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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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Narnaware S, Periasamy S, Tripathi B. Studies on pathology, cytokine gene expression and molecular typing of Mycobacterium avium subsp. paratuberculosis of naturally occurring Johne's disease in bullocks. Res Vet Sci 2016; 106:74-80. [DOI: 10.1016/j.rvsc.2016.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 02/25/2016] [Accepted: 03/13/2016] [Indexed: 11/26/2022]
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Liu G, Xu J, Wu H, Sun D, Zhang X, Zhu X, Magez S, Shi M. IL-27 Signaling Is Crucial for Survival of Mice Infected with African Trypanosomes via Preventing Lethal Effects of CD4+ T Cells and IFN-γ. PLoS Pathog 2015. [PMID: 26222157 PMCID: PMC4519326 DOI: 10.1371/journal.ppat.1005065] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
African trypanosomes are extracellular protozoan parasites causing a chronic debilitating disease associated with a persistent inflammatory response. Maintaining the balance of the inflammatory response via downregulation of activation of M1-type myeloid cells was previously shown to be crucial to allow prolonged survival. Here we demonstrate that infection with African trypanosomes of IL-27 receptor-deficient (IL-27R-/-) mice results in severe liver immunopathology and dramatically reduced survival as compared to wild-type mice. This coincides with the development of an exacerbated Th1-mediated immune response with overactivation of CD4+ T cells and strongly enhanced production of inflammatory cytokines including IFN-γ. What is important is that IL-10 production was not impaired in infected IL-27R-/- mice. Depletion of CD4+ T cells in infected IL-27R-/- mice resulted in a dramatically reduced production of IFN-γ, preventing the early mortality of infected IL-27R-/- mice. This was accompanied by a significantly reduced inflammatory response and a major amelioration of liver pathology. These results could be mimicked by treating IL-27R-/- mice with a neutralizing anti-IFN-γ antibody. Thus, our data identify IL-27 signaling as a novel pathway to prevent early mortality via inhibiting hyperactivation of CD4+ Th1 cells and their excessive secretion of IFN-γ during infection with African trypanosomes. These data are the first to demonstrate the essential role of IL-27 signaling in regulating immune responses to extracellular protozoan infections. Infection with extracellular protozoan parasites, African trypanosomes, is characterized by a persistent inflammatory immune response. It has been recently shown that maintaining the balance of the inflammatory responses via dampening M1-type myeloid cell activation is critical to guarantee control of the parasites and survival of the host. In this study, we demonstrated that IL-27 receptor-deficient (IL-27R-/-) mice infected with African trypanosomes developed an excessive inflammatory response and severe liver immunopathology, resulting in dramatically reduced survival, as compared to infected wild-type mice. The early mortality of infected IL-27R-/- mice was correlated with significantly elevated secretions of inflammatory cytokines, particularly IFN-γ, and enhanced activation of CD4+ Th1 cells. Importantly, IL-10 production was not impaired in infected IL-27R-/- mice. Either depletion of CD4+ T cells, resulting in a dramatically reduced secretion of IFN-γ, or neutralization of IFN-γ, prevented the early mortality of infected IL-27R-/- mice with a significantly reduced inflammatory response and a major amelioration of the liver pathology. Thus, our data identify IL-27 signaling as a novel pathway to prevent the early mortality via inhibiting hyperactivation of CD4+ Th1 cells and their excessive secretions of IFN-γ during experimental infection with extracellular protozoan parasites African trypanosomes.
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Affiliation(s)
- Gongguan Liu
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Jinjun Xu
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Hui Wu
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Donglei Sun
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Xiquan Zhang
- Department of Animal Genetics, Breeding and Reproduction, South China Agricultural University, Guangzhou, China
| | - Xiaoping Zhu
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Stefan Magez
- Laboratory for Cellular and Molecular Immunology, Vrije Universiteit Brussels, Brussels, Belgium
- Structural Biology Research Centre, VIB, Brussels, Belgium
| | - Meiqing Shi
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
- * E-mail:
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Magez S, Caljon G. Mouse models for pathogenic African trypanosomes: unravelling the immunology of host-parasite-vector interactions. Parasite Immunol 2011; 33:423-9. [PMID: 21480934 DOI: 10.1111/j.1365-3024.2011.01293.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
African trypanosomiasis is a parasitic disease that affects a variety of mammals, including humans, on the sub-Saharan African continent. To understand the diverse parameters that govern the host-parasite-vector interactions, mouse models for the disease have proven to be a cornerstone. Despite the fact that most trypanosomes cannot be considered natural pathogens for rodents, experimental infections in mice have shed a tremendous amount of light on the general biology of these parasites and their interaction with and evasion of the mammalian immune system. Different aspects including inflammation, vaccine failure, antigenic variation, resistance/sensitivity to normal human serum and the influence of tsetse compounds on parasite transmission have all been addressed using mouse models. In more recent years, the introduction of various 'knock-out' mouse strains has allowed to analyse the implication of various cytokines, particularly TNF, IFNγ and IL-10, in the regulation of parasitaemia and induction of pathological conditions during infection.
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Affiliation(s)
- S Magez
- Laboratory for Cellular and Molecular Immunology, VIB Department of Molecular and Cellular Interactions, Vrije Universiteit Brussel, Brussels, Belgium.
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Taraktsoglou M, Szalabska U, Magee DA, Browne JA, Sweeney T, Gormley E, MacHugh DE. Transcriptional profiling of immune genes in bovine monocyte-derived macrophages exposed to bacterial antigens. Vet Immunol Immunopathol 2011; 140:130-9. [DOI: 10.1016/j.vetimm.2010.12.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 11/30/2010] [Accepted: 12/03/2010] [Indexed: 01/07/2023]
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