani Singh
- Department of Immunology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Ping Jia
- Department of Immunology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Jude E. Uzonna
- Department of Immunology, University of Manitoba, Winnipeg, Manitoba, Canada
- * E-mail:
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La Greca F, Magez S. Vaccination against trypanosomiasis: can it be done or is the trypanosome truly the ultimate immune destroyer and escape artist? HUMAN VACCINES 2012; 7:1225-33. [PMID: 22205439 PMCID: PMC3323498 DOI: 10.4161/hv.7.11.18203] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
To date, human African trypanosomiasis (HAT) still threatens millions of people throughout sub-Sahara Africa, and new approaches to disease prevention and treatment remain a priority. It is commonly accepted that HAT is fatal unless treatment is provided. However, despite the well-described general symptoms of disease progression during distinct stages of the infection, leading to encephalitic complications, coma and death, a substantial body of evidence has been reported suggesting that natural acquired immunity could occur. Hence, if under favorable conditions natural infections can lead to correct immune activation and immune protection against HAT, the development of an effective anti-HAT vaccine should remain a central goal in the fight against this disease.<br />
In this review, we will (1) discuss the vaccine candidates that have been proposed over the past years, (2) highlight the main obstacles that an efficient anti-trypanosomiasis vaccine needs to overcome and (3) critically reflect on the validity of the widely used murine model for HAT.
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Affiliation(s)
- Florencia La Greca
- Laboratory for Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
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15
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Bucheton B, MacLeod A, Jamonneau V. Human host determinants influencing the outcome of Trypanosoma brucei gambiense infections. Parasite Immunol 2011; 33:438-47. [PMID: 21385185 PMCID: PMC3427891 DOI: 10.1111/j.1365-3024.2011.01287.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Since first identified, human African trypanosomiasis (HAT) or sleeping sickness has been described as invariably fatal. Increasing data however argue that infection by Trypanosoma brucei gambiense, the causative agent of HAT, results in a wide range of outcomes in its human host and importantly that a number of subjects in endemic areas are apparently able to control infection to low levels, undetectable by the classical parasitological tests used in the field. Thus, trypanotolerance seems to occur in humans as has already been described in cattle or in the rodent experimental models of infection. This review focuses on the description of the diversity of outcomes resulting from T. b. gambiense in humans and on the host factors involved. The consequences/impacts on HAT epidemiology resulting from this diversity are also discussed with regard to implementing sustainable HAT control strategies.
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Affiliation(s)
- B Bucheton
- Institut de Recherche pour le Développement (IRD), Unité Mixte de Recherche IRD-CIRAD 177, Campus International de Baillarguet, Montpellier, France.
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16
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Trypanosoma congolense Infections: Induced Nitric Oxide Inhibits Parasite Growth In Vivo. J Parasitol Res 2011; 2011:316067. [PMID: 21584233 PMCID: PMC3092548 DOI: 10.1155/2011/316067] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Accepted: 02/07/2011] [Indexed: 11/17/2022] Open
Abstract
Wild-type (WT) C57BL/6 mice infected intraperitoneally with 5 × 10(6) Trypanosoma congolense survive for more than 30 days. C57BL/6 mice deficient in inducible nitric oxide synthase (iNOS(-/-)) and infected with 10(3) or 5 × 10(6) parasites do not control the parasitemia and survive for only 14 ± 7 or 6.8 ± 0.1 days, respectively. Bloodstream trypanosomes of iNOS(-/-) mice infected with 5 × 10(6)T. congolense had a significantly higher ratio of organisms in the S+G2+M phases of the cell cycle than trypanosomes in WT mice. We have reported that IgM anti-VSG-mediated phagocytosis of T. congolense by macrophages inhibits nitric oxide (NO) synthesis via CR3 (CD11b/CD18). Here, we show that during the first parasitemia, but not at later stages of infection, T. congolense-infected CD11b(-/-) mice produce more NO and have a significantly lower parasitemia than infected WT mice. We conclude that induced NO contributes to the control of parasitemia by inhibiting the growth of the trypanosomes.
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17
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Wei G, Bull H, Zhou X, Tabel H. Intradermal infections of mice by low numbers of african trypanosomes are controlled by innate resistance but enhance susceptibility to reinfection. J Infect Dis 2010; 203:418-29. [PMID: 21208931 PMCID: PMC3071116 DOI: 10.1093/infdis/jiq051] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Antibodies are required to control blood-stage forms of African trypanosomes in humans and animals. Here, we report that intradermal infections by low numbers of African trypanosomes are controlled by innate resistance but prime the adaptive immune response to increase susceptibility to a subsequent challenge. Mice were found 100 times more resistant to intradermal infections by Trypanosoma congolense or Trypanosoma brucei than to intraperitoneal infections. B cell-deficient and RAG2(-/-) mice are as resistant as wild-type mice to intradermal infections, whereas inducible nitric oxide synthase (iNOS)(-/-) mice and wild-type mice treated with antibody to tumor necrosis factor (TNF) α are more susceptible. We conclude that primary intradermal infections with low numbers of parasites are controlled by innate defense mediated by induced nitric oxide (NO). CD1d(-/-) and major histocompatibility complex (MHC) class II(-/-) mice are more resistant than wild-type mice to primary intradermal infections. Trypanosome-specific spleen cells, as shown by cytokine production, are primed as early as 24 h after intradermal infection. Infecting mice intradermally with low numbers of parasites, or injecting them intradermally with a trypanosomal lysate, makes mice more susceptible to an intradermal challenge. We suggest that intradermal infections with low numbers of trypanosomes or injections with trypanosomal lysates prime the adaptive immune system to suppress protective immunity to an intradermal challenge.
