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Li X, Yuan W, He T, Guo R, Du X, He Y, Li X, El-Ashram S, Al-Olayan EM, Yang N, Sang X. Boosting Mouse Defense against Lethal Toxoplasma gondii Infection with Full-Length and Soluble SAG1 Recombinant Protein. Vaccines (Basel) 2023; 11:1678. [PMID: 38006011 PMCID: PMC10675489 DOI: 10.3390/vaccines11111678] [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: 09/28/2023] [Revised: 10/23/2023] [Accepted: 10/31/2023] [Indexed: 11/26/2023] Open
Abstract
Toxoplasmosis is a major worldwide protozoan zoonosis. The surface antigen 1 (SAG1) of Toxoplasma gondii (T. gondii) has always been recognized as an ideal vaccine candidate antigen. However, the intact and soluble SAG1 protein is usually difficult to acquire in vitro, which is unfavorable for employing the recombinant protein as a vaccine candidate antigen. In the present study, we obtained the full-length SAG1 recombinant protein in soluble form by Escherichia coli Transetta (DE3) cells under optimized expression conditions. The immunogenicity and protective ability of this recombinant protein against T. gondii acute infection were evaluated in a mouse model. Monitoring changes in serum antibody levels and types, the presence of cytokines, and the rate of lymphocyte proliferation in vaccinated mice were used to assess humoral and cellular immune responses. Additional assessments were performed to determine the protective potency of the recombinant protein in combating T. gondii RH tachyzoites. It was found that the titers of both IgG2a and IgG2b were considerably greater in the immunized mice compared to the titers of IgG1 and IgG3. The levels of Th1-type cytokines (IFN-γ, IL-12p70, IL-2, and TNF-α) and Th2-type cytokines (IL-10) significantly increased when splenocytes from immunological group mice were treated with T. gondii lysate antigen. Compared to the control group, a recombinant protein substantially increased the longevity of infected mice, with an average death time prolonged by 14.50 ± 0.34 days (p < 0.0001). These findings suggest that the full-length and soluble SAG1 recombinant protein produced potent immune responses in mice and could be a preferred subunit vaccine candidate for T. gondii, offering a feasible option for vaccination against acute toxoplasmosis.
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Affiliation(s)
- Xiang Li
- Key Laboratory of Livestock Infectious Diseases, Shenyang Agricultural University, Ministry of Education, Shenyang 110866, China; (X.L.); (W.Y.); (T.H.); (R.G.); (X.D.); (Y.H.); (X.L.)
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang 110866, China
| | - Wei Yuan
- Key Laboratory of Livestock Infectious Diseases, Shenyang Agricultural University, Ministry of Education, Shenyang 110866, China; (X.L.); (W.Y.); (T.H.); (R.G.); (X.D.); (Y.H.); (X.L.)
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang 110866, China
| | - Ting He
- Key Laboratory of Livestock Infectious Diseases, Shenyang Agricultural University, Ministry of Education, Shenyang 110866, China; (X.L.); (W.Y.); (T.H.); (R.G.); (X.D.); (Y.H.); (X.L.)
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang 110866, China
| | - Ruiying Guo
- Key Laboratory of Livestock Infectious Diseases, Shenyang Agricultural University, Ministry of Education, Shenyang 110866, China; (X.L.); (W.Y.); (T.H.); (R.G.); (X.D.); (Y.H.); (X.L.)
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang 110866, China
| | - Xiuxian Du
- Key Laboratory of Livestock Infectious Diseases, Shenyang Agricultural University, Ministry of Education, Shenyang 110866, China; (X.L.); (W.Y.); (T.H.); (R.G.); (X.D.); (Y.H.); (X.L.)
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang 110866, China
| | - Yanhong He
- Key Laboratory of Livestock Infectious Diseases, Shenyang Agricultural University, Ministry of Education, Shenyang 110866, China; (X.L.); (W.Y.); (T.H.); (R.G.); (X.D.); (Y.H.); (X.L.)
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang 110866, China
| | - Xuan Li
- Key Laboratory of Livestock Infectious Diseases, Shenyang Agricultural University, Ministry of Education, Shenyang 110866, China; (X.L.); (W.Y.); (T.H.); (R.G.); (X.D.); (Y.H.); (X.L.)
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang 110866, China
| | - Saeed El-Ashram
- Zoology Department, Faculty of Science, Kafrelsheikh University, Kafr El-Sheikh 33516, Egypt;
| | - Ebtesam M. Al-Olayan
- Department of Zoology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia;
| | - Na Yang
- Key Laboratory of Livestock Infectious Diseases, Shenyang Agricultural University, Ministry of Education, Shenyang 110866, China; (X.L.); (W.Y.); (T.H.); (R.G.); (X.D.); (Y.H.); (X.L.)
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang 110866, China
| | - Xiaoyu Sang
- Key Laboratory of Livestock Infectious Diseases, Shenyang Agricultural University, Ministry of Education, Shenyang 110866, China; (X.L.); (W.Y.); (T.H.); (R.G.); (X.D.); (Y.H.); (X.L.)
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang 110866, China
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Sánchez-López EF, Corigliano MG, Oliferuk S, Ramos-Duarte VA, Rivera M, Mendoza-Morales LF, Angel SO, Sander VA, Clemente M. Oral Immunization With a Plant HSP90-SAG1 Fusion Protein Produced in Tobacco Elicits Strong Immune Responses and Reduces Cyst Number and Clinical Signs of Toxoplasmosis in Mice. FRONTIERS IN PLANT SCIENCE 2021; 12:726910. [PMID: 34675949 PMCID: PMC8525317 DOI: 10.3389/fpls.2021.726910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 08/30/2021] [Indexed: 05/17/2023]
Abstract
Plant 90kDa heat shock protein (HSP90) is a potent adjuvant that increases both humoral and cellular immune responses to diverse proteins and peptides. In this study, we explored whether Arabidopsis thaliana HSP90 (AtHsp81.2) can improve the immune effects of a Toxoplasma gondii surface antigen 1 (SAG1). We designed two constructs containing the sequence of mature antigen (SAG1m), from aa77 to aa322, and B- and T-cell antigenic epitope-containing SAG1HC, from aa221 to aa319 fused to AtHsp81.2 sequence. When comparing the transient expression in Nicotiana tabacum X-27-8 leaves, which overexpress the suppressor helper component protease HC-Pro-tobacco etch virus (TEV), to that in N. benthamiana leaves, co-agroinfiltrated with the suppressor p19, optimal conditions included 6-week-old N. benthamiana plants, 7-day time to harvest, Agrobacterium tumefaciens cultures with an OD600nm of 0.6 for binary vectors and LED lights. While AtHsp81.2-SAG1m fusion protein was undetectable by Western blot in any of the evaluated conditions, AtHsp81.2-SAG1HC was expressed as intact fusion protein, yielding up to 90μg/g of fresh weight. Besides, the AtHsp81.2-SAG1HC mRNA was strongly expressed compared to the endogenous Nicotiana tabacum elongation factor-alpha (NtEFα) gene, whereas the AtHsp81.2-SAG1m mRNA was almost undetectable. Finally, mice were orally immunized with AtHsp81.2-SAG1HC-infiltrated fresh leaves (plAtHsp81.2-SAG1HC group), recombinant AtHsp81.2-SAG1HC purified from infiltrated leaves (rAtHsp81.2-SAG1HC group), non-infiltrated fresh leaves (control group), or phosphate-buffered saline (PBS group). Serum samples from plAtHsp81.2-SAG1HC-immunized mice had significantly higher levels of IgGt, IgG2a, and IgG2b anti-SAG1HC antibodies than serum from rAtHsp81.2-SAG1HC, control, and PBS groups. The number of cysts per brain in the plAtHsp81.2-SAG1HC-immunized mice was significantly reduced, and the parasite load in brain tissue was also lower in this group compared with the remaining groups. In an immunoblot assay, plant-expressed AtHsp81.2-SAG1HC was shown to react with antibodies present in sera from T. gondii-infected people. Therefore, the plant expression of a T. gondii antigen fused to the non-pathogenic adjuvant and carrier plant HSP90 as formulations against T. gondii can improve the vaccine efficacy, and plant extract can be directly used for vaccination without the need to purify the protein, making this platform a suitable and powerful biotechnological system for immunogenic antigen expression against toxoplasmosis.
