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Expanding the Known Repertoire of C-Type Lectin Receptors Binding to Toxoplasma gondii Oocysts Using a Modified High-Resolution Immunofluorescence Assay. mSphere 2021; 6:6/2/e01341-20. [PMID: 33789945 PMCID: PMC8546727 DOI: 10.1128/msphere.01341-20] [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] [Indexed: 01/22/2023] Open
Abstract
The environmental stage of the apicomplexan Toxoplasma gondii oocyst is vital to its life cycle but largely understudied. Because oocysts are excreted only by infected felids, their availability for research is limited. We report the adaptation of an agarose-based method to immobilize minute amounts of oocysts to perform immunofluorescence assays. Agarose embedding allows high-resolution confocal microscopy imaging of antibodies binding to the oocyst surface as well as unprecedented imaging of intracellular sporocyst structures with Maclura pomifera agglutinin after on-slide permeabilization of the immobilized oocysts. To identify new possible molecules binding to the oocyst surface, we used this method to screen a library of C-type lectin receptor (CLR)-human IgG constant region fusion proteins from the group of related CLRs called the Dectin-1 cluster against oocysts. In addition to CLEC7A that was previously reported to decorate T. gondii oocysts, we present experimental evidence for specific binding of three additional CLRs to the surface of this stage. We discuss how these CLRs, known to be expressed on neutrophils, dendritic cells, or macrophages, could be involved in the early immune response by the host, such as oocyst antigen uptake in the intestine. In conclusion, we present a modified immunofluorescence assay technique that allows material-saving immunofluorescence microscopy with T. gondii oocysts in a higher resolution than previously published, which allowed us to describe three additional CLRs binding specifically to the oocyst surface. IMPORTANCE Knowledge of oocyst biology of Toxoplasma gondii is limited, not the least due to its limited availability. We describe a method that permits us to process minute amounts of oocysts for immunofluorescence microscopy without compromising their structural properties. This method allowed us to visualize internal structures of sporocysts by confocal microscopy in unprecedented quality. Moreover, the method can be used as a low- to medium-throughput method to screen for molecules interacting with oocysts, such as antibodies, or compounds causing structural damage to oocysts (i.e., disinfectants). Using this method, we screened a small library of C-type lectin receptors (CLRs) present on certain immune cells and found three CLRs able to decorate the oocyst wall of T. gondii and which were not known before to bind to oocysts. These tools will allow further study into oocyst wall composition and could also provoke experiments regarding immunological recognition of oocysts.
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Song Y, Song L, Wan X, Shen B, Fang R, Hu M, Zhao J, Zhou Y. A Comparison of Transcriptional Diversity of Swine Macrophages Infected With TgHB1 Strain of Toxoplasma gondii Isolated in China. Front Cell Infect Microbiol 2020; 10:526876. [PMID: 33102248 PMCID: PMC7546811 DOI: 10.3389/fcimb.2020.526876] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 08/25/2020] [Indexed: 01/08/2023] Open
Abstract
Toxoplasma gondii is an apicomplexan parasite infecting human and animals, causing huge public health concerns and economic losses. Swine alveolar macrophage plays an important role in controlling T. gondii infection. However, the mechanism by which macrophages infected with T. gondii function in the immunity to the infection is unclear, especially for local isolates such as TgHB1 isolated in China. RNA-seq as a valuable tool was applied to simultaneously analyze transcriptional changes of pig alveolar macrophages infected with TgRH (typeI), TgME49 (typeII) or TgHB1 at different time points post infection (6, 12, and 24 h). Paired-end clean reads were aligned to the Sscrofa10.2 pig genome and T. gondii ME49 genome. The differentially expressed genes of macrophages and T. gondii were enriched through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes, respectively. Compared to the TgRH and TgME49 infection groups, 307 down-regulated macrophage genes (mainly enriched for development and metabolism) and 419 up-regulated genes (mainly enriched for immune pathways) were uniquely expressed in the TgHB1 infection group. Additionally, 557 down-regulated and 674 up-regulated T. gondii genes (mainly enriched in metabolism and biosynthesis) were uniquely expressed in the TgHB1 infection group. For validation purposes, some of the differentially expressed genes of macrophages involved in immune-related signaling pathways were used for further analysis via real time quantitative reverse-transcription polymerase-chain reaction (qRT-PCR). This work provides important insights into the temporal immune responses of swine alveolar macrophages to infection by the strain TgHB1 isolated from China, and is helpful for better understanding of the T. gondii genotype-associated activation of macrophages during early phase of the infection.
