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Jafari MM, Azimzadeh Tabrizi Z, Dayer MS, Kazemi-Sefat NA, Mohtashamifard M, Mohseni R, Bagheri A, Bahadory S, Karimipour-Saryazdi A, Ghaffarifar F. Immune system roles in pathogenesis, prognosis, control, and treatment of Toxoplasma gondii infection. Int Immunopharmacol 2023; 124:110872. [PMID: 37660595 DOI: 10.1016/j.intimp.2023.110872] [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: 04/19/2023] [Revised: 08/25/2023] [Accepted: 08/27/2023] [Indexed: 09/05/2023]
Abstract
Toxoplasma gondii is the protozoan causative agent of toxoplasmosis in humans and warm-blooded animals. Recent studies have illustrated that the immune system plays a pivotal role in the pathogenesis of toxoplasmosis by triggering immune cytokines like IL-12, TNF-α, and IFN-γ and immune cells like DCs, Th1, and Th17. On the other hand, some immune components can serve as prognosis markers of toxoplasmosis. In healthy people, the disease is often asymptomatic, but immunocompromised people and newborns may suffer severe symptoms and complications. Therefore, the immune prognostic markers may provide tools to measure the disease progress and help patients to avoid further complications. Immunotherapies using monoclonal antibody, cytokines, immune cells, exosomes, novel vaccines, and anti-inflammatory molecules open new horizon for toxoplasmosis treatment. In this review article, we discussed the immunopathogenesis, prognosis, and immunotherapy of Toxoplasma gondii infection.
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Affiliation(s)
- Mohammad Mahdi Jafari
- Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Zahra Azimzadeh Tabrizi
- Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mohammad Saaid Dayer
- Department of Parasitology and Medical Entomology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | | | - Mahshid Mohtashamifard
- Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Rahimeh Mohseni
- Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Atefeh Bagheri
- Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Saeed Bahadory
- Department of Parasitology and Medical Entomology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Amir Karimipour-Saryazdi
- Department of Parasitology and Medical Entomology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Fatemeh Ghaffarifar
- Department of Parasitology and Medical Entomology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
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Moretto MM, Chen J, Meador M, Phan J, Khan IA. A Lower Dose of Infection Generates a Better Long-Term Immune Response against Toxoplasma gondii. Immunohorizons 2023; 7:177-190. [PMID: 36883950 PMCID: PMC10563383 DOI: 10.4049/immunohorizons.2300006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 02/11/2023] [Indexed: 03/09/2023] Open
Abstract
Toxoplasma gondii, an obligate intracellular pathogen, induces a strong immune response in the infected host. In the encephalitis model of infection, long-term protective immunity is mediated by CD8 T cells, with the CD4 T cell population providing important help. Most of the immune studies have used a 10- to 20-cyst dose of T. gondii, which leads to T cell dysfunctionality during the late phase of chronic infection and increases the chances of reactivation. In the current study, we compared the immune response of mice orally infected with either 2 or 10 cysts of T. gondii. During the acute phase, we demonstrate that the lower dose of infection generates a reduced number of CD4 and CD8 T cells, but the frequency of functional CD4 or CD8 T cells is similar in animals infected with two different doses. However, Ag-experienced T cells (both CD4 and CD8) are better maintained in lower dose-infected mice at 8 wk postinfection, with an increase number functional cells that exhibit lower multiple inhibitory receptor expression. In addition to better long-term T cell immunity, animals infected with a lower dose display reduced inflammation manifested by lesser Ag-specific T cell and cytokine responses during the very early stage of the acute infection. Our studies suggest a previously unappreciated role of dose-dependent early programming/imprinting of the long-term CD4/CD8 T cell response during T. gondii infection. These observations point to the need for an in-depth analysis of how early events shape long-term immunity against this pathogen.
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Affiliation(s)
- Magali M. Moretto
- Department of Microbiology, Immunology, and Tropical Medicine, The George Washington University, Washington, DC
| | - Jie Chen
- Department of Medicine, The George Washington University, Washington, DC
| | - Morgan Meador
- Department of Microbiology, Immunology, and Tropical Medicine, The George Washington University, Washington, DC
| | - Jasmine Phan
- Department of Microbiology, Immunology, and Tropical Medicine, The George Washington University, Washington, DC
| | - Imtiaz A. Khan
- Department of Microbiology, Immunology, and Tropical Medicine, The George Washington University, Washington, DC
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3
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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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Seroprevalence of Toxoplasma gondii among Hemodialysis Patients: A Possible Link to Main T-lymphocyte Subsets Levels and Dialysis Adequacy. Acta Trop 2022; 237:106703. [DOI: 10.1016/j.actatropica.2022.106703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/27/2022] [Accepted: 09/27/2022] [Indexed: 11/23/2022]
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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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Souza SP, Splitt SD, Sànchez-Arcila JC, Alvarez JA, Wilson JN, Wizzard S, Luo Z, Baumgarth N, Jensen KDC. Genetic mapping reveals Nfkbid as a central regulator of humoral immunity to Toxoplasma gondii. PLoS Pathog 2021; 17:e1010081. [PMID: 34871323 PMCID: PMC8675933 DOI: 10.1371/journal.ppat.1010081] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 12/16/2021] [Accepted: 11/01/2021] [Indexed: 12/29/2022] Open
Abstract
Protective immunity to parasitic infections has been difficult to elicit by vaccines. Among parasites that evade vaccine-induced immunity is Toxoplasma gondii, which causes lethal secondary infections in chronically infected mice. Here we report that unlike susceptible C57BL/6J mice, A/J mice were highly resistant to secondary infection. To identify correlates of immunity, we utilized forward genetics to identify Nfkbid, a nuclear regulator of NF-κB that is required for B cell activation and B-1 cell development. Nfkbid-null mice (“bumble”) did not generate parasite-specific IgM and lacked robust parasite-specific IgG, which correlated with defects in B-2 cell maturation and class-switch recombination. Though high-affinity antibodies were B-2 derived, transfer of B-1 cells partially rescued the immunity defects observed in bumble mice and were required for 100% vaccine efficacy in bone marrow chimeric mice. Immunity in resistant mice correlated with robust isotype class-switching in both B cell lineages, which can be fine-tuned by Nfkbid gene expression. We propose a model whereby humoral immunity to T. gondii is regulated by Nfkbid and requires B-1 and B-2 cells for full protection. Eukaryotic parasitic diseases account for approximately one fifth of all childhood deaths, yet no highly protective vaccine exists for any human parasite. More research must be done to discover how to elicit protective vaccine-induced immunity to parasitic pathogens. We used an unbiased genetic screen to find key genes responsible for immunity to the eukaryotic parasite Toxoplasma gondii. Our screen found Nfkbid, a transcription factor regulator, which controls B cell activation and innate-like B-1 cell development. Mice without Nfkbid were not protected against T. gondii and were deficient at making antibodies against the parasite. Our survival studies of vaccinated mice with and without B-1 compartments found that B-1 cells improved survival, suggesting that B-1 cells act in conjunction with B-2 cells to provide vaccine-induced immunity. Nfkbid and other loci identified in our unbiased screen represent potential targets for vaccines to elicit protective immune responses against parasitic pathogens.
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Affiliation(s)
- Scott P. Souza
- School of Natural Sciences, Department of Molecular and Cell Biology, University of California, Merced, Merced, California, United States of America
- Graduate Program in Quantitative and Systems Biology, University of California, Merced, Merced, California, United States of America
| | - Samantha D. Splitt
- School of Natural Sciences, Department of Molecular and Cell Biology, University of California, Merced, Merced, California, United States of America
- Graduate Program in Quantitative and Systems Biology, University of California, Merced, Merced, California, United States of America
| | - Juan C. Sànchez-Arcila
- School of Natural Sciences, Department of Molecular and Cell Biology, University of California, Merced, Merced, California, United States of America
| | - Julia A. Alvarez
- School of Natural Sciences, Department of Molecular and Cell Biology, University of California, Merced, Merced, California, United States of America
- Graduate Program in Quantitative and Systems Biology, University of California, Merced, Merced, California, United States of America
| | - Jessica N. Wilson
- School of Natural Sciences, Department of Molecular and Cell Biology, University of California, Merced, Merced, California, United States of America
- Graduate Program in Quantitative and Systems Biology, University of California, Merced, Merced, California, United States of America
| | - Safuwra Wizzard
- School of Natural Sciences, Department of Molecular and Cell Biology, University of California, Merced, Merced, California, United States of America
| | - Zheng Luo
- Center for Immunology & Infectious Diseases, and Department of Pathology, Microbiology and Immunology, University of California, Davis, Davis, California, United States of America
| | - Nicole Baumgarth
- Center for Immunology & Infectious Diseases, and Department of Pathology, Microbiology and Immunology, University of California, Davis, Davis, California, United States of America
| | - Kirk D. C. Jensen
- School of Natural Sciences, Department of Molecular and Cell Biology, University of California, Merced, Merced, California, United States of America
- Health Science Research Institute, University of California, Merced, Merced, California, United States of America
- * E-mail:
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7
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Sasai M, Ma JS, Okamoto M, Nishino K, Nagaoka H, Takashima E, Pradipta A, Lee Y, Kosako H, Suh PG, Yamamoto M. Uncovering a novel role of PLCβ4 in selectively mediating TCR signaling in CD8+ but not CD4+ T cells. J Exp Med 2021; 218:212085. [PMID: 33970189 PMCID: PMC8111461 DOI: 10.1084/jem.20201763] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 02/24/2021] [Accepted: 03/23/2021] [Indexed: 11/08/2022] Open
Abstract
Because of their common signaling molecules, the main T cell receptor (TCR) signaling cascades in CD4+ and CD8+ T cells are considered qualitatively identical. Herein, we show that TCR signaling in CD8+ T cells is qualitatively different from that in CD4+ T cells, since CD8α ignites another cardinal signaling cascade involving phospholipase C β4 (PLCβ4). TCR-mediated responses were severely impaired in PLCβ4-deficient CD8+ T cells, whereas those in CD4+ T cells were intact. PLCβ4-deficient CD8+ T cells showed perturbed activation of peripheral TCR signaling pathways downstream of IP3 generation. Binding of PLCβ4 to the cytoplasmic tail of CD8α was important for CD8+ T cell activation. Furthermore, GNAQ interacted with PLCβ4, mediated double phosphorylation on threonine 886 and serine 890 positions of PLCβ4, and activated CD8+ T cells in a PLCβ4-dependent fashion. PLCβ4-deficient mice exhibited defective antiparasitic host defense and antitumor immune responses. Altogether, PLCβ4 differentiates TCR signaling in CD4+ and CD8+ T cells and selectively promotes CD8+ T cell–dependent adaptive immunity.
