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Bunkofske ME, Perumal N, White B, Strauch EM, Tarleton R. Epitopes in the Glycosylphosphatidylinositol Attachment Signal Peptide of Trypanosoma cruzi Mucin Proteins Generate Robust but Delayed and Nonprotective CD8+ T Cell Responses. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 210:420-430. [PMID: 36603035 PMCID: PMC9898211 DOI: 10.4049/jimmunol.2200723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 12/05/2022] [Indexed: 01/06/2023]
Abstract
Infection with the protozoan parasite Trypanosoma cruzi elicits substantial CD8+ T cell responses that disproportionately target epitopes encoded in the large trans-sialidase (TS) gene family. Within the C57BL/6 infection model, a significant proportion (30-40%) of the T. cruzi-specific CD8+ T cell response targets two immunodominant TS epitopes, TSKb18 and TSKb20. However, both TS-specific CD8+ T cell responses are dispensable for immune control, and TS-based vaccines have no demonstrable impact on parasite persistence, a determinant of disease. Besides TS, the specificity and protective capacity of CD8+ T cells that mediate immune control of T. cruzi infection are unknown. With the goal of identifying alternative CD8+ T cell targets, we designed and screened a representative set of genome-wide, in silico-predicted epitopes. Our screen identified a previously uncharacterized, to our knowledge, T cell epitope MUCKb25, found within mucin family proteins, the third most expanded large gene family in T. cruzi. The MUCKb25-specific response was characterized by delayed kinetics, relative to TS-specific responses, and extensive cross-reactivity with a large number of endogenous epitope variants. Similar to TS-specific responses, the MUCKb25 response was dispensable for control of the infection, and vaccination to generate MUCK-specific CD8+ T cells failed to confer protection. The lack of protection by MUCK vaccination was partly attributed to the fact that MUCKb25-specific T cells exhibit limited recognition of T. cruzi-infected host cells. Overall, these results indicate that the CD8+ T cell compartment in many T. cruzi-infected mice is occupied by cells with minimal apparent effector potential.
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Affiliation(s)
- Molly E. Bunkofske
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - Natasha Perumal
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Brooke White
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - Eva-Maria Strauch
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA 30602, USA
| | - Rick Tarleton
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
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Pathogen diversity, immunity, and the fate of infections: lessons learned from Trypanosoma cruzi human–host interactions. THE LANCET MICROBE 2022; 3:e711-e722. [DOI: 10.1016/s2666-5247(21)00265-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 01/02/2023] Open
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3
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Ferragut F, Acevedo GR, Gómez KA. T Cell Specificity: A Great Challenge in Chagas Disease. Front Immunol 2021; 12:674078. [PMID: 34267750 PMCID: PMC8276045 DOI: 10.3389/fimmu.2021.674078] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 06/09/2021] [Indexed: 11/13/2022] Open
Abstract
The CD4+ and CD8+ T cell immune response against T. cruzi, the parasite causing Chagas disease, are relevant for both parasite control and disease pathogenesis. Several studies have been focused on their phenotype and functionally, but only a few have drilled down to identify the parasite proteins that are processed and presented to these cells, especially to CD4+ T lymphocytes. Although approximately 10,000 proteins are encoded per haploid T. cruzi genome, fewer than 200 T cell epitopes from 49 T. cruzi proteins have been identified so far. In this context, a detailed knowledge of the specific targets of T cell memory response emerges as a prime tool for the conceptualization and development of prophylactic or therapeutic vaccines, an approach with great potential to prevent and treat this chronic disease. Here, we review the available information about this topic in a comprehensive manner and discuss the future challenges in the field.
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Affiliation(s)
- Fátima Ferragut
- Laboratorio de Inmunología de las Infecciones por Tripanosomátidos, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Gonzalo R Acevedo
- Laboratorio de Inmunología de las Infecciones por Tripanosomátidos, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Karina A Gómez
- Laboratorio de Inmunología de las Infecciones por Tripanosomátidos, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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4
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Rios L, Campos EE, Menon R, Zago MP, Garg NJ. Epidemiology and pathogenesis of maternal-fetal transmission of Trypanosoma cruzi and a case for vaccine development against congenital Chagas disease. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165591. [PMID: 31678160 PMCID: PMC6954953 DOI: 10.1016/j.bbadis.2019.165591] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 09/12/2019] [Accepted: 09/25/2019] [Indexed: 12/11/2022]
Abstract
Trypanos o ma cruzi (T. cruzi or Tc) is the causative agent of Chagas disease (CD). It is common for patients to suffer from non-specific symptoms or be clinically asymptomatic with acute and chronic conditions acquired through various routes of transmission. The expecting women and their fetuses are vulnerable to congenital transmission of Tc. Pregnant women face formidable health challenges because the frontline antiparasitic drugs, benznidazole and nifurtimox, are contraindicated during pregnancy. However, it is worthwhile to highlight that newborns can be cured if they are diagnosed and given treatment in a timely manner. In this review, we discuss the pathogenesis of maternal-fetal transmission of Tc and provide a justification for the investment in the development of vaccines against congenital CD.