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Affiliation(s)
- Guojian Wei
- Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Canada
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18
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Characterization of major surface protease homologues of Trypanosoma congolense. J Biomed Biotechnol 2010; 2010:418157. [PMID: 20145707 PMCID: PMC2817373 DOI: 10.1155/2010/418157] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Accepted: 10/12/2009] [Indexed: 12/16/2022] Open
Abstract
Trypanosomes encode a family of proteins known as Major Surface Metalloproteases (MSPs). We have identified six putative MSPs encoded within the partially sequenced T. congolense genome. Phylogenic analysis indicates that T. congolense MSPs belong to five subfamilies that are conserved among African trypanosome species. Molecular modeling, based on the known structure of Leishmania Major GP63, reveals subfamily-specific structural variations around the putative active site despite conservation of overall structure, suggesting that each MSP subfamily has evolved to recognize distinct substrates. We have cloned and purified a protein encoding the amino-terminal domain of the T. congolense homologue TcoMSP-D (most closely related to Leishmania GP63). We detect TcoMSP-D in the serum of T. congolense-infected mice. Mice immunized with the amino-terminal domain of TcoMSP-D generate a persisting IgG1 antibody response. Surprisingly, a low-dose challenge of immunized mice with T. congolense significantly increases susceptibility to infection, indicating that immunity to TcoMSP-D is a factor affecting virulence.
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19
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Clinical chemistry of congenic mice with quantitative trait loci for predicted responses to Trypanosoma congolense infection. Infect Immun 2009; 77:3948-57. [PMID: 19596769 DOI: 10.1128/iai.00658-09] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Trypanosoma congolense is a protozoan parasite that causes severe diseases in livestock. Three major quantative trait loci (QTL), Tir1, Tir2, and Tir3, control the survival time of mice after infection with T. congolense. Congenic mice carrying the C57BL/6 resistance alleles on the A/J background were developed for each of these loci. The congenic mice were used to physically map the regions containing the QTL gene(s) and to investigate the physiological effect of each locus. Clinical chemistry data for infected A/J, C57BL/6, and BALB/c mice were obtained for 15 analytes at five time points. Congenic mice were assessed for survival, parasitemia, and anemia as well as seven clinical-chemical analytes. The survival times were significantly increased in the Tir1 and Tir2 mice but not Tir3 congenic mice. The survival time of the parental inbred mice correlated negatively with parasitemia but positively with alanine aminotransferase activities in serum, suggesting that inflammatory reactions in the liver had a beneficial effect possibly associated with reduced parasitemia. However, there was no difference in parasitemia or liver enzyme activities of Tir1 and Tir2 congenic mice relative to their controls, showing that survival, parasitemia, and degree of liver damage are not associated with each other, despite the correlation in the parental lines. These data suggest that the congenic loci affect survival but do not affect control of parasite number. They may therefore act by limiting the pathological consequences of T. congolense infection.
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Bosschaerts T, Guilliams M, Stijlemans B, De Baetselier P, Beschin A. Understanding the role of monocytic cells in liver inflammation using parasite infection as a model. Immunobiology 2009; 214:737-47. [PMID: 19577324 DOI: 10.1016/j.imbio.2009.06.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Uncontrolled inflammation is a major cause of pathogenicity during chronic parasite infections. Novel therapies should therefore aim at re-establishing the balance between pro- and anti-inflammatory signals during disease to avoid tissue damage and ensure survival of the host. In this context, we are intending to identify strategies capable of inducing counter-inflammatory activity in injured liver and thereby increasing the resistance of the host to African trypanosomiasis as a model for parasite infection. Here, recent evidence is summarized revealing how monocytic cells recruited to the liver of African trypanosome-infected mice develop an M1 or M2 activation status, thereby maintaining the capacity of the host to control parasite growth while avoiding the development of liver damage, which otherwise culminates in early death of the host.