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Affiliation(s)
- Miwa Sasai
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.,Laboratory of Immunoparasitology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Ji Su Ma
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.,Laboratory of Immunoparasitology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Masaaki Okamoto
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Kohei Nishino
- Division of Cell Signaling, Fujii Memorial Institute of Medical Sciences, Tokushima University, Tokushima, Japan
| | - Hikaru Nagaoka
- Division of Malaria Research, Proteo-Science Center, Ehime University, Ehime, Japan
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Ehime, Japan
| | - Ariel Pradipta
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Youngae Lee
- Laboratory of Immunoparasitology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Hidetaka Kosako
- Division of Cell Signaling, Fujii Memorial Institute of Medical Sciences, Tokushima University, Tokushima, Japan
| | - Pann-Ghill Suh
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, South Korea.,Korea Brain Research Institute, Daegu, South Korea
| | - Masahiro Yamamoto
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.,Laboratory of Immunoparasitology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
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8
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Smith NC, Goulart C, Hayward JA, Kupz A, Miller CM, van Dooren GG. Control of human toxoplasmosis. Int J Parasitol 2020; 51:95-121. [PMID: 33347832 DOI: 10.1016/j.ijpara.2020.11.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/12/2020] [Accepted: 11/15/2020] [Indexed: 12/21/2022]
Abstract
Toxoplasmosis is caused by Toxoplasma gondii, an apicomplexan parasite that is able to infect any nucleated cell in any warm-blooded animal. Toxoplasma gondii infects around 2 billion people and, whilst only a small percentage of infected people will suffer serious disease, the prevalence of the parasite makes it one of the most damaging zoonotic diseases in the world. Toxoplasmosis is a disease with multiple manifestations: it can cause a fatal encephalitis in immunosuppressed people; if first contracted during pregnancy, it can cause miscarriage or congenital defects in the neonate; and it can cause serious ocular disease, even in immunocompetent people. The disease has a complex epidemiology, being transmitted by ingestion of oocysts that are shed in the faeces of definitive feline hosts and contaminate water, soil and crops, or by consumption of intracellular cysts in undercooked meat from intermediate hosts. In this review we examine current and future approaches to control toxoplasmosis, which encompass a variety of measures that target different components of the life cycle of T. gondii. These include: education programs about the parasite and avoidance of contact with infectious stages; biosecurity and sanitation to ensure food and water safety; chemo- and immunotherapeutics to control active infections and disease; prophylactic options to prevent acquisition of infection by livestock and cyst formation in meat; and vaccines to prevent shedding of oocysts by definitive feline hosts.
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Affiliation(s)
- Nicholas C Smith
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; Research School of Biology, Australian National University, Canberra, ACT 0200, Australia.
| | - Cibelly Goulart
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
| | - Jenni A Hayward
- Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
| | - Andreas Kupz
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD 4878, Australia
| | - Catherine M Miller
- College of Public Health, Medical and Veterinary Science, James Cook University, Cairns, QLD 4878, Australia
| | - Giel G van Dooren
- Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
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9
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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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10
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Bourque L, Greenwood SJ, Jones MEB. Acute toxoplasmosis and pox-viral dermatitis in a juvenile bald eagle ( Haliaeetus leucocephalus) in New Brunswick, Canada. THE CANADIAN VETERINARY JOURNAL = LA REVUE VETERINAIRE CANADIENNE 2020; 61:880-884. [PMID: 32741996 PMCID: PMC7350123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Although birds of prey are commonly subclinically infected by Toxoplasma gondii tissue cysts, clinical disease is relatively rare in these species. The present report describes a rare case of fatal toxoplasmosis in a juvenile bald eagle in New Brunswick. Necropsy investigation revealed severe emaciation and poxviral dermatitis which partially obscured the palpebral fissures. Microscopically there was severe lymphoplasmacytic inflammation and necrosis of the lung that was associated with abundant protozoal tachyzoites. Infection with T. gondii was confirmed in the lung via immunohistochemistry and DNA sequencing. Key clinical message: Wildlife rehabilitation centers should be aware of the potential occurrence of acute clinical toxoplasmosis in stressed malnourished raptors.
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Affiliation(s)
- Laura Bourque
- Canadian Wildlife Health Cooperative, Atlantic Region, Charlottetown, Prince Edward Island C1A 4P3 (Bourque, Jones); Atlantic Veterinary College, Charlottetown, Prince Edward Island C1A 4P3 (Greenwood)
| | - Spencer J Greenwood
- Canadian Wildlife Health Cooperative, Atlantic Region, Charlottetown, Prince Edward Island C1A 4P3 (Bourque, Jones); Atlantic Veterinary College, Charlottetown, Prince Edward Island C1A 4P3 (Greenwood)
| | - Megan E B Jones
- Canadian Wildlife Health Cooperative, Atlantic Region, Charlottetown, Prince Edward Island C1A 4P3 (Bourque, Jones); Atlantic Veterinary College, Charlottetown, Prince Edward Island C1A 4P3 (Greenwood)
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11
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Khan IA, Hwang S, Moretto M. Toxoplasma gondii: CD8 T Cells Cry for CD4 Help. Front Cell Infect Microbiol 2019; 9:136. [PMID: 31119107 PMCID: PMC6504686 DOI: 10.3389/fcimb.2019.00136] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 04/15/2019] [Indexed: 11/13/2022] Open
Abstract
Toxoplasma gondii, an apicomplexan parasite, is a pathogenic protozoan that can infect the central nervous system. In pregnant women, infection can result in congenital problems of the fetus, while in immunocompromised individual it can lead to severe neurological consequences. Although CD8 T cells play an important effector role in controlling the chronic infection, their maintenance is dependent on the critical help provided by CD4 T cells. In a recent study, we demonstrated that reactivation of the infection in chronically infected host is a consequence of CD8 T dysfunction caused by CD4 T cell exhaustion. Furthermore, treatment of chronically infected host with antigen-specific non-exhausted CD4 T cells can restore CD8 T cell functionality and prevent reactivation of the latent infection. The exhaustion status of CD4 T cells is mediated by the increased expression of the transcription factor BLIMP-1, and deletion of this molecule led to the restoration of CD4 T cell function, reversal of CD8 exhaustion and prevention of reactivation of the latent infection. In a recent study from our laboratory, we also observed an increased expression of miR146a levels by CD4 T cells from the chronically infected animals. Recent reports have demonstrated that microRNAs (especially miR146a) has a strong impact on the immune system of T. gondii infected host. Whether these molecules have any role in the BLIMP-1 up-regulation and dysfunctionality of these cells needs to be investigated.
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Affiliation(s)
- Imtiaz A. Khan
- Department Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC, United States
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12
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Khan IA, Ouellette C, Chen K, Moretto M. Toxoplasma: Immunity and Pathogenesis. CURRENT CLINICAL MICROBIOLOGY REPORTS 2019; 6:44-50. [PMID: 31179204 DOI: 10.1007/s40588-019-0114-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Toxoplasma gondii infection induces a strong immunity in the host. Although the response is manifested by innate response during early infection, adaptive immunity is critical for long-term protection. Amongst the adaptive immune response CD4 T cells play an important helper role for CD8 T cells which are the primary effector cells responsible for controlling the infection. Notwithstanding the induction of robust CD8 T immunity during acute infection, the parasite is not eradicated. One of the reasons for this is the functional exhaustion of CD8 T cells during latent infection. Recent studies from our laboratory have reported that primary cause of CD8 T cell exhaustion is compromised CD4 T cell help during latent toxoplasmosis. CD8 T cell dysfunctionality is preceded by CD4 exhaustion and effector immunity is severely compromised.
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Affiliation(s)
- Imtiaz A Khan
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington DC 20037
| | - Charlotte Ouellette
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington DC 20037
| | - Keer Chen
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington DC 20037
| | - Magali Moretto
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington DC 20037
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13
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Foroutan M, Ghaffarifar F, Sharifi Z, Dalimi A, Jorjani O. Rhoptry antigens as Toxoplasma gondii vaccine target. Clin Exp Vaccine Res 2019; 8:4-26. [PMID: 30775347 PMCID: PMC6369123 DOI: 10.7774/cevr.2019.8.1.4] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 07/10/2018] [Accepted: 01/14/2019] [Indexed: 01/14/2023] Open
Abstract
Toxoplasmosis is a cosmopolitan zoonotic infection, caused by a unicellular protozoan parasite known as Toxoplasma gondii that belongs to the phylum Apicomplexa. It is estimated that over one-third of the world's population has been exposed and are latently infected with the parasite. In humans, toxoplasmosis is predominantly asymptomatic in immunocompetent persons, while among immunocompromised individuals may be cause severe and progressive complications with poor prognosis. Moreover, seronegative pregnant mothers are other risk groups for acquiring the infection. The life cycle of T. gondii is very complex, indicating the presence of a plurality of antigenic epitopes. Despite of great advances, recognize and construct novel vaccines for prevent and control of toxoplasmosis in both humans and animals is still remains a great challenge for researchers to select potential protein sequences as the ideal antigens. Notably, in several past years, constant efforts of researchers have made considerable advances to elucidate the different aspects of the cell and molecular biology of T. gondii mainly on microneme antigens, dense granule antigens, surface antigens, and rhoptry proteins (ROP). These attempts thereby provided great impetus to the present focus on vaccine development, according to the defined subcellular components of the parasite. Although, currently there is no commercial vaccine for use in humans. Among the main identified T. gondii antigens, ROPs appear as a putative vaccine candidate that are vital for invasion procedure as well as survival within host cells. Overall, it is estimated that they occupy about 1%–30% of the total parasite cell volume. In this review, we have summarized the recent progress of ROP-based vaccine development through various strategies from DNA vaccines, epitope or multi epitope-based vaccines, recombinant protein vaccines to vaccines based on live-attenuated vectors and prime-boost strategies in different mouse models.