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Affiliation(s)
- Lizette Rios
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX, USA
| | - E Emanuel Campos
- Instituto de Patología Experimental, Universidad Nacional de Salta - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Salta, Argentina
| | - Ramkumar Menon
- Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX, USA
| | - M Paola Zago
- Instituto de Patología Experimental, Universidad Nacional de Salta - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Salta, Argentina.
| | - Nisha J Garg
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX, USA; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA.
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Rios LE, Vázquez-Chagoyán JC, Pacheco AO, Zago MP, Garg NJ. Immunity and vaccine development efforts against Trypanosoma cruzi. Acta Trop 2019; 200:105168. [PMID: 31513763 PMCID: PMC7409534 DOI: 10.1016/j.actatropica.2019.105168] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 08/27/2019] [Accepted: 09/07/2019] [Indexed: 12/28/2022]
Abstract
Trypanosoma cruzi (T. cruzi) is the causative agent for Chagas disease (CD). There is a critical lack of methods for prevention of infection or treatment of acute infection and chronic disease. Studies in experimental models have suggested that the protective immunity against T. cruzi infection requires the elicitation of Th1 cytokines, lytic antibodies and the concerted activities of macrophages, T helper cells, and cytotoxic T lymphocytes (CTLs). In this review, we summarize the research efforts in vaccine development to date and the challenges faced in achieving an efficient prophylactic or therapeutic vaccine against human CD.
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Affiliation(s)
- Lizette E Rios
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555-1070, USA
| | - Juan Carlos Vázquez-Chagoyán
- Centro de Investigación y Estudios Avanzados en Salud Animal, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma del Estado de México, Toluca, México
| | - Antonio Ortega Pacheco
- Departamento de Salud Animal y Medicina Preventiva, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
| | - M Paola Zago
- Instituto de Patología Experimental, Universidad Nacional de Salta - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Salta, Argentina
| | - Nisha J Garg
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555-1070, USA; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX.
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Long-Term Immunity to Trypanosoma cruzi in the Absence of Immunodominant trans-Sialidase-Specific CD8+ T Cells. Infect Immun 2016; 84:2627-38. [PMID: 27354447 DOI: 10.1128/iai.00241-16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 06/24/2016] [Indexed: 11/20/2022] Open
Abstract
Trypanosoma cruzi infection drives the expansion of remarkably focused CD8(+) T cell responses targeting epitopes encoded by variant trans-sialidase (TS) genes. Infection of C57BL/6 mice with T. cruzi results in up to 40% of all CD8(+) T cells committed to recognition of the dominant TSKB20 and subdominant TSKB18 TS epitopes. However, despite this enormous response, these mice fail to clear T. cruzi infection and subsequently develop chronic disease. One possible reason for the failure to cure T. cruzi infection is that immunodomination by these TS-specific T cells may interfere with alternative CD8(+) T cell responses more capable of complete parasite elimination. To address this possibility, we created transgenic mice that are centrally tolerant to these immunodominant epitopes. Mice expressing TSKB20, TSKB18, or both epitopes controlled T. cruzi infection and developed effector CD8(+) T cells that maintained an activated phenotype. Memory CD8(+) T cells from drug-cured TSKB-transgenic mice rapidly responded to secondary T. cruzi infection. In the absence of the response to TSKB20 and TSKB18, immunodominance did not shift to other known subdominant epitopes despite the capacity of these mice to expand epitope-specific T cells specific for the model antigen ovalbumin expressed by engineered parasites. Thus, CD8(+) T cell responses tightly and robustly focused on a few epitopes within variant TS antigens appear to neither contribute to, nor detract from, the ability to control T. cruzi infection. These data also indicate that the relative position of an epitope within a CD8(+) immunodominance hierarchy does not predict its importance in pathogen control.