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Affiliation(s)
- Edwin F. Sánchez-López
- Laboratorio de Molecular Farming y Vacunas, Instituto Tecnológico Chascomús (INTECH), Universidad Nacional de General San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Chascomús, Argentina
| | - Mariana G. Corigliano
- Laboratorio de Molecular Farming y Vacunas, Instituto Tecnológico Chascomús (INTECH), Universidad Nacional de General San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Chascomús, Argentina
| | - Sonia Oliferuk
- Laboratorio de Molecular Farming y Vacunas, Instituto Tecnológico Chascomús (INTECH), Universidad Nacional de General San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Chascomús, Argentina
| | - Victor A. Ramos-Duarte
- Laboratorio de Molecular Farming y Vacunas, Instituto Tecnológico Chascomús (INTECH), Universidad Nacional de General San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Chascomús, Argentina
| | - Maximiliano Rivera
- Laboratorio de Parasitología Molecular, Instituto Tecnológico Chascomús (INTECH), Universidad Nacional de General San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Chascomús, Argentina
| | - Luisa F. Mendoza-Morales
- Laboratorio de Molecular Farming y Vacunas, Instituto Tecnológico Chascomús (INTECH), Universidad Nacional de General San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Chascomús, Argentina
| | - Sergio O. Angel
- Laboratorio de Parasitología Molecular, Instituto Tecnológico Chascomús (INTECH), Universidad Nacional de General San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Chascomús, Argentina
| | - Valeria A. Sander
- Laboratorio de Molecular Farming y Vacunas, Instituto Tecnológico Chascomús (INTECH), Universidad Nacional de General San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Chascomús, Argentina
| | - Marina Clemente
- Laboratorio de Molecular Farming y Vacunas, Instituto Tecnológico Chascomús (INTECH), Universidad Nacional de General San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Chascomús, Argentina
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Naghi Vishteh M, Javadi Mamaghani A, Rashidi S, Seyyed Tabaei SJ, Jeddi-Tehrani M. Peptide-Based Monoclonal Antibody Production Against SAG1 (P30) Protein of Toxoplasma gondii. Monoclon Antib Immunodiagn Immunother 2020; 39:51-56. [DOI: 10.1089/mab.2019.0041] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Mohadeseh Naghi Vishteh
- Monoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Tehran, Iran
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Amirreza Javadi Mamaghani
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Parasitology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sama Rashidi
- Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Seyyed Javad Seyyed Tabaei
- Department of Parasitology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahmood Jeddi-Tehrani
- Monoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Tehran, Iran
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Xicoténcatl-García L, Enriquez-Flores S, Correa D. Testing New Peptides From Toxoplasma gondii SAG1, GRA6, and GRA7 for Serotyping: Better Definition Using GRA6 in Mother/Newborns Pairs With Risk of Congenital Transmission in Mexico. Front Cell Infect Microbiol 2019; 9:368. [PMID: 31709197 PMCID: PMC6819317 DOI: 10.3389/fcimb.2019.00368] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 10/09/2019] [Indexed: 01/23/2023] Open
Abstract
Toxoplasma gondii variant influences clinical profile in human congenital and ocular toxoplasmosis. Parasite genotyping represents a challenge due to insufficient amount of genetic material of the protozoan in the host samples, and isolates are hard to obtain, especially from pediatric patients. An alternative is serotyping, which is based on the presence of specific antibodies against polymorphic proteins related to virulence; the more widely used are GRA6 and GRA7, but most works report cross reactions among the classical strains (I, II, and III). We designed new peptides of GRA6, GRA7, and SAG1 proteins, with more SNPs among the three clonal strains than those previously designed. This was done by identifying BcR and polymorphic epitopes by means of bioinformatics; then we designed peptides with linkers joining the specific regions and predicted their 3D structure. With the commercial molecules synthesized on the basis of these designs, we tested 86 serum samples from 42 mother/newborn pairs and two congenitally infected newborns, by indirect ELISA. We implemented a strategy to determine the serotype based on scatter plots and a mathematical formula, using ratios among reactivity indexes to peptides. We found low frequency of samples reactive to GRA7 and SAG1, and cross reactions between GRA6 serotypes I and III; we modified these later peptides and largely improved distinction among the three clonal strains. The chronicity of the infection negatively affected the reactivity index against the peptides. Serotyping both members of the mother/child pair improves the test, i.e., among 26% of them only one member was positive. Serotype I was the most frequent (38%), which was congruent with previous genotyping results in animals and humans of the same area. This serotype was significantly more frequent among mothers who transmitted the infection to their offspring than among those who did not (53 vs. 8%, p = 0.04) and related to disease dissemination in congenitally infected children, although non-significantly. In conclusion, serotyping using the improved GRA6 peptide triad is useful to serotype T. gondii in humans and could be implemented for clinical management and epidemiological studies, to provide information on the parasite type in specific areas.
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Affiliation(s)
- Lizbeth Xicoténcatl-García
- Laboratorio de Inmunología Experimental, Instituto Nacional de Pediatría, Secretaría de Salud, Mexico City, Mexico
| | - Sergio Enriquez-Flores
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Instituto Nacional de Pediatría, Secretaría de Salud, Mexico City, Mexico
| | - Dolores Correa
- Laboratorio de Inmunología Experimental, Instituto Nacional de Pediatría, Secretaría de Salud, Mexico City, Mexico
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Guo J, Zhou A, Sun X, Sha W, Ai K, Pan G, Zhou C, Zhou H, Cong H, He S. Immunogenicity of a Virus-Like-Particle Vaccine Containing Multiple Antigenic Epitopes of Toxoplasma gondii Against Acute and Chronic Toxoplasmosis in Mice. Front Immunol 2019; 10:592. [PMID: 30984177 PMCID: PMC6449433 DOI: 10.3389/fimmu.2019.00592] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 03/05/2019] [Indexed: 12/12/2022] Open
Abstract
There is no effective protective vaccine against human toxoplasmosis, which is a potential threat to nearly a third of the world population. Vaccines based on virus-like particles (VLPs) have been highly successful in humans for many years, but have rarely been applied against Toxoplasma gondii infection. In this study, we inserted a B cell epitope (SAG182−102 or SAG1301−320), a CD8+ cell epitope (HF10 or ROP7), and a CD4+ cell epitope (AS15) of T. gondii into a truncated HBcΔ(amino acids1–149) particle to construct four chimeric VLP vaccine formulations, i.e., HBcΔH82, HBcΔH301, HBcΔ R82, and HBcΔ R301. When these chimeric HBc particles were expressed in Escherichia coli, they showed icosahedral morphology similar to that of the original VLPs and were evaluated as vaccine formulations against acute and chronic toxoplasmosis in a mouse model (BALB/c mice (H-2d). All these chimeric HBc VLPs induced strong humoral and cellular immune responses with high IgG antibody titers and interferon(IFN)-γ production. Only the mice immunized with HBcΔH82 showed prolonged survival time (15.6 ± 3.8 vs. 5.6 ± 0.8 days) against acute infection with RH tachyzoites and decrease in brain parasite load (1,454 ± 239 vs. 2,091 ± 263) against chronic infection with Prugniuad cysts, as compared to the findings for the control group. These findings suggest that HBc VLPs would act as an effective carrier for delivering effective multiple antigenic epitopes and would be beneficial for developing a safe and long-acting vaccine against toxoplasmosis.