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Affiliation(s)
- Masoud Foroutan
- Abadan School of Medical Sciences, Abadan, Iran.,Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Fatemeh Ghaffarifar
- Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Zohreh Sharifi
- Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran
| | - Abdolhosein Dalimi
- Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ogholniaz Jorjani
- Laboratory Science Research Center, Golestan University of Medical Sciences, Gorgan, Iran
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PD-L1, TIM-3, and CTLA-4 Blockade Fails To Promote Resistance to Secondary Infection with Virulent Strains of Toxoplasma gondii. Infect Immun 2018; 86:IAI.00459-18. [PMID: 29967089 DOI: 10.1128/iai.00459-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 06/19/2018] [Indexed: 01/05/2023] Open
Abstract
T cell exhaustion is a state of hyporesponsiveness that develops during many chronic infections and cancer. Neutralization of inhibitory receptors, or "checkpoint blockade," can reverse T cell exhaustion and lead to beneficial prognoses in experimental and clinical settings. Whether checkpoint blockade can resolve lethal acute infections is less understood but may be beneficial in vaccination protocols that fail to elicit sterilizing immunity. Since a fully protective vaccine for any human parasite has yet to be developed, we explored the efficacy of checkpoint inhibitors in a mouse model of Toxoplasma gondii reinfection. Mice chronically infected with an avirulent type III strain survive reinfection with the type I RH strain but not the MAS, GUY-DOS, and GT1 parasite strains. We report here that mouse susceptibility to secondary infection correlates with the initial parasite burden and that protection against the RH strain is dependent on CD8 but not CD4 T cells in this model. When given a lethal secondary infection, CD8 and CD4 T cells upregulate several coinhibitory receptors, including PD-1, TIM-3, 4-1bb, and CTLA-4. Moreover, the gamma interferon (IFN-γ) response of CD8 but not CD4 T cells is significantly reduced during secondary infection with virulent strains, suggesting that checkpoint blockade may reduce disease severity. However, single and combination therapies targeting TIM-3, CTLA-4, and/or PD-L1 failed to reverse susceptibility to secondary infection. These results suggest that additional host responses, which are refractory to checkpoint blockade, are likely required for immunity to this pathogen.
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Zhang NZ, Gao Q, Wang M, Elsheikha HM, Wang B, Wang JL, Zhang FK, Hu LY, Zhu XQ. Immunization With a DNA Vaccine Cocktail Encoding TgPF, TgROP16, TgROP18, TgMIC6, and TgCDPK3 Genes Protects Mice Against Chronic Toxoplasmosis. Front Immunol 2018; 9:1505. [PMID: 30008721 PMCID: PMC6033959 DOI: 10.3389/fimmu.2018.01505] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 06/18/2018] [Indexed: 01/29/2023] Open
Abstract
Toxoplasmosis is a zoonotic disease caused by the intracellular protozoan Toxoplasma gondii; and a major source of infection in humans is via ingestion of T. gondii tissue cysts. Ultimately, the goal of anti-toxoplasmosis vaccines is to elicit a sustainable immune response, capable of preventing formation of the parasite tissue cysts-or, at least, to restrain its growth. In this study, we formulated a cocktail DNA vaccine and investigated its immunologic efficacy as a protection against the establishment of T. gondii cysts in the mouse brain. This multicomponent DNA vaccine, encoded the TgPF, TgROP16, TgROP18, TgMIC6, and TgCDPK3 genes, which play key roles in the pathogenesis of T. gondii infection. Results showed that mice immunized via intramuscular injection three times, at 2-week intervals with this multicomponent DNA vaccine, mounted a strong humoral and cellular immune response, indicated by significantly high levels of total IgG, CD4+ and CD8+ T lymphocytes, and antigen-specific lymphocyte proliferation when compared with non-immunized mice. Immunization also induced a mixed Th1/Th2 response, with a slightly elevated IgG2a to IgG1 ratio. The increased production of proinflammatory cytokines gamma-interferon, interleukin-2, and interleukin-12 (p < 0.0001) correlated with increased expression of p65/RelA and T-bet genes of the NF-κB pathway. However, no significant difference was detected in level of interleukin-4 (p > 0.05). The number of brain cysts in immunized mice was significantly less than those in non-immunized mice (643.33 ± 89.63 versus 3,244.33 ± 96.42, p < 0.0001), resulting in an 80.22% reduction in the parasite cyst burden. These findings indicate that a multicomponent DNA vaccine, encoding TgPF, TgROP16, TgROP18, TgMIC6, and TgCDPK3 genes, shows promise as an immunization strategy against chronic toxoplasmosis in mice, and calls for a further evaluation in food-producing animals.
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Affiliation(s)
- Nian-Zhang Zhang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Qi Gao
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China.,Hunan Entry-Exit Inspection and Quarantine Bureau, Changsha, China
| | - Meng Wang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Loughborough, United Kingdom
| | - Bo Wang
- Department of Mathematics, University of Leicester, Leicester, United Kingdom
| | - Jin-Lei Wang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Fu-Kai Zhang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Ling-Ying Hu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University College of Veterinary Medicine, Yangzhou, China
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Moretto MM, Hwang S, Khan IA. Downregulated IL-21 Response and T Follicular Helper Cell Exhaustion Correlate with Compromised CD8 T Cell Immunity during Chronic Toxoplasmosis. Front Immunol 2017; 8:1436. [PMID: 29163509 PMCID: PMC5671557 DOI: 10.3389/fimmu.2017.01436] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/16/2017] [Indexed: 12/14/2022] Open
Abstract
CD8 T cells are important for maintaining the chronicity of Toxoplasma gondii infection. In a T. gondii encephalitis susceptible model, we recently demonstrated that CD4 T cells play an essential helper role in the maintenance of the effector response and CD8 T cell dysfunctionality was linked to CD4 T cell exhaustion. However, CD4 T cells are constituted of different subsets with various functions and the population(s) providing help to the CD8 T cells has not yet been determined. In the present study, T follicular helper cells (Tfh), which are known to be essential for B cell maturation and are one of the main sources of IL-21, were significantly increased during chronic toxoplasmosis. However, at week 7 p.i., when CD8 T cells are exhausted, the Tfh population exhibited increased expression of several inhibitory receptors and levels of IL-21 in the serum were decreased. The importance of IL-21 in the maintenance of CD8 T cells function after T. gondii infection was further demonstrated in IL-21R KO mouse model. Interestingly, while CD8 T cells from both knockout (KO) and wild-type mice expressed similar levels of PD-1, animals with defective IL-21 signaling exhibited lower polyfunctionality than wild-type controls. This reduced polyfunctional ability observed in CD8 T cells from KO mice was associated with a significant increase in other inhibitory receptors like Tim-3, LAG-3, and 2B4. Furthermore, the animals exhibited greater signs of Toxoplasma reactivation manifested by the reduced number of cysts and increased expression of tachyzoite (replicative form of the parasite) specific genes (SAG1 and ENO2) in the brain. Also, IL-21R KO mice displayed a higher frequency of tachyzoite-infected monocytes in the blood and spleen. Our findings suggest the importance of Tfh and IL-21 during chronic toxoplasmosis and establish a critical role for this cytokine in regulating CD8 T cell dysfunction by preventing the co-expression of multiple inhibitory receptors during chronic parasitic infection.
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Affiliation(s)
- Magali M Moretto
- Department Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC, United States
| | - SuJin Hwang
- Department Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC, United States
| | - Imtiaz A Khan
- Department Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC, United States
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Li XZ, Lv L, Zhang X, Anchang KY, Abdullahi AY, Tu L, Wang X, Xia L, Zhang XX, Feng W, Lu C, Li S, Yuan ZG. Recombinant canine adenovirus type-2 expressing TgROP16 provides partial protection against acute Toxoplasma gondii infection in mice. INFECTION GENETICS AND EVOLUTION 2016; 45:447-453. [PMID: 27742446 DOI: 10.1016/j.meegid.2016.10.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 10/07/2016] [Accepted: 10/10/2016] [Indexed: 02/08/2023]
Abstract
We previously demonstrated that the survival time of BALB/c mice challenged with Toxoplasma gondii RH strain was prolonged by immunising the mice with a eukaryotic vector expressing the protein ROP16 of T. gondii. Building upon previous findings, we are exploring improved vaccination strategies to enhance protection. In this work, a novel recombinant canine adenovirus type 2 expressing ROP16 (CAV-2-ROP16) of T. gondii was constructed and identified to express ROP16 in Madin-Darby canine kidney cells (MDCK) cells by western blot (WB) and indirect immunofluorescence (IFA) assays. Intramuscular immunisation of BALB/c mice with CAV-2-ROP16 was performed to evaluate the humoral and cellular immune responses. This vaccination triggered significant humoral and cellular responses, including ROP16-stimulated lymphoproliferation (P<0.05). Compared to control groups, the CAV-2-ROP16 immunised mice had high production of IFN-γ, IL-2 and IL-12 (P<0.05), with a predominance of IgG2a production, but not IL-10 (P>0.05), revealing that a predominant Th1-type response had developed. The cell-mediated cytotoxic activity with high levels of IFN-γ and TNF-α was significantly increased in both CD4+ and CD8+ T-cell compartments in the mice immunised with CAV-2-ROP16 (P<0.05), compared to three control groups. In addition, when immunised mice were challenged with the RH strain of T. gondii, they showed a significantly increased survival rate (25%) 80days post infection compared with control mice that all died within seven days (P<0.05). The 25% protection rate elicited by the recombinant virus CAV-2-ROP16 has not been achieved in the field of anti-T. gondii vaccination until now. Our work presents the successful use of recombinant virus CAV-2-ROP16 in vaccination protocols to protect against intraperitoneal challenge with the virulent RH strain of T. gondii. This system was shown to be extremely efficient in eliciting humoral and cellular immune responses that led to a significant improvement in survival time in mice.
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Affiliation(s)
- Xiu-Zhen Li
- Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China
| | - Lin Lv
- Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China
| | - Xu Zhang
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang Province 163319, PR China
| | - Kenneth Yongabi Anchang
- Phytobiotechnology Research Foundation Institute (PRF), Catholic University of Cameroon, 999108 Bamenda, Cameroon
| | - Auwalu Yusuf Abdullahi
- Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China
| | - Liqing Tu
- Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China
| | - Xiaohu Wang
- Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong Province 510642, PR China
| | - Lijun Xia
- Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China
| | - Xiu-Xiang Zhang
- College of Agriculture, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China
| | - Weili Feng
- Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China
| | - Chunxia Lu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China
| | - Shoujun Li
- Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China
| | - Zi-Guo Yuan
- Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, 483 Wushan Rd, Tianhe District, Guangzhou 510642, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China.