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Kurup SP, Tarleton RL. The Trypanosoma cruzi flagellum is discarded via asymmetric cell division following invasion and provides early targets for protective CD8⁺ T cells. Cell Host Microbe 2015; 16:439-49. [PMID: 25299330 DOI: 10.1016/j.chom.2014.09.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 07/11/2014] [Accepted: 08/27/2014] [Indexed: 12/27/2022]
Abstract
During invasion of host cells by Trypanosoma cruzi, the parasite that causes Chagas disease, the elongated, flagellated trypomastigotes remodel into oval amastigotes with no external flagellum. The underlying mechanism of this remodeling and the fate of the flagellum are obscure. We discovered that T. cruzi trypomastigotes discard their flagella via an asymmetric cellular division. The flagellar proteins liberated become among the earliest parasite proteins to enter the MHC-I processing pathway in infected cells. Indeed, paraflagellar rod protein PAR4-specific CD8(+) T cells detect infected host cells >20 hr earlier than immunodominant trans-sialidase-specific T cells. Overexpression of PAR4 in T. cruzi enhanced the subdominant PAR4-specific CD8(+) T cell response, resulting in improved control of a challenge infection. These results provide insights into previously unappreciated events in intracellular invasion by T. cruzi and highlight the importance of T cells that recognize infected host cells early in the infectious process, in the control of infections.
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Affiliation(s)
- Samarchith P Kurup
- Department of Cellular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - Rick L Tarleton
- Department of Cellular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA.
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8
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Villarino N, Schmidt NW. CD8 + T Cell Responses to Plasmodium and Intracellular Parasites. ACTA ACUST UNITED AC 2014; 9:169-178. [PMID: 24741372 PMCID: PMC3983867 DOI: 10.2174/1573395509666131126232327] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 11/14/2013] [Accepted: 11/19/2013] [Indexed: 12/29/2022]
Abstract
Parasitic protozoa are major threats to human health affecting millions of people around the world. Control of these infections by the host immune system relies on a myriad of immunological mechanisms that includes both humoral and cellular immunity. CD8+ T cells contribute to the control of these parasitic infections in both animals and humans. Here, we will focus on the CD8+ T cell response against a subset of these protozoa: Plasmodium, Toxoplasma gondii, Leishmania and Trypanosoma cruzi, with an emphasis on experimental rodent systems. It is evident a complex interaction occurs between CD8+ T cells and the invading protozoa. A detailed understanding of how CD8+ T cells mediate protection should provide the basis for the development of effective vaccines that prevent and control infections by these parasites.
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Affiliation(s)
- Nicolas Villarino
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
| | - Nathan W Schmidt
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
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Trypanosoma cruzi paraflagellar rod proteins 2 and 3 contain immunodominant CD8(+) T-cell epitopes that are recognized by cytotoxic T cells from Chagas disease patients. Mol Immunol 2012; 52:289-98. [PMID: 22750229 DOI: 10.1016/j.molimm.2012.05.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 05/24/2012] [Accepted: 05/31/2012] [Indexed: 12/21/2022]
Abstract
The protozoan parasite Trypanosoma cruzi is the etiological agent of Chagas disease. To date, no vaccine is available for protection against T. cruzi infection. The CD8(+) T cells immune response against specific antigens has shown to efficiently control the spread of the parasite in murine experimental infection. However, data concerning CD8(+) response in Chagas patients are still restricted to a few epitopes. We have studied the existence of immunodominant CD8(+) T cell epitopes in the paraflagellar rod proteins 2 and 3 (PFR2 and PFR3) from T. cruzi in a mouse model, and analyzed their recognition by cytotoxic T lymphocytes from Chagas disease patients. Immunization of C57BL/6-A2/K(b) transgenic mice with plasmids coding for the fusion proteins PFR2-HSP70 and PFR3-HSP70 induced a specific CTL response against two PFRs epitopes (PFR2(449-457) and PFR3(481-489)), and showed specific lysis percentages of 24 and 12, respectively. Moreover, the PFR2(19-28), PFR2(156-163), PFR2(449-457), PFR3(428-436), PFR3(475-482) and PFR3(481-489) peptides were observed to have a high binding affinity to the HLA-A*02:01 molecule. Remarkably, these HLA-A*02:01-binding peptides are successfully processed and presented during natural infection by T. cruzi in the context of MHC class I as evidenced by using peptide-pulsed K562-A2 cells as antigen presenting cells. The T cells from Chagas disease chronic patients specific for PFR2/PFR3 selected CD8(+) epitopes showed a pro-inflammatory cytokine secretion profile (IFN-γ, TNF-α and IL-6). A positive Granzime B secretion was observed in three out of 16 patients in response to PFR2(156-163) and PFR2(449-457) peptides, two out of 11 patients in response to PFR2(19-28) peptide and one out of 14 and 11 patients in response to PFR3(428-436) and PFR3(481-489) peptides, respectively. The PFRs-specific cytotoxic activity in purified PBMC was only detected in patients in the indeterminate phase of the disease.
