1
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Porte R, Belloy M, Audibert A, Bassot E, Aïda A, Alis M, Miranda-Capet R, Jourdes A, van Gisbergen KPJM, Masson F, Blanchard N. Protective function and differentiation cues of brain-resident CD8+ T cells during surveillance of latent Toxoplasma gondii infection. Proc Natl Acad Sci U S A 2024; 121:e2403054121. [PMID: 38838017 PMCID: PMC11181119 DOI: 10.1073/pnas.2403054121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 05/01/2024] [Indexed: 06/07/2024] Open
Abstract
Chronic Toxoplasma gondii infection induces brain-resident CD8+ T cells (bTr), but the protective functions and differentiation cues of these cells remain undefined. Here, we used a mouse model of latent infection by T. gondii leading to effective CD8+ T cell-mediated parasite control. Thanks to antibody depletion approaches, we found that peripheral circulating CD8+ T cells are dispensable for brain parasite control during chronic stage, indicating that CD8+ bTr are able to prevent brain parasite reactivation. We observed that the retention markers CD69, CD49a, and CD103 are sequentially acquired by brain parasite-specific CD8+ T cells throughout infection and that a majority of CD69/CD49a/CD103 triple-positive (TP) CD8+ T cells also express Hobit, a transcription factor associated with tissue residency. This TP subset develops in a CD4+ T cell-dependent manner and is associated with effective parasite control during chronic stage. Conditional invalidation of Transporter associated with Antigen Processing (TAP)-mediated major histocompatibility complex (MHC) class I presentation showed that presentation of parasite antigens by glutamatergic neurons and microglia regulates the differentiation of CD8+ bTr into TP cells. Single-cell transcriptomic analyses revealed that resistance to encephalitis is associated with the expansion of stem-like subsets of CD8+ bTr. In summary, parasite-specific brain-resident CD8+ T cells are a functionally heterogeneous compartment which autonomously ensure parasite control during T. gondii latent infection and which differentiation is shaped by neuronal and microglial MHC I presentation. A more detailed understanding of local T cell-mediated immune surveillance of this common parasite is needed for harnessing brain-resident CD8+ T cells in order to enhance control of chronic brain infections.
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Affiliation(s)
- Rémi Porte
- Toulouse Institute for Infectious and Inflammatory Diseases, Infinity, Inserm, CNRS, University of Toulouse, Toulouse31300, France
| | - Marcy Belloy
- Toulouse Institute for Infectious and Inflammatory Diseases, Infinity, Inserm, CNRS, University of Toulouse, Toulouse31300, France
| | - Alexis Audibert
- Toulouse Institute for Infectious and Inflammatory Diseases, Infinity, Inserm, CNRS, University of Toulouse, Toulouse31300, France
| | - Emilie Bassot
- Toulouse Institute for Infectious and Inflammatory Diseases, Infinity, Inserm, CNRS, University of Toulouse, Toulouse31300, France
| | - Amel Aïda
- Toulouse Institute for Infectious and Inflammatory Diseases, Infinity, Inserm, CNRS, University of Toulouse, Toulouse31300, France
| | - Marine Alis
- Toulouse Institute for Infectious and Inflammatory Diseases, Infinity, Inserm, CNRS, University of Toulouse, Toulouse31300, France
| | - Romain Miranda-Capet
- Toulouse Institute for Infectious and Inflammatory Diseases, Infinity, Inserm, CNRS, University of Toulouse, Toulouse31300, France
| | - Aurélie Jourdes
- Toulouse Institute for Infectious and Inflammatory Diseases, Infinity, Inserm, CNRS, University of Toulouse, Toulouse31300, France
| | | | - Frédérick Masson
- Toulouse Institute for Infectious and Inflammatory Diseases, Infinity, Inserm, CNRS, University of Toulouse, Toulouse31300, France
| | - Nicolas Blanchard
- Toulouse Institute for Infectious and Inflammatory Diseases, Infinity, Inserm, CNRS, University of Toulouse, Toulouse31300, France
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2
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Xu X, Wang J, Chen G. Circadian cycle and neuroinflammation. Open Life Sci 2023; 18:20220712. [PMID: 37872969 PMCID: PMC10590615 DOI: 10.1515/biol-2022-0712] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/05/2023] [Accepted: 08/06/2023] [Indexed: 10/25/2023] Open
Abstract
Circadian cycle is a fundamental characteristic of life formed in the long-term evolution of organisms and plays an important role in maintaining the proliferation, migration, and activation of immune cells. Studies have shown that circadian rhythm disorders affect the occurrence and development of neuroinflammation by inducing glial cell activation and peripheral immune responses. In this article, we briefly described the research progress of neuroinflammation and circadian rhythm in recent years and explored the effects and possible mechanism of circadian rhythmicity on microglia, astrocytes, and peripheral immune function.
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Affiliation(s)
- Xinzi Xu
- College of Clinical Chinese Medicine, Hubei University of Chinese Medicine, Wuhan430065, China
| | - Junli Wang
- Department of Neurology, Wuhan No. 1 Hospital, Wuhan430022, China
| | - Guohua Chen
- Department of Neurology, Wuhan No. 1 Hospital, Wuhan430022, China
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3
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Sanchez SG, Bassot E, Cerutti A, Mai Nguyen H, Aïda A, Blanchard N, Besteiro S. The apicoplast is important for the viability and persistence of Toxoplasma gondii bradyzoites. Proc Natl Acad Sci U S A 2023; 120:e2309043120. [PMID: 37590416 PMCID: PMC10450435 DOI: 10.1073/pnas.2309043120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 06/27/2023] [Indexed: 08/19/2023] Open
Abstract
Toxoplasma gondii is responsible for toxoplasmosis, a disease that can be serious when contracted during pregnancy, but can also be a threat for immunocompromised individuals. Acute infection is associated with the tachyzoite form that spreads rapidly within the host. However, under stress conditions, some parasites can differentiate into cyst-forming bradyzoites, residing mainly in the central nervous system, retina and muscle. Because this latent form of the parasite is resistant to all currently available treatments, and is central to persistence and transmission of the parasite, specific therapeutic strategies targeting this developmental stage need to be found. T. gondii contains a plastid of endosymbiotic origin called the apicoplast, which is an appealing drug target because it is essential for tachyzoite viability and contains several key metabolic pathways that are largely absent from the mammalian host. Its function in bradyzoites, however, is unknown. Our objective was thus to study the contribution of the apicoplast to the viability and persistence of bradyzoites during chronic toxoplasmosis. We have used complementary strategies based on stage-specific promoters to generate conditional bradyzoite mutants of essential apicoplast genes. Our results show that specifically targeting the apicoplast in both in vitro or in vivo-differentiated bradyzoites leads to a loss of long-term bradyzoite viability, highlighting the importance of this organelle for this developmental stage. This validates the apicoplast as a potential area to look for therapeutic targets in bradyzoites, with the aim to interfere with this currently incurable parasite stage.