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Hwang S, Cobb DA, Bhadra R, Youngblood B, Khan IA. Blimp-1-mediated CD4 T cell exhaustion causes CD8 T cell dysfunction during chronic toxoplasmosis. J Exp Med 2016; 213:1799-818. [PMID: 27481131 PMCID: PMC4995081 DOI: 10.1084/jem.20151995] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 06/03/2016] [Indexed: 12/26/2022] Open
Abstract
CD8, but not CD4, T cells are considered critical for control of chronic toxoplasmosis. Although CD8 exhaustion has been previously reported in Toxoplasma encephalitis (TE)-susceptible model, our current work demonstrates that CD4 not only become exhausted during chronic toxoplasmosis but this dysfunction is more pronounced than CD8 T cells. Exhausted CD4 population expressed elevated levels of multiple inhibitory receptors concomitant with the reduced functionality and up-regulation of Blimp-1, a transcription factor. Our data demonstrates for the first time that Blimp-1 is a critical regulator for CD4 T cell exhaustion especially in the CD4 central memory cell subset. Using a tamoxifen-dependent conditional Blimp-1 knockout mixed bone marrow chimera as well as an adoptive transfer approach, we show that CD4 T cell-intrinsic deletion of Blimp-1 reversed CD8 T cell dysfunction and resulted in improved pathogen control. To the best of our knowledge, this is a novel finding, which demonstrates the role of Blimp-1 as a critical regulator of CD4 dysfunction and links it to the CD8 T cell dysfunctionality observed in infected mice. The critical role of CD4-intrinsic Blimp-1 expression in mediating CD4 and CD8 T cell exhaustion may provide a rational basis for designing novel therapeutic approaches.
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Affiliation(s)
- SuJin Hwang
- Department of Microbiology, Immunology, and Tropical Medicine, George Washington University, Washington, DC 20037
| | - Dustin A Cobb
- Department of Microbiology, Immunology, and Tropical Medicine, George Washington University, Washington, DC 20037 Department of Microbiology, Immunology, and Cancer Biology, Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, VA 22908
| | - Rajarshi Bhadra
- Department of Microbiology, Immunology, and Tropical Medicine, George Washington University, Washington, DC 20037
| | - Ben Youngblood
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Imtiaz A Khan
- Department of Microbiology, Immunology, and Tropical Medicine, George Washington University, Washington, DC 20037
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MIF Promotes Classical Activation and Conversion of Inflammatory Ly6C(high) Monocytes into TipDCs during Murine Toxoplasmosis. Mediators Inflamm 2016; 2016:9101762. [PMID: 27057101 PMCID: PMC4789477 DOI: 10.1155/2016/9101762] [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: 10/30/2015] [Accepted: 12/27/2015] [Indexed: 11/19/2022] Open
Abstract
Macrophage migration inhibitory factor (MIF) mediates immunity against Toxoplasma gondii infection by inducing inflammatory cytokines required to control the parasite replication. However, the role of this inflammatory mediator in the cell-mediated immune response against this infection is still poorly understood. Here, we used T. gondii-infected WT and Mif−/− mice to analyze the role of MIF in the maturation of CD11b+ and CD8α+ dendritic cells (DCs). We found that MIF promotes maturation of CD11b+ but not CD8α+ DCs, by inducing IL-12p70 production and CD86 expression. Infected Mif−/− mice showed significantly lower numbers of TNF and inducible nitric oxide synthase- (iNOS-) producing DCs (TipDCs) compared to infected WT mice. The adoptive transfer of Ly6Chigh monocytes into infected WT or Mif−/− mice demonstrated that MIF participates in the differentiation of Ly6Chigh monocytes into TipDCs. In addition, infected Mif−/− mice display a lower percentage of IFN-γ-producing natural killer (NK) cells compared to WT mice, which is associated with reducing numbers of TipDCs in Mif−/− mice. Furthermore, administration of recombinant MIF (rMIF) into T. gondii-infected Mif−/− mice restored the numbers of TipDCs and reversed the susceptible phenotype of Mif−/− mice. Collectively, these results demonstrate an important role for MIF inducing cell-mediated immunity to T. gondii infection.
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Chen J, Li ZY, Petersen E, Liu WG, Zhu XQ. Co-administration of interleukins 7 and 15 with DNA vaccine improves protective immunity against Toxoplasma gondii. Exp Parasitol 2015; 162:18-23. [PMID: 26706605 DOI: 10.1016/j.exppara.2015.12.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 12/02/2015] [Accepted: 12/14/2015] [Indexed: 10/22/2022]
Abstract
Toxoplasma gondii is an obligatory intracellular parasite, which can infect all warm-blooded animals including humans. Cytokines, including IL-15 and IL-7, play a critical role in the regulation of the homeostasis of naive and memory T cells. Co-administration the DNA vaccine with cytokines may improve its efficacy. IL-7 and IL-15 from splenic tissues of Kunming mice were cloned, and eukaryotic plasmid pVAX-IL-7-IL-15 was constructed. Kunming mice were administrated with DNA vaccine expressing T. gondii calcium-dependent protein kinase 1 (TgCDPK1), pVAX-CDPK1, in the presence or absence of IL-7 and IL-15 plasmids (pVAX-IL-7-IL-15), immune responses were analyzed including lymphoproliferative assay, cytokine and serum antibody measurements, flow cytometric surface markers on lymphocytes, and thus protective immunity against acute and chronic T. gondii infection was estimated. Mice injected with pVAX-CDPK1 supplemented with pVAX-IL-7-IL-15 showed higher Toxoplasma-specific IgG2a titers, Th1 responses associated with the production of IFN-γ, IL-2 as well as cell-mediated cytotoxic activity where stronger frequencies of IFN-γ secreting CD8+ and CD4+ T cells (CD8+/CD4+ IFN-γ+ T cells) compared to controls. Co-administration of pVAX-IL-7-IL-15 and pVAX-CDPK1 significantly (P < 0.05) increased survival time (18.07 ± 5.43 days) compared with pVAX-CDPK1 (14.13 ± 3.85 days) or pVAX-IL-7-IL-15 (11.73 ± 1.83 days) alone, and pVAX-IL-7-IL-15 + pVAX-CDPK1 significantly reduced the number of brain cysts (73.5%) in contrast to pVAX-CDPK1 (46.0%) or pVAX-IL-7-IL-15 alone (45.0%). Our results indicate that supplementation of DNA vaccine with IL-7 and IL-15 would facilitate specific humoral and cellular immune responses elicited by DNA vaccine against acute and chronic T. gondii infection in mice.
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Affiliation(s)
- Jia Chen
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China; Ningbo University School of Medicine, Ningbo, Zhejiang province 315211, PR China
| | - Zhong-Yuan Li
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China
| | - Eskild Petersen
- Department of Infectious Diseases and Clinical Microbiology, Institute for Clinical Medicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
| | - Wen-Ge Liu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University College of Veterinary Medicine, Yangzhou, Jiangsu Province 225009, PR China.
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Chen J, Li ZY, Petersen E, Huang SY, Zhou DH, Zhu XQ. DNA vaccination with genes encoding Toxoplasma gondii antigens ROP5 and GRA15 induces protective immunity against toxoplasmosis in Kunming mice. Expert Rev Vaccines 2015; 14:617-24. [PMID: 25749394 DOI: 10.1586/14760584.2015.1011133] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVES To evaluate the protective efficacy of a DNA vaccine encoding Toxoplasma gondii rhoptry protein 5 (ROP5) and GRA15 antigens. METHODS We constructed eukaryotic plasmids expressing pVAX-ROP5 and pVAX-GRA15, and measured the immune responses to these DNA vaccines. RESULTS Kunming mice immunized with pVAX-ROP5 or pVAX-GRA15 showed significantly increased serum IgG2a titers; Th1 responses association with the production of IFN-γ, IL-2, IL12 p40 and IL-12 p70; cell-mediated cytotoxic activity with increased frequencies of IFN-γ secreting CD8(+) T cells (CD8(+) IFN-γ+ T cells), as well as prolonged survival time (19.4 ± 4.9 days for ROP5; 17.8 ± 3.8 days for GRA15) and brain cyst reduction (57.4% for ROP5; 65.9% for GRA15) compared to control mice. Co-administration with pVAX-ROP5 and pVAX-GRA15 boosted the cellular and humoral immune responses, and significantly increased cyst reduction (79%) and prolonged the survival of immunized mice (22.7 ± 7.2 days). CONCLUSION Co-immunization of pVAX-ROP5 and pVAX-GRA15 increase the protective efficacy.
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Affiliation(s)
- Jia Chen
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China
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Hwang S, Khan IA. CD8+ T cell immunity in an encephalitis model of Toxoplasma gondii infection. Semin Immunopathol 2015; 37:271-9. [PMID: 25944514 DOI: 10.1007/s00281-015-0483-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 03/22/2015] [Indexed: 12/19/2022]
Abstract
Toxoplasma gondii infection induces a robust CD8 T cell immunity in the infected host, which is critical for keeping chronic infection under control. IFNγ production and cytolytic activity exhibited by CD8 T cells are critical functions needed to prevent the reactivation of latent infection. Paradoxically, the susceptible mice infected with the parasite develop encephalitis irrespective of the presence of vigorous CD8 T cell immunity. Recent studies from our laboratory have demonstrated that these animals have defect in the memory CD8 T cell population, which become dysfunctional due to exhibition of inhibitory receptors like PD-1. Although the blockade of PD-1-PDL-1 pathway rescues the CD8 response, PD-1(hi) expressing cells are refractory to the treatment. In this review, we discuss the development of CD8 memory response during chronic infection, mechanism responsible for their dysfunctionality, and possible therapeutic measures that can be taken to reverse the process.