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Affiliation(s)
- Jingjing Guo
- Department of Parasitology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Aihua Zhou
- Department of Pediatrics, Provincial Hospital Affiliated to Shandong University, School of Medicine, Shandong University, Jinan, China
| | - Xiahui Sun
- Department of Parasitology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Wenchao Sha
- Department of Parasitology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Kang Ai
- Department of Parasitology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Ge Pan
- Department of Parasitology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Chunxue Zhou
- Department of Parasitology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Huaiyu Zhou
- Department of Parasitology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Hua Cong
- Department of Parasitology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Shenyi He
- Department of Parasitology, School of Basic Medical Sciences, Shandong University, Jinan, China
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Sánchez-López EF, Corigliano MG, Albarracín RM, Sander VA, Legarralde A, Bengoa-Luoni SA, Clemente M. Plant Hsp90 is a novel adjuvant that elicits a strong humoral and cellular immune response against B- and T-cell epitopes of a Toxoplasma gondii SAG1 peptide. Parasit Vectors 2019; 12:140. [PMID: 30909938 PMCID: PMC6434815 DOI: 10.1186/s13071-019-3362-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 02/26/2019] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The 90-kDa heat-shock protein (Hsp90) from Nicotiana benthamiana (NbHsp90.3) is a promising adjuvant, especially for those vaccines that require a T cell-mediated immune response. Toxoplasma gondii SAG1 is considered one of the most important antigens for the development of effective subunit vaccines. Some epitopes located in the SAG1 C-terminus region have showed a strong humoral and cellular immune response. In the present study, we aimed to assess the efficacy of NbHsp90.3 as carrier/adjuvant of SAG1-derived peptide (SAG1HC) in a T. gondii infection murine model. METHODS In the present study, C57BL/6 mice were intraperitoneal immunized with the NbHsp90.3-SAG1HC fusion protein (NbHsp90.3-SAG1HC group), mature SAG1 (SAG1m group), NbHsp90.3 (NbHsp90.3 group) or PBS buffer 1× (PBS group). The levels of IgG antibodies and the cytokine profile were determined by ELISA. Two weeks after the last immunization, all mice were orally challenged with 20 cysts of T. gondii Me49 strain and the number of brain cysts was determined. In addition, both humoral and cellular immune responses were also evaluated during the acute and chronic phase of T. gondii infection by ELISA. RESULTS The characterization of the immune response generated after vaccination with NbHsp90.3 as an adjuvant showed that NbHsp90.3-SAG1HC-immunized mice produced antibodies that were able to recognize not only rSAG1m but also the native SAG1 present in the total lysate antigen extract (SAG1TLA) from T. gondii tachyzoites, while control groups did not. Furthermore, anti-rSAG1m IgG2a/2b antibodies were significantly induced. In addition, only the spleen cell cultures from NbHsp90.3-SAG1HC-immunized mice showed a significantly increased production of IFN-γ. During the chronic phase of T. gondii infection, the antibodies generated by the infection were unable to detect the recombinant protein, but they did react with TLA extract. In addition, splenocytes from all groups showed a high production of IFN-γ when stimulated with rGRA4, but only those from NbHsp90.3-SAG1HC group stimulated with rSAG1m showed high production of IFN-γ. Finally, NbHsp90.3-SAG1HC-immunized mice exhibited a significant reduction in the cyst load (56%) against T. gondii infection. CONCLUSIONS We demonstrated that NbHsp90.3 enhances the humoral and cell-mediated immune response through a Th1 type cytokine production. Mice vaccinated with NbHsp90.3-SAG1HC exhibited a partial protection against T. gondii infection and it was correlated with the induction of memory immune response. We developed and validated a vaccine formulation which, to our knowledge, for the first time includes the NbHsp90.3 protein covalently fused to a peptide from T. gondii SAG1 protein that contains T- and B-cell epitopes.
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Affiliation(s)
- Edwin F. Sánchez-López
- Unidad de Biotecnología 6-UB6, IIB-INTECH, CONICET-UNSAM, Intendente Marino Km 8.2, B7130IWA Chascomús, Buenos Aires Province Argentina
| | - Mariana G. Corigliano
- Unidad de Biotecnología 6-UB6, IIB-INTECH, CONICET-UNSAM, Intendente Marino Km 8.2, B7130IWA Chascomús, Buenos Aires Province Argentina
| | - Romina M. Albarracín
- Unidad de Biotecnología 6-UB6, IIB-INTECH, CONICET-UNSAM, Intendente Marino Km 8.2, B7130IWA Chascomús, Buenos Aires Province Argentina
| | - Valeria A. Sander
- Unidad de Biotecnología 6-UB6, IIB-INTECH, CONICET-UNSAM, Intendente Marino Km 8.2, B7130IWA Chascomús, Buenos Aires Province Argentina
| | - Ariel Legarralde
- Unidad de Biotecnología 6-UB6, IIB-INTECH, CONICET-UNSAM, Intendente Marino Km 8.2, B7130IWA Chascomús, Buenos Aires Province Argentina
| | - Sofía A. Bengoa-Luoni
- Unidad de Biotecnología 6-UB6, IIB-INTECH, CONICET-UNSAM, Intendente Marino Km 8.2, B7130IWA Chascomús, Buenos Aires Province Argentina
| | - Marina Clemente
- Unidad de Biotecnología 6-UB6, IIB-INTECH, CONICET-UNSAM, Intendente Marino Km 8.2, B7130IWA Chascomús, Buenos Aires Province Argentina
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Wang Y, Wang G, Cai JP. Identifying Novel B Cell Epitopes within Toxoplasma gondii GRA6. THE KOREAN JOURNAL OF PARASITOLOGY 2016; 54:431-7. [PMID: 27658594 PMCID: PMC5040083 DOI: 10.3347/kjp.2016.54.4.431] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 10/21/2015] [Accepted: 11/26/2015] [Indexed: 01/18/2023]
Abstract
The study of antigenic epitopes from Toxoplasma gondii has not only enhanced our understanding of the structure and function of antigens, the reactions between antigens and antibodies, and many other aspects of immunology, but it also plays a significant role in the development of new diagnostic reagents and vaccines. In the present study, T. gondii GRA6 epitopes were identified using bioinformatics tools and a synthetic peptide technique. The potential B cell epitopes of GRA6 predicted by bioinformatics tools concentrated upon 3 regions of GRA6, 1-20 aa, 44-103 aa, and 172-221 aa. Ten shorter peptides from the 3 regions were synthesized and assessed by ELISA using pig sera from different time points after infection. Three of the 10 peptides (amino acids 44-63, 172-191, and 192-211) tested were recognized by all sera and determined to be immunodominant B-cell epitopes of GRA6. The results indicated that we precisely and accurately located the T. gondii GRA6 epitopes using pig sera collected at different time points after infection. The identified epitopes may be very useful for further studies of epitope-based vaccines and diagnostic reagents.
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Affiliation(s)
- Yanhua Wang
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China
| | - Guangxiang Wang
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China
| | - Jian Ping Cai
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China
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Review on the identification and role of Toxoplasma gondii antigenic epitopes. Parasitol Res 2015; 115:459-68. [PMID: 26581372 DOI: 10.1007/s00436-015-4824-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 11/10/2015] [Indexed: 12/12/2022]
Abstract
Toxoplasma gondii is an obligate intracellular protozoan parasite with a broad range of hosts, and it causes severe toxoplasmasis in both humans and animals. It is well known that the progression and severity of a disease depend on the immunological status of the host. Immunological studies on antigens indicate that antigens do not exert their functions through the entire protein molecule, but instead, specific epitopes are responsible for the immune response. Protein antigens not only contain epitope structures used by B, T, cytotoxic T lymphocyte (CTL), and NK cells to mediate immunological responses but can also contain structures that are unfavorable for protective immunity. Therefore, the study of antigenic epitopes from T. gondii has not only enhanced our understanding of the structure and function of antigens, the reactions between antigens and antibodies, and many other aspects of immunology but it also plays a significant role in the development of new diagnostic reagents and vaccines. In this review, we summarized the immune mechanisms induced by antigen epitopes and the latest advances in identifying T. gondii antigen epitopes. Particular attention was paid to the potential clinical usefulness of epitopes in this context. Through a critical analysis of the current state of knowledge, we elucidated the latest data concerning the biological effects of epitopes and the immune results aimed at the development of future epitope-based applications, such as vaccines and diagnostic reagents.
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Hegazy S, Farid A, Rabae I, El-Amir A. Novel IMB-ELISA Assay for Rapid Diagnosis of Human Toxoplasmosis Using SAG1 Antigen. Jpn J Infect Dis 2015; 68:474-80. [DOI: 10.7883/yoken.jjid.2014.444] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
| | - Alyaa Farid
- Zoology Department, Science Faculty, Cairo University
| | | | - Azza El-Amir
- Zoology Department, Science Faculty, Cairo University
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Goodswen SJ, Kennedy PJ, Ellis JT. Enhancing in silico protein-based vaccine discovery for eukaryotic pathogens using predicted peptide-MHC binding and peptide conservation scores. PLoS One 2014; 9:e115745. [PMID: 25545691 PMCID: PMC4278717 DOI: 10.1371/journal.pone.0115745] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 11/26/2014] [Indexed: 11/19/2022] Open
Abstract
Given thousands of proteins constituting a eukaryotic pathogen, the principal objective for a high-throughput in silico vaccine discovery pipeline is to select those proteins worthy of laboratory validation. Accurate prediction of T-cell epitopes on protein antigens is one crucial piece of evidence that would aid in this selection. Prediction of peptides recognised by T-cell receptors have to date proved to be of insufficient accuracy. The in silico approach is consequently reliant on an indirect method, which involves the prediction of peptides binding to major histocompatibility complex (MHC) molecules. There is no guarantee nevertheless that predicted peptide-MHC complexes will be presented by antigen-presenting cells and/or recognised by cognate T-cell receptors. The aim of this study was to determine if predicted peptide-MHC binding scores could provide contributing evidence to establish a protein's potential as a vaccine. Using T-Cell MHC class I binding prediction tools provided by the Immune Epitope Database and Analysis Resource, peptide binding affinity to 76 common MHC I alleles were predicted for 160 Toxoplasma gondii proteins: 75 taken from published studies represented proteins known or expected to induce T-cell immune responses and 85 considered less likely vaccine candidates. The results show there is no universal set of rules that can be applied directly to binding scores to distinguish a vaccine from a non-vaccine candidate. We present, however, two proposed strategies exploiting binding scores that provide supporting evidence that a protein is likely to induce a T-cell immune response-one using random forest (a machine learning algorithm) with a 72% sensitivity and 82.4% specificity and the other, using amino acid conservation scores with a 74.6% sensitivity and 70.5% specificity when applied to the 160 benchmark proteins. More importantly, the binding score strategies are valuable evidence contributors to the overall in silico vaccine discovery pool of evidence.
