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Ronizi RR, Namavari M, Moazamian E. Evaluation of the protective immune response of an attenuated strain of Toxoplasma gondii with long-term passages on the Gecko cell line. Vet Parasitol 2023; 320:109969. [PMID: 37301090 DOI: 10.1016/j.vetpar.2023.109969] [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: 01/27/2023] [Revised: 05/27/2023] [Accepted: 06/01/2023] [Indexed: 06/12/2023]
Abstract
Toxoplasma gondii is an obligate intracellular parasite that causes the zoonoses disease, named toxoplasmosis, with global prevalence. Until now, no cost-effective treatment method has been found to deal with toxoplasma, and vaccination is the best way to deal with the infection. In the case of pathogenic protozoa, mainly live vaccines have had successful results compared to other vaccine platforms. This study evaluated the efficacy of a live experimental vaccine through long-term passages on the Gecko cell line (Z1) in inducing a protective immune response in BALB/c mice. Thirty mice were divided into three equal groups; G1: the immunized/challenged group (injection of attenuated strain), G2: the immunized/unchallenged group (injection of attenuated strain), and G3: the control group (injection of culture medium).One month after immunization, the studied mice were challenged with 1ₓ103 live tachyzoites of Toxoplasma acute RH strain. We performed Serological investigations, including evaluating antibodies, interferon-gamma (IFN-γ), and interleukins 2, 4, 10, and 12 (IL-2,4,10,12). At the study's end, a molecular test was performed on brain and liver tissues in the immunized groups to check the presence of parasites. The results from the serological tests for the evaluation of antibodies, interferon-gamma (IFN-γ), and interleukins 10 and 12 (IL-10, 12) show a significant difference (p < 0.05) between the vaccinated group and the control group, which are essential indicators of protective immunity against toxoplasma infection. Thus, in the vaccinated group, the survival rate of mice against the challenge was 70%. Also, in group two (G2), the attenuated strain of Toxoplasma gondii had no pathogenicity, and all mice survived until the end of the study period. Molecular results also showed the absence of parasites in the brain and liver tissues in this immunized group and the parasite was found in only one case of liver tissue in G1. Therefore, the attenuated strain has caused significant and protective humoral and cellular immune responses in vaccinated groups. This study showed that with the long-term passage of the acute strain on the Gecko cell line, it is possible to quickly obtain a non-diseased attenuated strain with the ability to induce protective immunity. This successful finding can introduce further research to achieve a promising vaccine in the target animals.
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Affiliation(s)
- Roghayeh Ramezanpoor Ronizi
- Department of Microbiology, Faculty of Sciences, Agriculture and Modern Technology, Shiraz branch, Islamic Azad University, Shiraz, Iran
| | - Mehdi Namavari
- Razi Vaccine and Serum Research Institute; Agricultural Research, Agricultural and Extension Organization, Shiraz, Iran.
| | - Elham Moazamian
- Department of Microbiology, Faculty of Sciences, Agriculture and Modern Technology, Shiraz branch, Islamic Azad University, Shiraz, Iran
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Zhang Y, Li D, Lu S, Zheng B. Toxoplasmosis vaccines: what we have and where to go? NPJ Vaccines 2022; 7:131. [PMID: 36310233 PMCID: PMC9618413 DOI: 10.1038/s41541-022-00563-0] [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: 07/02/2022] [Accepted: 10/17/2022] [Indexed: 11/16/2022] Open
Abstract
Despite recent major advances in developing effective vaccines against toxoplasmosis, finding new protective vaccination strategies remains a challenging and elusive goal as it is critical to prevent the disease. Over the past few years, various experimental approaches have shown that developing an effective vaccine against T. gondii is achievable. However, more remains unknown due to its complicated life cycle, difficulties in clinical translation, and lack of a standardized platform. This minireview summarizes the recent advances in the development of T. gondii vaccines and the main obstacles to developing a safe, effective and durable T. gondii vaccine. The successes and failures in developing and testing vaccine candidates for the T. gondii vaccine are also discussed, which may facilitate the future development of T. gondii vaccines.