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Affiliation(s)
- SuJin Hwang
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington, DC, USA
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Dimier-Poisson I, Carpentier R, N'Guyen TTL, Dahmani F, Ducournau C, Betbeder D. Porous nanoparticles as delivery system of complex antigens for an effective vaccine against acute and chronic Toxoplasma gondii infection. Biomaterials 2015; 50:164-75. [DOI: 10.1016/j.biomaterials.2015.01.056] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 01/08/2015] [Accepted: 01/20/2015] [Indexed: 10/24/2022]
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Li XZ, Wang XH, Xia LJ, Weng YB, Hernandez JA, Tu LQ, Li LT, Li SJ, Yuan ZG. Protective efficacy of recombinant canine adenovirus type-2 expressing TgROP18 (CAV-2-ROP18) against acute and chronic Toxoplasma gondii infection in mice. BMC Infect Dis 2015; 15:114. [PMID: 25886737 PMCID: PMC4397727 DOI: 10.1186/s12879-015-0815-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 02/09/2015] [Indexed: 12/31/2022] Open
Abstract
Background The use of recombinant viral vectors expressing T. gondii antigens is a safe and efficient approach to induce immune responses against the parasite, as well as a valuable tool for vaccine development. We have previously prolonged the survival time of mice challenged with the RH strain of T. gondii by immunizing the mice with a eukaryotic vector expressing the protein ROP18 of T. gondii. We are now looking for ways to improve this vaccination strategy and enhance protection. Methods In this study, we constructed and characterized a novel recombinant canine adenovirus type 2 expressing ROP18 (CAV-2-ROP18) of T. gondii by cytopathic effect (CPE) and indirect immunofluorescence assay (IFA) following transfection into MDCK cells. Intramuscular immunization of Kunming mice with CAV-2-ROP18 was carried out to evaluate humoral and cellular immune responses. Results The vaccination of experimental mice with CAV-2-ROP18 elicited antibody production against ROP18, including high levels of a mixed IgG1/IgG2a and significant production of IFN-γ or IL-2, and displayed a significant bias towards a helper T cell type 1 (Th1) profile. Furthermore, the presence of T. gondii-specific IFN-γ-production and TNF-α-production T cells was elicited in both CD4+ and CD8+ T cell compartments. Significantly higher survival rates (40%) occurred in the experimental group, and a reduction in brain cyst burden was detected in vaccinated mice. Conclusion These results demonstrate the potential use of a CAV vector harboring the ROP18 gene in the development of a vaccine against acute and chronic toxoplasmosis. Electronic supplementary material The online version of this article (doi:10.1186/s12879-015-0815-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiu-Zhen Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, PR China. .,Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, Guangzhou, Guangdong Province, 510642, PR China.
| | - Xiao-Hu Wang
- Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong Province, 510642, PR China.
| | - Li-Jun Xia
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, PR China. .,Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, Guangzhou, Guangdong Province, 510642, PR China.
| | - Ya-Biao Weng
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, PR China.
| | - Jorge A Hernandez
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA.
| | - Li-Qing Tu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, PR China. .,Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, Guangzhou, Guangdong Province, 510642, PR China.
| | - Lu-Tao Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, PR China. .,Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, Guangzhou, Guangdong Province, 510642, PR China.
| | - Shou-Jun Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, PR China. .,Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, Guangzhou, Guangdong Province, 510642, PR China.
| | - Zi-Guo Yuan
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, PR China. .,Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases, Guangzhou, Guangdong Province, 510642, PR China.
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Toxoplasma gondii superinfection and virulence during secondary infection correlate with the exact ROP5/ROP18 allelic combination. mBio 2015; 6:e02280. [PMID: 25714710 PMCID: PMC4358003 DOI: 10.1128/mbio.02280-14] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The intracellular parasite Toxoplasma gondii infects a wide variety of vertebrate species globally. Infection in most hosts causes a lifelong chronic infection and generates immunological memory responses that protect the host against new infections. In regions where the organism is endemic, multiple exposures to T. gondii likely occur with great frequency, yet little is known about the interaction between a chronically infected host and the parasite strains from these areas. A widely used model to explore secondary infection entails challenge of chronically infected or vaccinated mice with the highly virulent type I RH strain. Here, we show that although vaccinated or chronically infected C57BL/6 mice are protected against the type I RH strain, they are not protected against challenge with most strains prevalent in South America or another type I strain, GT1. Genetic and genomic analyses implicated the parasite-secreted rhoptry effectors ROP5 and ROP18, which antagonize the host’s gamma interferon-induced immunity-regulated GTPases (IRGs), as primary requirements for virulence during secondary infection. ROP5 and ROP18 promoted parasite superinfection in the brains of challenged survivors. We hypothesize that superinfection may be an important mechanism to generate T. gondii strain diversity, simply because two parasite strains would be present in a single meal consumed by the feline definitive host. Superinfection may drive the genetic diversity of Toxoplasma strains in South America, where most isolates are IRG resistant, compared to North America, where most strains are IRG susceptible and are derived from a few clonal lineages. In summary, ROP5 and ROP18 promote Toxoplasma virulence during reinfection. Toxoplasma gondii is a widespread parasite of warm-blooded animals and currently infects one-third of the human population. A long-standing assumption in the field is that prior exposure to this parasite protects the host from subsequent reexposure, due to the generation of protective immunological memory. However, this assumption is based on clinical data and mouse models that analyze infections with strains common to Europe and North America. In contrast, we found that the majority of strains sampled from around the world, in particular those from South America, were able to kill or reinfect the brains of hosts previously exposed to T. gondii. The T. gondii virulence factors ROP5 and ROP18, which inhibit key host effectors that mediate parasite killing, were required for these phenotypes. We speculate that these results underpin clinical observations that pregnant women previously exposed to Toxoplasma can develop congenital infection upon reexposure to South American strains.
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Harms Pritchard G, Hall AO, Christian DA, Wagage S, Fang Q, Muallem G, John B, Glatman Zaretsky A, Dunn WG, Perrigoue J, Reiner SL, Hunter CA. Diverse roles for T-bet in the effector responses required for resistance to infection. THE JOURNAL OF IMMUNOLOGY 2015; 194:1131-40. [PMID: 25556247 DOI: 10.4049/jimmunol.1401617] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The transcription factor T-bet has been most prominently linked to NK and T cell production of IFN-γ, a cytokine required for the control of a diverse array of intracellular pathogens. Indeed, in mice challenged with the parasite Toxoplasma gondii, NK and T cell responses are characterized by marked increases of T-bet expression. Unexpectedly, T-bet(-/-) mice infected with T. gondii develop a strong NK cell IFN-γ response that controls parasite replication at the challenge site, but display high parasite burdens at secondary sites colonized by T. gondii and succumb to infection. The loss of T-bet had a modest effect on T cell production of IFN-γ but did not impact on the generation of parasite-specific T cells. However, the absence of T-bet resulted in lower T cell expression of CD11a, Ly6C, KLRG-1, and CXCR3 and fewer parasite-specific T cells at secondary sites of infection, associated with a defect in parasite control at these sites. Together, these data highlight T-bet-independent pathways to IFN-γ production and reveal a novel role for this transcription factor in coordinating the T cell responses necessary to control this infection in peripheral tissues.
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Affiliation(s)
- Gretchen Harms Pritchard
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Aisling O'Hara Hall
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - David A Christian
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Sagie Wagage
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Qun Fang
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Gaia Muallem
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Beena John
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Arielle Glatman Zaretsky
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - William G Dunn
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Jacqueline Perrigoue
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Steven L Reiner
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032; and Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, NY 10032
| | - Christopher A Hunter
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104;
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Hassan IA, Wang S, Xu L, Yan R, Song X, Li X. Immunoglobulin and cytokine changes induced following immunization with a DNA vaccine encoding Toxoplasma gondii selenium-dependent glutathione reductase protein. Exp Parasitol 2014; 146:1-10. [DOI: 10.1016/j.exppara.2014.08.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Revised: 08/07/2014] [Accepted: 08/11/2014] [Indexed: 01/30/2023]
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Hassan IA, Wang S, Xu L, Yan R, Song X, Li X. DNA vaccination with a gene encoding Toxoplasma gondii Deoxyribose Phosphate Aldolase (TgDPA) induces partial protective immunity against lethal challenge in mice. Parasit Vectors 2014; 7:431. [PMID: 25201636 PMCID: PMC4164750 DOI: 10.1186/1756-3305-7-431] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 09/03/2014] [Indexed: 12/02/2022] Open
Abstract
Background Toxoplasma gondii is an obligate intracellular parasite that causes a pathological status known as toxoplasmosis, which has a huge impact on human and animal health. Currently, the main control strategy depends on the usage of drugs that target the acute stage of the infection, however, drawbacks were encountered while applying this method; therefore, development of an alternative effective method would be important progress. Deoxyribose Phosphate Aldolase (TgDPA) plays an important role supporting cell invasion and providing energy for the parasite. Methods TgDPA was expressed in Escherichia coli and the purified recombinant protein was used to immunize rats. The antibodies obtained were used to verify in vitro expression of TgDPA. The vector pVAX1 was utilized to formulate a DNA vaccine designated as pTgDPA, which was used to evaluate the immunological changes and the level of protection against challenge with the virulent RH strain of T. gondii. Results DNA vaccine, TgDPA revealed that it can induce a strong humoral as well as cellular mediated response in mice. These responses were a contribution of TH1, TH2 and TH17 type of responses. Following challenge, mice immunized with TgDPA showed longer survival rates than did those in control groups. Conclusions Further investigation regarding TgDPA is required to shed more light on its immunogenicity and its possible selection as a vaccine candidate.
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Affiliation(s)
| | | | | | | | | | - Xiangrui Li
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, People's Republic of China.
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Chuang SC, Yang CDA. Sustained release of recombinant surface antigen 2 (rSAG2) from poly(lactide-co-glycolide) microparticles extends protective cell-mediated immunity against Toxoplasma gondii in mice. Parasitology 2014; 141:1-10. [PMID: 25036078 DOI: 10.1017/s0031182014000997] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARY Current development efforts of subunit vaccines against Toxoplasma gondii, the aetiological agent of toxoplasmosis, have been focused mainly on tachyzoite surface antigens (SAGs) such as SAG2, due to their attachment roles in the process of host-cell invasion. In the present study, we aimed to produce poly(lactide-co-glycolide) (PLG) microparticles (MPs) containing recombinant SAG2 (rSAG2) to induce improved immunity against T. gondii. The resulting PLG-encapsulated rSAG2 (PLG-rSAG2) MPs, 2·14-3·63 μm in diameter, showed 74-80% entrapment efficiency and gradually released antigenic rSAG2 protein (88·3% of the total protein load) for a long 33-day period. Peritoneal immunization with PLG-rSAG2 MPs in BALB/c mice resulted in not only sustained (10 weeks) lymphocyte proliferation and IFN-γ production but also an improved protective capacity (87%) against a lethal subcutaneous challenge of 1×104 live tachyzoites of T. gondii (RH strain). In conclusion, the sustained release of rSAG2 protein from PLG-rSAG2 MPs extends Th1 cell-mediated immunity (lymphocyte proliferation and IFN-γ production) and induces improved protection against T. gondii tachyzoite infection in mice.