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Affiliation(s)
- Stephen J. Goodswen
- School of Medical and Molecular Sciences, University of Technology Sydney (UTS), Ultimo, NSW, Australia
| | - Paul J. Kennedy
- School of Software, Faculty of Engineering and Information Technology and the Centre for Quantum Computation and Intelligent Systems at the University of Technology Sydney (UTS), Ultimo, NSW, Australia
| | - John T. Ellis
- School of Medical and Molecular Sciences, University of Technology Sydney (UTS), Ultimo, NSW, Australia
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11
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Wang Y, Wang G, Ou J, Yin H, Zhang D. Analyzing and identifying novel B cell epitopes within Toxoplasma gondii GRA4. Parasit Vectors 2014; 7:474. [PMID: 25301141 PMCID: PMC4195951 DOI: 10.1186/s13071-014-0474-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 10/03/2014] [Indexed: 12/14/2022] Open
Abstract
Background The identification of specific epitopes targeted by the host antibody response is important for understanding the natural response to infection and for the development of epitope-based marker vaccines and diagnostic tools for toxoplasmosis. In this study, Toxoplasma gondii GRA4 epitopes were identified using software-based prediction and a synthetic peptide technique. Methods The complete GRA4 gene sequence was obtained from T. gondii of the Gansu Jingtai strain of tachyzoites. The potential B cell epitopes of GRA4 was predicted using the PROTEAN subroutine in the DNASTAR software package. The peptides with good hydrophilicity, high accessibility, high flexibility and strong antigenicity were chemically synthesized and assessed by ELISA using pig sera from different time points after infection. Results The potential B cell epitopes of GRA4 predicted by bioinformatics tools focused on six regions of GRA4, 52–77 aa, 93–112 aa, 127–157 aa, 178–201 aa, 223–252 aa and 314–333 aa. Eleven shorter peptides from the six regions were synthesized and assessed by ELISA using pig sera from different time points after infection. Three of the eleven peptides (amino acids 62–77, 233–252 and 314–333) tested were recognized by all sera. Conclusions We precisely located the T. gondii GRA4 epitopes using pig sera collected at different time points after infection. The identified epitopes may be useful for additional studies of epitope-based vaccines and diagnostic reagents.
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Affiliation(s)
- Yanhua Wang
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China.
| | - Guangxiang Wang
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China.
| | - Jiangtao Ou
- School of Chemical and Biological Engineering, Yancheng Institute of Technology, 9 Yingbin Road, Yancheng, 224051, China.
| | - Hong Yin
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China.
| | - Delin Zhang
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China.
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12
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Research progress on surface antigen 1 (SAG1) of Toxoplasma gondii. Parasit Vectors 2014; 7:180. [PMID: 24726014 PMCID: PMC3989796 DOI: 10.1186/1756-3305-7-180] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 04/04/2014] [Indexed: 11/20/2022] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasitic protozoan that has a wide host range and causes a zoonotic parasitosis called toxoplasmosis. This infection causes significant morbidity, costs for care and loss of productivity and suffering. The most effective measures to minimize this parasite’s harm to patients are prompt diagnosis and treatment and preventing infection. A parasite surface antigen, SAG1, is considered an important antigen for the development of effective diagnostic tests or subunit vaccines. This review covers several aspects of this antigen, including its gene structure, contribution to host invasion, mechanisms of the immune responses and its applications for diagnosis and vaccine development. This significant progress on this antigen provides foundations for further development of more effective and precise approaches to diagnose toxoplasmosis in the clinic, and also have important implications for exploring novel measures to control toxoplasmosis in the near future.
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Kur J, Holec-Gąsior L, Hiszczyńska-Sawicka E. Current status of toxoplasmosis vaccine development. Expert Rev Vaccines 2014; 8:791-808. [DOI: 10.1586/erv.09.27] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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14
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Wang Y, Wang G, Zhang D, Yin H, Wang M. Identification of novel B cell epitopes within Toxoplasma gondii GRA1. Exp Parasitol 2013; 135:606-10. [PMID: 24090568 DOI: 10.1016/j.exppara.2013.09.019] [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: 07/02/2013] [Revised: 09/18/2013] [Accepted: 09/22/2013] [Indexed: 11/28/2022]
Abstract
Newly synthesized epitopes are one of the most promising antigens for the development of diagnostic kits and peptide vaccines. Very little is known about the B cell epitopes on GRA1 of Toxoplasma gondii, which are recognized by the humoral immune response in pigs. In this study, epitopes derived from GRA1 of T. gondii were identified using synthetic peptide techniques and bioinformatics. Three (PG10, PG13 and PG18) out of the eighteen peptides tested were recognized by all pig sera from different time points after infection, and the other peptides were recognized by select sera from various time points after infection. Our data indicate that many regions of GRA1, and in particular, the regions represented by the peptides PG10, PG13 and PG18, are involved in the pig antibody response. The identification of specific epitopes targeted by the host antibody response is important both for understanding the natural response to infection and for the development of epitope-based marker vaccines and diagnostic tools for toxoplasmosis.
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Affiliation(s)
- Yanhua Wang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Key Laboratory of Veterinary Public Health of the Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China.
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15
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Immunization with excreted–secreted antigens reduces tissue cyst formation in pigs. Parasitol Res 2013; 112:3835-42. [DOI: 10.1007/s00436-013-3571-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 08/01/2013] [Indexed: 01/02/2023]
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16
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Toxoplasma gondii: the vaccine potential of three trivalent antigen-cocktails composed of recombinant ROP2, ROP4, GRA4 and SAG1 proteins against chronic toxoplasmosis in BALB/c mice. Exp Parasitol 2012; 131:133-8. [PMID: 22445587 DOI: 10.1016/j.exppara.2012.02.026] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Revised: 02/26/2012] [Accepted: 02/27/2012] [Indexed: 01/18/2023]
Abstract
Toxoplasmosis is one of the world's most widespread zoonoses caused by protozoan parasite Toxoplasma gondii. The development of an effective vaccine for controlling toxoplasmosis is an extremely important issue due to the serious clinical and veterinary outcomes of this parasitosis. The objective of this study was evaluation of vaccine potential of three trivalent subunit recombinant vaccines composed of rROP2+rGRA4+rSAG1, rROP2+rROP4+rGRA4 and rROP2+rROP4+rSAG1 against chronic toxoplasmosis in BALB/c (H-2(d)) mice. All tested vaccines provided a partial protection against challenge with tissue cysts of the low virulence DX T. gondii strain, but the strongest level of protection was induced by the mixtures of both rhoptry proteins (rROP2 and rROP4) administered with the dense granule rGRA4 antigen or the main surface rSAG1 protein. The average parasite burden in these groups of vaccinated BALB/c mice was reduced by 84% and 77%, respectively, compared to the control PBS-injected animals. The vaccine-induced protection was correlated with the development of cellular and humoral immune responses demonstrated by the antigen-specific in vitro proliferation of spleen cells, the specific antigen-induced in vitro synthesis of Th1-type cytokines, IFN-γ and IL-2, and the generation of the high titers of systemic antigen-specific IgG1 and IgG2a antibodies. This study completed and confirmed our earlier investigations in C3H/HeJ (H-2(k)) and C57BL/6 (H-2(b)) mouse strains on the utility of the tested trivalent recombinant antigen-cocktails as potential vaccines against chronic toxoplasmosis and showed that particularly rROP2+rROP4+rGRA4 and rROP2+rROP4+rSAG1 protein-combinations are very effective in the development of a high level of protection irrespective of the genetic backgrounds and innate resistance to toxoplasmosis of the laboratory mice. It makes these two mixtures of recombinant antigens very promising for further experiments.