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Affiliation(s)
- Tom Bosschaerts
- Department of Molecular and Cellular Interactions, VIB, Brussel, Belgium
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21
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Namangala B, Yokoyama N, Ikehara Y, Taguchi O, Tsujimura K, Sugimoto C, Inoue N. Effect of CD4+CD25+ T cell-depletion on acute lethal infection of mice with Trypanosoma congolense. J Vet Med Sci 2008; 70:751-9. [PMID: 18772548 DOI: 10.1292/jvms.70.751] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Despite the immense socio-economic repercussions of African trypanosomosis (AT), there is currently no effective control measure against the disease. Characterization of mechanisms governing resistance and/or susceptibility to AT could suggest interventions that might lead to more effective disease control. The present study was designed in an attempt to address the possible role of CD4+CD25+ T cells during an acute lethal infection of mice with Trypanosoma congolense, the causative agent of AT in domestic animals, through selective depletion using anti-CD25 monoclonal antibody. Accordingly, CD4+CD25+ T-cell-depletion resulted in a significant reduction or delay in parasitemia, pathology, and mortality, as compared to controls. The apparent resistance in CD4+CD25+-T-cell-depleted mice correlated with a profound suppression of Th2 cytokines in vitro and in vivo, culminating in a net Th1 cytokine environment. Cumulatively, these findings suggest that CD4+CD25+ T-cell- depletion improves the trypanotolerance of highly susceptible BALB/c mice acutely infected with the lethal T. congolense.
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Affiliation(s)
- Boniface Namangala
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
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22
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Guilliams M, Bosschaerts T, Hérin M, Hünig T, Loi P, Flamand V, De Baetselier P, Beschin A. Experimental expansion of the regulatory T cell population increases resistance to African trypanosomiasis. J Infect Dis 2008; 198:781-91. [PMID: 18627271 DOI: 10.1086/590439] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Inflammatory responses mounted to eliminate parasites can be lethal if not counterbalanced by regulatory responses protecting the host from collateral tissue damage. Here, we show that the maintained inflammation associated with tissue damage, anemia, and reduced survival of Trypanosoma brucei-infected mice correlates with the absence of the expansion of the regulatory T (T(reg)) cell population. Induction of T(reg) cell expansion via CD28 superagonist antibody treatment in these mice down-regulated interferon-gamma production by T cells and tumor necrosis factor-alpha and reactive oxygen species production by classically activated macrophages, triggered the development of alternatively activated macrophages, delayed the onset of liver injury, diminished the anemia burden, and prolonged the survival of infected animals. Thus, triggering the expansion of the T(reg) cell population coupled with the induction of alternatively activated macrophages can restore the balance between pro- and anti-inflammatory signals and thereby limit the pathogenicity of African trypanosomiasis.
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Affiliation(s)
- Martin Guilliams
- Department of Molecular and Cellular Interactions, Vlaams Instituut voor Biotechnologie, Vrije Universiteit Brussel, Brussels, Belgium
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23
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Magez S, Schwegmann A, Atkinson R, Claes F, Drennan M, De Baetselier P, Brombacher F. The role of B-cells and IgM antibodies in parasitemia, anemia, and VSG switching in Trypanosoma brucei-infected mice. PLoS Pathog 2008; 4:e1000122. [PMID: 18688274 PMCID: PMC2483930 DOI: 10.1371/journal.ppat.1000122] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Accepted: 07/10/2008] [Indexed: 11/24/2022] Open
Abstract
African trypanosomes are extracellular parasitic protozoa, predominantly transmitted by the bite of the haematophagic tsetse fly. The main mechanism considered to mediate parasitemia control in a mammalian host is the continuous interaction between antibodies and the parasite surface, covered by variant-specific surface glycoproteins. Early experimental studies have shown that B-cell responses can be strongly protective but are limited by their VSG-specificity. We have used B-cell (µMT) and IgM-deficient (IgM−/−) mice to investigate the role of B-cells and IgM antibodies in parasitemia control and the in vivo induction of trypanosomiasis-associated anemia. These infection studies revealed that that the initial setting of peak levels of parasitemia in Trypanosoma brucei–infected µMT and IgM−/− mice occurred independent of the presence of B-cells. However, B-cells helped to periodically reduce circulating parasites levels and were required for long term survival, while IgM antibodies played only a limited role in this process. Infection-associated anemia, hypothesized to be mediated by B-cell responses, was induced during infection in µMT mice as well as in IgM−/− mice, and as such occurred independently from the infection-induced host antibody response. Antigenic variation, the main immune evasion mechanism of African trypanosomes, occurred independently from host antibody responses against the parasite's ever-changing antigenic glycoprotein coat. Collectively, these results demonstrated that in murine experimental T. brucei trypanosomiasis, B-cells were crucial for periodic peak parasitemia clearance, whereas parasite-induced IgM antibodies played only a limited role in the outcome of the infection. African trypanosomiasis is a disease caused by different species of extracellular flagellated protozoan trypanosome parasites. Trypanosomes have developed a mechanism of regular antigenic variation of their variant-specific surface glycoprotein (VSG) coat which allows chronic infection. Replacement of this coat occurs at rapid regular time intervals, allowing the parasite to escape from an effective host antibody responses. So far, primary T-cell independent antibody responses have been described to constitute the main host defense mechanism, relying largely on IgM antibody induction. Using genetically engineered B lymphocyte- or IgM-deficient mouse strains, we show that lack of B-cells or IgM did not prevent infection-associated anemia. More importantly, we show that in the absence of IgM, parasitemia was controlled almost as well as in wild-type mice, with only slightly increased mortality. In addition, we show in vivo that antigenic variation is not affected by the lack of IgM.