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Affiliation(s)
- Syrian G. Sanchez
- Laboratory of Pathogens and Host Immunity, CNRS, University of Montpellier, 34095Montpellier, France
| | - Emilie Bassot
- Toulouse Institute for Infectious and Inflammatory Diseases, Infinity, University of Toulouse, CNRS, Inserm, Université Paul Sabatier, 31059Toulouse, France
| | - Aude Cerutti
- Laboratory of Pathogens and Host Immunity, CNRS, University of Montpellier, 34095Montpellier, France
| | - Hoa Mai Nguyen
- Laboratory of Pathogens and Host Immunity, CNRS, University of Montpellier, 34095Montpellier, France
| | - Amel Aïda
- Toulouse Institute for Infectious and Inflammatory Diseases, Infinity, University of Toulouse, CNRS, Inserm, Université Paul Sabatier, 31059Toulouse, France
| | - Nicolas Blanchard
- Toulouse Institute for Infectious and Inflammatory Diseases, Infinity, University of Toulouse, CNRS, Inserm, Université Paul Sabatier, 31059Toulouse, France
| | - Sébastien Besteiro
- Laboratory of Pathogens and Host Immunity, CNRS, University of Montpellier, 34095Montpellier, France
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4
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Abstract
Toxoplasma gondii infection in the central nervous system commonly occurs among immunodeficient patients. Its prevalence is high in countries with a high burden of HIV and low coverage of antiretroviral drugs. The brain is one of the predilections for T. gondii infection due to its low inflammatory reaction, and cerebral toxoplasmosis occurs solely due to the reactivation of a latent infection rather than a new infection. Several immune elements have recently been recognized to have an essential role in the immunopathogenesis of cerebral toxoplasmosis. Although real-time isothermal amplification, next-generation sequencing, and enzyme-linked aptamer assays from blood samples have been the recommended diagnostic tools in some in-vivo studies, a combination of clinical symptoms, serology examination, and neuroimaging are still the daily standard for the presumptive diagnosis of cerebral toxoplasmosis and early anti-toxoplasma administration. Clinical trials are needed to find a new therapy that is less likely to affect folate synthesis, have neuroprotective properties, or cure the latent phase of infection. The development of a vaccine is being extensively tested in animals, but its efficacy and safety for humans are still not proven.
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Affiliation(s)
- Sofiati Dian
- Department of Neurology, Faculty of Medicine, Universitas Padjdjaran/Hasan Sadikin Hospital, Bandung, Indonesia
- Health Research Unit, Faculty of Medicine, Padjadjaran University/Hasan Sadikin Hospital, Bandung, Indonesia
| | - Ahmad Rizal Ganiem
- Department of Neurology, Faculty of Medicine, Universitas Padjdjaran/Hasan Sadikin Hospital, Bandung, Indonesia
- Health Research Unit, Faculty of Medicine, Padjadjaran University/Hasan Sadikin Hospital, Bandung, Indonesia
| | - Savira Ekawardhani
- Parasitology Division, Department of Biomedical Sciences, Faculty of Medicine, Padjadjaran University, Bandung, Indonesia
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5
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Figueiredo CA, Dunay IR. IFN-γ-mediated neuronal defense mechanism targets Toxoplasma. Trends Parasitol 2022; 38:1023-1025. [PMID: 36280528 DOI: 10.1016/j.pt.2022.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 11/05/2022]
Abstract
Toxoplasma gondii encysts preferentially within neurons in the central nervous system, establishing lifelong persistence. Despite recent discoveries, this neuronal preference was thought, in part, to be secondary to a lack of neuronal cell-autonomous immunity. By showing that neurons can mount interferon-gamma (IFN-γ)-mediated cell-autonomous anti-T. gondii defenses, Chandrasekaran et al. have challenged long held assumptions.
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Affiliation(s)
- Caio Andreeta Figueiredo
- Institute of Inflammation and Neurodegeneration, Health Campus Immunology, Infectiology and Inflammation (GC-I3), Otto-von-Guericke University, Magdeburg, Germany
| | - Ildiko Rita Dunay
- Institute of Inflammation and Neurodegeneration, Health Campus Immunology, Infectiology and Inflammation (GC-I3), Otto-von-Guericke University, Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany.
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6
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T cell surveillance of Toxoplasma gondii: Basic insights into how T cells operate in the central nervous system. Curr Opin Neurobiol 2022; 77:102640. [PMID: 36240583 DOI: 10.1016/j.conb.2022.102640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/06/2022] [Accepted: 09/07/2022] [Indexed: 01/10/2023]
Abstract
The ability of T cells to operate in the central nervous system (CNS) is required for resistance to multiple pathogens that affect this tissue. The intracellular parasite Toxoplasma gondii has evolved to persist in the CNS and poses unique challenges to the immune system with the need to control parasite replication while balancing the adverse pathology associated with local inflammation. This article reviews the models used to study the response to T. gondii during toxoplasmic encephalitis and highlights some of the broader lessons that are relevant to understanding how T cells function in the CNS.
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7
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Pan M, Ge CC, Fan YM, Jin QW, Shen B, Huang SY. The determinants regulating Toxoplasma gondii bradyzoite development. Front Microbiol 2022; 13:1027073. [PMID: 36439853 PMCID: PMC9691885 DOI: 10.3389/fmicb.2022.1027073] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 10/24/2022] [Indexed: 11/04/2023] Open
Abstract
Toxoplasma gondii is an obligate intracellular zoonotic pathogen capable of infecting almost all cells of warm-blooded vertebrates. In intermediate hosts, this parasite reproduces asexually in two forms, the tachyzoite form during acute infection that proliferates rapidly and the bradyzoite form during chronic infection that grows slowly. Depending on the growth condition, the two forms can interconvert. The conversion of tachyzoites to bradyzoites is critical for T. gondii transmission, and the reactivation of persistent bradyzoites in intermediate hosts may lead to symptomatic toxoplasmosis. However, the mechanisms that control bradyzoite differentiation have not been well studied. Here, we review recent advances in the study of bradyzoite biology and stage conversion, aiming to highlight the determinants associated with bradyzoite development and provide insights to design better strategies for controlling toxoplasmosis.
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Affiliation(s)
- Ming Pan
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Ceng-Ceng Ge
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Yi-Min Fan
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Qi-Wang Jin
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Bang Shen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Si-Yang Huang
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, China
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8
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Experimental infection of Toxoplasma gondii in specific pathogen-free and commercial broiler chicks. Comp Immunol Microbiol Infect Dis 2022; 90-91:101890. [DOI: 10.1016/j.cimid.2022.101890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 09/18/2022] [Accepted: 09/29/2022] [Indexed: 11/20/2022]
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9
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Johnson HJ, Koshy AA. Understanding neuroinflammation through central nervous system infections. Curr Opin Neurobiol 2022; 76:102619. [PMID: 35985075 PMCID: PMC10147316 DOI: 10.1016/j.conb.2022.102619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/09/2022] [Accepted: 07/08/2022] [Indexed: 11/28/2022]
Abstract
Neuroinflammation is now recognized to compound many central nervous system (CNS) pathologies, from stroke to dementia. As immune responses evolved to handle infections, studying CNS infections can offer unique insights into the CNS immune response and address questions such as: What defenses and strategies do CNS parenchymal cells deploy in response to a dangerous pathogen? How do CNS cells interact with each other and infiltrating immune cells to control microbes? What pathways are beneficial for the host or for the pathogen? Here, we review recent studies that use CNS-tropic infections in combination with cutting-edge techniques to delve into the complex relationships between microbes, immune cells, and cells of the CNS.