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Affiliation(s)
- Shu-Chun Chuang
- Department of Physiology, College of Medicine,Kaohsiung Medical University,No. 100, Shih-Chuan 1st Road, Kaohsiung 807,Taiwan
| | - Chung-DA Yang
- Graduate Institute of Animal Vaccine Technology,National Pingtung University of Science and Technology,No. 1, Shuefu Road, Neipu, Pingtung 912,Taiwan
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McGovern KE, Wilson EH. Role of Chemokines and Trafficking of Immune Cells in Parasitic Infections. ACTA ACUST UNITED AC 2014; 9:157-168. [PMID: 25383073 DOI: 10.2174/1573395509666131217000000] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Parasites are diverse eukaryotic pathogens that can have complex life cycles. Their clearance, or control within a mammalian host requires the coordinated effort of the immune system. The cell types recruited to areas of infection can combat the disease, promote parasite replication and survival, or contribute to disease pathology. Location and timing of cell recruitment can be crucial. In this review, we explore the role chemokines play in orchestrating and balancing the immune response to achieve optimal control of parasite replication without promoting pathology.
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Affiliation(s)
- Kathryn E McGovern
- School of Medicine, Division of Biomedical Sciences, University of California, Riverside, CA, 92521-0129, USA
| | - Emma H Wilson
- School of Medicine, Division of Biomedical Sciences, University of California, Riverside, CA, 92521-0129, USA
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A comparative study between excretory/secretory and autoclaved vaccines against RH strain of Toxoplasma gondii in murine models. J Parasit Dis 2013; 39:526-35. [PMID: 26345065 DOI: 10.1007/s12639-013-0390-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 10/31/2013] [Indexed: 01/27/2023] Open
Abstract
Toxoplasma gondii is an obligate intracellular protozoan that has a major importance in public health, in addition to veterinary medicine. Therefore, the development of an effective vaccine for controlling toxoplasmosis is an important goal. Excretory/secretory antigens (ESA), were previously identified as potential vaccine candidates, proved to play important roles in the pathogenesis and immune escape of the parasite. In addition, autoclaved Toxoplasma vaccine (ATV) is a special type of killed vaccine, recently characterized. The aim of the present work was, to compare between excretory/secretory and ATV against RH strain of T. gondii in mice based on; parasitological and histopathological levels. Tachyzoites were harvested from peritoneal exudates of infected mice and were used for challenge infection and vaccine preparation. BCG was used as an adjuvant. Mice were allocated equally into five groups; they were vaccinated intradermally over the sternum. The results of this study showed that the survival time after challenge, extended up to 16 days in ESA vaccinated group and up to 15 days in autoclaved Toxoplasma vaccinated group. ESA vaccinated group exhibited a profound decrease in parasite load following parasite challenge with a higher percentage of reduction in parasite count in all examined organs than the autoclaved Toxoplasma vaccinated group. The histopathological picture of the liver in both immunized groups, revealed marked reduction in the pathological changes observed as compared to controls, especially in ESA vaccinated group. It was concluded that vaccination with ESA showed more promising results versus ATV, as demonstrated by the survival rate of vaccinated mice, tachyzoites count and histopathological examination.
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Chen J, Huang SY, Zhou DH, Li ZY, Petersen E, Song HQ, Zhu XQ. DNA immunization with eukaryotic initiation factor-2α of Toxoplasma gondii induces protective immunity against acute and chronic toxoplasmosis in mice. Vaccine 2013; 31:6225-31. [PMID: 24183979 DOI: 10.1016/j.vaccine.2013.10.034] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Revised: 09/20/2013] [Accepted: 10/08/2013] [Indexed: 12/22/2022]
Abstract
Toxoplasma gondii infection is a serious health problem of humans and animals worldwide. T. gondii eukaryotic initiation factor-2α (TgIF2α) plays a crucial role in parasite viability and is an important virulence factor of T. gondii. To evaluate the vaccine potential of TgIF2α, we constructed a novel eukaryotic plasmid pVAX-IF2α expressing TgIF2α from the RH strain and validated expression and immunogenicity in vitro in the Marc145 cell expression system by indirect immunofluorescence (IFA). Administration of pVAX-IF2α intramuscularly induced specific humoral immune responses including high levels of specific TgIF2α IgG antibody and a mixed IgG1/IgG2a response with a predominance of IgG2a production. The cellular immune response was elicited, showing significant production of IFN-γ and IL-2 associated with Th1 type response, and thus strong cell-mediated cytotoxic activity with increased frequencies of IFN-γ parameters analyzed in both CD4(+) and CD8(+) T cell compartments (CD4(+) IFN-γ(+) T cells and CD8(+) IFN-γ(+) T cells). Immunization resulted in partial protection against acute and chronic toxoplamosis in outbred Kunming mice, demonstrated by a significantly prolonged survival time (15.9±4.6 days) after challenge with the virulent RH strain and significant reduction in brain cysts (44.1%) against chronic infection with PRU cyst in contrast to control mice. Our data suggested that pVAX-IF2α could be used as a DNA vaccine candidate against both acute and chronic T. gondii infection by the activation of effective humoral and cellular immune responses.
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Affiliation(s)
- Jia Chen
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China
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Evaluation of the adjuvant effect of pidotimod on the immune protection induced by UV-attenuated Toxoplasma gondii in mouse models. Parasitol Res 2013; 112:3151-60. [DOI: 10.1007/s00436-013-3491-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 06/03/2013] [Indexed: 10/26/2022]
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Chuang SC, Ko JC, Chen CP, Du JT, Yang CD. Induction of long-lasting protective immunity against Toxoplasma gondii in BALB/c mice by recombinant surface antigen 1 protein encapsulated in poly (lactide-co-glycolide) microparticles. Parasit Vectors 2013; 6:34. [PMID: 23398973 PMCID: PMC3584932 DOI: 10.1186/1756-3305-6-34] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Accepted: 02/05/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Current development efforts of subunit vaccines against Toxoplasma gondii, the etiological agent of toxoplasmosis, have been focused mainly on tachyzoite surface antigen 1 (SAG1). Since microparticles made from poly (lactide-co-glycolide) (PLG) polymers have been developed as safe, potent adjuvants or delivery systems, we aimed to encapsulate recombinant SAG1 (rSAG1) with the PLG polymers to prepare PLG-encapsulated rSAG1 (PLG-rSAG1) microparticles that would sustain rSAG1 release and generate long-lasting protective immunity against T. gondii in BALB/c mice. METHODS In the present study, rSAG1 was encapsulated into PLG microparticles by the double emulsion method. PLG-rSAG1 microparticles were then intraperitoneally injected twice at a 14-day interval into BALB/c mice. We examined the ability of PLG-rSAG1 microparticles to induce and prolong effective anti-Toxoplasma immune responses, in comparison with rSAG1 formulated with a Vet L-10 adjuvant (rSAG1 (Vet L-10)). Eight weeks after the last immunization, protective activities were also evaluated after a lethal subcutaneous challenge of 1 x 10(4) live T. gondii tachyzoites. RESULTS PLG-rSAG1 microparticles, 4.25~6.58 micrometers in diameter, showed 69%~81% entrapment efficiency. The amount of released rSAG1 protein from microparticles increased gradually over a 35-day period and the protein still retained native SAG1 antigenicity. Intraperitoneal vaccination of mice with the microparticles resulted in enhanced SAG1-specific IgG titers as well as lymphocyte proliferation and, more importantly, these enhanced activities were maintained for 10 weeks. In addition, eight weeks after the last immunization, maximum production of gamma interferon was detected in mice immunized with PLG-rSAG1 microparticles. Furthermore, 80% (8/10) of mice immunized with PLG-rSAG1 microparticles survived at least 28 days after a lethal subcutaneous tachyzoite challenge. CONCLUSIONS Encapsulation of rSAG1 into PLG microparticles preserves the native SAG1 antigenicity and sustains the release of rSAG1 from microparticles. PLG-rSAG1 microparticles can effectively induce not only significant long-lasting SAG1-specific humoral and cell-mediated immune responses but also high protection against T. gondii tachyzoite infection. Our study provides a valuable basis for developing long-lasting vaccines against T. gondii for future use in humans and animals.
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Affiliation(s)
- Shu-Chun Chuang
- Department of Physiology, College of Medicine, Kaohsiung Medical University, No 100, Shih-Chuan 1st Road, Kaohsiung 807, Taiwan
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Wiehagen KR, Corbo-Rodgers E, Li S, Staub ES, Hunter CA, Morrisey EE, Maltzman JS. Foxp4 is dispensable for T cell development, but required for robust recall responses. PLoS One 2012; 7:e42273. [PMID: 22912696 PMCID: PMC3418275 DOI: 10.1371/journal.pone.0042273] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 07/02/2012] [Indexed: 11/19/2022] Open
Abstract
Transcription factors regulate T cell fates at every stage of development and differentiation. Members of the Foxp family of forkhead transcription factors are essential for normal T lineage development; Foxp3 is required for T regulatory cell generation and function, and Foxp1 is necessary for generation and maintenance of naïve T cells. Foxp4, an additional member of the Foxp family, is highly homologous to Foxp1 and has been shown to dimerize with other Foxp proteins. We report the initial characterization of Foxp4 in T lymphocytes. Foxp4 is expressed in both thymocytes and peripheral CD4+ and CD8+ T cells. We used a CD4Cre mediated approach to evaluate the cell autonomous role for Foxp4 in murine T lymphocytes. T cell development, peripheral cellularity and cell surface phenotype are normal in the absence of Foxp4. Furthermore, Foxp3+ T regulatory cells develop normally in Foxp4 deficient animals and naïve Foxp4 deficient CD4 T cells can differentiate to inducible T regulatory cells in vitro. In wild-type T cells, expression of Foxp4 increases following activation, but deletion of Foxp4 does not affect T cell proliferative responses or in vitro effector T cell differentiation. In vivo, despite effective control of Toxoplasma gondii and acute lymphocytic choriomeningitis virus infections, effector cytokine production during antigen specific recall responses are reduced in the absence of Foxp4. We conclude that Foxp4 is dispensable for T cell development, but necessary for normal T cell cytokine recall responses to antigen following pathogenic infection.