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Affiliation(s)
- Stefan Magez
- Division of Immunology, Institute for Infectious Diseases and Molecular Medicine (IIDMM), Health Science Faculty, University of Cape Town, and International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town, South Africa
- Department of Molecular and Cellular Recognition, VIB, Brussels, Belgium
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Anita Schwegmann
- Division of Immunology, Institute for Infectious Diseases and Molecular Medicine (IIDMM), Health Science Faculty, University of Cape Town, and International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town, South Africa
| | - Robert Atkinson
- Division of Immunology, Institute for Infectious Diseases and Molecular Medicine (IIDMM), Health Science Faculty, University of Cape Town, and International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town, South Africa
| | - Filip Claes
- Laboratory of Serology, Institute for Tropical Medicine “Prins Leopold”, Antwerpen, Belgium
| | - Michael Drennan
- Division of Immunology, Institute for Infectious Diseases and Molecular Medicine (IIDMM), Health Science Faculty, University of Cape Town, and International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town, South Africa
- Department of Molecular and Cellular Recognition, VIB, Brussels, Belgium
| | - Patrick De Baetselier
- Department of Molecular and Cellular Recognition, VIB, Brussels, Belgium
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Frank Brombacher
- Division of Immunology, Institute for Infectious Diseases and Molecular Medicine (IIDMM), Health Science Faculty, University of Cape Town, and International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town, South Africa
- * E-mail:
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24
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Antoine-Moussiaux N, Magez S, Desmecht D. Contributions of experimental mouse models to the understanding of African trypanosomiasis. Trends Parasitol 2008; 24:411-8. [PMID: 18684669 DOI: 10.1016/j.pt.2008.05.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Revised: 05/08/2008] [Accepted: 05/27/2008] [Indexed: 12/01/2022]
Abstract
African trypanosomiasis is the collective name for a wide variety of trypanosome infections that affect humans and livestock. In recent years, experimental mice infection models have provided new insights into both human and animal trypanosomiasis. Mouse models seem to be a valuable and versatile tool in trypanosomiasis-associated pathology and immunology research and highlight the variety shown by African trypanosomiases. Indeed, inbred mouse strains have enabled the study of genetic determinants of susceptibility and of the roles of anti-parasite antibodies, inflammatory mediators and anti-inflammatory mediators for each trypanosome species. Remarkable advances relating to the encephalitic stage of sleeping sickness have also been achieved thanks to murine models. The different contributions of murine models to the African trypanosomiases knowledge are presented here. Future search directions are finally proposed, with respect to mouse model opportunities and limitations.
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Affiliation(s)
- Nicolas Antoine-Moussiaux
- Department of Animal Pathology, Veterinary College, University of Liege, 20 Boulevard de Colonster, B43, 4000 Liege, Belgium.
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25
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Bosschaerts T, Guilliams M, Noel W, Hérin M, Burk RF, Hill KE, Brys L, Raes G, Ghassabeh GH, De Baetselier P, Beschin A. Alternatively activated myeloid cells limit pathogenicity associated with African trypanosomiasis through the IL-10 inducible gene selenoprotein P. THE JOURNAL OF IMMUNOLOGY 2008; 180:6168-75. [PMID: 18424738 DOI: 10.4049/jimmunol.180.9.6168] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Uncontrolled inflammation is a major cause of tissue injury/pathogenicity often resulting in death of a host infected with African trypanosomes. Thus, comparing the immune response in hosts that develop different degrees of disease severity represents a promising approach to discover processes contributing to trypanosomiasis control. It is known that limitation of pathogenicity requires a transition in the course of infection, from an IFN-gamma-dependent response resulting in the development of classically activated myeloid cells (M1), to a counterbalancing IL-10-dependent response associated with alternatively activated myeloid cells (M2). Herein, mechanisms and downstream effectors by which M2 contribute to lower the pathogenicity and the associated susceptibility to African trypanosomiasis have been explored. Gene expression analysis in IL-10 knockout and wild-type mice, that are susceptible and relatively resistant to Trypanosoma congolense infection, respectively, revealed a number of IL-10-inducible genes expressed by M2, including Sepp1 coding for selenoprotein P. Functional analyses confirm that selenoprotein P contributes to limit disease severity through anti-oxidant activity. Indeed, Sepp1 knockout mice, but not Sepp1(Delta)(240-361) mice retaining the anti-oxidant motif but lacking the selenium transporter domain of selenoprotein P, exhibited increased tissue injury that associated with increased production of reactive oxygen species and increased apoptosis in the liver immune cells, reduced parasite clearance capacity of myeloid cells, and decreased survival. These data validate M2-associated molecules as functioning in reducing the impact of parasite infection on the host.