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Affiliation(s)
- Hannah J Johnson
- Neuroscience Graduate Interdisciplinary Program, University of Arizona, Tucson, AZ, USA
| | - Anita A Koshy
- Neuroscience Graduate Interdisciplinary Program, University of Arizona, Tucson, AZ, USA; Department of Neurology, University of Arizona, Tucson, AZ, USA; BIO5 Institute, University of Arizona, Tucson, AZ, USA; Department of Immunobiology, University of Arizona, Tucson, AZ, USA.
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10
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Chandrasekaran S, Kochanowsky JA, Merritt EF, Lagas JS, Swannigan A, Koshy AA. IFN-γ stimulated murine and human neurons mount anti-parasitic defenses against the intracellular parasite Toxoplasma gondii. Nat Commun 2022; 13:4605. [PMID: 35941154 PMCID: PMC9360015 DOI: 10.1038/s41467-022-32225-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 07/19/2022] [Indexed: 01/13/2023] Open
Abstract
Dogma holds that Toxoplasma gondii persists in neurons because neurons cannot clear intracellular parasites, even with IFN-γ stimulation. As several recent studies questioned this idea, here we use primary murine neuronal cultures from wild type and transgenic mice in combination with IFN-γ stimulation and parental and transgenic parasites to reassess IFN-γ dependent neuronal clearance of intracellular parasites. We find that neurons respond to IFN-γ and that a subset of neurons clear intracellular parasites via immunity regulated GTPases. Whole neuron reconstructions from mice infected with parasites that trigger neuron GFP expression only after full invasion reveal that ~50% of these T. gondii-invaded neurons no longer harbor parasites. Finally, IFN-γ stimulated human pluripotent stem cell derived neurons show an ~50% decrease in parasite infection rate when compared to unstimulated cultures. This work highlights the capability of human and murine neurons to mount cytokine-dependent anti-T. gondii defense mechanisms in vitro and in vivo.
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Affiliation(s)
| | - Joshua A Kochanowsky
- Department of Immunobiology, University of Arizona, Tucson, AZ, USA
- University of California, Los Angeles, CA, USA
| | - Emily F Merritt
- Department of Immunobiology, University of Arizona, Tucson, AZ, USA
| | - Joseph S Lagas
- Undergraduate Biology Research Program, University of Arizona, Tucson, AZ, USA
| | - Ayesha Swannigan
- Undergraduate Research Opportunities Consortium, University of Arizona, Tucson, AZ, USA
| | - Anita A Koshy
- BIO5 Institute, University of Arizona, Tucson, AZ, USA.
- Department of Immunobiology, University of Arizona, Tucson, AZ, USA.
- Department of Neurology, University of Arizona, Tucson, AZ, USA.
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11
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Immune responses to Toxoplasma gondii. Curr Opin Immunol 2022; 77:102226. [PMID: 35785567 DOI: 10.1016/j.coi.2022.102226] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 04/19/2022] [Accepted: 05/19/2022] [Indexed: 11/22/2022]
Abstract
Toxoplasma gondii is an obligate intracellular parasite that can cause severe complications in the newborn and immunocompromised individuals. The parasite evokes a strong innate immune response in the infected hosts which is followed by a robust adaptive immunity. In the last few years, importance of innate immune mechanisms dependent on the role of MyD-88 independent pathways, inflammatory monocytes and innate lymphocyte have been identified. However, notwithstanding the strong immune response to the parasite, the chronic infection persists in the host. The inability to prevent chronic infection can be attributed to aberration in the memory CD8 T cell response caused by an increased expression of inhibitory receptors that leads to their dysfunctionality.
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12
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Impact of secondary TCR engagement on the heterogeneity of pathogen-specific CD8+ T cell response during acute and chronic toxoplasmosis. PLoS Pathog 2022; 18:e1010296. [PMID: 35727849 PMCID: PMC9249239 DOI: 10.1371/journal.ppat.1010296] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 07/01/2022] [Accepted: 05/06/2022] [Indexed: 11/19/2022] Open
Abstract
Initial TCR engagement (priming) of naive CD8+ T cells results in T cell expansion, and these early events influence the generation of diverse effector and memory populations. During infection, activated T cells can re-encounter cognate antigen, but how these events influence local effector responses or formation of memory populations is unclear. To address this issue, OT-I T cells which express the Nur77-GFP reporter of TCR activation were paired with the parasite Toxoplasma gondii that expresses OVA to assess how secondary encounter with antigen influences CD8+ T cell responses. During acute infection, TCR stimulation in affected tissues correlated with parasite burden and was associated with markers of effector cells while Nur77-GFP- OT-I showed signs of effector memory potential. However, both Nur77-GFP- and Nur77-GFP+ OT-I from acutely infected mice formed similar memory populations when transferred into naive mice. During the chronic stage of infection in the CNS, TCR activation was associated with large scale transcriptional changes and the acquisition of an effector T cell phenotype as well as the generation of a population of CD103+ CD69+ Trm like cells. While inhibition of parasite replication resulted in reduced effector responses it did not alter the Trm population. These data sets highlight that recent TCR activation contributes to the phenotypic heterogeneity of the CD8+ T cell response but suggest that this process has a limited impact on memory populations at acute and chronic stages of infection.
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13
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Castaño BL, Silva AA, Hernandez-Velasco LL, Pinheiro APDS, Gibaldi D, Mineo JR, Silva NM, Lannes-Vieira J. Sulfadiazine Plus Pyrimethamine Therapy Reversed Multiple Behavioral and Neurocognitive Changes in Long-Term Chronic Toxoplasmosis by Reducing Brain Cyst Load and Inflammation-Related Alterations. Front Immunol 2022; 13:822567. [PMID: 35572567 PMCID: PMC9091718 DOI: 10.3389/fimmu.2022.822567] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 03/28/2022] [Indexed: 11/13/2022] Open
Abstract
Toxoplasma gondii infects one-third of the world population. For decades, it has been considered a silent lifelong infection. However, chronically T. gondii-infected persons may present psychiatric and neurocognitive changes as anxiety, depression, and memory loss. In a model of long-term chronic infection, behavioral alterations parallel neuroinflammation and systemic high cytokine levels, and may reflect brain cyst load. Recent findings support that in chronic infection an active parasite-host interplay involves an immune-mediated control of tissue cysts. Here, we tested the idea that etiological treatment in chronic phase may add advantage to intrinsic immune-mediated cyst control and impact behavioral changes. Thus, we combined sulfadiazine-plus-pyrimethamine (S+P), the first-choice therapy for toxoplasmosis, to study the association of brain cyst load and biological processes related to the immune response (neuroinflammation, blood-brain barrier -BBB- disruption and serum cytokine levels), with behavioral and neurocognitive changes of long-term chronic infection. Female C57BL/6 mice (H-2b) were infected (5 cysts, ME-49 strain) and treated with S+P from 30 to 60 days postinfection (dpi), compared with vehicle (Veh)-treated and noninfected controls. At endpoints (pre-therapy, 30 dpi; S+P therapy, 60 dpi; after ceased therapy, 90 dpi), independent groups were subjected to behavioral tests, and brain tissues and sera were collected. Multiple behavioral and neurocognitive changes were detected in the early (30 dpi) and long-term (60 and 90 dpi) chronic infection. S+P therapy resolved locomotor alterations, anxiety, and depressive-like behavior, partially or transiently ameliorated hyperactivity and habituation memory loss. Analysis after therapy cessation showed that S+P therapy reduced the number of stimuli required for aversive memory consolidation. S+P therapy resulted in reduced brain cyst load, neuroinflammation and BBB disruption, and lowered systemic Th1-cytokine levels. Correlation analysis revealed association between IFNγ, TNF and MCP-1/CCL2 serum levels, brain cyst load and behavioral and neurocognitive alterations. Moreover, principal-component analysis (PCA-2D and 3D projections) highlighted distinction between clusters (noninfected; Veh-treated and S+P-treated infected). Thus, our data suggest that S+P therapy added gain to intrinsic brain cyst control and, direct or indirectly, ameliorated inflammation-related alterations, traits associated with behavioral and neurocognitive alterations.
