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Wen J, Zou J, Huang X, Wen H, Tselmeg, Suo X, Liu X. Identification of candidate antigens by 2-DE Immunoblotting for diagnosis of Toxoplasma gondii infection in chickens and rabbits. Exp Parasitol 2019; 204:107723. [PMID: 31299265 DOI: 10.1016/j.exppara.2019.107723] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 06/04/2019] [Accepted: 07/03/2019] [Indexed: 11/29/2022]
Abstract
Toxoplasmosis, caused by apicomplexan parasite Toxoplasma gondii, is a common food-borne disease in humans. Undercooked meat is a potential source of T. gondii infection. As meat of chicken or rabbit is consumed worldwide, tools such as ELISA for the detection of infection of this parasite in rabbits and chickens are much-needed. To search diagnostic antigens of T. gondii special for rabbits and chickens, we conducted two dimensional electrophoresis (2-DE), Western blotting and mass spectrometry (MS) with T. gondii tachyzoite proteins. When probed with rabbit or chicken anti-T. gondii sera, about 60 positive spots among over 500 visible protein spots were detected. In subsequent mass spectrometric analysis, microneme 4 (MIC4) and a putative rhoptry protein are of diagnositic value among the 13 spots selectively picked from the equivalent gel. This study encourages further validation of these candidate antigens for the development of immunologic tools for the detection of T. gondii infection in chickens and rabbits.
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Affiliation(s)
- Jing Wen
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture & National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China; Key Laboratory of Clinical Diagnosis and Treatment Techniques for Animal Disease, Ministry of Agriculture and College of Veterinary Medicine, Inner Mongolia Agricultural University, Huhhot, 010018, China.
| | - Jun Zou
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture & National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
| | - Xiaoxi Huang
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture & National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
| | - Hao Wen
- Inner Mongolia Yili Industrial Group Co.,Ltd, Information Technology Center, Huhhot, 010018, China
| | - Tselmeg
- College of Foreign Language, Inner Mongolia Agricultural University, Huhhot, 010018, China
| | - Xun Suo
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture & National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
| | - Xianyong Liu
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture & National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
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2
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Identification of antigenic proteins of Toxoplasma gondii RH strain recognized by human immunoglobulin G using immunoproteomics. J Proteomics 2012; 77:423-32. [PMID: 23026549 DOI: 10.1016/j.jprot.2012.09.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 09/12/2012] [Accepted: 09/16/2012] [Indexed: 11/21/2022]
Abstract
Toxoplasma gondii, a ubiquitous intracellular protozoan, infects one third of the world human population. It is of great medical significance, especially for pregnant women and immune-compromised patients. Accurate and early detection of T. gondii infection is crucial in the management of this disease. To obtain potential diagnostic markers, immunoproteomics was employed to identify immunodominant proteins separated by 2-D immunobloting and probed with sera collected from Toxoplasma-positive pregnant women. MALDI-TOF MS and MS/MS analyses identified a total of 18 immunoreactive proteins that were recognized by Toxoplasma-positive sera, whereas none was reactive with the negative-control sera from healthy, Toxoplasma-negative volunteers. Pregnant women showed a diverse immunoreactivity pattern with each serum recognizing one to eight identified tachyzoite proteins. The identified proteins were localized in the membrane, cytoplasm and specific organelles of T. gondii, and are involved in host cell invasion, metabolism and cell structure. Among these 18 proteins, actin, catalase, GAPDH, and three hypothetical proteins had a broad reactivity with Toxoplasma-positive sera, indicating their potential as diagnostic markers for toxoplasmosis. Each of several combinations of the identified proteins offered 100% detection of Toxoplasma infections of all 28 Toxoplasma-positive women. The study findings suggest that Toxoplasma tachyzoites are highly immunogenic and highlights the heterogeneity of host responses to Toxoplasma infection and the importance of using combinations of immunogens as diagnostic antigens. The findings have significant implications to the development of diagnostic reagents with high sensitivity and specificity.