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Affiliation(s)
- Yongle Song
- Key Laboratory Preventive Veterinary of Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Lindong Song
- Key Laboratory Preventive Veterinary of Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Xiaoting Wan
- Key Laboratory Preventive Veterinary of Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Bang Shen
- Key Laboratory Preventive Veterinary of Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Rui Fang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Min Hu
- Key Laboratory Preventive Veterinary of Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Junlong Zhao
- Key Laboratory Preventive Veterinary of Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Yanqin Zhou
- Key Laboratory Preventive Veterinary of Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
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Ndao O, Puech PH, Bérard C, Limozin L, Rabhi S, Azas N, Dubey JP, Dumètre A. Dynamics of Toxoplasma gondii Oocyst Phagocytosis by Macrophages. Front Cell Infect Microbiol 2020; 10:207. [PMID: 32509593 PMCID: PMC7248298 DOI: 10.3389/fcimb.2020.00207] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Accepted: 04/16/2020] [Indexed: 01/23/2023] Open
Abstract
Oocysts are the environmentally resistant stage of the protozoan parasite Toxoplasma gondii. They are responsible for foodborne infections in humans and animals worldwide. Infectious oocysts contain sporozoites that have to exit the sporocyst and oocyst walls to initiate replication of the parasite within the host tissues. Given their robustness and resistance to chemical degradation, it is still unclear how the oocyst and sporocyst walls release the sporozoites. This process called excystation is thought to occur in the small intestine as a result of the combined action of digestive agents, yet to be identified. By using an oocyst-macrophage co-culture platform, we previously demonstrated in vitro that the excystation of sporozoites and their differentiation into replicative tachyzoites could occur in absence of digestive factors, following phagocytosis by macrophages. Here, we further characterize the dynamics of the oocyst phagocytosis at the single-cell level by using optical tweezers and micropipette aspiration techniques. Our results show that the oocyst internalization kinetics can vary among a given population of macrophages, but similar processes and dynamics could be observed. Most of the cells manipulate oocysts for ~15 min before internalizing them in typically 30 min. This process mainly involves the actin cytoskeleton of the macrophages. Liberated sporozoites within macrophages then differentiate into tachyzoites within 4-6 h following oocyst-macrophage contact. Tachyzoites appear to develop better in macrophages challenged with free sporocysts or sporozoites than with whole oocysts, suggesting that opening of the oocyst wall is one of the most limiting steps for sporozoite excystation completion.
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Affiliation(s)
- Omar Ndao
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France
- IHU-Méditerranée Infection, Marseille, France
| | - Pierre-Henri Puech
- Aix Marseille Univ, LAI UM 61, Marseille, France
- Inserm, UMR_S 1067, Marseille, France
- CNRS, UMR 7333, Marseille, France
| | - Camille Bérard
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France
- IHU-Méditerranée Infection, Marseille, France
| | - Laurent Limozin
- Aix Marseille Univ, LAI UM 61, Marseille, France
- Inserm, UMR_S 1067, Marseille, France
- CNRS, UMR 7333, Marseille, France
| | - Sameh Rabhi
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France
- IHU-Méditerranée Infection, Marseille, France
| | - Nadine Azas
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France
- IHU-Méditerranée Infection, Marseille, France
| | - Jitender P. Dubey
- Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, United States Department of Agriculture, Agricultural Research Service, Beltsville, MD, United States
| | - Aurélien Dumètre
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France
- IHU-Méditerranée Infection, Marseille, France
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Sousa S, Almeida A, Delgado L, Conceição A, Marques C, da Costa JMC, Castro A. rTgOWP1-f, a specific biomarker for Toxoplasma gondii oocysts. Sci Rep 2020; 10:7947. [PMID: 32409659 PMCID: PMC7224171 DOI: 10.1038/s41598-020-64590-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 04/16/2020] [Indexed: 01/26/2023] Open
Abstract
Toxoplasma gondii oocyst wall protein 1 (TgOWP1) integrates a family of seven proteins, consensually assumed as specific antigens of Toxoplasma gondii oocyst stage, located in the outer layer of the oocyst wall. Herein, we notice the expression of a recombinant antigen, rTgOWP1-f, derived from a fragment selected on basis of its structural homology with Plasmodium MSP1-19. Rabbit polyclonal antibodies anti-rTgOWP1-f evidence ability for specific identification of environmental T. gondii oocysts. We assume, rTgOWP1-f, as a possible biomarker of oocysts. In addition, we present findings supporting this vision, including the development of an immunodetection method for T. gondii oocysts identification.