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Affiliation(s)
- Barrios Leda Castaño
- Laboratory of Biology of the Interactions, Oswaldo Cruz Institute/Fiocruz, Rio de Janeiro, Brazil
| | - Andrea Alice Silva
- Multiuser Laboratory for Research Support in Nephrology and Medical Sciences, Federal University Fluminense, Niterói, Brazil
| | | | | | - Daniel Gibaldi
- Laboratory of Biology of the Interactions, Oswaldo Cruz Institute/Fiocruz, Rio de Janeiro, Brazil
| | - José Roberto Mineo
- Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Brazil
| | - Neide Maria Silva
- Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Brazil
| | - Joseli Lannes-Vieira
- Laboratory of Biology of the Interactions, Oswaldo Cruz Institute/Fiocruz, Rio de Janeiro, Brazil
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14
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Bernard-Valnet R, Frieser D, Nguyen XH, Khajavi L, Quériault C, Arthaud S, Melzi S, Fusade-Boyer M, Masson F, Zytnicki M, Saoudi A, Dauvilliers Y, Peyron C, Bauer J, Liblau RS. Influenza vaccination induces autoimmunity against orexinergic neurons in a mouse model for narcolepsy. Brain 2022; 145:2018-2030. [PMID: 35552381 DOI: 10.1093/brain/awab455] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 11/03/2021] [Accepted: 11/24/2021] [Indexed: 11/12/2022] Open
Abstract
Narcolepsy with cataplexy or narcolepsy type 1 is a disabling chronic sleep disorder resulting from the destruction of orexinergic neurons in the hypothalamus. The tight association of narcolepsy with HLA-DQB1*06:02 strongly suggest an autoimmune origin to this disease. Furthermore, converging epidemiological studies have identified an increased incidence for narcolepsy in Europe following Pandemrix® vaccination against the 2009-2010 pandemic 'influenza' virus strain. The potential immunological link between the Pandemrix® vaccination and narcolepsy remains, however, unknown. Deciphering these mechanisms may reveal pathways potentially at play in most cases of narcolepsy. Here, we developed a mouse model allowing to track and study the T-cell response against 'influenza' virus haemagglutinin, which was selectively expressed in the orexinergic neurons as a new self-antigen. Pandemrix® vaccination in this mouse model resulted in hypothalamic inflammation and selective destruction of orexin-producing neurons. Further investigations on the relative contribution of T-cell subsets in this process revealed that haemagglutinin-specific CD4 T cells were necessary for the development of hypothalamic inflammation, but insufficient for killing orexinergic neurons. Conversely, haemagglutinin-specific CD8 T cells could not initiate inflammation but were the effectors of the destruction of orexinergic neurons. Additional studies revealed pathways potentially involved in the disease process. Notably, the interferon-γ pathway was proven essential, as interferon-γ-deficient CD8 T cells were unable to elicit the loss of orexinergic neurons. Our work demonstrates that an immunopathological process mimicking narcolepsy can be elicited by immune cross-reactivity between a vaccine antigen and a neuronal self-antigen. This process relies on a synergy between autoreactive CD4 and CD8 T cells for disease development. This work furthers our understanding of the mechanisms and pathways potentially involved in the development of a neurological side effect due to a vaccine and, likely, to narcolepsy in general.
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Affiliation(s)
- Raphaël Bernard-Valnet
- Toulouse Institute for Infectious and Inflammatory Diseases (Infinity), University of Toulouse, CNRS, INSERM, UPS, Toulouse, France.,Service of Neurology, Clinical Neurosciences Department, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - David Frieser
- Toulouse Institute for Infectious and Inflammatory Diseases (Infinity), University of Toulouse, CNRS, INSERM, UPS, Toulouse, France
| | - Xuan-Hung Nguyen
- Toulouse Institute for Infectious and Inflammatory Diseases (Infinity), University of Toulouse, CNRS, INSERM, UPS, Toulouse, France.,Vinmec Institute of Applied Science and Regenerative Medicine, Vinmec Healthcare System, Hanoi, Vietnam
| | - Leila Khajavi
- Toulouse Institute for Infectious and Inflammatory Diseases (Infinity), University of Toulouse, CNRS, INSERM, UPS, Toulouse, France
| | - Clémence Quériault
- Toulouse Institute for Infectious and Inflammatory Diseases (Infinity), University of Toulouse, CNRS, INSERM, UPS, Toulouse, France
| | - Sébastien Arthaud
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience, University of Lyon 1, Bron, France
| | - Silvia Melzi
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience, University of Lyon 1, Bron, France
| | | | - Frederick Masson
- Toulouse Institute for Infectious and Inflammatory Diseases (Infinity), University of Toulouse, CNRS, INSERM, UPS, Toulouse, France
| | - Matthias Zytnicki
- Unité de Mathématiques et Informatique Appliquées, INRAE, Castanet-Tolosan, France
| | - Abdelhadi Saoudi
- Toulouse Institute for Infectious and Inflammatory Diseases (Infinity), University of Toulouse, CNRS, INSERM, UPS, Toulouse, France
| | - Yves Dauvilliers
- National Reference Center for Orphan Diseases, Narcolepsy, Idiopathic hypersomnia and Kleine-Levin Syndrome, Department of Neurology, Gui-de-Chauliac Hospital, CHU de Montpellier, INSERM U1061, Montpellier, France
| | - Christelle Peyron
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience, University of Lyon 1, Bron, France
| | - Jan Bauer
- Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Roland S Liblau
- Toulouse Institute for Infectious and Inflammatory Diseases (Infinity), University of Toulouse, CNRS, INSERM, UPS, Toulouse, France.,Department of Immunology, Toulouse University Hospitals, Toulouse, France
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15
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Idro R, Ogwang R, Barragan A, Raimondo JV, Masocha W. Neuroimmunology of Common Parasitic Infections in Africa. Front Immunol 2022; 13:791488. [PMID: 35222377 PMCID: PMC8866860 DOI: 10.3389/fimmu.2022.791488] [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: 10/08/2021] [Accepted: 01/18/2022] [Indexed: 11/13/2022] Open
Abstract
Parasitic infections of the central nervous system are an important cause of morbidity and mortality in Africa. The neurological, cognitive, and psychiatric sequelae of these infections result from a complex interplay between the parasites and the host inflammatory response. Here we review some of the diseases caused by selected parasitic organisms known to infect the nervous system including Plasmodium falciparum, Toxoplasma gondii, Trypanosoma brucei spp., and Taenia solium species. For each parasite, we describe the geographical distribution, prevalence, life cycle, and typical clinical symptoms of infection and pathogenesis. We pay particular attention to how the parasites infect the brain and the interaction between each organism and the host immune system. We describe how an understanding of these processes may guide optimal diagnostic and therapeutic strategies to treat these disorders. Finally, we highlight current gaps in our understanding of disease pathophysiology and call for increased interrogation of these often-neglected disorders of the nervous system.
