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Nayeri T, Sarvi S, Daryani A. Effective factors in the pathogenesis of Toxoplasmagondii. Heliyon 2024; 10:e31558. [PMID: 38818168 PMCID: PMC11137575 DOI: 10.1016/j.heliyon.2024.e31558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 05/11/2024] [Accepted: 05/17/2024] [Indexed: 06/01/2024] Open
Abstract
Toxoplasma gondii (T. gondii) is a cosmopolitan protozoan parasite in humans and animals. It infects about 30 % of the human population worldwide and causes potentially fatal diseases in immunocompromised hosts and neonates. For this study, five English-language databases (ScienceDirect, ProQuest, Web of Science, PubMed, and Scopus) and the internet search engine Google Scholar were searched. This review was accomplished to draw a global perspective of what is known about the pathogenesis of T. gondii and various factors affecting it. Virulence and immune responses can influence the mechanisms of parasite pathogenesis and these factors are in turn influenced by other factors. In addition to the host's genetic background, the type of Toxoplasma strain, the routes of transmission of infection, the number of passages, and different phases of parasite life affect virulence. The identification of virulence factors of the parasite could provide promising insights into the pathogenesis of this parasite. The results of this study can be an incentive to conduct more intensive research to design and develop new anti-Toxoplasma agents (drugs and vaccines) to treat or prevent this infection. In addition, further studies are needed to better understand the key agents in the pathogenesis of T. gondii.
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Affiliation(s)
- Tooran Nayeri
- Infectious and Tropical Diseases Research Center, Dezful University of Medical Sciences, Dezful, Iran
- Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Shahabeddin Sarvi
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ahmad Daryani
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
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Zhang L, Song Z, Li P, Song X, Tang X, Hu D. Molecular characterization and immune protective efficacy of 3 Eimeria tenella antigens. Poult Sci 2024; 103:103234. [PMID: 37980744 PMCID: PMC10685023 DOI: 10.1016/j.psj.2023.103234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/18/2023] [Accepted: 10/21/2023] [Indexed: 11/21/2023] Open
Abstract
Avian coccidiosis caused by Eimeria is a serious parasitic disease that poses a threat to the poultry industry. Currently, prevention and treatment mainly rely on the administration of anticoccidials and live oocyst vaccines. However, the prevalence of drug resistance and the inherent limitations of live vaccines have driven the development of novel vaccines. In this study, the surface protein (Et-SAG14), a previously annotated rhoptry protein (Eten5-B), and a gametocyte phosphoglucomutase (Et-PGM1) were characterized and the vaccine potential of the recombinant proteins were evaluated. Et-SAG14 was dispersed in the form of particles in the sporozoite and merozoite stages, whereas Et-PGM1 was distributed in the apical part of the sporozoite and merozoite stages. The previously annotated rhoptry Eten5-B was found not to be located in the rhoptry but distributed in the cytoplasm of sporozoites and merozoites. Immunization with rEten5-B significantly elevated host interferon gamma (IFN-γ) and interleukin 10 (IL-10) transcript levels and exhibited moderate anticoccidial effects with an anticoccidial index (ACI) of 161. Unexpectedly, both recombinant Et-SAG14 and Et-PGM1 immunization significantly reduced host IFN-γ and IL-10 transcription levels, and did not show protection against E. tenella challenge (ACI < 80). These results suggest that the rEten5-B protein can trigger immune protection against E. tenella and may be a potential and effective subunit vaccine for the control of coccidiosis in poultry.
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Affiliation(s)
- Lei Zhang
- College of Animal Science and Technology, Guangxi University, Nanning 530004, China
| | - Zhixuan Song
- College of Animal Science and Technology, Guangxi University, Nanning 530004, China
| | - Peiyao Li
- College of Animal Science and Technology, Guangxi University, Nanning 530004, China
| | - Xingju Song
- College of Animal Science and Technology, Guangxi University, Nanning 530004, China; Guangxi Zhuang Autonomous Region Engineering Research Center of Veterinary Biologics, Nanning 530004, China; Guangxi Key Laboratory of Animal Breeding, Disease Control and Prevention, Nanning 530004, China
| | - Xinming Tang
- Institute of Animal Science (IAS), Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Dandan Hu
- College of Animal Science and Technology, Guangxi University, Nanning 530004, China; Guangxi Zhuang Autonomous Region Engineering Research Center of Veterinary Biologics, Nanning 530004, China; Guangxi Key Laboratory of Animal Breeding, Disease Control and Prevention, Nanning 530004, China.