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17
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Zhou H, Min J, Zhao Q, Gu Q, Cong H, Li Y, He S. Protective immune response against Toxoplasma gondii elicited by a recombinant DNA vaccine with a novel genetic adjuvant. Vaccine 2012; 30:1800-6. [PMID: 22240340 DOI: 10.1016/j.vaccine.2012.01.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 12/05/2011] [Accepted: 01/02/2012] [Indexed: 12/11/2022]
Abstract
Previous immunological studies from our laboratory have demonstrated the potential role of Toxoplasma gondii antigens SAG1 and GRA2 as vaccine candidates. To further evaluate the vaccine's effects, a series of recombinant DNA vaccines pVAX1-SAG1, pVAX1-GRA2 and pVAX1-SAG1-GRA2, termed pSAG1, pGRA2 and pSAG1-GRA2, respectively, were constructed. A plasmid pVAX1-S/PreS2, termed pSPreS2 encoding hepatitis B virus (HBV) surface antigen (HBsAg) S and PreS2 as a novel genetic adjuvant, was also constructed. The expression abilities of those DNA plasmids were examined in HFF cells by Western blotting. Then BALB/c mice were intramuscularly immunized with DNA plasmids and followed by challenging with the highly virulent T. gondii RH strain. The results demonstrated that the recombinant DNA vaccine pSAG1-GRA2 was capable of eliciting high levels of antibodies, a Th1 type of immune response with significant production of IFN-γ and low levels of IL-4 or IL-10 in BALB/c mice, and partial protection against the acute phase of toxoplasmosis as compared to pSAG1, pGRA2 and controls. In addition, the adjuvant pSPreS2 formulated with DNA vaccine induced a Th1 type of immune response and therefore might be a novel genetic adjuvant to DNA vaccine for further investigation.
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Affiliation(s)
- Huaiyu Zhou
- Department of Parasitology, Shandong University School of Medicine, Jinan, Shandong, PR China.
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18
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Cardona N, de-la-Torre A, Siachoque H, Patarroyo MA, Gomez-Marin JE. Toxoplasma gondii: P30 peptides recognition pattern in human toxoplasmosis. Exp Parasitol 2009; 123:199-202. [PMID: 19567250 DOI: 10.1016/j.exppara.2009.06.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 06/20/2009] [Accepted: 06/23/2009] [Indexed: 11/30/2022]
Abstract
In this study, human sera reactivity against nine peptides derived from the Toxoplasma gondii P30 protein was assessed by ELISA in patients with different clinical forms of toxoplasmosis. Same as has been reported in mice, sera from congenital, ocular and chronic asymptomatic toxoplasmosis patients recognized more strongly peptides from the protein's carboxy-terminus, being peptide 2017 (amino acids 301-320) the one most strongly recognized by sera from patients with ocular toxoplasmosis. Serum samples collected from 13 patients without ocular infection, 13 with inactive chorioretinal scars, 6 with active ocular infection and 10 seronegative individuals were then screened for anti-2017 IgG. Peptide 2017 was recognized by all patients' samples but not by sera from T. gondii-seronegative individuals. No statistically significant differences were found between the absorbance levels of groups with and without lesions or with active or inactive ocular lesions, as determined by ANOVA.
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Affiliation(s)
- Nestor Cardona
- Centro de Investigaciones Biomedicas, Universidad del Quindio, Armenia, Colombia
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19
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Liu S, Shi L, Cheng YB, Fan GX, Ren HX, Yuan YK. Evaluation of protective effect of multi-epitope DNA vaccine encoding six antigen segments of Toxoplasma gondii in mice. Parasitol Res 2009; 105:267-74. [PMID: 19288132 DOI: 10.1007/s00436-009-1393-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Accepted: 03/03/2009] [Indexed: 11/28/2022]
Abstract
To investigate the vaccine potential of multi-epitope vaccines against toxoplasmosis, a multi-epitope DNA vaccine, eukaryotic plasmid pcDNA3.1/T-ME expressing six antigen segments (SAG1(238-256), SAG1(281-320), GRA1(170-193), GRA4(331-345), GRA4(229-245), and GRA2(171-185)) of Toxoplasma gondii was constructed. We investigated the efficacy of pcDNA3.1/T-ME with or without co-administration of a CpG-oligodeoxynucleotide (CpG-ODN) as an adjuvant to protect mice (BALB/c and C57BL/6) against toxoplasmosis. High survival rates were observed in mice immunized with pcDNA3.1/T-ME when challenged with T. gondii RH strain. Lymphocyte proliferation assays, cytokine, and antibody determinations show that mice immunized with pcDNA3.1/T-ME produced stronger humoral and Th1-type cellular immune responses compared to untreated mice or those immunized with empty plasmids. However, co-immunization with CpG-ODN resulted in impaired immune responses. Our data demonstrates that multi-epitope DNA vaccination is a potential strategy for the control of toxoplasmosis and paves the way for further investigations into producing a multi-epitope anti-T. gondii DNA vaccine.
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Affiliation(s)
- Shan Liu
- Department of Immunology and Microbiology, Xi'an Jiaotong University, China
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20
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Chang HT, Liu CH, Pai TW. Estimation and extraction of B-cell linear epitopes predicted by mathematical morphology approaches. J Mol Recognit 2009; 21:431-41. [PMID: 18680207 DOI: 10.1002/jmr.910] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
B-cell epitope prediction facilitates the design and synthesis of short peptides for various immunological applications. Several algorithms have been developed to predict B-cell linear epitopes (LEs) from primary sequences of antigens, providing important information for immunobiological experiments and antibody design. This paper describes two robust methods, LE prediction with/without local peak extraction (LEP-LP and LEP-NLP), based on antigenicity scale and mathematical morphology for the prediction of B-cell LEs. Previous studies revealed that LEs could occur in regions with low-to-moderate but not globally high antigenicity scales. Hence, we developed a method adopting mathematical morphology to extract local peaks from a linear combination of the propensity scales of physico-chemical characteristics at each antigen residue. Comparison among LEP-LP/LEP-NLP, BepiPred and BEPITOPE revealed that our algorithms performed better in retrieving epitopes with low-to-moderate antigenicity and achieved comparable performance according to receiver operation characteristics (ROC) curve analysis. Of the identified LEs, over 30% were unable to be predicted by BepiPred and BEPITOPE employing an average threshold of antigenicity index or default settings. Our LEP-LP method provides a bioinformatics approach for predicting B-cell LEs with low- to-moderate antigenicity. The web-based server was established at http://biotools.cs.ntou.edu.tw/lepd_antigenicity. php for free use.
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Affiliation(s)
- Hao-Teng Chang
- Graduate Institute of Molecular Systems Biomedicine, China Medical University, Taichung, Taiwan, ROC
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21
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Cong H, Gu QM, Yin HE, Wang JW, Zhao QL, Zhou HY, Li Y, Zhang JQ. Multi-epitope DNA vaccine linked to the A2/B subunit of cholera toxin protect mice against Toxoplasma gondii. Vaccine 2008; 26:3913-21. [DOI: 10.1016/j.vaccine.2008.04.046] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 04/04/2008] [Accepted: 04/22/2008] [Indexed: 01/11/2023]
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22
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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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23
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Hartati S, Kusumawati A, Wuryastuti H, Widada JS. Primary structure of mature SAG1 gene of an Indonesian Toxoplasma gondii and comparison with other strains. J Vet Sci 2006; 7:263-70. [PMID: 16871021 PMCID: PMC3242126 DOI: 10.4142/jvs.2006.7.3.263] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Toxoplasma gondii is a persistent protozoan parasite capable of infecting almost any warm-blooded vertebrates. SAG1 (p30) is the prototypic member of a superfamily of surface antigens called SRS (SAG1-related sequence). It constitutes the most abundant and predominant antigen. In this paper the primary structure of mature SAG1 gene of an Indonesian T. gondii isolate is described and sequence comparison is made with published sequence data of 7 other strains or isolates. Sequence comparison indicated that SAG1 is highly conserved through evolution and despite parasite spreading world-wide. Sequences may be divided into two major families, independent of the strain/isolate geographic origin. Variations were mainly localized at the C-terminal half or domain 2 and some clustered in restricted areas. Sequence comparison allowed us to define the Indonesian isolate as genuine virulent RH strain. A phylogenetic tree of Toxoplasma strains/isolates was constructed based on SAG1.
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Affiliation(s)
- Sri Hartati
- Department of Internal Medicine, Gadjah Mada University, Yogyakarta, 55281, Indonesia
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24
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Zhou H, Gu Q, Zhao Q, Zhang J, Cong H, Li Y, He S. Toxoplasma gondii: expression and characterization of a recombinant protein containing SAG1 and GRA2 in Pichia pastoris. Parasitol Res 2006; 100:829-35. [PMID: 17058109 DOI: 10.1007/s00436-006-0341-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Accepted: 09/08/2006] [Indexed: 10/24/2022]
Abstract
Toxoplasma gondii is an obligate intracellular protozoan which infects most species of warm-blooded animals and causes toxoplasmosis. Previous immunological and immunization studies have demonstrated the potential role of T. gondii antigens SAG1 and GRA2 as a vaccine candidate. In the present study, we have cloned, expressed, and purified a recombinant protein SAG1-GRA2 in Pichia pastoris. Results showed that P. pastoris was a robust system producing a large amount of highly purified and biological activity protein. BALB/c mice immunized with SAG1-GRA2 elicited stronger humoral and cellular responses in comparison to control groups. This immunization resulted in an enhanced Th1 immune response as measured by IgG2a antibody production and increased splenocyte IFN-gamma production, whereas no IL-4 was detected. After a lethal challenge with the highly virulent T. gondii RH strain, a prolonged survival time in SAG1-GRA2-immunized mice was observed in comparison to control groups. Our data demonstrate that SAG1-GRA2 triggered a protective response against toxoplasmosis. Therefore, SAG1-GRA2 protein might be a good candidate for the further development of a multiantigenic vaccine.