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Affiliation(s)
- Richard Idro
- College of Health Sciences, Makerere University, Kampala, Uganda.,Centre of Tropical Neuroscience, Kitgum, Uganda.,Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Rodney Ogwang
- College of Health Sciences, Makerere University, Kampala, Uganda.,Centre of Tropical Neuroscience, Kitgum, Uganda.,Kenya Medical Research Institute (KEMRI) - Wellcome Trust Research Programme, Nairobi, Kenya
| | - Antonio Barragan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Joseph Valentino Raimondo
- Division of Cell Biology, Department of Human Biology, Neuroscience Institute and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Willias Masocha
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Kuwait University, Safat, Kuwait
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16
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Ross EC, Olivera GC, Barragan A. Early passage of Toxoplasma gondii across the blood–brain barrier. Trends Parasitol 2022; 38:450-461. [DOI: 10.1016/j.pt.2022.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 02/01/2022] [Accepted: 02/02/2022] [Indexed: 12/29/2022]
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17
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Hobson BD, Sulzer D. Neuronal Presentation of Antigen and Its Possible Role in Parkinson's Disease. JOURNAL OF PARKINSON'S DISEASE 2022; 12:S137-S147. [PMID: 35253783 PMCID: PMC9440948 DOI: 10.3233/jpd-223153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Patients with Parkinson's disease (PD) and other synucleinopathies often exhibit autoimmune features, including CD4+ and some CD8+ T lymphocytes that recognize epitopes derived from alpha-synuclein. While neurons have long been considered to not present antigens, recent data indicate that they can be induced to do so, particularly in response to interferons and other forms of stress. Here, we review literature on neuronal antigen presentation and its potential role in PD. Although direct evidence for CD8+ T cell-mediated neuronal death is lacking in PD, neuronal antigen presentation appears central to the pathology of Rasmussen's encephalitis, a pediatric neurological disorder driven by cytotoxic T cell infiltration and neuroinflammation. Emerging data suggest that T cells enter the brain in PD and other synucleinopathies, where the majority of neuromelanin-containing substantia nigra and locus coeruleus neurons express MHC Class I molecules. In cell culture, CD8+ T cell recognition of antigen:MHC Class I complexes on neuronal membranes leads to cytotoxic responses and neuronal cell death. Recent animal models suggest the possibility of T cell autoreactivity to mitochondrial antigens in PD. It remains unclear if neuronal antigen presentation plays a role in PD or other neurodegenerative disorders, and efforts are underway to better elucidate the potential impact of autoimmune responses on neurodegeneration.
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Affiliation(s)
- Benjamin D. Hobson
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, USA
- Department of Psychiatry, Columbia University Irving Medical Center, New York, NY, USA
- Medical Scientist Training Program, Columbia University Irving Medical Center, New York, NY, USA
| | - David Sulzer
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, USA
- Department of Psychiatry, Columbia University Irving Medical Center, New York, NY, USA
- Department of Pharmacology, Columbia University Irving Medical Center, New York, NY, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
- Correspondence to: David Sultzer, Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA. E-mail:
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18
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Bangs DJ, Tsitsiklis A, Steier Z, Chan SW, Kaminski J, Streets A, Yosef N, Robey EA. CXCR3 regulates stem and proliferative CD8+ T cells during chronic infection by promoting interactions with DCs in splenic bridging channels. Cell Rep 2022; 38:110266. [PMID: 35045305 PMCID: PMC8896093 DOI: 10.1016/j.celrep.2021.110266] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/17/2021] [Accepted: 12/22/2021] [Indexed: 12/01/2022] Open
Abstract
Production of effector CD8+ T cells during persistent infection requires a stable pool of stem-like cells that can give rise to effector cells via a proliferative intermediate population. In infection models marked by T cell exhaustion, this process can be transiently induced by checkpoint blockade but occurs spontaneously in mice chronically infected with the protozoan intracellular parasite Toxoplasma gondii. We observe distinct locations for parasite-specific T cell subsets, implying a link between differentiation and anatomical niches in the spleen. Loss of the chemokine receptor CXCR3 on T cells does not prevent white pulp-to-red pulp migration but reduces interactions with CXCR3 ligand-producing dendritic cells (DCs) and impairs memory-to-intermediate transition, leading to a buildup of memory T cells in the red pulp. Thus, CXCR3 increases T cell exposure to differentiation-inducing signals during red pulp migration, providing a dynamic mechanism for modulating effector differentiation in response to environmental signals. Bangs et al. report that distinct subsets of CD8+ T cells found during chronic infection occupy distinct regions of the spleen. CXCR3 regulates differentiation of T cells but not their migration. Instead, CXCR3 promotes the interaction of T cells with ligand-producing DCs in bridging channels, resulting in effector differentiation.
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Affiliation(s)
- Derek J Bangs
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Alexandra Tsitsiklis
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Zoë Steier
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA; Center for Computational Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Shiao Wei Chan
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - James Kaminski
- Center for Computational Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Aaron Streets
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA; Center for Computational Biology, University of California, Berkeley, Berkeley, CA, USA; Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Nir Yosef
- Center for Computational Biology, University of California, Berkeley, Berkeley, CA, USA; Chan Zuckerberg Biohub, San Francisco, CA, USA; Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, USA; Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
| | - Ellen A Robey
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
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19
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Frickel EM, Hunter CA. Lessons from Toxoplasma: Host responses that mediate parasite control and the microbial effectors that subvert them. J Exp Med 2021; 218:212714. [PMID: 34670268 PMCID: PMC8532566 DOI: 10.1084/jem.20201314] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/03/2021] [Accepted: 09/29/2021] [Indexed: 11/15/2022] Open
Abstract
The intracellular parasite Toxoplasma gondii has long provided a tractable experimental system to investigate how the immune system deals with intracellular infections. This review highlights the advances in defining how this organism was first detected and the studies with T. gondii that contribute to our understanding of how the cytokine IFN-γ promotes control of vacuolar pathogens. In addition, the genetic tractability of this eukaryote organism has provided the foundation for studies into the diverse strategies that pathogens use to evade antimicrobial responses and now provides the opportunity to study the basis for latency. Thus, T. gondii remains a clinically relevant organism whose evolving interactions with the host immune system continue to teach lessons broadly relevant to host–pathogen interactions.
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Affiliation(s)
- Eva-Maria Frickel
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, UK
| | - Christopher A Hunter
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA
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20
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Goddery EN, Fain CE, Lipovsky CG, Ayasoufi K, Yokanovich LT, Malo CS, Khadka RH, Tritz ZP, Jin F, Hansen MJ, Johnson AJ. Microglia and Perivascular Macrophages Act as Antigen Presenting Cells to Promote CD8 T Cell Infiltration of the Brain. Front Immunol 2021; 12:726421. [PMID: 34526998 PMCID: PMC8435747 DOI: 10.3389/fimmu.2021.726421] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/09/2021] [Indexed: 01/01/2023] Open
Abstract
CD8 T cell infiltration of the central nervous system (CNS) is necessary for host protection but contributes to neuropathology. Antigen presenting cells (APCs) situated at CNS borders are thought to mediate T cell entry into the parenchyma during neuroinflammation. The identity of the CNS-resident APC that presents antigen via major histocompatibility complex (MHC) class I to CD8 T cells is unknown. Herein, we characterize MHC class I expression in the naïve and virally infected brain and identify microglia and macrophages (CNS-myeloid cells) as APCs that upregulate H-2Kb and H-2Db upon infection. Conditional ablation of H-2Kb and H-2Db from CNS-myeloid cells allowed us to determine that antigen presentation via H-2Db, but not H-2Kb, was required for CNS immune infiltration during Theiler's murine encephalomyelitis virus (TMEV) infection and drives brain atrophy as a consequence of infection. These results demonstrate that CNS-myeloid cells are key APCs mediating CD8 T cell brain infiltration.