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Wang X, Qu L, Chen J, Jin Y, Hu K, Zhou Z, Zhang J, An Y, Zheng J. Toxoplasma rhoptry proteins that affect encephalitis outcome. Cell Death Discov 2023; 9:439. [PMID: 38049394 PMCID: PMC10696021 DOI: 10.1038/s41420-023-01742-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 11/07/2023] [Accepted: 11/23/2023] [Indexed: 12/06/2023] Open
Abstract
Toxoplasma gondii, a widespread obligate intracellular parasite, can infect almost all warm-blooded animals, including humans. The cellular barrier of the central nervous system (CNS) is generally able to protect the brain parenchyma from infectious damage. However, T. gondii typically causes latent brain infections in humans and other vertebrates. Here, we discuss how T. gondii rhoptry proteins (ROPs) affect signaling pathways in host cells and speculate how this might affect the outcome of Toxoplasma encephalitis.
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Affiliation(s)
- Xinlei Wang
- Department of Clinical Laboratory, The Second Hospital of Jilin University, Changchun, 130021, China
| | - Lai Qu
- Department of Intensive Care Unit, First Hospital of Jilin University, Changchun, 130021, China
| | - Jie Chen
- Institute of Theoretical Chemistry, Jilin University, Changchun, 130021, China
| | - Yufen Jin
- Department of Clinical Laboratory, The Second Hospital of Jilin University, Changchun, 130021, China
| | - Kaisong Hu
- Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, Changchun, 130021, China
| | - Zhengjie Zhou
- Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, Changchun, 130021, China
| | - Jiaqi Zhang
- Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, Changchun, 130021, China
| | - Yiming An
- Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, Changchun, 130021, China
| | - Jingtong Zheng
- Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, Changchun, 130021, China.
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Nayeri T, Sarvi S, Fasihi-Ramandi M, Valadan R, Asgarian-Omran H, Ajami A, Khalilian A, Hosseininejad Z, Dodangeh S, Javidnia J, Daryani A. Enhancement of immune responses by vaccine potential of three antigens, including ROP18, MIC4, and SAG1 against acute toxoplasmosis in mice. Exp Parasitol 2022; 244:108427. [PMID: 36379272 DOI: 10.1016/j.exppara.2022.108427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/31/2022] [Accepted: 11/08/2022] [Indexed: 11/13/2022]
Abstract
Toxoplasma gondii (T. gondii) causes considerable financial losses in the livestock industry and can present serious threats to pregnant women, as well as immunocompromised patients. Therefore, it is required to design and produce an efficient vaccine for controlling toxoplasmosis. The present study aimed to evaluate the protective immunity induced by RMS protein (ROP18, MIC4, and SAG1) with Freund adjuvant, calcium phosphate nanoparticles (CaPNs), and chitosan nanoparticles (CNs) in BALB/c mice. The RMS protein was expressed in Escherichia coli (E. coli) and purified using a HisTrap HP column. Thereafter, cellular and humoral immunity was assessed by injecting RMS protein on days 0, 21, and 35 into four groups [RMS, RMS-chitosan nanoparticles (RMS-CNs), RMS-calcium phosphate nanoparticles (RMS-CaPNs), and RMS-Freund]. Phosphate buffered saline (PBS), CNs, CaPNs, and Freund served as the four control groups. The results displayed that vaccination with RMS protein and adjuvants significantly elicited the levels of specific IgG antibodies and cytokines against toxoplasmosis. There were high levels of total IgG, IgG2a, and IFN-γ in vaccinated mice, compared to those in the control groups, especially in the RMS-Freund, indicating a Th-1 type response. The vaccinated and control mice were challenged intraperitoneally with 1 × 103 tachyzoites of the T. gondii RH strain four weeks after the last injection, and in RMS-Freund and RMS-CaPNs groups, the highest increase in survival time was observed (15 days). The RMS can significantly increase Th1 and Th2 responses; moreover, multi-epitope vaccines with adjuvants can be a promising strategy for the production of a vaccine against toxoplasmosis.
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Affiliation(s)
- Tooran Nayeri
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Toxoplasmosis Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran
| | - Shahabeddin Sarvi
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Toxoplasmosis Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mahdi Fasihi-Ramandi
- Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Reza Valadan
- Immunology Department, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Hossein Asgarian-Omran
- Immunology Department, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Abolghasem Ajami
- Immunology Department, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Molecular and Cell Biology Research Center, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Antimicrobial Resistance Research Center, Mazandaran University of Medical Sciences, Sari, Iran
| | - Alireza Khalilian
- Department of Biostatistics and Community Medicine, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Zahra Hosseininejad
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Toxoplasmosis Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran; Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Samira Dodangeh
- Medical Microbiology Research Center, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Javad Javidnia
- Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran; Department of Medical Mycology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ahmad Daryani
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Toxoplasmosis Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran.