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Affiliation(s)
- Karla R. Wiehagen
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Evann Corbo-Rodgers
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Shanru Li
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Elizabeth S. Staub
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Christopher A. Hunter
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Edward E. Morrisey
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jonathan S. Maltzman
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Eissa MM, El-Azzouni MZ, Mady RF, Fathy FM, Baddour NM. Initial characterization of an autoclaved Toxoplasma vaccine in mice. Exp Parasitol 2012; 131:310-6. [DOI: 10.1016/j.exppara.2012.05.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Revised: 04/25/2012] [Accepted: 05/01/2012] [Indexed: 12/17/2022]
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Bhadra R, Gigley JP, Khan IA. The CD8 T-cell road to immunotherapy of toxoplasmosis. Immunotherapy 2012; 3:789-801. [PMID: 21668315 DOI: 10.2217/imt.11.68] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Toxoplasma gondii infection induces a robust CD8 T-cell immunity that is critical for keeping chronic infection under control. In studies using animal models, it has been demonstrated that the absence of this response can compromise the host ability to keep chronic infection under check. Therapeutic agents that facilitate the induction and maintenance of CD8 T-cell response against the pathogen need to be developed. In the last decade, major strides in understanding the development of effector and memory response, particularly in viral and tumor models, have been made. However, factors involved in the generation of effector or memory response against T. gondii infection have not been extensively investigated. This information will be invaluable in designing immunotherapeutic regimens needed for combating this intracellular pathogen that poses a severe risk for pregnant women and immunocompromised individuals.
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Affiliation(s)
- Rajarshi Bhadra
- Department of Microbiology, Immunology & Tropical Medicine, George Washington University, Washington, DC 20037, USA
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Moon JH, Pyo KH, Jung BK, Chun HS, Chai JY, Shin EH. Resistance to Toxoplasma gondii infection in mice treated with silk protein by enhanced immune responses. THE KOREAN JOURNAL OF PARASITOLOGY 2011; 49:303-8. [PMID: 22072834 PMCID: PMC3210851 DOI: 10.3347/kjp.2011.49.3.303] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 08/07/2011] [Accepted: 08/10/2011] [Indexed: 11/25/2022]
Abstract
This study investigated whether elevated host immune capacity can inhibit T. gondii infection. For this purpose, we used silk protein extracted from Bombyx mori cocoons as a natural supplement to augment immune capacity. After silk protein administration to BALB/c mice for 6 weeks, ratios of T lymphocytes (CD4+ and CD8+ T-cells) and splenocyte proliferative capacities in response to Con A or T. gondii lysate antigen (TLA) were increased. Of various cytokines, which regulate immune systems, Th1 cytokines, such as IFN-γ, IL-2, and IL-12, were obviously increased in splenocyte primary cell cultures. Furthermore, the survival of T. gondii (RH strain)-infected mice increased from 2 days to 5 or more days. In a state of immunosuppression induced by methylprednisolone acetate, silk protein-administered mice were resistant to reduction in T-lymphocyte (CD4+ and CD8+ T-cells) numbers and the splenocyte proliferative capacity induced by Con A or TLA with a statistical significance. Taken together, our results suggest that silk protein augments immune capacity in mice and the increased cellular immunity by silk protein administration increases host protection against acute T. gondii infection.
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Affiliation(s)
- Joung-Ho Moon
- Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, and Institute of Endemic Diseases, Seoul National University Medical Research Center, Seoul 110-799, Korea
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Vallochi AL, Goldberg AC, Falcai A, Ramasawmy R, Kalil J, Silveira C, Belfort R, Rizzo LV. Molecular markers of susceptibility to ocular toxoplasmosis, host and guest behaving badly. Clin Ophthalmol 2011; 2:837-48. [PMID: 19668438 PMCID: PMC2699811 DOI: 10.2147/opth.s1629] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Infection with Toxoplasma gondii results in retinochoroiditis in 6% to 20% of immunocompetent individuals. The outcome of infection is the result of a set of interactions involving host genetic background, environmental, and social factors, and the genetic background of the parasite, all of which can be further modified by additional infections or even reinfection. Genes that encode several components of the immune system exhibit polymorphisms in their regulatory and coding regions that affect level and type of expression in response to stimuli, directing the immune response into different pathways. These variant alleles have been associated with susceptibility to immune-mediated diseases and with severity of pathology. We have investigated polymorphisms in several of these genes, identified as candidates for progression to retinochoroiditis caused by toxoplasmosis, namely chemokine (C-C motif) receptor 5 (CCR5), toll-like receptor-2 (TLR2), and TLR4. Furthermore, because interleukin-12 (IL-12) has been shown to be fundamental both in mice and in man to control a protective response against T. gondii, molecules that have a key function in IL-12 production will be emphasized in this review, in addition to discussing the importance of the genetic background of the parasite in the establishment of ocular disease.
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Affiliation(s)
- Adriana Lima Vallochi
- Oswaldo Cruz Institution (IOC), Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, RJ, Brazil
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Yamamoto M, Ma JS, Mueller C, Kamiyama N, Saiga H, Kubo E, Kimura T, Okamoto T, Okuyama M, Kayama H, Nagamune K, Takashima S, Matsuura Y, Soldati-Favre D, Takeda K. ATF6beta is a host cellular target of the Toxoplasma gondii virulence factor ROP18. ACTA ACUST UNITED AC 2011; 208:1533-46. [PMID: 21670204 PMCID: PMC3135360 DOI: 10.1084/jem.20101660] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Toxoplasma virulence factor ROP18 targets endoplasmic reticulum–bound transcription factor ATF6β in the host cell, leading to the detrimental loss of ATF6β through proteasome-dependent degradation. The ROP18 kinase has been identified as a key virulence determinant conferring a high mortality phenotype characteristic of type I Toxoplasma gondii strains. This major effector molecule is secreted by the rhoptries into the host cells during invasion; however, the molecular mechanisms by which this kinase exerts its pathogenic action remain poorly understood. In this study, we show that ROP18 targets the host endoplasmic reticulum–bound transcription factor ATF6β. Disruption of the ROP18 gene severely impairs acute toxoplasmosis by the type I RH strain. Because another virulence factor ROP16 kinase modulates immune responses through its N-terminal portion, we focus on the role of the N terminus of ROP18 in the subversion of host cellular functions. The N-terminal extension of ROP18 contributes to ATF6β-dependent pathogenicity by interacting with ATF6β and destabilizing it. The kinase activity of ROP18 is essential for proteasome-dependent degradation of ATF6β and for parasite virulence. Consistent with a key role for ATF6β in resistance against this intracellular pathogen, ATF6β-deficient mice exhibit a high susceptibility to infection by ROP18-deficient parasites. The results reveal that interference with ATF6β-dependent immune responses is a novel pathogenic mechanism induced by ROP18.
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Affiliation(s)
- Masahiro Yamamoto
- Department of Microbiology and Immunology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
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CD8 T Cells and Toxoplasma gondii: A New Paradigm. J Parasitol Res 2011; 2011:243796. [PMID: 21687650 PMCID: PMC3112509 DOI: 10.1155/2011/243796] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Accepted: 03/10/2011] [Indexed: 01/09/2023] Open
Abstract
CD8 T cells are essential for control of Toxoplasma gondii infection. Once activated they undergo differentiation into short-lived effector and memory precursor effector cells. As effector cells, CD8 T cells exert immune pressure on the parasite via production of inflammatory cytokines and through their cytolytic activity. Once immune control has been established, the parasite encysts and develops into chronic infection regulated by the memory CD8 T-cell population. Several signals are needed for this process to be initiated and for development of fully differentiated memory CD8 T cells. With newly developed tools including CD8 T-cell tetramers and TCR transgenic mice, dissecting the biology behind T. gondii-specific CD8 T-cell responses can now be more effectively addressed. In this paper, we discuss what is known about the signals required for effective T. gondii-specific CD8 T-cell development, their differentiation, and effector function.
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Kim WH, Shin EH, Kim JL, Yu SY, Jung BK, Chai JY. Suppression of CD4 T-Cells in the spleen of mice infected with Toxoplasma gondii KI-1 tachyzoites. THE KOREAN JOURNAL OF PARASITOLOGY 2010; 48:325-9. [PMID: 21234236 PMCID: PMC3018583 DOI: 10.3347/kjp.2010.48.4.325] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 10/21/2010] [Accepted: 10/22/2010] [Indexed: 11/23/2022]
Abstract
Toxoplasma gondii KI-1, a recent new isolate from Korea, shows similar pathogenicity and infectivity to mice compared to the virulent RH strain. To understand characteristics of host immunity, including immune enhancement or suppression, we investigated proliferative responses and phenotypes of spleen cells. In addition, kinetics of IFN-γ, a Th1 cytokine, was examined in BALB/c mice up to day 6 post-infection (PI). Intraperitoneal injection of mice with 103 KI-1 tachyzoites induced significant decreases (P < 0.05) in proliferative responses of spleen cells. This occurred at days 2-6 PI even when concanavalin A (con A) was added and when stimulated with KI-1 antigen, suggesting suppression of the immunity. CD4+ T-cells decreased markedly at day 2 PI (P < 0.05), whereas CD8+ T-cells, NK cells, and macrophages did not show significant changes, except a slight, but significant, increase of CD8+ T-cells at day 6 PI. The capacity of splenocytes to produce IFN-γ by con A stimulation dropped significantly at days 2-6 PI. These results demonstrate that intraperitoneal injection of KI-1 tachyzoites can induce immunosuppression during the early stage of infection, as revealed by the decrease of CD4+ T-cells and IFN-γ.
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Affiliation(s)
- Won-Hee Kim
- Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, Seoul, Korea
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Bhadra R, Guan H, Khan IA. Absence of both IL-7 and IL-15 severely impairs the development of CD8 T cell response against Toxoplasma gondii. PLoS One 2010; 5:e10842. [PMID: 20520779 PMCID: PMC2877110 DOI: 10.1371/journal.pone.0010842] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 05/02/2010] [Indexed: 11/21/2022] Open
Abstract
CD8+ T cells play an essential role in the protection against both acute as well as chronic Toxoplasma gondii infection. Although the role of IL-15 has been reported to be important for the development of long-term CD8+ T cell immunity against the pathogen, the simultaneous roles played by both IL-15 and related γ-chain family cytokine IL-7 in the generation of this response during acute phase of infection has not been described. We demonstrate that while lack of IL-7 or IL-15 alone has minimal impact on splenic CD8+ T cell maturation or effector function development during acute Toxoplasmosis, absence of both IL-7 and IL-15 only in the context of infection severely down-regulates the development of a potent CD8+ T cell response. This impairment is characterized by reduction in CD44 expression, IFN-γ production, proliferation and cytotoxicity. However, attenuated maturation and decreased effector functions in these mice are essentially downstream consequences of reduced number of antigen-specific CD8+ T cells. Interestingly, the absence of both cytokines did not impair initial CD8+ T cell generation but affected their survival and differentiation into memory phenotype IL-7Rαhi cells. Significantly lack of both cytokines severely affected expression of Bcl-2, an anti-apoptotic protein, but minimally affected proliferation. The overarching role played by these cytokines in eliciting a potent CD8+ T cell immunity against T. gondii infection is further evidenced by poor survival and high parasite burden in anti IL-7 treated IL-15−/− mice. These studies demonstrate that the two cytokines, IL-7 and IL-15, are exclusively important for the development of protective CD8+ T cell immune response against T. gondii. To the best of our knowledge this synergism between IL-7 and IL-15 in generating an optimal CD8+ T cell immunity against intracellular parasite or any other infectious disease model has not been previously reported.