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Affiliation(s)
- Emma N. Goddery
- Department of Immunology, Mayo Clinic, Rochester, MN, United States
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, United States
| | - Cori E. Fain
- Department of Immunology, Mayo Clinic, Rochester, MN, United States
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, United States
| | - Chloe G. Lipovsky
- Department of Immunology, Mayo Clinic, Rochester, MN, United States
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, United States
| | | | - Lila T. Yokanovich
- Department of Immunology, Mayo Clinic, Rochester, MN, United States
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, United States
| | - Courtney S. Malo
- Department of Immunology, Mayo Clinic, Rochester, MN, United States
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, United States
| | - Roman H. Khadka
- Department of Immunology, Mayo Clinic, Rochester, MN, United States
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, United States
| | - Zachariah P. Tritz
- Department of Immunology, Mayo Clinic, Rochester, MN, United States
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, United States
| | - Fang Jin
- Department of Immunology, Mayo Clinic, Rochester, MN, United States
| | | | - Aaron J. Johnson
- Department of Immunology, Mayo Clinic, Rochester, MN, United States
- Department of Neurology, Mayo Clinic, Rochester, MN, United States
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN, United States
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21
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Abou-El-Naga IF, Gomaa MM, ElAchy SN. Effect of HIV aspartyl protease inhibitors on experimental infection with a cystogenic Me49 strain of Toxoplasma gondii. Pathog Glob Health 2021; 116:107-118. [PMID: 34420500 DOI: 10.1080/20477724.2021.1967628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Toxoplasmosis is a zoonotic disease of major significant perspectives in public health and veterinary medicine. So far, the available drugs control only the active infection, once the parasite encysts in the tissues, they lose their efficacy. Cytokines; IFN-γ and IL-10, play a critical role in the modulation of toxoplasmic encephalitis and neuro-inflammation in chronic toxoplasmosis. Antiretroviral protease inhibitors applied in the treatment of acquired immunodeficiency syndrome, revealed activity against multiple parasites. Aluvia (lopinavir/ritonavir) (L/R); an aspartyl protease inhibitor, had efficiently treated T. gondii RH strain infection. We investigated the potential activity of L/R against experimental T. gondii infection with a cystogenic Me49 strain in mice, considering the role of IFN-γ and IL-10 in the neuropathology versus pyrimethamine-sulfadiazine combination therapy. Three aluvia regimens were applied; starting on the day of infection (acute phase), 2-week PI (early chronic phase) and eight weeks PI (late chronic phase). L/R reduced the brain-tissue cyst burden significantly in all treatment regimens. It impaired the parasite infectivity markedly in the late chronic phase. Ultrastructural changes were detected in Toxoplasma cyst membrane and wall, bradyzoite membrane and nuclear envelope. The signs of bradyzoite paraptosis and cytoplasmic lipid droplets were observed. L/R had significantly reduced the brain-homogenate levels of IFN-γ and IL-10 in its three regimens however, they could not reach the normal level in chronic phases. Cerebral hypercellularity, perivascular inflammatory response, lymphoplasmacytic infiltrates and glial cellular reaction were ameliorated by L/R treatment. Herein, L/R was proved to possess promising preventive and therapeutic perspectives in chronic cerebral toxoplasmosis.
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Affiliation(s)
- Iman Fathy Abou-El-Naga
- Department Of Medical Parasitology, Faculty Of Medicine, Alexandria University, Alexandria, Egypt
| | - Maha Mohamed Gomaa
- Department Of Medical Parasitology, Faculty Of Medicine, Alexandria University, Alexandria, Egypt
| | - Samar Nabil ElAchy
- Department Of Pathology, Faculty Of Medicine, Alexandria University, Alexandria, Egypt
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22
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Matta SK, Rinkenberger N, Dunay IR, Sibley LD. Toxoplasma gondii infection and its implications within the central nervous system. Nat Rev Microbiol 2021; 19:467-480. [PMID: 33627834 DOI: 10.1038/s41579-021-00518-7] [Citation(s) in RCA: 94] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/19/2021] [Indexed: 01/31/2023]
Abstract
Toxoplasma gondii is a parasite that infects a wide range of animals and causes zoonotic infections in humans. Although it normally only results in mild illness in healthy individuals, toxoplasmosis is a common opportunistic infection with high mortality in individuals who are immunocompromised, most commonly due to reactivation of infection in the central nervous system. In the acute phase of infection, interferon-dependent immune responses control rapid parasite expansion and mitigate acute disease symptoms. However, after dissemination the parasite differentiates into semi-dormant cysts that form within muscle cells and neurons, where they persist for life in the infected host. Control of infection in the central nervous system, a compartment of immune privilege, relies on modified immune responses that aim to balance infection control while limiting potential damage due to inflammation. In response to the activation of interferon-mediated pathways, the parasite deploys an array of effector proteins to escape immune clearance and ensure latent survival. Although these pathways are best studied in the laboratory mouse, emerging evidence points to unique mechanisms of control in human toxoplasmosis. In this Review, we explore some of these recent findings that extend our understanding for proliferation, establishment and control of toxoplasmosis in humans.
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Affiliation(s)
- Sumit K Matta
- Department of Molecular Microbiology, School of Medicine, Washington University in St. Louis, St. Louis, MO, USA
| | - Nicholas Rinkenberger
- Department of Molecular Microbiology, School of Medicine, Washington University in St. Louis, St. Louis, MO, USA
| | - Ildiko R Dunay
- Institute of Inflammation and Neurodegeneration, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - L David Sibley
- Department of Molecular Microbiology, School of Medicine, Washington University in St. Louis, St. Louis, MO, USA.
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23
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Mévélec MN, Lakhrif Z, Dimier-Poisson I. Key Limitations and New Insights Into the Toxoplasma gondii Parasite Stage Switching for Future Vaccine Development in Human, Livestock, and Cats. Front Cell Infect Microbiol 2020; 10:607198. [PMID: 33324583 PMCID: PMC7724089 DOI: 10.3389/fcimb.2020.607198] [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: 09/16/2020] [Accepted: 10/19/2020] [Indexed: 12/19/2022] Open
Abstract
Toxoplasmosis is a parasitic disease affecting human, livestock and cat. Prophylactic strategies would be ideal to prevent infection. In a One Health vaccination approach, the objectives would be the prevention of congenital disease in both women and livestock, prevention/reduction of T. gondii tissue cysts in food-producing animals; and oocyst shedding in cats. Over the last few years, an explosion of strategies for vaccine development, especially due to the development of genetic-engineering technologies has emerged. The field of vaccinology has been exploring safer vaccines by the generation of recombinant immunogenic proteins, naked DNA vaccines, and viral/bacterial recombinants vectors. These strategies based on single- or few antigens, are less efficacious than recombinant live-attenuated, mostly tachyzoite T. gondii vaccine candidates. Reflections on the development of an anti-Toxoplasma vaccine must focus not only on the appropriate route of administration, capable of inducing efficient immune response, but also on the choice of the antigen (s) of interest and the associated delivery systems. To answer these questions, the choice of the animal model is essential. If mice helped in understanding the protection mechanisms, the data obtained cannot be directly transposed to humans, livestock and cats. Moreover, effectiveness vaccines should elicit strong and protective humoral and cellular immune responses at both local and systemic levels against the different stages of the parasite. Finally, challenge protocols should use the oral route, major natural route of infection, either by feeding tissue cysts or oocysts from different T. gondii strains. Effective Toxoplasma vaccines depend on our understanding of the (1) protective host immune response during T. gondii invasion and infection in the different hosts, (2) manipulation and modulation of host immune response to ensure survival of the parasites able to evade and subvert host immunity, (3) molecular mechanisms that define specific stage development. This review presents an overview of the key limitations for the development of an effective vaccine and highlights the contributions made by recent studies on the mechanisms behind stage switching to offer interesting perspectives for vaccine development.