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Bingxiang W, Ningning Z, Yakun W, Lingyu S, Hongmei L, Zhang X, Zhao X. Characterization of the Eimeria tenella rhoptry protein with a nuclear localization sequence (EtROP30). Parasitol Res 2022; 121:1507-1516. [PMID: 35314894 PMCID: PMC8938219 DOI: 10.1007/s00436-022-07499-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 03/16/2022] [Indexed: 01/25/2023]
Abstract
Rhoptry proteins (ROPs), secreted by specific rhoptry organelles of apicomplexan parasites, are determinants of parasite pathogenesis and sources of vaccine candidates. Twenty-eight ROPs of Eimeria tenella have been predicted by genomic approaches, and in the present study, E. tenella rhoptry protein 30 (EtROP30) was characterized. Subcellular localizations of EtROP30 in sporozoites and merozoites were in the apical complex and rhoptry-like bulb, suggesting that EtROP30 is a member of ROPs in E. tenella. Sequence analysis showed that EtROP30 contained an N-terminal secretory signal, a protein kinase domain with eight E. tenella-specific rhoptry kinase 1 subfamily (ROPK-Eten1) motifs, and a C-terminal nuclear localization sequence (NLS), making EtROP30 the only ROP that contains both a secretory signal and an NLS in E. tenella. Subsequent experiments showed that EtROP30 was a secreted protein in the sporozoite stage, relying on NLS for migration to the host nucleus. In addition, EtROP30 showed significantly higher expression levels in the parasite merozoite stage, indicating that EtROP30 plays a critical role during parasite reinvasion and development and may be a viable option as a vaccine candidate for anti-parasitic infection. The immunization protection efficacies of EtROP30 were evaluated. Significant improvements in mean body weight gain, reduction of cecum lesion score, and number of oocysts excreted were observed, indicating that EtROP30 has good immunogenicity against E. tenella. In the present study, a ROP of E. tenella with secretory and nuclear localization characteristics has been identified, and proved to be an effective vaccine candidate against this parasite.
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Affiliation(s)
- Wang Bingxiang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, China
| | - Zhao Ningning
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, China
| | - Wang Yakun
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, China
| | - Sun Lingyu
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, China
| | - Li Hongmei
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, China
| | - Xiao Zhang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, China.
| | - Xiaomin Zhao
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, China. .,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian, Shandong, China. .,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Taian, Shandong, China.
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Nguyen TT, Kamyingkird K, Phimpraphai W, Inpankaew T. Viability of Toxoplasma gondii tachyzoites in different conditions for parasite transportation. Vet World 2022; 15:198-204. [PMID: 35369589 PMCID: PMC8924386 DOI: 10.14202/vetworld.2022.198-204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 12/31/2021] [Indexed: 11/20/2022] Open
Abstract
Background and Aim: Toxoplasma gondii tachyzoite is the infective stage that causes acute infection, leading to severe toxoplasmosis. The tachyzoite stage has been extensively used for several inoculation purposes, including antigen production, immunological studies, nutrition mechanisms, and in vitro drug trials. The use of fresh tachyzoites is required for inoculation in either in vitro or in vivo studies. However, there is a lack of information on preserving live tachyzoites during transportation from laboratories to inoculation sites. Therefore, this study aimed to validate suitable preservative conditions for maintaining live parasites by determining the survival and viability of T. gondii tachyzoites on the basis of different media, temperatures, and incubation times. Materials and Methods: The free live T. gondii tachyzoites were evaluated on their viability when maintained in different media without 5% Carbon dioxide (CO2). The purified tachyzoites of the RH and PLK strains were individually suspended in normal saline (NS), phosphate-buffered saline (PBS), minimum essential medium (MEM), and MEM with 10% fetal bovine serum (MEM-FBS) and incubated for 6 h at ice-cold (IC; 3-9°C) and room temperature (RT; 25°C). Parasite survival was measured at the 0, 1st, 2nd, 3rd, 4th, 5th, and 6th h post-incubation using the trypan blue exclusion test. Results: The viability was in the range of 85.0%–91.0% for IC using NS and 81.0%–85.1% (IC) and 75.3%–77.5% (RT) using PBS. The viability was approximately 75.0%–83.0% (IC) and 70.0%–79.0% (RT) using MEM and MEM-FBS. There was a significant difference in the viability between the seven periods on the basis of one-way repeated Analysis of variance and Friedman analyses. Parasite survival slightly reduced (20.0%–30.0%) in NS and MEM-FBS at both temperatures during incubation. Notably, PBS could not support tachyzoite viability after 3 h post-incubation. Conclusion: NS was a suitable preservative for maintaining purified T. gondii tachyzoites during transportation at IC and RT without 5% CO2 supplementation. This could be a valuable medium for parasite transportation, especially when there is a large distance between the laboratory and inoculation site.