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The Toxoplasma gondii peptide AS15 elicits CD4 T cells that can control parasite burden. Infect Immun 2012; 80:3279-88. [PMID: 22778097 DOI: 10.1128/iai.00425-12] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The apicomplexan parasite Toxoplasma gondii can cause severe disease in immunocompromised individuals. Previous studies in mice have focused largely on CD8(+) T cells, and the role of CD4 T cells is relatively unexplored. Here, we show that immunization of the C57BL/6 strain of mice, in which the immunodominant CD8 T cell response to the parasite dense-granule protein GRA6 cannot be generated, leads to a prominent CD4 T cell response. To identify the CD4 T cell-stimulating antigens, we generated a T. gondii-specific, lacZ-inducible, CD4 T cell hybridoma and used it as a probe to screen a T. gondii cDNA library. We isolated a cDNA encoding a protein of unknown function that we call CD4Ag28m and identified the minimal peptide, AS15, which was presented by major histocompatibility complex (MHC) class II molecules to the CD4 T cells. Immunization of mice with the AS15 peptide provided significant protection against subsequent parasite challenge, resulting in a lower parasite burden in the brain. Our findings identify the first CD4 T cell-stimulating peptide that can confer protection against toxoplasmosis and provide an important tool for the study of CD4 T cell responses and the design of effective vaccines against the parasite.
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Yeng C, Osman E, Mohamed Z, Noordin R. Detection of immunogenic parasite and host-specific proteins in the sera of active and chronic individuals infected with Toxoplasma gondii. Electrophoresis 2011; 31:3843-9. [PMID: 21080484 DOI: 10.1002/elps.201000038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Toxoplasma gondii infection in pregnant women may result in abortion and foetal abnormalities, and may be life-threatening in immunocompromised hosts. To identify the potential infection markers of this disease, 2-DE and Western blot methods were employed to study the parasite circulating antigens and host-specific proteins in the sera of T. gondii-infected individuals. The comparisons were made between serum protein profiles of infected (n=31) and normal (n=10) subjects. Antigenic proteins were identified by immunoblotting using pooled sera and monoclonal anti-human IgM-HRP. Selected protein spots were characterised using mass spectrometry. Prominent differences were observed when serum samples of T. gondii-infected individuals and normal controls were compared. A significant up-regulation of host-specific proteins, α(2)-HS glycoprotein and α(1)-B glycoprotein, was also observed in the silver-stained gels of both active and chronic infections. However, only α(2)-HS glycoprotein and α(1)-B glycoprotein in the active infection showed immunoreactivity in Western blots. In addition, three spots of T. gondii proteins were detected, namely (i) hypothetical protein chrXII: 3984434-3 TGME 49, (ii) dual specificity protein phosphatase, catalytic domain TGME 49 and (iii) NADPH-cytochrome p450 reductase TGME 49. Thus, 2-DE approach followed by Western blotting has enabled the identification of five potential infection markers for the diagnosis of toxoplasmosis: three are parasite-specific proteins and two are host-specific proteins.
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Affiliation(s)
- Chen Yeng
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Penang, Malaysia
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Dzitko K, Malicki S, Komorowski J. Effect of hyperprolactinaemia on Toxoplasma gondii prevalence in humans. Parasitol Res 2007; 102:723-9. [DOI: 10.1007/s00436-007-0824-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Accepted: 11/23/2007] [Indexed: 11/30/2022]
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6
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Gatkowska J, Hiszczynska-Sawicka E, Kur J, Holec L, Dlugonska H. Toxoplasma gondii: An evaluation of diagnostic value of recombinant antigens in a murine model. Exp Parasitol 2006; 114:220-7. [DOI: 10.1016/j.exppara.2006.03.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Revised: 03/15/2006] [Accepted: 03/25/2006] [Indexed: 11/16/2022]
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Brosson D, Kuhn L, Delbac F, Garin J, P Vivarès C, Texier C. Proteomic analysis of the eukaryotic parasite Encephalitozoon cuniculi (microsporidia): a reference map for proteins expressed in late sporogonial stages. Proteomics 2006; 6:3625-35. [PMID: 16691553 DOI: 10.1002/pmic.200500796] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The microsporidian Encephalitozoon cuniculi is a unicellular obligate intracellular parasite considered as an emerging opportunistic human pathogen. The differentiation phase of its life cycle leads to the formation of stress-resistant spores. The E. cuniculi genome (2.9 Mbp) having been sequenced, we undertook a descriptive proteomic study of a spore-rich cell population isolated from culture supernatants. A combination of 2-DE and 2-DE-free techniques was applied to whole-cell protein extracts. Protein identification was performed using an automated MALDI-TOF-MS platform and a nanoLC-MS/MS instrument. A reference 2-DE map of about 350 major spots with multiple isoforms was obtained, and for the first time in microsporidia, a large set of unique proteins (177) including proteins with unknown function in a proportion of 25.6% was identified. The data are mainly discussed with reference to secretion and spore structural features, energy and carbohydrate metabolism, cell cycle control and parasite survival in the environment.