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Rodrigues MM, Oliveira AC, Bellio M. The Immune Response to Trypanosoma cruzi: Role of Toll-Like Receptors and Perspectives for Vaccine Development. J Parasitol Res 2012; 2012:507874. [PMID: 22496959 PMCID: PMC3306967 DOI: 10.1155/2012/507874] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 10/31/2011] [Indexed: 02/06/2023] Open
Abstract
In the past ten years, studies have shown the recognition of Trypanosoma cruzi-associated molecular patterns by members of the Toll-like receptor (TLR) family and demonstrated the crucial participation of different TLRs during the experimental infection with this parasite. In the present review, we will focus on the role of TLR-activated pathways in the modulation of both innate and acquired immune responses to T. cruzi infection, as well as discuss the state of the art of vaccine research and development against the causative agent of Chagas disease (or American trypanosomiasis).
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Affiliation(s)
- Mauricio M. Rodrigues
- Centro de Terapia Celular e Molecular (CTCMol), Universidade Federal de São Paulo (UNIFESP), 04044-010 São Paulo, SP, Brazil
| | - Ana Carolina Oliveira
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-902 Rio de Janeiro, RJ, Brazil
| | - Maria Bellio
- Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), CCS, Avenida Carlos Chagas Filho, 373 Bloco D, sala 35, Cidade Universitária, 21941-902 Rio de Janeiro, RJ, Brazil
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Vázquez-Chagoyán JC, Gupta S, Garg NJ. Vaccine development against Trypanosoma cruzi and Chagas disease. ADVANCES IN PARASITOLOGY 2011; 75:121-46. [PMID: 21820554 DOI: 10.1016/b978-0-12-385863-4.00006-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The pathology of Chagas disease presents a complicated and diverse picture in humans. The major complications and destructive evolutionary outcomes of chronic infection by Trypanosoma cruzi in humans include ventricular fibrillation, thromboembolism and congestive heart failure. Studies in animal models and human patients have revealed the pathogenic mechanisms during disease progression, pathology of disease and features of protective immunity. Accordingly, several antigens, antigen-delivery vehicles and adjuvants have been tested to elicit immune protection to T. cruzi in experimental animals. This review summarizes the research efforts in vaccine development against Chagas disease during the past decade.
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Affiliation(s)
- Juan C Vázquez-Chagoyán
- Centro de Investigación y Estudios Avanzados en Salud Animal, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Estado de México, Toluca, Mexico
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Regulation of CD8+ T cell responses to infection with parasitic protozoa. Exp Parasitol 2010; 126:318-25. [PMID: 20493842 DOI: 10.1016/j.exppara.2010.05.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 04/05/2010] [Accepted: 05/15/2010] [Indexed: 11/24/2022]
Abstract
There are over 10,000 species of parasitic protozoa, a subset of which can cause considerable disease in humans. Here we examine in detail the complex immune response generated during infection with a subset of these parasites: Trypanosoma cruzi, Leishmania sp., Toxoplasma gondii, and Plasmodium sp. While these particular species perhaps represent the most studied parasites in terms of understanding how T cells function during infection, it is clear that the lessons learned from this body of work are also relevant to the other protozoa known to induce a CD8(+) T cell response. This review will highlight some of the key studies that established that CD8(+) T cells play a major role in protective immunity to protozoa, the factors that promote the generation as well as maintenance of the CD8(+) T cell response during these infections, and draw attention to some of the gaps in our knowledge. Moreover, the development of new tools, including MHC-Class I tetramer reagents and the use of TCR transgenic mice or genetically modified parasites, has provided a better appreciation of how parasite specific CD8(+) T cell responses are initiated and new insights into their phenotypic plasticity.