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Affiliation(s)
- Tom Bosschaerts
- Department of Molecular and Cellular Interactions, Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, Belgium
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26
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Wei G, Tabel H. Regulatory T Cells Prevent Control of Experimental African Trypanosomiasis. THE JOURNAL OF IMMUNOLOGY 2008; 180:2514-21. [DOI: 10.4049/jimmunol.180.4.2514] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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27
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Guilliams M, Oldenhove G, Noel W, Hérin M, Brys L, Loi P, Flamand V, Moser M, De Baetselier P, Beschin A. African Trypanosomiasis: Naturally Occurring Regulatory T Cells Favor Trypanotolerance by Limiting Pathology Associated with Sustained Type 1 Inflammation. THE JOURNAL OF IMMUNOLOGY 2007; 179:2748-57. [PMID: 17709488 DOI: 10.4049/jimmunol.179.5.2748] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Tolerance to African trypanosomes requires the production of IFN-gamma in the early stage of infection that triggers the development of classically activated macrophages controlling parasite growth. However, once the first peak of parasitemia has been controlled, down-regulation of the type 1 immune response has been described. In this study, we have evaluated whether regulatory T cells (Tregs) contribute to the limitation of the immune response occurring during Trypanosoma congolense infection and hereby influence the outcome of the disease in trypanotolerant C57BL/6 host. Our data show that Foxp3+ Tregs originating from the naturally occurring Treg pool expanded in the spleen and the liver of infected mice. These cells produced IL-10 and limited the production of IFN-gamma by CD4+ and CD8+ effector T cells. Tregs also down-regulated classical activation of macrophages resulting in reduced TNF-alpha production. The Treg-mediated suppression of the type 1 inflammatory immune response did not hamper parasite clearance, but was beneficial for the host survival by limiting the tissue damages, including liver injury. Collectively, these data suggest a cardinal role for naturally occurring Tregs in the development of a trypanotolerant phenotype during African trypanosomiasis.
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Affiliation(s)
- Martin Guilliams
- Department of Molecular and Cellular Interactions, Vlaams Instituut voor Biotechnologie, Vrije Universiteit Brussel, 1050 Brussels, Belgium
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28
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Stijlemans B, Guilliams M, Raes G, Beschin A, Magez S, De Baetselier P. African trypanosomosis: From immune escape and immunopathology to immune intervention. Vet Parasitol 2007; 148:3-13. [PMID: 17560035 DOI: 10.1016/j.vetpar.2007.05.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
African trypanosomes can cause prolonged chronic infections through a mechanism of antigen variation whereby they manipulate the humoral immune system of their hosts. However, besides antigenic variation these extracellular parasites exert other immunoregulatory activities mainly mediated by innate cells in particular macrophage-like (M) cells. In this review, the modulation of M cells through parasite factors and host cytokines as well as their role in parasite control and immunopathology will be examined. The concept of M cell polarization into distinct activation states (M1, M2) that may contribute to trypanosusceptibility or resistance will be discussed. Finally, the possibility to interfere with such activation states hereby providing new therapeutical modalities in the treatment of this infectious disease will be illustrated.
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Affiliation(s)
- Benoît Stijlemans
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.
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29
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Shi MQ, Wei GJ, Tabel H. Trypanosoma congolense infections: MHC class II-restricted immune responses mediate either protection or disease, depending on IL-10 function. Parasite Immunol 2007; 29:107-11. [PMID: 17241399 DOI: 10.1111/j.1365-3024.2006.00925.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BALB/c mice are highly susceptible and C57BL/6 relatively resistant to Trypanosoma congolense infections. Here we show that relatively resistant wild-type B6 mice infected with T. congolense survive significantly longer (> 200 days) than infected major histocompatibility complex (MHC) class II-deficient B6 mice (approximately 50 days). We also show that blocking of the interleukin-10 (IL-10) receptor induces early death of wild-type B6 mice infected with T. congolense (approximately 10 days), but does not affect the survival of infected MHC class II-deficient B6 mice. We conclude that MHC class II-restricted immune responses mediate protection and, when IL-10 function is impaired, MHC class II-restricted immune responses mediate early mortality in otherwise resistant B6 mice. Thus, in T. congolense infections, MHC class II-restricted immune responses mediate either protection or disease, depending on IL-10 function.
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Affiliation(s)
- M Q Shi
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
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30
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Shi MQ, Wang CR, Wei GJ, Pan WL, Appleyard G, Tabel H. Experimental African trypanosomiasis: lack of effective CD1d-restricted antigen presentation. Parasite Immunol 2006; 28:643-7. [PMID: 17096643 DOI: 10.1111/j.1365-3024.2006.00898.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BALB/c mice are highly susceptible to African trypanosomiasis, whereas C57BL/6 mice are relatively resistant. Other investigators have reported that the synthesis of IgG antibodies to purified membrane form of variant surface glycoprotein (mfVSG) of Trypanosoma brucei is CD1 restricted. In this study, we examine the role of the CD1d/NKT cell pathway in susceptibility and resistance of mice to infection by African trypanosomes. Administration of anti-CD1d antibodies to Trypanosoma congolense-infected BALB/c mice neither affects the parasitemia nor the survival time. Correspondingly, CD1d(-/-) and CD1d(+/+) BALB/c mice infected with T. congolense or T. brucei show no differences in either parasitaemia or survival time. The course of disease in relative resistant C57BL/6 mice infected with T. congolense is also not affected by the absence of CD1d. Parasitaemia, survival time, and plasma levels of IgG2a and IgG3 parasite-specific antibodies in infected CD1d(-/-) C57BL/6 are not different from those of infected CD1d(+/+) C57BL/6 mice. We conclude that CD1d-restricted immune responses do not play an important role in susceptibility/resistance of mice infected with virulent African trypanosomes. We speculate that virulent trypanosomes have an evasion mechanism that prevents the induction of a parasite-specific, CD1d-restricted immune response by the host.