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Affiliation(s)
- Damien Brosson
- Equipe Parasitologie Moléculaire et Cellulaire, LBP, UMR CNRS 6023, Université Blaise Pascal, Aubière, France
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Gubbels MJ, Striepen B, Shastri N, Turkoz M, Robey EA. Class I major histocompatibility complex presentation of antigens that escape from the parasitophorous vacuole of Toxoplasma gondii. Infect Immun 2005; 73:703-11. [PMID: 15664908 PMCID: PMC547086 DOI: 10.1128/iai.73.2.703-711.2005] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The intracellular parasite Toxoplasma gondii, the causative agent of toxoplasmosis, induces a protective CD8 T-cell response in its host; however, the mechanisms by which T. gondii proteins are presented by the class I major histocompatibility complex remain largely unexplored. T. gondii resides within a specialized compartment, the parasitophorous vacuole, that sequesters the parasite and its secreted proteins from the host cell cytoplasm, suggesting that an alternative cross-priming pathway might be necessary for class I presentation of T. gondii antigens. Here we used a strain of T. gondii expressing yellow fluorescent protein and a secreted version of the model antigen ovalbumin to investigate this question. We found that presentation of ovalbumin secreted by the parasite requires the peptide transporter TAP (transporter associated with antigen processing) and occurs primarily in actively infected cells rather than bystander cells. We also found that dendritic cells are a major target of T. gondii infection in vivo and account for much of the antigen-presenting activity in the spleen. Finally, we obtained evidence that Cre protein secreted by T. gondii can mediate recombination in the nucleus of the host cell. Together, these results indicate that Toxoplasma proteins can escape from the parasitophorous vacuole into the host cytoplasm and be presented by the endogenous class I pathway, leading to direct recognition of infected cells by CD8 T cells.
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Affiliation(s)
- Marc-Jan Gubbels
- Department of Molecular and Cell Biology, 471 Life Sciences Addition, University of California-Berkeley, Berkeley, CA 94720, USA
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Belli SI, Walker RA, Flowers SA. Global protein expression analysis in apicomplexan parasites: Current status. Proteomics 2005; 5:918-24. [PMID: 15759314 DOI: 10.1002/pmic.200401161] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Members of the phylum Apicomplexa are important protozoan parasites that cause some of the most serious, and in some cases, deadly diseases in humans and animals. They include species from the genus Plasmodium, Toxoplasma, Eimeria, Neospora, Cryptosporidium, Babesia and Theileria. The medical, veterinary and economic impact of these pathogens on a global scale is enormous. Although chemo- and immuno-prophylactic strategies are available to control some of these parasites, they are inadequate. Currently, there is an urgent need to design new vaccines or chemotherapeutics for apicomplexan diseases. High-throughput global protein expression analyses using gel or non-gel based protein separation technologies coupled with mass spectrometry and bioinformatics provide a means to identify new drug and vaccine targets in these pathogens. Protein identification based proteomic projects in apicomplexan parasites is currently underway, with the most significant progress made in the malaria parasite, Plasmodium falciparum. More recently, preliminary two-dimensional gel electrophoresis maps of Toxoplasma gondii and Neospora caninum tachyzoites and Eimeria tenella sporozoites, have been produced, as well as for micronemes in E. tenella. In this review, the status of proteomics in the analysis of global protein expression in apicomplexan parasites will be compared and the challenges associated with these investigations discussed.
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Affiliation(s)
- Sabina I Belli
- Institute for the Biotechnology of Infectious Diseases, University of Technology Sydney, Australia.
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Dabrowski S, Kiaer Ahring B. Cloning, expression, and purification of the His6-tagged hyper-thermostable dUTPase from Pyrococcus woesei in Escherichia coli: application in PCR. Protein Expr Purif 2003; 31:72-8. [PMID: 12963343 DOI: 10.1016/s1046-5928(03)00108-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The gene encoding dUTPase from Pyrococcus woesei was cloned into Escherichia coli expression system. It shows 100% gene identity to homologous gene in Pyrococcus furiosus. The expression of N-terminal His(6)-tagged Pwo dUTPase was performed in E. coli BL21(DE3)pLysS and E. coli Rosetta(DE3)pLysS strain that contains plasmid encoding additional copies of rare E. coli tRNAs. E. coli Rosetta(pLysS) strain was found with two times higher expression yield of His(6)-tagged Pwo dUTPase than E. coli BL21(DE3)pLysS. The His(6)-tagged Pwo dUTPase was purified on Ni(2+)-IDA-Sepharose, dialyzed, and the enzyme activity was investigated. We found that His(6)-tag domain has no influence on dUTP hydrolytic activity. dUTP is generated during PCR from dCTP, which inhibits the polymerization of DNA catalyzed by DNA polymerase with 3(')-5(') exonuclease activity. We observed that the thermostable His(6)-tagged Pwo dUTPase used for the polymerase chain reaction with P. woesei DNA polymerase improves the efficiency of PCR and it allows for amplification of longer targets.