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Affiliation(s)
- Yizhuo Zhang
- grid.506977.a0000 0004 1757 7957Institute of Parasitic Diseases, School of Basic Medicine and Forensics, Hangzhou Medical College, Hangzhou, China ,grid.506977.a0000 0004 1757 7957Engineering Research Center of Novel Vaccine of Zhejiang Province, Hangzhou Medical College, Hangzhou, China
| | - Dan Li
- grid.506977.a0000 0004 1757 7957Institute of Parasitic Diseases, School of Basic Medicine and Forensics, Hangzhou Medical College, Hangzhou, China ,grid.506977.a0000 0004 1757 7957Engineering Research Center of Novel Vaccine of Zhejiang Province, Hangzhou Medical College, Hangzhou, China
| | - Shaohong Lu
- grid.506977.a0000 0004 1757 7957Institute of Parasitic Diseases, School of Basic Medicine and Forensics, Hangzhou Medical College, Hangzhou, China ,grid.506977.a0000 0004 1757 7957Engineering Research Center of Novel Vaccine of Zhejiang Province, Hangzhou Medical College, Hangzhou, China ,grid.506977.a0000 0004 1757 7957Key Laboratory of Bio-tech Vaccine of Zhejiang Province, Hangzhou Medical College, Hangzhou, China
| | - Bin Zheng
- grid.506977.a0000 0004 1757 7957Institute of Parasitic Diseases, School of Basic Medicine and Forensics, Hangzhou Medical College, Hangzhou, China ,grid.506977.a0000 0004 1757 7957Engineering Research Center of Novel Vaccine of Zhejiang Province, Hangzhou Medical College, Hangzhou, China ,grid.506977.a0000 0004 1757 7957Key Laboratory of Bio-tech Vaccine of Zhejiang Province, Hangzhou Medical College, Hangzhou, China
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Hänggeli KPA, Hemphill A, Müller N, Schimanski B, Olias P, Müller J, Boubaker G. Single- and duplex TaqMan-quantitative PCR for determining the copy numbers of integrated selection markers during site-specific mutagenesis in Toxoplasma gondii by CRISPR-Cas9. PLoS One 2022; 17:e0271011. [PMID: 36112587 PMCID: PMC9481009 DOI: 10.1371/journal.pone.0271011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 09/04/2022] [Indexed: 11/30/2022] Open
Abstract
Herein, we developed a single and a duplex TaqMan quantitative PCR (qPCR) for absolute quantification of copy numbers of integrated dihydrofolate reductase-thymidylate synthase (mdhfr-ts) drug selectable marker for pyrimethamine resistance in Toxoplasma gondii knockouts (KOs). The single TaqMan qPCR amplifies a 174 bp DNA fragment of the inserted mdhfr-ts and of the wild-type (WT) dhfr-ts (wtdhfr-ts) which is present as single copy gene in Toxoplasma and encodes a sensitive enzyme to pyrimethamine. Thus, the copy number of the dhfr-ts fragment in a given DNA quantity from KO parasites with a single site-specific integration should be twice the number of dhfr-ts copies recorded in the same DNA quantity from WT parasites. The duplex TaqMan qPCR allows simultaneous amplification of the 174 bp dhfr-ts fragment and the T. gondii 529-bp repeat element. Accordingly, for a WT DNA sample, the determined number of tachyzoites given by dhfr-ts amplification is equal to the number of tachyzoites determined by amplification of the Toxoplasma 529-bp, resulting thus in a ratio of 1. However, for a KO clone having a single site-specific integration of mdhfr-ts, the calculated ratio is 2. We then applied both approaches to test T. gondii RH mutants in which the major surface antigen (SAG1) was disrupted through insertion of mdhfr-ts using CRISPR-Cas9. Results from both assays were in correlation showing a high accuracy in detecting KOs with multiple integrated mdhfr-ts. Southern blot analyses using BsaBI and DraIII confirmed qPCRs results. Both TaqMan qPCRs are needed for reliable diagnostic of T. gondii KOs following CRISPR-Cas9-mediated mutagenesis, particularly with respect to off-target effects resulting from multiple insertions of mdhfr-ts. The principle of the duplex TaqMan qPCR is applicable for other selectable markers in Toxoplasma. TaqMan qPCR tools may contribute to more frequent use of WT Toxoplasma strains during functional genomics.