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Affiliation(s)
- M Q Shi
- Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Canada
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31
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O'Gorman GM, Park SDE, Hill EW, Meade KG, Mitchell LC, Agaba M, Gibson JP, Hanotte O, Naessens J, Kemp SJ, MacHugh DE. Cytokine mRNA profiling of peripheral blood mononuclear cells from trypanotolerant and trypanosusceptible cattle infected with Trypanosoma congolense. Physiol Genomics 2006; 28:53-61. [PMID: 16985010 DOI: 10.1152/physiolgenomics.00100.2006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To examine differences in cytokine profiles that may confer tolerance/susceptibility to bovine African trypanosomiasis, N'Dama (trypanotolerant, n = 8) and Boran (trypanosusceptible, n = 8) cattle were experimentally challenged with Trypanosoma congolense. Blood samples were collected over a 34-day period, and RNA was extracted from peripheral blood mononuclear cells. The expression levels of a panel of 14 cytokines were profiled over the time course of infection and between breeds. Messenger RNA (mRNA) transcript levels for the IL2, IL8, and IL1RN genes were significantly downregulated across the time course of infection in both breeds. There was an early increase in transcripts for genes encoding proinflammatory mediators (IFNG, IL1A, TNF, and IL12) in N'Dama by 14 days postinfection (dpi) compared with preinfection levels that was not detected in the susceptible Boran breed. By the time of peak parasitemia, a type 2 helper T cells (T(H)2)-like cytokine environment was prevalent that was particularly evident in the Boran. Increases in transcripts for the IL6 (29 and 34 dpi) and IL10 (21, 25, and 29 dpi) genes were detected that were higher in the Boran compared with N'Dama. These findings highlight the implications for using murine models to study the bovine immune response to trypanosomiasis, where in some cases cytokine expression patterns differ. Overall, these data suggest that the trypanotolerant N'Dama are more capable of responding very early in infection with proinflammatory and T(H)1 type cytokines than the trypanosusceptible Boran and may explain why N'Dama control parasitemia more efficiently than Boran during the early stages of infection.
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Affiliation(s)
- Grace M O'Gorman
- Animal Genomics Laboratory, School of Agriculture, Food Science and Veterinary Medicine, College of Life Sciences, University College Dublin, Belfield, Dublin, Ireland
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32
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Utz S, Roditi I, Kunz Renggli C, Almeida IC, Acosta-Serrano A, Bütikofer P. Trypanosoma congolense procyclins: unmasking cryptic major surface glycoproteins in procyclic forms. EUKARYOTIC CELL 2006; 5:1430-40. [PMID: 16896226 PMCID: PMC1539152 DOI: 10.1128/ec.00067-06] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Accepted: 06/20/2006] [Indexed: 11/20/2022]
Abstract
In the tsetse fly, the protozoan parasite Trypanosoma congolense is covered by a dense layer of glycosylphosphatidylinositol (GPI)-anchored molecules. These include a protease-resistant surface molecule (PRS), which is expressed by procyclic forms early in infection, and a glutamic acid- and alanine-rich protein (GARP), which appears at later stages. Since neither of these surface antigens is expressed at intermediate stages, we investigated whether a GPI-anchored protein of 50 to 58 kDa, previously detected in procyclic culture forms, might constitute the coat of these parasites. We therefore partially purified the protein from T. congolense Kilifi procyclic forms, obtained an N-terminal amino acid sequence, and identified its gene. Detailed analyses showed that the mature protein consists almost exclusively of 13 heptapeptide repeats (EPGENGT). The protein is densely N glycosylated, with up to 13 high-mannose oligosaccharides ranging from Man(5)GlcNAc(2) to Man(9)GlcNAc(2) linked to the peptide repeats. The lipid moiety of the glycosylphosphatidylinositol is composed of sn-1-stearoyl-2-lyso-glycerol-3-HPO(4)-1-(2-O-acyl)-d-myo-inositol. Heavily glycosylated proteins with similar repeats were subsequently identified in T. congolense Savannah procyclic forms. Collectively, this group of proteins was named T. congolense procyclins to reflect their relationship to the EP and GPEET procyclins of T. brucei. Using an antiserum raised against the EPGENGT repeat, we show that T. congolense procyclins are expressed continuously in the fly midgut and thus form the surface coat of cells that are negative for both PRS and GARP.