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Affiliation(s)
- Susana Sousa
- Center for Parasite Biology and Immunology, National Institute of Health Dr Ricardo Jorge, Rua Alexandre Herculano 321, 4000-055, Porto, Portugal.
- Center for the Study of Animal Science (CECA)/Institute for Agricultural and Agro-Alimentary Science and Technology (ICETA), University of Porto, Porto, Portugal.
- LAQV, REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal.
| | - André Almeida
- Center for the Study of Animal Science (CECA)/Institute for Agricultural and Agro-Alimentary Science and Technology (ICETA), University of Porto, Porto, Portugal
| | - Lurdes Delgado
- Center for Parasite Biology and Immunology, National Institute of Health Dr Ricardo Jorge, Rua Alexandre Herculano 321, 4000-055, Porto, Portugal
| | | | - Cláudia Marques
- Center for Parasite Biology and Immunology, National Institute of Health Dr Ricardo Jorge, Rua Alexandre Herculano 321, 4000-055, Porto, Portugal
- Center for the Study of Animal Science (CECA)/Institute for Agricultural and Agro-Alimentary Science and Technology (ICETA), University of Porto, Porto, Portugal
| | - José Manuel Correia da Costa
- Center for Parasite Biology and Immunology, National Institute of Health Dr Ricardo Jorge, Rua Alexandre Herculano 321, 4000-055, Porto, Portugal
- Center for the Study of Animal Science (CECA)/Institute for Agricultural and Agro-Alimentary Science and Technology (ICETA), University of Porto, Porto, Portugal
| | - António Castro
- Center for Parasite Biology and Immunology, National Institute of Health Dr Ricardo Jorge, Rua Alexandre Herculano 321, 4000-055, Porto, Portugal
- Center for the Study of Animal Science (CECA)/Institute for Agricultural and Agro-Alimentary Science and Technology (ICETA), University of Porto, Porto, Portugal
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Freppel W, Ferguson DJ, Shapiro K, Dubey JP, Puech PH, Dumètre A. Structure, composition, and roles of the Toxoplasma gondii oocyst and sporocyst walls. Cell Surf 2019; 5:100016. [PMID: 32743133 PMCID: PMC7389338 DOI: 10.1016/j.tcsw.2018.100016] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 12/03/2018] [Accepted: 12/14/2018] [Indexed: 01/01/2023] Open
Abstract
Toxoplasma gondii is a coccidian parasite with the cat as its definitive host but any warm-blooded animal, including humans, may act as intermediate hosts. It has a worldwide distribution where it may cause acute and chronic toxoplasmosis. Infection can result from ingestion either of tissue cysts in infected meat of intermediate hosts or oocysts found in cat faeces via contaminated water or food. In this review, we highlight how the oocyst and sporocyst walls sustain the persistence and transmission of infective T. gondii parasites from terrestrial and aquatic environments to the host. We further discuss why targeting the oocyst wall structure and molecules may reduce the burden of foodborne and waterborne T. gondii infections.
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Gamma irradiation of Toxoplasma gondii protein extract improve immune response and protection in mice models. Biomed Pharmacother 2018; 106:599-604. [PMID: 29990848 DOI: 10.1016/j.biopha.2018.06.155] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 06/27/2018] [Accepted: 06/27/2018] [Indexed: 02/08/2023] Open
Abstract
Gamma radiation induces protein changes that enhance immunogenicity for venoms, used in antivenin production. Coccidian parasites exposed to gamma radiation elicit immune response with protection in mice and man, but without studies on the effect of gamma radiation in soluble acellular extracts or isolated proteins. Toxoplasmosis is a highly prevalent coccidian disease with only one vaccine for veterinary use but with remaining tissue cysts. Total parasite extracts or recombinant proteins used as immunogen induce usually low protection. Here, we study gamma radiation effect on T. gondii extracts proteins (STAG) and its induced immunity in experimental mice models. By SDS-PAGE, protein degradation is seen at high radiation doses, but at ideal dose (1500 Gy), there are preservation of the antigenicity and immunogenicity, detected by specific antibody recognition or production after mice immunization. Immunization with STAG irradiated at 1500 Gy induced significant protection in mice immunized and challenged with distinct T. gondii strains. In their blood, higher levels of specific CD19+, CD3+CD4+ and CD3+CD8+ activated cells were found when compared to mice immunized with STAG. Irradiated T. gondii tachyzoites extracts induce immune response and protection in mice in addition, could be a feasible alternative for Toxoplasma vaccine.
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