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Affiliation(s)
- Thi Thuy Nguyen
- Department of Parasitology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand; Department of Veterinary Medicine, Faculty of Animal Science and Veterinary Medicine, University of Agriculture and Forestry, Hue University, Hue, Vietnam
| | - Ketsarin Kamyingkird
- Department of Parasitology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand
| | - Waraphon Phimpraphai
- Department of Veterinary Public Health, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand
| | - Tawin Inpankaew
- Department of Parasitology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand
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Daher D, Shaghlil A, Sobh E, Hamie M, Hassan ME, Moumneh MB, Itani S, El Hajj R, Tawk L, El Sabban M, El Hajj H. Comprehensive Overview of Toxoplasma gondii-Induced and Associated Diseases. Pathogens 2021; 10:pathogens10111351. [PMID: 34832507 PMCID: PMC8625914 DOI: 10.3390/pathogens10111351] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/07/2021] [Accepted: 10/14/2021] [Indexed: 12/03/2022] Open
Abstract
Toxoplasma gondii (T. gondii) is a prevalent protozoan parasite of medical and veterinary significance. It is the etiologic agent of toxoplasmosis, a neglected disease in which incidence and symptoms differ between patients and regions. In immunocompetent patients, toxoplasmosis manifests as acute and chronic forms. Acute toxoplasmosis presents as mild or asymptomatic disease that evolves, under the host immune response, into a persistent chronic disease in healthy individuals. Chronic toxoplasmosis establishes as latent tissue cysts in the brain and skeletal muscles. In immunocompromised patients, chronic toxoplasmosis may reactivate, leading to a potentially life-threatening condition. Recently, the association between toxoplasmosis and various diseases has been shown. These span primary neuropathies, behavioral and psychiatric disorders, and different types of cancer. Currently, a direct pre-clinical or clinical molecular connotation between toxoplasmosis and most of its associated diseases remains poorly understood. In this review, we provide a comprehensive overview on Toxoplasma-induced and associated diseases with a focus on available knowledge of the molecular players dictating these associations. We will also abridge the existing therapeutic options of toxoplasmosis and highlight the current gaps to explore the implications of toxoplasmosis on its associated diseases to advance treatment modalities.
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Affiliation(s)
- Darine Daher
- Department of Experimental Pathology, Microbiology and Immunology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (D.D.); (M.H.); (M.E.H.); (M.B.M.); (S.I.)
| | - Ahmad Shaghlil
- Department of Biology, Faculty of Sciences, R. Hariri Campus, Lebanese University, Beirut 1107 2020, Lebanon; (A.S.); (E.S.)
| | - Eyad Sobh
- Department of Biology, Faculty of Sciences, R. Hariri Campus, Lebanese University, Beirut 1107 2020, Lebanon; (A.S.); (E.S.)
| | - Maguy Hamie
- Department of Experimental Pathology, Microbiology and Immunology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (D.D.); (M.H.); (M.E.H.); (M.B.M.); (S.I.)
| | - Malika Elhage Hassan
- Department of Experimental Pathology, Microbiology and Immunology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (D.D.); (M.H.); (M.E.H.); (M.B.M.); (S.I.)
| | - Mohamad Bahij Moumneh
- Department of Experimental Pathology, Microbiology and Immunology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (D.D.); (M.H.); (M.E.H.); (M.B.M.); (S.I.)
| | - Shaymaa Itani
- Department of Experimental Pathology, Microbiology and Immunology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (D.D.); (M.H.); (M.E.H.); (M.B.M.); (S.I.)
| | - Rana El Hajj
- Department of Biological Sciences, Beirut Arab University, Beirut 1107 2809, Lebanon;
| | - Lina Tawk
- Department of Medical Laboratory Sciences, Faculty of Health Sciences, University of Balamand, Beirut 1100 2807, Lebanon;
| | - Marwan El Sabban
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon;
| | - Hiba El Hajj
- Department of Experimental Pathology, Microbiology and Immunology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (D.D.); (M.H.); (M.E.H.); (M.B.M.); (S.I.)
- Correspondence: ; Tel.: +961–1-350000 (ext. 4897)
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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: 20] [Impact Index Per Article: 5.0] [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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