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Affiliation(s)
- Huaiyu Zhou
- Department of Parasitology, School of Medicine, Shandong University, Jinan, 250012, People's Republic of China
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25
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Siachoque H, Guzman F, Burgos J, Patarroyo ME, Gomez Marin JE. Toxoplasma gondii: Immunogenicity and protection by P30 peptides in a murine model. Exp Parasitol 2006; 114:62-5. [PMID: 16545806 DOI: 10.1016/j.exppara.2006.02.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2005] [Revised: 02/07/2006] [Accepted: 02/07/2006] [Indexed: 11/24/2022]
Abstract
Vaccines are promising for the control of toxoplasmosis. Here, we evaluated the immunogenicity of 17 peptides derived from SAG1 surface protein of Toxoplasma gondii in CH3 mice. Only 8 of 16 peptides induced specific antibodies. After a lethal challenge, only the vaccination with 4 of 17 peptides that were from the carboxy terminal end of the protein conferred significant survival. Our work shows that vaccination with peptides from the carboxy-terminal positions of SAG1 major surface protein of Toxoplasma protects mice against a lethal challenge.
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Affiliation(s)
- Heber Siachoque
- Laboratorio de Inmunologia, Facultad de Medicina, Universidad del Rosario, Bogota, Colombia
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26
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van Dijk ADJ, de Vries SJ, Dominguez C, Chen H, Zhou HX, Bonvin AMJJ. Data-driven docking: HADDOCK's adventures in CAPRI. Proteins 2006; 60:232-8. [PMID: 15981252 DOI: 10.1002/prot.20563] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We have shown previously that given high-resolution structures of the unbound molecules, structure determination of protein complexes is possible by including biochemical and/or biophysical data as highly ambiguous distance restraints in a docking approach. We applied this method, implemented in the HADDOCK (High Ambiguity Driven DOCKing) package (Dominguez et al., J Am Chem Soc 2003;125:1731-1737), to the targets in the fourth and fifth rounds of CAPRI. Here we describe our results and analyze them in detail. Special attention is given to the role of flexibility in our docking method and the way in which this improves the docking results. We describe extensions to our approach that were developed as a direct result of our participation in CAPRI. In addition to experimental information, we also included interface residue predictions from PPISP (Protein-Protein Interaction Site Predictor; Zhou and Shan, Proteins 2001;44:336-343), a neural network method. Using HADDOCK we were able to generate acceptable structures for 6 of the 8 targets, and to submit at least 1 acceptable structure for 5 of them. Of these 5 submissions, 3 were of medium quality (Targets 10, 11, and 15) and 2 of high quality (Targets 13 and 14). In all cases, predictions were obtained containing at least 40% of the correct epitope at the interface for both ligand and receptor simultaneously.
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Affiliation(s)
- A D J van Dijk
- Department of NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
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27
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Couper KN, Roberts CW, Brombacher F, Alexander J, Johnson LL. Toxoplasma gondii-specific immunoglobulin M limits parasite dissemination by preventing host cell invasion. Infect Immun 2006; 73:8060-8. [PMID: 16299300 PMCID: PMC1307022 DOI: 10.1128/iai.73.12.8060-8068.2005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An important role for immunoglobulin M (IgM) during early acute virulent Toxoplasma gondii infection was identified using IgM-/- mice that lack surface and secretory IgM but maintain normal B-cell functionality and isotype class switching. Following intraperitoneal inoculation with the virulent RH strain, IgM-/- mice displayed significantly fewer peritoneal parasites than wild-type (WT) mice, which correlated with increased tachyzoite dissemination to the liver, lung, and spleen in IgM-/- mice compared with WT mice. Early splenic T-cell activation, as measured by CD69 expression, was augmented in IgM-/- mice, and serum and peritoneal cavity gamma interferon levels were also elevated in IgM-/- mice compared with WT controls. Consequently, the difference in parasite dissemination was not attributable to an impaired proinflammatory immune response in the IgM-/- mice. Specific IgM was found to bind to tachyzoites in vivo in WT mice, and this correlated with an increased ability of antiserum collected from WT mice at day 6 postinfection to block tachyzoite cell invasion, compared with comparable serum collected from IgM-/- mice at the same time point. Tachyzoite invasion of host cells was similar if parasites were incubated with WT or IgM-/- nonimmune serum, suggesting that natural IgM does not function to limit parasite dissemination during early T. gondii infection. Our results highlight an important role for parasite-specific IgM in limiting systemic dissemination of tachyzoites during early acute T. gondii infection.
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Affiliation(s)
- Kevin N Couper
- Department of Immunology, Strathclyde Institute for Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow G4 0NR, United Kingdom
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28
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Graille M, Stura EA, Bossus M, Muller BH, Letourneur O, Battail-Poirot N, Sibaï G, Gauthier M, Rolland D, Le Du MH, Ducancel F. Crystal Structure of the Complex between the Monomeric Form of Toxoplasma gondii Surface Antigen 1 (SAG1) and a Monoclonal Antibody that Mimics the Human Immune Response. J Mol Biol 2005; 354:447-58. [PMID: 16242717 DOI: 10.1016/j.jmb.2005.09.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Revised: 09/01/2005] [Accepted: 09/02/2005] [Indexed: 11/21/2022]
Abstract
Toxoplasma gondii, the intracellular parasite responsible for toxoplasmosis infects more than one-third of the world population and can be life-threatening for fetuses and immunocompromised patients. The surface protein SAG1 is an important immune target, which provides a strong immune response against the invasive tachyzoite while the other forms of the parasite, devoid of SAG1 at their surface, are multiplying. In addition to this role as a "hot spot" decoy, SAG1 is predicted to act as an adhesin during host-cell attachment through its binding to proteoglycans. To begin to understand the relationships between SAG1 epitopes and the ligand-binding site, we have solved the crystal structure of the monomeric form of T.gondii SAG1 complexed to a Fab derived from a monoclonal antibody raised against tachyzoite particles. This antibody competes strongly with human Toxoplasma-specific sera, suggesting that its epitope is part of an immunodominant region present on the surface of SAG1. The structure reveals that this conformational epitope, located within the SAG1 N-terminal domain, does not overlap with the proposed ligand-binding pocket. This study provides the first structural description of the monomeric form of SAG1, and significant insights into its dual role of adhesin and immune target during parasite infection.
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Affiliation(s)
- Marc Graille
- Département d'Ingénierie et d'Etudes des Protéines, Centre d'Etudes de Saclay, 91191 Gif-sur-Yvette, France
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29
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Ben-Zeev E, Kowalsman N, Ben-Shimon A, Segal D, Atarot T, Noivirt O, Shay T, Eisenstein M. Docking to single-domain and multiple-domain proteins: Old and new challenges. Proteins 2005; 60:195-201. [PMID: 15981268 DOI: 10.1002/prot.20557] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The diverse selection of targets in the CAPRI experiments provides grounds for determining the limits of our rigid-body docking program MolFit, and for extending it. We find that the sensitivity of MolFit is high, enabling it to produce reasonably accurate docking solutions when the structures undergo moderate local conformation changes upon complex formation or when the docked molecules are modeled. Yet the ranks of these solutions are sometimes too low to meet the requirements of CAPRI assessment. This indicates that the selectivity of MolFit, which was optimized for docking of unbound X-ray structures, and which relies on the availability of external data from biochemical and bioinformatic sources, needs readjustment in order to meet the challenges presented by NMR or modeled structures. A different challenge is presented by large global conformation changes such as movements of domains. We show that such changes can be accommodated within the rigid-body approximation by employing rigid multibody multistage docking procedures. We also address the difficulty of ranking results from 2-body and multibody docking scans in cases in which there are no external data favoring one option over the other.