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Genetic immunization converts the trypanosoma cruzi B-Cell mitogen proline racemase to an effective immunogen. Infect Immun 2009; 78:810-22. [PMID: 19917711 DOI: 10.1128/iai.00926-09] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Trypanosoma cruzi is the etiologic agent of Chagas' disease. Acute T. cruzi infection results in polyclonal B-cell activation and delayed specific humoral immunity. T. cruzi proline racemase (TcPRAC), a T. cruzi B-cell mitogen, may contribute to this dysfunctional humoral response. Stimulation of murine splenocytes with recombinant protein (rTcPRAC) induced B-cell proliferation, antibody secretion, interleukin-10 (IL-10) production, and upregulation of CD69 and CD86 on B cells. Marginal zone (MZ) B cells are more responsive to T-cell-independent (TI) rTcPRAC stimulation than are follicular mature (FM) B cells in terms of proliferation, antibody secretion, and IL-10 production. During experimental T. cruzi infection, TcPRAC-specific IgG remained undetectable when responses to other T. cruzi antigens developed. Conversely, intradermal genetic immunization via gene gun (GG) delivered TcPRAC as an immunogen, generating high-titer TcPRAC-specific IgG without B-cell dysfunction. TcPRAC GG immunization led to antigen-specific splenic memory B-cell and bone marrow plasma cell formation. TcPRAC-specific IgG bound mitogenic rTcPRAC, decreasing subsequent B-cell activation. GG immunization with rTcPRAC DNA was nonmitogenic and did not affect the generation of specific IgG to another T. cruzi antigen, complement regulatory protein (CRP). These data demonstrate the utility of genetic immunization for the conversion of a protein mitogen to an effective antigen. Furthermore, coimmunization of TcPRAC with another T. cruzi antigen indicates the usefulness of this approach for multivalent vaccine development.
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Portman N, Gull K. The paraflagellar rod of kinetoplastid parasites: from structure to components and function. Int J Parasitol 2009; 40:135-48. [PMID: 19879876 PMCID: PMC2813431 DOI: 10.1016/j.ijpara.2009.10.005] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 10/13/2009] [Accepted: 10/16/2009] [Indexed: 01/06/2023]
Abstract
The role of the eukaryotic flagellum in cell motility is well established but its importance in many other aspects of cell biology, from cell signalling to developmental regulation, is becoming increasingly apparent. In addition to this diversity of function the core structure of the flagellum, which has been inherited from the earliest ancestor of all eukaryotes, is embellished with a range of extra-axonemal structures in many organisms. One of the best studied of these structures is the paraflagellar rod of kinetoplastid protozoa in which the morphological characteristics have been well defined and some of the major protein constituents have been identified. Here we discuss recent advances in the identification of further molecular components of the paraflagellar rod, how these impact on our understanding of its function and regulation and the implications for therapeutic intervention in a number of devastating human pathologies.
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Affiliation(s)
- Neil Portman
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX13RE, UK
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Rodrigues MM, Alencar BCD, Claser C, Tzelepis F, Silveira EL, Haolla FA, Dominguez MR, Vasconcelos JR. Swimming against the current: genetic vaccination against Trypanosoma cruzi infection in mice. Mem Inst Oswaldo Cruz 2009; 104 Suppl 1:281-7. [DOI: 10.1590/s0074-02762009000900037] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Accepted: 04/30/2009] [Indexed: 11/22/2022] Open
Affiliation(s)
| | | | | | | | | | | | | | - José Ronnie Vasconcelos
- Centro Interdisciplinar de Terapia Gênica; Escola Paulista de Medicina, Brasil; Universidade de São Paulo, Brasil
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Tzelepis F, de Alencar BCG, Penido MLO, Claser C, Machado AV, Bruna-Romero O, Gazzinelli RT, Rodrigues MM. Infection with Trypanosoma cruzi restricts the repertoire of parasite-specific CD8+ T cells leading to immunodominance. THE JOURNAL OF IMMUNOLOGY 2008; 180:1737-48. [PMID: 18209071 DOI: 10.4049/jimmunol.180.3.1737] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Interference or competition between CD8(+) T cells restricted by distinct MHC-I molecules can be a powerful means to establish an immunodominant response. However, its importance during infections is still questionable. In this study, we describe that following infection of mice with the human pathogen Trypanosoma cruzi, an immunodominant CD8(+) T cell immune response is developed directed to an H-2K(b)-restricted epitope expressed by members of the trans-sialidase family of surface proteins. To determine whether this immunodominance was exerted over other non-H-2K(b)-restricted epitopes, we measured during infection of heterozygote mice, immune responses to three distinct epitopes, all expressed by members of the trans-sialidase family, recognized by H-2K(b)-, H-2K(k)-, or H-2K(d)-restricted CD8(+) T cells. Infected heterozygote or homozygote mice displayed comparably strong immune responses to the H-2K(b)-restricted immunodominant epitope. In contrast, H-2K(k)- or H-2K(d)-restricted immune responses were significantly impaired in heterozygote infected mice when compared with homozygote ones. This interference was not dependent on the dose of parasite or the timing of infection. Also, it was not seen in heterozygote mice immunized with recombinant adenoviruses expressing T. cruzi Ags. Finally, we observed that the immunodominance was circumvented by concomitant infection with two T. cruzi strains containing distinct immunodominant epitopes, suggesting that the operating mechanism most likely involves competition of T cells for limiting APCs. This type of interference never described during infection with a human parasite may represent a sophisticated strategy to restrict priming of CD8(+) T cells of distinct specificities, avoiding complete pathogen elimination by host effector cells, and thus favoring host parasitism.