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Affiliation(s)
- Rajarshi Bhadra
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington, D. C., United States of America
| | - Hongbing Guan
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
| | - Imtiaz A. Khan
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington, D. C., United States of America
- * E-mail:
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Regulation of CD8+ T cell responses to infection with parasitic protozoa. Exp Parasitol 2010; 126:318-25. [PMID: 20493842 DOI: 10.1016/j.exppara.2010.05.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 04/05/2010] [Accepted: 05/15/2010] [Indexed: 11/24/2022]
Abstract
There are over 10,000 species of parasitic protozoa, a subset of which can cause considerable disease in humans. Here we examine in detail the complex immune response generated during infection with a subset of these parasites: Trypanosoma cruzi, Leishmania sp., Toxoplasma gondii, and Plasmodium sp. While these particular species perhaps represent the most studied parasites in terms of understanding how T cells function during infection, it is clear that the lessons learned from this body of work are also relevant to the other protozoa known to induce a CD8(+) T cell response. This review will highlight some of the key studies that established that CD8(+) T cells play a major role in protective immunity to protozoa, the factors that promote the generation as well as maintenance of the CD8(+) T cell response during these infections, and draw attention to some of the gaps in our knowledge. Moreover, the development of new tools, including MHC-Class I tetramer reagents and the use of TCR transgenic mice or genetically modified parasites, has provided a better appreciation of how parasite specific CD8(+) T cell responses are initiated and new insights into their phenotypic plasticity.
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Prandota J. The importance of toxoplasma gondii infection in diseases presenting with headaches. Headaches and aseptic meningitis may be manifestations of the Jarisch-Herxheimer reaction. Int J Neurosci 2010; 119:2144-82. [PMID: 19916846 DOI: 10.3109/00207450903149217] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Worldwide, approximately 2 billion people are chronically infected with T. gondii with largely unknown consequences. This review presents clinical symptoms, differential diagnosis, triggering factors, treatment, and pathomechanisms responsible for idiopathic intracranial hypertension, pseudotumor cerebri, and aseptic meningitis. Literature cited in this work illustrates that immune state and other biologic mediator imbalances due to various endogenous and exogenous triggering factors may markedly affect latent central nervous system T. gondii infection/inflammation intensity, and cause reactivation of cerebral toxoplasmosis (CT). Irregularities in pro- and anti-inflammatory processes may markedly disturb the host and/or T. gondii defense mechanisms important for immune control of the parasite thereby manifesting as a wide range of neurologic symptoms and signs observed in some patients with migraine, epilepsy, celiac disease, Henoch-Schönlein purpura, and other brain disorders. This is consistent with reactivation of CT in mice after treatment with dexamethasone associated with depression of type T(H)1 immune response, and development of CT after administration of etanercept or other bioproducts. It seems that various types of headaches, epilepsy, aseptic meningitis, systemic adverse reactions to drugs or other substances represent the Jarisch-Herxheimer reaction due to apoptosis of T. gondii tachyzoites. Also development of some brain tumors, such as ependymoma and glioma may be associated with a chronic course of CT. Thus, all these patients should be tested for T. gondii infection.
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Affiliation(s)
- Joseph Prandota
- Department of Social Pediatrics, Faculty of Public Health, University Medical School, Wroclaw, Poland.
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Evaluation of the adjuvant properties of Astragalus membranaceus and Scutellaria baicalensis GEORGI in the immune protection induced by UV-attenuated Toxoplasma gondii in mouse models. Vaccine 2010; 28:737-43. [DOI: 10.1016/j.vaccine.2009.10.065] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 09/18/2009] [Accepted: 10/14/2009] [Indexed: 11/24/2022]
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Gigley JP, Fox BA, Bzik DJ. Long-term immunity to lethal acute or chronic type II Toxoplasma gondii infection is effectively induced in genetically susceptible C57BL/6 mice by immunization with an attenuated type I vaccine strain. Infect Immun 2009; 77:5380-8. [PMID: 19797073 PMCID: PMC2786442 DOI: 10.1128/iai.00649-09] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Revised: 07/07/2009] [Accepted: 09/15/2009] [Indexed: 11/20/2022] Open
Abstract
C57BL/6 (B6) mice are genetically highly susceptible to chronic type II Toxoplasma gondii infections that invariably cause lethal toxoplasmic encephalitis. We examined the ability of an attenuated type I vaccine strain to elicit long-term immunity to lethal acute or chronic type II infections in susceptible B6 mice. Mice immunized with the type I cps1-1 vaccine strain were not susceptible to a lethal (100-cyst) challenge with the type II strain ME49. Immunized mice challenged with 10 ME49 cysts exhibited significant reductions in brain cyst and parasite burdens compared to naive mice, regardless of the route of challenge infection. Remarkably, cps1-1 strain-immunized B6 mice chronically infected with ME49 survived for at least 12 months without succumbing to the chronic infection. Potent immunity to type II challenge infections persisted for at least 10 months after vaccination. While the cps1-1 strain-elicited immunity did not prevent the establishment of a chronic infection or clear established brain cysts, cps1-1 strain-elicited CD8(+) immune T cells significantly inhibited recrudescence of brain cysts during chronic ME49 infection. In addition, we show that uracil starvation of the cps1-1 strain induces early markers of bradyzoite differentiation. Collectively, these results suggest that more effective immune control of chronic type II infection in the genetically susceptible B6 background is established by vaccination with the nonreplicating type I uracil auxotroph cps1-1 strain.
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Affiliation(s)
- Jason P. Gigley
- Department of Microbiology and Immunology, Dartmouth Medical School, 1 Medical Center Drive, Lebanon, New Hampshire 03756
| | - Barbara A. Fox
- Department of Microbiology and Immunology, Dartmouth Medical School, 1 Medical Center Drive, Lebanon, New Hampshire 03756
| | - David J. Bzik
- Department of Microbiology and Immunology, Dartmouth Medical School, 1 Medical Center Drive, Lebanon, New Hampshire 03756
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GUITON R, ZAGANI R, DIMIER-POISSON I. Major role for CD8+T cells in the protection againstToxoplasma gondiifollowing dendritic cell vaccination. Parasite Immunol 2009; 31:631-40. [DOI: 10.1111/j.1365-3024.2009.01146.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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49
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Kinetics and phenotype of vaccine-induced CD8+ T-cell responses to Toxoplasma gondii. Infect Immun 2009; 77:3894-901. [PMID: 19528214 DOI: 10.1128/iai.00024-09] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multiple studies have established that the ability of CD8(+) T cells to act as cytolytic effectors and produce gamma interferon is important in mediating resistance to the intracellular parasite Toxoplasma gondii. To better understand the generation of the antigen-specific CD8(+) T-cell responses induced by T. gondii, mice were immunized with replication-deficient parasites that express the model antigen ovalbumin (OVA). Class I tetramers specific for SIINFEKL were used to track the OVA-specific endogenous CD8(+) T cells. The peak CD8(+) T-cell response was found at day 10 postimmunization, after which the frequency and numbers of antigen-specific cells declined. Unexpectedly, replication-deficient parasites were found to induce antigen-specific cells with faster kinetics than replicating parasites. The generation of optimal numbers of antigen-specific CD8(+) effector T cells was found to require CD4(+) T-cell help. At 7 days following immunization, antigen-specific cells were found to be CD62L(low), KLRG1(+), and CD127(low), and they maintained this phenotype for more than 70 days. Antigen-specific CD8(+) effector T cells in immunized mice exhibited potent perforin-dependent OVA-specific cytolytic activity in vivo. Perforin-dependent cytolysis appeared to be the major cytolytic mechanism; however, a perforin-independent pathway that was not mediated via Fas-FasL was also detected. This study provides further insight into vaccine-induced cytotoxic T-lymphocyte responses that correlate with protective immunity to T. gondii and identifies a critical role for CD4(+) T cells in the generation of protective CD8(+) T-cell responses.
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Further analysis of protection induced by the MIC3 DNA vaccine against T. gondii: CD4 and CD8 T cells are the major effectors of the MIC3 DNA vaccine-induced protection, both Lectin-like and EGF-like domains of MIC3 conferred protection. Vaccine 2009; 27:2959-66. [PMID: 19428907 DOI: 10.1016/j.vaccine.2009.02.107] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 02/27/2009] [Accepted: 02/28/2009] [Indexed: 11/24/2022]
Abstract
The present study was conducted mainly to evaluate the contribution of the cellular and the humoral responses in protection conferred by the MIC3 DNA vaccine (pMIC3i) that was proved as a potent vaccine against toxoplasmosis. We performed the adoptive transfer of CD4(+) and CD8(+) T lymphocytes from pMIC3i immunized mice to naive ones and the role of humoral immunity was evaluated by in vitro invasion assays. We also constructed plasmids encoding the EGF-like domains and the Lectin-like domain of MIC3, to define which domains of MIC3 are involved in the protection. Furthermore, the adjuvant effect of the GM-CSF-expressing vector (granulocyte-macrophage colony-stimulating factor) required the precise temporal and spatial codelivery of GM-CSF with antigen, thus, we constructed a bicistronic plasmid expressing MIC3 and GM-CSF. In conclusion, the protection induced by pMIC3i was mainly mediated by CD4(+) and CD8(+) T lymphocytes and both EGF and Lectin domains of MIC3 conferred protection. Furthermore, the codelivery of GM-CSF by a bicistronic plasmid appeared to be a most effective way for enhancing the adjuvant properties of GM-CSF.
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