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Affiliation(s)
- E Ben-Zeev
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
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30
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Hafid J, Vincent N, Flori P, Bellete B, Raberin H, Sung RTM. Production of antibodies in murine mucosal immunization with Toxoplasma gondii excreted/secreted antigens. Vet Parasitol 2004; 128:23-8. [PMID: 15725529 DOI: 10.1016/j.vetpar.2004.11.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2004] [Revised: 09/09/2004] [Accepted: 11/01/2004] [Indexed: 11/23/2022]
Abstract
Toxoplasmagondii RH strain excreted/secreted antigens (ESA) were administrated weekly by the oral route, to two groups of 40 OF1 mice for 4 weeks. One group received ESA associated with cholera toxin (CT+) and the other, ESA only (CT-). Five animals from each group were sacrificed from day 4 (D4) to D49 following the first immunization and their feces and sera were collected and tested by ELISA for IgA, IgG and IgM antibody detection. In feces, IgA antibodies were detected on D4 and on D12 in the CT+ and CT- groups, respectively, and they persisted up to D49. IgG antibodies were detected from D12 to D41 in the CT+ group and on D12 only in the CT- group. No IgM antibodies were detected. In sera, IgA antibodies were detected on D27, D41 and D49 only in the CT+ group. IgG and IgM antibodies were found on D12 and D4, respectively, in the CT+ group and starting from D27 in the CT- group. To our knowledge, this is the first demonstration that ESA, with or without CT, are immunogenic when administrated by the oral route.
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Affiliation(s)
- Jamal Hafid
- Groupe immunité des muqueuses et agents pathogènes (GIMAP), Faculté de médecine Jacques Lisfranc, 15 rue Ambroise Paré, 42023 Saint Etienne Cedex 02, France.
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31
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Drabner B, Reineke U, Schneider-Mergener J, Humphreys RE, Hartmann S, Lucius R. Identification of T helper cell-recognized epitopes in the chitinase of the filarial nematode Onchocerca volvulus. Vaccine 2002; 20:3685-94. [PMID: 12399196 DOI: 10.1016/s0264-410x(02)00395-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
T helper cell-recognized epitopes were determined in chitinase of Onchocerca volvulus, a vaccine candidate protein. The proliferation of splenic T cells of mice immunized with recombinant protein was tested with a library of chitinase-peptides of 16 amino acids with termini overlapping by 12 amino acids, and a library of "designer peptides", i.e. sequences identified with three epitope-predicting algorithms. Fourteen epitope-bearing stretches were identified with the peptides of the overlapping library. Testing of the designer peptides partially confirmed these data and revealed additional epitopes. Five clusters of epitopes were identified for the creation of peptide or minigene DNA vaccines with good potency and potential range of MHC allele presentation.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigens, Helminth/biosynthesis
- Antigens, Helminth/chemistry
- Antigens, Helminth/genetics
- Antigens, Helminth/immunology
- Chitinases/biosynthesis
- Chitinases/chemistry
- Chitinases/genetics
- Chitinases/immunology
- Cloning, Molecular
- DNA, Complementary/genetics
- DNA, Helminth/genetics
- Epitopes, T-Lymphocyte/genetics
- Epitopes, T-Lymphocyte/immunology
- H-2 Antigens/genetics
- Helminth Proteins/biosynthesis
- Helminth Proteins/chemistry
- Helminth Proteins/genetics
- Helminth Proteins/immunology
- Mice
- Mice, Inbred BALB C
- Molecular Sequence Data
- Onchocerca volvulus/enzymology
- Onchocerca volvulus/immunology
- Peptides/chemistry
- Peptides/genetics
- Peptides/immunology
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- T-Lymphocyte Subsets/immunology
- T-Lymphocytes, Helper-Inducer/immunology
- Vaccines, Synthetic/genetics
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Affiliation(s)
- Birgit Drabner
- Department of Biology, Humboldt-University Berlin, Philippstr 13, 10115, Berlin, Germany
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32
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Abstract
Peptide dendrimers are radial or wedge-like branched macromolecules consisting of a peptidyl branching core and/or covalently attached surface functional units. The multimeric nature of these constructs, the unambiguous composition and ease of production make this type of dendrimer well suited to various biotechnological and biochemical applications. Applications include use as biomedical diagnostic reagents, protein mimetics, anticancer and antiviral agents, vaccines and drug and gene delivery vehicles. This review focuses on the different types of peptide dendrimers currently in use and the synthetic methods commonly employed to generate peptide dendrimers ranging from stepwise solid-phase synthesis to chemoselective and orthogonal ligation.
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Affiliation(s)
- Kristen Sadler
- Department of Microbiology and Immunology, Vanderbilt University, Nashville, TN 37232, USA
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33
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Son ES, Ahn HJ, Kim JH, Kim DY, Nam HW. Determination of antigenic domain in GST fused major surface protein (Nc-p43) of Neospora caninum. THE KOREAN JOURNAL OF PARASITOLOGY 2001; 39:241-6. [PMID: 11590914 PMCID: PMC2721073 DOI: 10.3347/kjp.2001.39.3.241] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The antigenic domain of the major surface protein (Nc-p43) of Neospora caninum was examined by polymerase chain reaction of its gene fragments and recombinant expression as GST fusion proteins. The fragments of Nc-p43 were as follow: a total open reading frame (OFR), T; OFR without signal sequence and C-terminal hydrophobic sequence, S; N-terminal 2/3 parts of S, A; C-terminal 2/3 parts, P; N-terminal 1/3 part, X; middle 1/3 part, Y; and C-terminal 1/3 part, Z, respectively. The DNA fragments were cloned into pGEX-4T vector. Recombinant plasmids transformed into Escherichia coli of BL21 pLysS (DE3) strain were induced to express GST or GST fused fragments of Nc-p43 such as 69 kDa protein for T, 66 kDa for S, 52 kDa for A, 53 kDa for P, and 40 kDa proteins for X, Y, and Z, respectively in SDS-PAGE. The Nc-p43 fragments of T, S, and P reacted with a bovine serum of neosporosis while those of A, X, Y, and Z together with GST did not in the western blot. These findings suggest that the antigenic domain of Nc-p43 of N. caninum may be localized in the C-terminal 2/3 parts. Together with A19 clone in SAG1 of Toxoplasma gondii (Nam et al., 1996), the P fragment of Nc-p43 could be used as efficient antigens to diagnose and differentiate those infections with both species.
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Affiliation(s)
- E S Son
- Department of Parasitology, Catholic Institute of Parasitic Diseases, Catholic University of Korea
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34
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El Kasmi KC, Deroo S, Theisen DM, Brons NH, Muller CP. Crossreactivity of mimotopes and peptide homologues of a sequential epitope with a monoclonal antibody does not predict crossreactive immunogenicity. Vaccine 1999; 18:284-90. [PMID: 10506653 DOI: 10.1016/s0264-410x(99)00199-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The sequence H236-256 of the measles virus (MV) hemagglutinin (H) contains the sequential epitope of the neutralizing and protective monoclonal antibody (mAb) BH129 with the minimal epitope E(245)L-QL(249). Using this mAb, we have recently developed 7mer mimotopes binding up to 135x better than the corresponding 7mer epitope H244-250. In this study, we combined T cell epitopes (TCE) with either highly crossreactive 7mer mimotopes, 13mer mimotopes or less crossreactive MV-derived B cell epitopes (BCE). Antigenicity of these TBB, TTB and TTBB peptides was determined with BH129 in a competition ELISA against MV. We found that chimeric peptides including mimotopes were up to 80x better binders to the mAb than peptides containing the original BCEs. All peptides irrespective of their antigenicity were used for immunization to compare their virus- crossreactive immunogenicity. Unexpectedly, none of the highly antigenic mimotope-based peptides induced MV-crossreactive antibodies. In contrast, a number of peptides with the viral BCE sequence that did not bind to the mAb, induced MV-crossreactive and even neutralizing antibodies. This report describes a striking example of disparity between antigenicity and crossreactive immunogenicity and casts considerable doubt on the predictive value of antigenicity in immunogenicity studies, considerably complicating the selection of potential vaccine candidates.
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Affiliation(s)
- K C El Kasmi
- Laboratoire National de Santé, P. O. Box 1102, L-1011, Luxembourg, Luxembourg
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35
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Abstract
A single small segment (sequence recognition) or domain (conformation recognition) of a protein could act as an antigen (antigenic determinant) vs an antibody. Epitopes of the first kind being a continuous segment along the sequence (linear), generally bent with a typical non-ordered structure (turns and/or loops), can be predicted from the only knowledge of the primary structure. After reviewing the different algorithms, we present PEOPLE (Predictive Estimation Of Protein Linear Epitopes) which uses combined prediction methods, taking into account the basic fundamental properties corresponding to what should be an ideal epitope: bent (secondary structure mainly beta-turns), surface accessible, hydrophilic and mobile and/or flexible. Four classes of basic biophysical parameters are considered for the determination of an antigenic index AG - secondary structure; hydrophilicity; surface accessibility; flexibility. The AG index is finally defined as a linear combination of the four class profiles. Typical applications are presented.