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Affiliation(s)
- Fanny Tzelepis
- Centro Interdisciplinar de Terapia Gênica and Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Mirasol 207, São Paulo, Brazil
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Garg N, Bhatia V. Current status and future prospects for a vaccine against American trypanosomiasis. Expert Rev Vaccines 2007; 4:867-80. [PMID: 16372882 DOI: 10.1586/14760584.4.6.867] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The clinically relevant pathognomonic consequences of human infection by Trypanosoma cruzi are dilation and hypertrophy of the left ventricle walls and thinning of the apex. The major complications and debilitating evolutionary outcomes of chronic infection include ventricular fibrillation, thromboembolism and congestive heart failure. American trypanosomiasis (Chagas disease) poses serious public healthcare and budgetary concerns. The currently available drugs, although effective against acute infection, are highly toxic and ineffective in arresting or attenuating clinical disease symptoms in chronic patients. The development of an efficacious prophylactic vaccine faces many challenges, and progress is slow, despite several years of effort. Studies in animal models and human patients have revealed the pathogenic mechanisms during disease progression, pathology of disease and features of protective immunity. Accordingly, several antigens, antigen-delivery vehicles and adjuvants have been tested in animal models, and some efforts have been successful in controlling infection and disease. This review will summarize the accumulated knowledge about the parasite and disease, as well as pathogenesis and protective immunity. The authors will discuss the efforts to date, and the challenges faced in achieving an efficient prophylactic vaccine against human American trypanosomiasis, and present the future perspectives.
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Affiliation(s)
- Nisha Garg
- Sealy Center for Vaccine Development, Department of Microbiology, Immunology and Pathology, University of Texas Medical Branch, Galveston TX 77555, USA.
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Martin DL, Weatherly DB, Laucella SA, Cabinian MA, Crim MT, Sullivan S, Heiges M, Craven SH, Rosenberg CS, Collins MH, Sette A, Postan M, Tarleton RL. CD8+ T-Cell responses to Trypanosoma cruzi are highly focused on strain-variant trans-sialidase epitopes. PLoS Pathog 2006; 2:e77. [PMID: 16879036 PMCID: PMC1526708 DOI: 10.1371/journal.ppat.0020077] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Accepted: 06/26/2006] [Indexed: 01/30/2023] Open
Abstract
CD8+ T cells are crucial for control of a number of medically important protozoan parasites, including Trypanosoma cruzi, the agent of human Chagas disease. Yet, in contrast to the wealth of information from viral and bacterial infections, little is known about the antigen specificity or the general development of effector and memory T-cell responses in hosts infected with protozoans. In this study we report on a wide-scale screen for the dominant parasite peptides recognized by CD8+ T cells in T. cruzi–infected mice and humans. This analysis demonstrates that in both hosts the CD8+ T-cell response is highly focused on epitopes encoded by members of the large trans-sialidase family of genes. Responses to a restricted set of immunodominant peptides were especially pronounced in T. cruzi–infected mice, with more than 30% of the CD8+ T-cell response at the peak of infection specific for two major groups of trans-sialidase peptides. Experimental models also demonstrated that the dominance patterns vary depending on the infective strain of T. cruzi, suggesting that immune evasion may be occurring at a population rather than single-parasite level. The authors of this paper conducted a broad screen to identify the major proteins in Trypanosoma cruzi, the causative agent of Chagas disease, that allow for detection and control of this intracellular pathogen by CD8+ T cells. This study is the first to show that a complex pathogen such as T. cruzi elicits a T-cell response focused on a few peptides, despite having a genome of >12,000 genes capable of encoding hundreds of thousands of potential target epitopes. The immunodominant CD8+ T-cell targets in both murine and human T. cruzi infection are almost exclusively peptides within multiple trans-sialidase proteins that are encoded by the large and diverse trans-sialidase gene family. trans-sialidase genes show great potential for variation, and the frequency of individual trans-sialidase epitopes appears to vary significantly in different parasite strains, giving rise to distinct patterns of T-cell responses to different T. cruzi isolates. The authors hypothesize that the massive expansion of this gene family under immunological pressure and the resulting variable expression of specific T-cell epitopes provides a mechanism of immune escape for T. cruzi.