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Affiliation(s)
- Sławomir Dabrowski
- The Environmental Microbiology and Biotechnology Research Group, BioCentrum, Søltofts Plads, Building 227, The Technical University of Denmark, DK-2800 Kgs., Lyngby, Denmark
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Gastens MH, Fischer HG. Toxoplasma gondii eukaryotic translation initiation factor 4A associated with tachyzoite virulence is down-regulated in the bradyzoite stage. Int J Parasitol 2002; 32:1225-34. [PMID: 12204222 DOI: 10.1016/s0020-7519(02)00096-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Comparative proteome analysis of mouse-virulent and attenuated Toxoplasma gondii strain revealed that steady-state synthesis of an unknown 53 kDa protein is markedly reduced in attenuated parasites. The results from protein microsequencing allowed isolation of a single-copy gene encoding a T. gondii homologue of eukaryotic translation initiation factor (eIF)4A. The deduced primary structure exhibits all sequence motifs typical of eIF4A. Differential expression of eIF4A between virulent and attenuated parasites was reconfirmed by immunoblot. Consistent with an involvement in the ribosomal preinitiation complex, the protein was localised in the tachyzoite extranuclear cytosol, being loosely associated with microsomal particles. Immunofluorescence detection of eIF4A in T. gondii stages of the intermediate host indicated that the protein is tachyzoite-specific. Stage-dependent expression is regulated at the transcriptional level as determined by reverse transcription-polymerase chain reaction and immunoblot. The down-regulation of eIF4A in attenuated T. gondii parasites and in the bradyzoite stage implies a role in tuning of the homeostasis of protein biosynthesis.
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Affiliation(s)
- Martin H Gastens
- Institute for Medical Microbiology and Virology, Heinrich-Heine-University, Universitätsstrasse 1, Geb. 22.21, D-40225 Düsseldorf, Germany
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Neudeck A, Stachelhaus S, Nischik N, Striepen B, Reichmann G, Fischer HG. Expression variance, biochemical and immunological properties of Toxoplasma gondii dense granule protein GRA7. Microbes Infect 2002; 4:581-90. [PMID: 12048027 DOI: 10.1016/s1286-4579(02)01576-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
During intracellular stay, Toxoplasma gondii secretes dense granule proteins (GRA) which remodel the parasitophorous vacuole and are considered functional in parasite-host interrelation. Comparative analysis of parasites from mouse-virulent strain BK and an in vitro attenuated variant revealed that the level of GRA7 expression correlates with T. gondii virulence: proteome analysis and quantitation by immunoblot demonstrated a massive decrease in GRA7 steady-state synthesis parallel to the loss of virulence. Properties of GRA7 that are pertinent to its membrane targeting and to GRA7-directed immune resistance were studied in detail. GRA7 is exclusively membrane-associated in both parasites and infected host cells as demonstrated by subcellular fractionations. Triton X-114 partitioning of isolated parasites substantiated that GRA7 is an integral membrane protein, the hydrophobic stretch from amino acid 181 to 202 providing a possible membrane anchor. A fraction enriched for membranous material from infected host cells contained additional forms of GRA7 with reduced mobility in gel electrophoresis, indicating that the protein is modified after exocytosis from the parasite. By flow cytometric analysis, GRA7 was detected on the surface of intact host cells. An intracellular origin of surface-associated GRA7 seems likely since GRA7 released from extracellular parasites failed to label the host cell surface. Consistent with a role at a parasite-host interface, GRA7 proved to be a target antigen of the intracerebral immune response as evidenced by the presence of GRA7-specific antibodies in mouse cerebrospinal fluid during chronic infection.
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Affiliation(s)
- Anja Neudeck
- Institute for Medical Microbiology and Virology, Heinrich-Heine-University, Universitätsstrasse 1 Geb. 22.21, 40225 Düsseldorf, Germany
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