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Affiliation(s)
- A J Alix
- Laboratoire de Spectroscopies et Structures Biomoléculaires, Université de Reims Champagne Ardenne, Faculté des Sciences, BP 1039, 51687 Reims Cedex 2, France.
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36
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Letscher-Bru V, Villard O, Risse B, Zauke M, Klein JP, Kien TT. Protective effect of vaccination with a combination of recombinant surface antigen 1 and interleukin-12 against toxoplasmosis in mice. Infect Immun 1998; 66:4503-6. [PMID: 9712808 PMCID: PMC108546 DOI: 10.1128/iai.66.9.4503-4506.1998] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We studied the immune response induced in mice by recombinant Toxoplasma gondii surface antigen 1 (rSAG1) protein, alone or combined with interleukin-12 (IL-12) as an adjuvant, and the protective effect against toxoplasmosis. Immunization with rSAG1 alone induced a specific humoral type 2 immunity and did not protect the animals from infection. In contrast, immunization with rSAG1 plus IL-12 redirected humoral and cellular immunity toward a type 1 pattern and reduced the brain parasite load by 40%.
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Affiliation(s)
- V Letscher-Bru
- Institut de Parasitologie et de Pathologie Tropicale, Inserm U392, Faculté de Médecine, 67000 Strasbourg, France
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37
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Shin DW, Lee YH, Rho TJ. [Immunological properties of the 30 kDa antigen of toxoplasma gondii]. THE KOREAN JOURNAL OF PARASITOLOGY 1997; 35:55-62. [PMID: 9100440 DOI: 10.3347/kjp.1997.35.1.55] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The molecular weight 30 kDa membrane protein of Toxoplasma gondii (Toxoplasma 30 kDa) apparently conserved in most strains of T. gondii and sera of infected hosts. The present study aimed to elucidate Toxoplasma 30 kDa as a useful diagnostic antigen for serodiagnosis of toxoplasmosis by ELISA and for induction of protective immunity. Murine spleen cells immunized with the membrane antigen of T. gondii were fused with mouse Sp2/O-Ag14 myeloma cells. Out of 8 clones selected, five were IgG2b, the others belonged to IgG1 and IgG2a. The 30 kDa antigen was distributed mainly on the surface membrane of tachyzoites by indirect fluorescence method. Murine peritoneal macrophages which were activated by 30 kDa antigen produced more amounts of NO2 compared with crude antigen-treated group, however there were no significant differences in toxoplamacidal activity between the two groups. Higher specificity of Toxoplasma 30 kDa antigen was recognized for serodiagnosis of toxoplasmosis than the crude antigen. From these results, Toxoplasma 30 kDa antigen enhances the cytotoxic effect of macrophages as well as a more reliable means for the serodiagnosis of toxoplasmosis by ELISA.
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Affiliation(s)
- D W Shin
- Department of Parasitology, College of Medicine, Chungnam National University, Taejon, Korea
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38
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Gómez Marín JE, Pinon JM, Bonhomme A, Guenounou M. Does human toxoplasmosis involve an imbalance in T1/T2 cytokines? Med Hypotheses 1997; 48:161-9. [PMID: 9076698 DOI: 10.1016/s0306-9877(97)90283-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The T1 (interferon-gamma, interleukin-12, interleukin-2) and T2 (interleukin-4, interleukin-10, interleukin-6) cytokine groups constitute two polar responses of the immune system. The T1 group is a predominantly cellular response, while the T2 group response is mainly humoral. The hypothesis forwarded here links these subgroups of induced cytokines to the various clinical forms of human toxoplasmosis. Ocular toxoplasmosis in immunocompetent patients could be attributed to a T1 hyper-response, whereas congenital toxoplasmosis, toxoplasmic encephalitis (in immunodeficient patients) and active chronic toxoplasmosis (with persistent lymphadenophathy) would be characterized by a predominantly T2 response. Confirmation that this kind of immunological imbalance effectively underlies the various clinical forms of toxoplasmosis would open the way for a new range of treatments based on immunomodulation.
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Affiliation(s)
- J E Gómez Marín
- Laboratoire de Parasitologie, Hôpital Maison Blanche, Reims, France.
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39
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Saavedra R, Becerril MA, Dubeaux C, Lippens R, De Vos MJ, Hérion P, Bollen A. Epitopes recognized by human T lymphocytes in the ROP2 protein antigen of Toxoplasma gondii. Infect Immun 1996; 64:3858-62. [PMID: 8751939 PMCID: PMC174303 DOI: 10.1128/iai.64.9.3858-3862.1996] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The ROP2 protein of Toxoplasma gondii possesses immunological and biological properties which have led to its proposal as a vaccine candidate. To identify epitopes recognized by human T cells in the ROP2 antigen, we submitted the sequence of this protein to three reported T-cell epitope prediction algorithms. Three sequences that were predicted by all three methods were selected (sequences 197 to 216, 393 to 410, and 501 to 524), and the corresponding peptides were synthesized. The peptides were first tested in a proliferation assay with a DPw4-restricted, ROP2-specific human T-cell clone, and the peptide corresponding to residues 197 to 216 was shown to stimulate the T-cell clone. The three peptides were further tested in proliferation assays with peripheral blood mononuclear cells from a panel of T. gondii-seropositive and -seronegative individuals. We found that cells from a high proportion of the seropositive donors (64%) recognized at least one of the three peptides. The most frequently recognized ones were peptides 197 to 216 (45%) and 501 to 524 (36%). None of the seronegative donors responded to any peptide. These results show that the ROP2 antigen of T. gondii contains T-cell epitopes recognized by a high percentage of the immune population and further strengthen its potential as a vaccine candidate.
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Affiliation(s)
- R Saavedra
- Departmento de Inmunologia, Universidad Nacional Autónoma de México, Mexico City, Mexico.
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40
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Nam HW, Im KS, Baek EJ, Choi WY, Cho SY. Analysis of antigenic domain of GST fused major surface protein (p30) fragments of Toxoplasma gondii. THE KOREAN JOURNAL OF PARASITOLOGY 1996; 34:135-41. [PMID: 8925246 DOI: 10.3347/kjp.1996.34.2.135] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Antigenic domain of major surface protein (p30) of Toxoplasma gondii was analyzed after polymerase chain reaction (PCR) of its gene fragments. Hydrophilic or hydrophobic moiety of amino acid sequences were expressed as glutathione S-transferase (GST) fusion proteins. Fragments of p30 gene were as follows: T37, total p30 open reading frame (ORF); S28, total ORF excluding N-terminal signal sequence and C-terminal hydrophobic sequence: A19, N-terminal 2/3 parts of S28; P19, C-terminal 2/3 of S28; X9, N-terminal 1/3 part of S28; Y10, middle 1/3 of S28; and Z9, C-terminal 1/3 of S28, respectively. Primer of each fragment was synthesized to include clamp sequence of EcoR I restriction site. PCR amplified DNA was inserted into GST (26 kDa) expression vector, pGEX-4T-1 to transform into Escherichia coli (JM105 strain). GST fusion proteins were expressed with IPTG induction as 63, 54, 45, 45, 35, 36, and 35 kDa proteins measured by SDS-PAGE. Each fusion protein was confirmed with GST detection kit. Western blot analysis with the serum of a toxoplasmosis patient revealed antigenicity in proteins expressed by T37, S28, and A19 but not those by P18, X9, Y10, and Z9. Antigenicity of p30 seems to be located either in N-terminal 1/3 part in the presence of middle 1/3 part or in the oligopeptides between margins of the first and second 1/3 parts.
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Affiliation(s)
- H W Nam
- Department of Parasitology, Catholic University of Korea, School of Medicine, Seoul, Korea
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41
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Alexander J, Jebbari H, Bluethmann H, Satoskar A, Roberts CW. Immunological control of Toxoplasma gondii and appropriate vaccine design. Curr Top Microbiol Immunol 1996; 219:183-95. [PMID: 8791700 DOI: 10.1007/978-3-642-51014-4_17] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- J Alexander
- Department of Immunology, University of Strathclyde, Glasgow, UK
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42
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Fischer HG, Reichmann G, Hadding U. Toxoplasma proteins recognized by protective T lymphocytes. Curr Top Microbiol Immunol 1996; 219:175-82. [PMID: 8791699 DOI: 10.1007/978-3-642-51014-4_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- H G Fischer
- Institut für Medizinische Mikrobiologie und Virologie, Heinrich-Heine-Universität, Düsseldorf, Germany
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43
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