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Affiliation(s)
- Silvia Utz
- Institute of Biochemistry & Molecular Medicine, University of Bern, Bern, Switzerland
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33
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Pan W, Ogunremi O, Wei G, Shi M, Tabel H. CR3 (CD11b/CD18) is the major macrophage receptor for IgM antibody-mediated phagocytosis of African trypanosomes: Diverse effect on subsequent synthesis of tumor necrosis factor α and nitric oxide. Microbes Infect 2006; 8:1209-18. [PMID: 16616573 DOI: 10.1016/j.micinf.2005.11.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2005] [Revised: 11/19/2005] [Accepted: 11/23/2005] [Indexed: 10/25/2022]
Abstract
Immunoglobulin M (IgM) antibodies to the variant surface glycoproteins (VSG) of African trypanosomes are the first and predominant class of anti-trypanosomal antibodies in the infected host. They are a major factor in controlling waves of parasitemia, but not in long-term survival. The macrophage receptor(s) that enables phagocytosis of IgM anti-VSG-coated African trypanosomes is unknown. We assessed whether complement receptor CR3 (CD11b/CD18) might be involved in mediating phagocytosis of Trypanosoma congolense. We show that murine complement C3 fragments are deposited onto T. congolense when the trypanosomes are incubated with IgM anti-VSG and fresh mouse serum. In the presence of fresh mouse serum, there is significantly and markedly less phagocytosis of IgM-opsonized T. congolense by CD11b-deficient macrophages compared to phagocytosis by wild-type macrophages (78% fewer T. congolense are ingested per macrophage). Significantly less tumor necrosis factor (TNF)-alpha (38% less), but significantly more nitric oxide (NO) (63% more) are released by CD11b-deficient macrophages that have engulfed trypanosomes than by equally treated wild-type macrophages. We conclude that CR3 is the major, but not the only, receptor involved in IgM anti-VSG-mediated phagocytosis of T. congolense by macrophages. We further conclude that IgM anti-VSG-mediated phagocytosis of T. congolense enhances synthesis of disease-producing TNF-alpha and inhibits synthesis of parasite-controlling NO. We suggest that signaling of inhibition of NO synthesis is mediated via CR3.
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Affiliation(s)
- Wanling Pan
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada
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34
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Shi M, Wei G, Pan W, Tabel H. Experimental African trypanosomiasis: a subset of pathogenic, IFN-gamma-producing, MHC class II-restricted CD4+ T cells mediates early mortality in highly susceptible mice. THE JOURNAL OF IMMUNOLOGY 2006; 176:1724-32. [PMID: 16424202 DOI: 10.4049/jimmunol.176.3.1724] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Infections of highly susceptible BALB/c mice with virulent strains of Trypanosoma congolense or Trypanosoma brucei result in rapid death (8 days). We have previously shown that this mortality is IFN-gamma dependent. In this study we show that IFN-gamma is produced predominantly by CD3+Thy1.2+TCRbeta+CD4+ T cells shortly before the death of infected mice. Mortality may therefore be dependent on IFN-gamma-producing CD4+ T cells. Surprisingly, infected CD4+/+ and CD4-/- BALB/c mice have similar parasitemia and survival time. In infected CD4-/- mice, the production of both IFN-gamma and IL-10 is very low, suggesting that both cytokines are predominantly produced by CD4+ T cells and that the outcome of the disease might depend on the balance of their effects. Infected BALB/c mice partially depleted of CD4+ T cells or MHC class II function have lower parasitemia and survive significantly longer than infected normal BALB/c mice or infected BALB/c mice whose CD4+ T cells are fully depleted. Partial depletion of CD4+ T cells markedly reduces IFN-gamma secretion without a major effect on the production of IL-10 and parasite-specific IgG2a Abs. Based on our previous and current data, we conclude that a subset of a pathogenic, MHC class II-restricted CD4+ T cells (Tp cells), activated during the course of T. congolense infection, mediates early mortality in infected BALB/c mice via excessive synthesis of IFN-gamma. IFN-gamma, in turn, exerts its pathological effect by enhancing the cytokine release syndrome of the macrophage system activated by the phagocytosis of parasites. We speculate that IL-10-producing CD4+ T cells might counteract this effect.