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Affiliation(s)
| | - Zineb Lakhrif
- Team BioMAP, Université de Tours, INRAE, ISP, Tours, France
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24
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Laing C, Blanchard N, McConkey GA. Noradrenergic Signaling and Neuroinflammation Crosstalk Regulate Toxoplasma gondii-Induced Behavioral Changes. Trends Immunol 2020; 41:1072-1082. [PMID: 33214056 DOI: 10.1016/j.it.2020.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 10/05/2020] [Accepted: 10/08/2020] [Indexed: 12/11/2022]
Abstract
Infections of the nervous system elicit neuroimmune responses and alter neurotransmission, affecting host neurological functions. Chronic infection with the apicomplexan parasite Toxoplasma correlates with certain neurological disorders in humans and alters behavior in rodents. Here, we propose that the crosstalk between neurotransmission and neuroinflammation may underlie some of these cognitive changes. We discuss how T. gondii infection suppresses noradrenergic signaling and how the restoration of this pathway improves behavioral aberrations, suggesting that altered neurotransmission and neuroimmune responses may act in concert to perturb behavior. This interaction might apply to other infectious agents, such as viruses, that elicit cognitive changes. We hypothesize that neurotransmitter signaling in immune cells can contribute to behavioral changes associated with brain infection, offering opportunities for potential therapeutic targeting.
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Affiliation(s)
- Conor Laing
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Nicolas Blanchard
- Centre de Physiopathologie Toulouse Purpan (CPTP), Inserm, CNRS, Université de Toulouse, Toulouse, France.
| | - Glenn A McConkey
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
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25
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Transcriptional Profiling Suggests T Cells Cluster around Neurons Injected with Toxoplasma gondii Proteins. mSphere 2020; 5:5/5/e00538-20. [PMID: 32878927 PMCID: PMC7471001 DOI: 10.1128/msphere.00538-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Like other persistent intracellular pathogens, Toxoplasma gondii, a protozoan parasite, has evolved to evade the immune system and establish a chronic infection in specific cells and organs, including neurons in the CNS. Understanding T. gondii’s persistence in neurons holds the potential to identify novel, curative drug targets. The work presented here offers new insights into the neuron-T. gondii interaction in vivo. By transcriptionally profiling neurons manipulated by T. gondii, we unexpectedly revealed that immune cells, and specifically CD8+ T cells, appear to cluster around these neurons, suggesting that CD8+ T cells specifically recognize parasite-manipulated neurons. Such a possibility supports evidence from other labs that questions the long-standing dogma that neurons are often persistently infected because they are not directly recognized by immune cells such as CD8+ T cells. Collectively, these data suggest we reconsider the broader role of neurons in the context of infection and neuroinflammation. Toxoplasma gondii’s tropism for and persistence in the central nervous system (CNS) underlies the symptomatic disease that T. gondii causes in humans. Our recent work has shown that neurons are the primary CNS cell with which Toxoplasma interacts and which it infects in vivo. This predilection for neurons suggests that T. gondii’s persistence in the CNS depends specifically upon parasite manipulation of the host neurons. Yet, most work on T. gondii-host cell interactions has been done in vitro and in nonneuronal cells. We address this gap by utilizing our T. gondii-Cre system that allows permanent marking and tracking of neurons injected with parasite effector proteins in vivo. Using laser capture microdissection (LCM) and RNA sequencing using RNA-seq, we isolated and transcriptionally profiled T. gondii-injected neurons (TINs), Bystander neurons (nearby non-T. gondii-injected neurons), and neurons from uninfected mice (controls). These profiles show that TIN transcriptomes significantly differ from the transcriptomes of Bystander and control neurons and that much of this difference is driven by increased levels of transcripts from immune cells, especially CD8+ T cells and monocytes. These data suggest that when we used LCM to isolate neurons from infected mice, we also picked up fragments of CD8+ T cells and monocytes clustering in extreme proximity around TINs and, to a lesser extent, Bystander neurons. In addition, we found that T. gondii transcripts were primarily found in the TIN transcriptome, not in the Bystander transcriptome. Collectively, these data suggest that, contrary to common perception, neurons that directly interact with or harbor parasites can be recognized by CD8+ T cells. IMPORTANCE Like other persistent intracellular pathogens, Toxoplasma gondii, a protozoan parasite, has evolved to evade the immune system and establish a chronic infection in specific cells and organs, including neurons in the CNS. Understanding T. gondii’s persistence in neurons holds the potential to identify novel, curative drug targets. The work presented here offers new insights into the neuron-T. gondii interaction in vivo. By transcriptionally profiling neurons manipulated by T. gondii, we unexpectedly revealed that immune cells, and specifically CD8+ T cells, appear to cluster around these neurons, suggesting that CD8+ T cells specifically recognize parasite-manipulated neurons. Such a possibility supports evidence from other labs that questions the long-standing dogma that neurons are often persistently infected because they are not directly recognized by immune cells such as CD8+ T cells. Collectively, these data suggest we reconsider the broader role of neurons in the context of infection and neuroinflammation.
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26
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Smith JR, Ashander LM, Arruda SL, Cordeiro CA, Lie S, Rochet E, Belfort R, Furtado JM. Pathogenesis of ocular toxoplasmosis. Prog Retin Eye Res 2020; 81:100882. [PMID: 32717377 DOI: 10.1016/j.preteyeres.2020.100882] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/26/2020] [Accepted: 06/30/2020] [Indexed: 12/12/2022]
Abstract
Ocular toxoplasmosis is a retinitis -almost always accompanied by vitritis and choroiditis- caused by intraocular infection with Toxoplasma gondii. Depending on retinal location, this condition may cause substantial vision impairment. T. gondii is an obligate intracellular protozoan parasite, with both sexual and asexual life cycles, and infection is typically contracted orally by consuming encysted bradyzoites in undercooked meat, or oocysts on unwashed garden produce or in contaminated water. Presently available anti-parasitic drugs cannot eliminate T. gondii from the body. In vitro studies using T. gondii tachyzoites, and human retinal cells and tissue have provided important insights into the pathogenesis of ocular toxoplasmosis. T. gondii may cross the vascular endothelium to access human retina by at least three routes: in leukocyte taxis; as a transmigrating tachyzoite; and after infecting endothelial cells. The parasite is capable of navigating the human neuroretina, gaining access to a range of cell populations. Retinal Müller glial cells are preferred initial host cells. T. gondii infection of the retinal pigment epithelial cells alters the secretion of growth factors and induces proliferation of adjacent uninfected epithelial cells. This increases susceptibility of the cells to parasite infection, and may be the basis of the characteristic hyperpigmented toxoplasmic retinal lesion. Infected epithelial cells also generate a vigorous immunologic response, and influence the activity of leukocytes that infiltrate the retina. A range of T. gondii genotypes are associated with human ocular toxoplasmosis, and individual immunogenetics -including polymorphisms in genes encoding innate immune receptors, human leukocyte antigens and cytokines- impacts the clinical manifestations. Research into basic pathogenic mechanisms of ocular toxoplasmosis highlights the importance of prevention and suggests new biological drug targets for established disease.