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Affiliation(s)
- Diana L Martin
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
| | - D. Brent Weatherly
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Susana A Laucella
- Instituto Nacional de Parasiologia Dr. Mario Fatala Chaben/Administración Nacional de Laboratorios e Institutos de Salud “Dr. Carlos G. Malbrán” (ANLIS/Malbran), Buenos Aires, Argentina
| | - Melissa A Cabinian
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America
| | - Matthew T Crim
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Susan Sullivan
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Mark Heiges
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Sarah H Craven
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America
| | - Charles S Rosenberg
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America
| | - Matthew H Collins
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Alessandro Sette
- La Jolla Institute for Allergy and Immunology, San Diego, California, United States of America
| | - Miriam Postan
- Instituto Nacional de Parasiologia Dr. Mario Fatala Chaben/Administración Nacional de Laboratorios e Institutos de Salud “Dr. Carlos G. Malbrán” (ANLIS/Malbran), Buenos Aires, Argentina
| | - Rick L Tarleton
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- * To whom correspondence should be addressed. E-mail:
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Liu W, Meng X, Xu Q, Flower DR, Li T. Quantitative prediction of mouse class I MHC peptide binding affinity using support vector machine regression (SVR) models. BMC Bioinformatics 2006; 7:182. [PMID: 16579851 PMCID: PMC1513606 DOI: 10.1186/1471-2105-7-182] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Accepted: 03/31/2006] [Indexed: 11/20/2022] Open
Abstract
Background The binding between peptide epitopes and major histocompatibility complex proteins (MHCs) is an important event in the cellular immune response. Accurate prediction of the binding between short peptides and the MHC molecules has long been a principal challenge for immunoinformatics. Recently, the modeling of MHC-peptide binding has come to emphasize quantitative predictions: instead of categorizing peptides as "binders" or "non-binders" or as "strong binders" and "weak binders", recent methods seek to make predictions about precise binding affinities. Results We developed a quantitative support vector machine regression (SVR) approach, called SVRMHC, to model peptide-MHC binding affinities. As a non-linear method, SVRMHC was able to generate models that out-performed existing linear models, such as the "additive method". By adopting a new "11-factor encoding" scheme, SVRMHC takes into account similarities in the physicochemical properties of the amino acids constituting the input peptides. When applied to MHC-peptide binding data for three mouse class I MHC alleles, the SVRMHC models produced more accurate predictions than those produced previously. Furthermore, comparisons based on Receiver Operating Characteristic (ROC) analysis indicated that SVRMHC was able to out-perform several prominent methods in identifying strongly binding peptides. Conclusion As a method with demonstrated performance in the quantitative modeling of MHC-peptide binding and in identifying strong binders, SVRMHC is a promising immunoinformatics tool with not inconsiderable future potential.