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MESH Headings
- Animals
- Antibodies, Monoclonal
- CD3 Complex/metabolism
- CD4 Antigens/genetics
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- CD8 Antigens/genetics
- Cells, Cultured
- Disease Models, Animal
- Epitopes, T-Lymphocyte/immunology
- Female
- Genetic Predisposition to Disease
- Histocompatibility Antigens Class II/immunology
- Interferon-gamma/biosynthesis
- Interleukin-10/biosynthesis
- Interleukin-12/blood
- Interleukin-12 Subunit p40
- Mice
- Mice, Inbred BALB C
- Mice, Knockout
- Protein Subunits/blood
- Rats
- Receptors, Antigen, T-Cell/metabolism
- Spleen/cytology
- Spleen/metabolism
- Trypanosoma congolense/immunology
- Trypanosomiasis, African/genetics
- Trypanosomiasis, African/immunology
- Trypanosomiasis, African/mortality
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Affiliation(s)
- Meiqing Shi
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
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35
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Shi M, Wei G, Pan W, Tabel H. Impaired Kupffer cells in highly susceptible mice infected with Trypanosoma congolense. Infect Immun 2006; 73:8393-6. [PMID: 16299337 PMCID: PMC1307053 DOI: 10.1128/iai.73.12.8393-8396.2005] [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: 11/20/2022] Open
Abstract
In highly susceptible BALB/c mice infected with Trypanosoma congolense, the total number of Kupffer cells in the liver remains constant; however, their mean size increases fivefold towards the terminal stage. About 25% of Kupffer cells undergo apoptosis. We suggest that development of an impairment of the macrophage system might be a major mechanism for inefficient elimination of trypanosomes.
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Affiliation(s)
- Meiqing Shi
- Department of Veterinary Microbiology, WCVM, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, S7N 5B4, Canada
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36
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Abstract
Human African trypanosomiasis or sleeping sickness is caused by infection with two subspecies of the tsetse-fly-vectored haemoflagellate parasite Trypanosoma brucei. Historically, epidemic sleeping sickness has caused massive loss of life, and related animal diseases have had a crucial impact on development in sub-Saharan Africa. After a period of moderately successful control during the mid-part of the 20th century, sleeping sickness incidence is currently rising, and control is hampered by a combination of factors, including civil unrest and the possible development of drug resistance by the parasites. The prevailing view is that the disease is invariably fatal without anti-trypanosomal drug treatment. However, there have also been intriguing reports of wide variations in disease severity as well as evidence of asymptomatic carriers of trypanosomes. These differences in the presentation of the disease will be discussed in the context of our knowledge of the immunology of trypanosomiasis. The impact of dysregulated inflammatory responses in both systemic and CNS pathology will be examined and the potential for host genotype variation in disease severity and control will be discussed.
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Affiliation(s)
- J M Sternberg
- Zoology Building, School of Biological Sciences, University of Aberdeen, UK.
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37
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Shi M, Wei G, Pan W, Tabel H. Trypanosoma congolenseinfections: antibody-mediated phagocytosis by Kupffer cells. J Leukoc Biol 2004; 76:399-405. [PMID: 15136584 DOI: 10.1189/jlb.1003500] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Immunohistochemical double-label technique was used to detect trypanosomal antigen in macrophages. Immunoglobulin (Ig)M as well as IgG2a monoclonal antibodies (mAb) specific for the variant surface glycoprotein (VSG) mediated phagocytosis of Trypanosoma congolense variant antigenic type (VAT) TC13 by macrophages [bone marrow-derived macrophage cell line from BALB/c (BALB.BM)] in vitro. Administration of these IgM or IgG2a antibodies to BALB/c mice 30 min after injection of 3 x 10(8) T. congolense mediated phagocytosis of trypanosomes by Kupffer cells of the liver within 1 h. Plasma levels of the monokines interleukin (IL)-1beta, IL-10, and IL-12p40 were significantly increased 6-48 h after phagocytosis. In BALB/c mice infected with 10(3) T. congolense, a small degree of phagocytosis of trypanosomes by Kupffer cells, mediated by actively synthesized antibodies, was detected as early as 5 days after infection. Phagocytosis of trypanosomes was dramatically enhanced on day 6. Concomitantly, the Kupffer cells trippled in size. In BALB/c mice infected for 6 days, treatment with IgM or IgG2a mAb specific for T. congolense VSG led to clearance of VAT TC13 parasitemia but did not prevent death at the second parasitemia of a different VAT. We conclude that IgM as well as IgG antibody mediate phagocytosis of trypanosomes by Kupffer cells.
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Affiliation(s)
- Meiqing Shi
- Department of Veterinary Microbiology, WCVM, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, S7N 5B4, Canada
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38
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Graefe SEB, Meyer BS, Müller-Myhsok B, Rüschendorf F, Drosten C, Laue T, Steeg C, Nürnberg P, Fleischer B. Murine susceptibility to Chagas' disease maps to chromosomes 5 and 17. Genes Immun 2003; 4:321-5. [PMID: 12847546 DOI: 10.1038/sj.gene.6363972] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Chagas' disease is caused by the protozoan parasite Trypanosoma cruzi and commonly modelled in inbred mice. Susceptibility of mouse strains to experimental infection varies considerably. We quantified parasite tissue burdens in resistant and susceptible strains by real time PCR and applied a backcross strategy to map the genomic loci linked to susceptibility in inbred mice. Resistant B6D2F1 mice were backcrossed with susceptible C57BL/6 mice, and 46 of a total 192 offspring died after infection. Their genomes were scanned with microsatellite markers. One region on chromosome 17 was significantly linked to susceptibility, while another on chromosome 5 was suggestive of linkage.
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Affiliation(s)
- S E B Graefe
- Department of Immunology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany.
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