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Affiliation(s)
- Justine R Smith
- Eye & Vision Health and Flinders Centre for Innovation in Cancer, Flinders University College of Medicine & Public Health, Adelaide, Australia; Formerly of Casey Eye Institute, Oregon Health & Science University, USA.
| | - Liam M Ashander
- Eye & Vision Health and Flinders Centre for Innovation in Cancer, Flinders University College of Medicine & Public Health, Adelaide, Australia; Formerly of Casey Eye Institute, Oregon Health & Science University, USA
| | - Sigrid L Arruda
- Department of Ophthalmology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Cynthia A Cordeiro
- Cordeiro et Costa Ophtalmologie, Campos dos Goytacazes, Brazil; Formerly of Department of Ophthalmology, Federal University of Minas Gerais School of Medicine, Belo Horizonte, Brazil
| | - Shervi Lie
- Eye & Vision Health and Flinders Centre for Innovation in Cancer, Flinders University College of Medicine & Public Health, Adelaide, Australia
| | - Elise Rochet
- Eye & Vision Health and Flinders Centre for Innovation in Cancer, Flinders University College of Medicine & Public Health, Adelaide, Australia
| | - Rubens Belfort
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
| | - João M Furtado
- Department of Ophthalmology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil; Formerly of Casey Eye Institute, Oregon Health & Science University, USA
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Zhao XY, Ewald SE. The molecular biology and immune control of chronic Toxoplasma gondii infection. J Clin Invest 2020; 130:3370-3380. [PMID: 32609097 PMCID: PMC7324197 DOI: 10.1172/jci136226] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Toxoplasma gondii is an incredibly successful parasite owing in part to its ability to persist within cells for the life of the host. Remarkably, at least 350 host species of T. gondii have been described to date, and it is estimated that 30% of the global human population is chronically infected. The importance of T. gondii in human health was made clear with the first reports of congenital toxoplasmosis in the 1940s. However, the AIDS crisis in the 1980s revealed the prevalence of chronic infection, as patients presented with reactivated chronic toxoplasmosis, underscoring the importance of an intact immune system for parasite control. In the last 40 years, there has been tremendous progress toward understanding the biology of T. gondii infection using rodent models, human cell experimental systems, and clinical data. However, there are still major holes in our understanding of T. gondii biology, including the genes controlling parasite development, the mechanisms of cell-intrinsic immunity to T. gondii in the brain and muscle, and the long-term effects of infection on host homeostasis. The need to better understand the biology of chronic infection is underscored by the recent rise in ocular disease associated with emerging haplotypes of T. gondii and our lack of effective treatments to sterilize chronic infection. This Review discusses the cell types and molecular mediators, both host and parasite, that facilitate persistent T. gondii infection. We highlight the consequences of chronic infection for tissue-specific pathology and identify open questions in this area of host-Toxoplasma interactions.
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The Bradyzoite: A Key Developmental Stage for the Persistence and Pathogenesis of Toxoplasmosis. Pathogens 2020; 9:pathogens9030234. [PMID: 32245165 PMCID: PMC7157559 DOI: 10.3390/pathogens9030234] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 12/19/2022] Open
Abstract
Toxoplasma gondii is a ubiquitous parasitic protist found in a wide variety of hosts, including a large proportion of the human population. Beyond an acute phase which is generally self-limited in immunocompetent individuals, the ability of the parasite to persist as a dormant stage, called bradyzoite, is an important aspect of toxoplasmosis. Not only is this stage not eliminated by current treatments, but it can also reactivate in immunocompromised hosts, leading to a potentially fatal outcome. Yet, despite its critical role in the pathology, the bradyzoite stage is relatively understudied. One main explanation is that it is a considerably challenging model, which essentially has to be derived from in vivo sources. However, recent progress on genetic manipulation and in vitro differentiation models now offers interesting perspectives for tackling key biological questions related to this particularly important developmental stage.
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Abstract
Toxoplasma gondii is a ubiquitous, intracellular protozoan parasite with a broad range of intermediate hosts, including humans and rodents. In many hosts, T. gondii establishes a latent long-term infection by converting from its rapidly dividing or lytic form to its slowly replicating and encysting form. In humans and rodents, the major organ for encystment is the central nervous system (CNS), which has led many to investigate how this persistent CNS infection might influence rodent and human behavior and, more recently, neurodegenerative diseases. Toxoplasma gondii is a ubiquitous, intracellular protozoan parasite with a broad range of intermediate hosts, including humans and rodents. In many hosts, T. gondii establishes a latent long-term infection by converting from its rapidly dividing or lytic form to its slowly replicating and encysting form. In humans and rodents, the major organ for encystment is the central nervous system (CNS), which has led many to investigate how this persistent CNS infection might influence rodent and human behavior and, more recently, neurodegenerative diseases. Given the interest in this topic, here we seek to take a global approach to the data for and against the effects of latent T. gondii on behavior and neurodegeneration and the proposed mechanisms that might underlie behavior modifications.
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Tsitsiklis A, Bangs DJ, Robey EA. CD8+ T Cell Responses to Toxoplasma gondii: Lessons from a Successful Parasite. Trends Parasitol 2019; 35:887-898. [DOI: 10.1016/j.pt.2019.08.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/22/2019] [Accepted: 08/26/2019] [Indexed: 01/21/2023]
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Poncet AF, Blanchard N, Marion S. Toxoplasma and Dendritic Cells: An Intimate Relationship That Deserves Further Scrutiny. Trends Parasitol 2019; 35:870-886. [PMID: 31492624 DOI: 10.1016/j.pt.2019.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/01/2019] [Accepted: 08/04/2019] [Indexed: 02/07/2023]
Abstract
Toxoplasma gondii (Tg), an obligate intracellular parasite of the phylum Apicomplexa, infects a wide range of animals, including humans. A hallmark of Tg infection is the subversion of host responses, which is thought to favor parasite persistence and propagation to new hosts. Recently, a variety of parasite-secreted modulatory effectors have been uncovered in fibroblasts and macrophages, but the specific interplay between Tg and dendritic cells (DCs) is just beginning to emerge. In this review, we summarize the current knowledge on Tg-DC interactions, including innate recognition, cytokine production, and antigen presentation, and discuss open questions regarding how Tg-secreted effectors may shape DC functions to perturb innate and adaptive immunity.
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Affiliation(s)
- Anaïs F Poncet
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Nicolas Blanchard
- Centre de Physiopathologie Toulouse Purpan (CPTP), Université de Toulouse, INSERM, CNRS, UPS, Toulouse, France. @inserm.fr
| | - Sabrina Marion
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France. @pasteur-lille.fr
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