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Affiliation(s)
- Kai Pascal Alexander Hänggeli
- Department of Infectious Diseases and Pathobiology, Institute of Parasitology, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Andrew Hemphill
- Department of Infectious Diseases and Pathobiology, Institute of Parasitology, University of Bern, Bern, Switzerland
- * E-mail: (GB); (AH)
| | - Norbert Müller
- Department of Infectious Diseases and Pathobiology, Institute of Parasitology, University of Bern, Bern, Switzerland
| | - Bernd Schimanski
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Philipp Olias
- Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Joachim Müller
- Department of Infectious Diseases and Pathobiology, Institute of Parasitology, University of Bern, Bern, Switzerland
| | - Ghalia Boubaker
- Department of Infectious Diseases and Pathobiology, Institute of Parasitology, University of Bern, Bern, Switzerland
- * E-mail: (GB); (AH)
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Borkens Y. [Toxoplasma gondii-Current drugs and future vaccines against an underestimated protozoan infection]. Internist (Berl) 2021; 62:1123-1132. [PMID: 34467425 DOI: 10.1007/s00108-021-01155-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2021] [Indexed: 12/01/2022]
Abstract
Toxoplasma gondii is a unicellular organism of the Apicomplexa that occurs worldwide and is therefore a close relative of the malaria pathogen Plasmodium. As T. gondii infests every warm-blooded vertebrate species as an intermediate host and has a very high prevalence worldwide, toxoplasmosis is one of the most important international foodborne diseases. Potential vaccines (human as well as veterinary) play a crucial role in controlling this disease.
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Affiliation(s)
- Yannick Borkens
- College of Public Health, Medical and Veterinary Science, James Cook University, 1 James Cook Drive, 4811, Townsville, Queensland, Australien.
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Chu KB, Quan FS. Advances in Toxoplasma gondii Vaccines: Current Strategies and Challenges for Vaccine Development. Vaccines (Basel) 2021; 9:vaccines9050413. [PMID: 33919060 PMCID: PMC8143161 DOI: 10.3390/vaccines9050413] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 02/06/2023] Open
Abstract
Toxoplasmosis, caused by the apicomplexan parasite Toxoplasma gondii, is one of the most damaging parasite-borne zoonotic diseases of global importance. While approximately one-third of the entire world’s population is estimated to be infected with T. gondii, an effective vaccine for human use remains unavailable. Global efforts in pursuit of developing a T. gondii vaccine have been ongoing for decades, and novel innovative approaches have been introduced to aid this process. A wide array of vaccination strategies have been conducted to date including, but not limited to, nucleic acids, protein subunits, attenuated vaccines, and nanoparticles, which have been assessed in rodents with promising results. Yet, translation of these in vivo results into clinical studies remains a major obstacle that needs to be overcome. In this review, we will aim to summarize the current advances in T. gondii vaccine strategies and address the challenges hindering vaccine development.
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Affiliation(s)
- Ki-Back Chu
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Korea;
| | - Fu-Shi Quan
- Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, School of Medicine, Graduate School, Kyung Hee University, Seoul 02447, Korea
- Department of Medical Zoology, School of Medicine, Kyung Hee University, Seoul 02447, Korea
- Correspondence:
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Cianci R, Franza L. Genomic Medicine and Advances in Vaccine Technology and Development in the Developing and Developed World. Vaccines (Basel) 2020; 9:vaccines9010009. [PMID: 33374343 PMCID: PMC7823288 DOI: 10.3390/vaccines9010009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 12/01/2020] [Indexed: 12/20/2022] Open
Affiliation(s)
- Rossella Cianci
- Internal Medicine, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Roma, Italy
- Correspondence: ; Tel.: +39-06-3015-7597; Fax: +39-06-3550-2775
| | - Laura Franza
- Emergency Medicine, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Roma, Italy;
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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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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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