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Affiliation(s)
- Wen Liu
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Xiangshan Meng
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Qiqi Xu
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Darren R Flower
- The Jenner Institute, University of Oxford, Compton, Berkshire RG20 7NN, UK
| | - Tongbin Li
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
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Araújo AFS, de Alencar BCG, Vasconcelos JRC, Hiyane MI, Marinho CRF, Penido MLO, Boscardin SB, Hoft DF, Gazzinelli RT, Rodrigues MM. CD8+-T-cell-dependent control of Trypanosoma cruzi infection in a highly susceptible mouse strain after immunization with recombinant proteins based on amastigote surface protein 2. Infect Immun 2005; 73:6017-25. [PMID: 16113322 PMCID: PMC1231112 DOI: 10.1128/iai.73.9.6017-6025.2005] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We previously described that DNA vaccination with the gene encoding amastigote surface protein 2 (ASP-2) protects approximately 65% of highly susceptible A/Sn mice against the lethal Trypanosoma cruzi infection. Here, we explored the possibility that bacterial recombinant proteins of ASP-2 could be used to improve the efficacy of vaccinations. Initially, we compared the protective efficacy of vaccination regimens using either a plasmid DNA, a recombinant protein, or both sequentially (DNA priming and protein boosting). Survival after the challenge was not statistically different among the three mouse groups and ranged from 53.5 to 75%. The fact that immunization with a recombinant protein alone induced protective immunity revealed the possibility that this strategy could be pursued for vaccination. We investigated this possibility by using six different recombinant proteins representing distinct portions of ASP-2. The vaccination of mice with glutathione S-transferase fusion proteins representing amino acids 261 to 500 or 261 to 380 of ASP-2 in the presence of the adjuvants alum and CpG oligodeoxynucleotide 1826 provided remarkable immunity, consistently protecting 100% of the A/Sn mice. Immunity was completely reversed by the in vivo depletion of CD8(+) T cells, but not CD4(+) T cells, and was associated with the presence of CD8(+) T cells specific for an epitope located between amino acids 320 and 327 of ASP-2. We concluded that a relatively simple formulation consisting of a recombinant protein with a selected portion of ASP-2, alum, and CpG oligodeoxynucleotide 1826 might be used to cross-prime strong CD8(+)-T-cell-dependent protective immunity against T. cruzi infection.
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Affiliation(s)
- Adriano F S Araújo
- CINTERGEN, UNIFESP-Escola Paulista de Medicina, Rua Mirassol, 207, São Paulo-SP 04044-010, Brazil
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Martin DL, Tarleton RL. Antigen-specific T cells maintain an effector memory phenotype during persistent Trypanosoma cruzi infection. THE JOURNAL OF IMMUNOLOGY 2005; 174:1594-601. [PMID: 15661921 DOI: 10.4049/jimmunol.174.3.1594] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Infection with the protozoan parasite Trypanosoma cruzi is a major cause of morbidity and mortality in Central and South America. Control of acute experimental infection with T. cruzi is dependent on a robust T cell and type 1 cytokine response. However, little evidence exists demonstrating the development and persistence of a potent antiparasite T cell memory response, and there has been much speculation that the majority of the immune response to T. cruzi infection is not directed against the parasite. In this study, we used an experimental mouse model of T. cruzi infection to test both the Ag specificity and the functional and phenotypic characteristics of the responding T cell population. We observed a vigorous antiparasite response from both CD4(+) and CD8(+) T cells that was maintained in the face of persistent infection. T cells from infected mice also proliferated in response to re-exposure to Ag, and CD8(+) T cells underwent spontaneous proliferation when transferred to naive congenic mice, both characteristic of central memory T cells. Interestingly, T cells from infected mice showed significant down-regulation of CD62L, a characteristic associated with an effector memory phenotype. These results suggest that T cells maintained in mice with chronic T. cruzi infection are fully functional memory cells that cannot be easily categorized in the current central/effector memory paradigm.
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Affiliation(s)
- Diana L Martin
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
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Abstract
CD8(+) T cells are crucial to the control of Trypanosoma cruzi infection and probably act via multiple mechanisms, the most important being the production of interferon-gamma (IFN-gamma). In the absence of CD8(+) T cells, mice quickly succumb to the infection or develop a more severe chronic disease. Reduced production of IFN-gamma by CD8(+) T cells is also associated with increased severity of chagasic disease in humans. CD8(+) T cells in chronic T. cruzi infection are maintained as effector memory cells, undergo rapid expansion, and demonstrate effector functions following re-exposure to antigen. However, the initial generation of T. cruzi-specific CD8(+) T-cell responses appears to be relatively slow to develop. In addition, the expression of the effector function of the CD8(+) T cells is compromised in some tissues, particularly in muscle. The targets of effective CD8(+) T-cell responses in T. cruzi infection are multiple and varied, and they represent some of the best vaccine candidates described to date. Further analysis of CD8(+) T cells will provide insight into the disease process in T. cruzi infection and should identify methods to assess and enhance immunity to T. cruzi infection and protection from the symptoms of Chagas' disease.
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Affiliation(s)
- Diana Martin
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, USA
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Gull K. Host-parasite interactions and trypanosome morphogenesis: a flagellar pocketful of goodies. Curr Opin Microbiol 2003; 6:365-70. [PMID: 12941406 DOI: 10.1016/s1369-5274(03)00092-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Trypanosomes are characterised by the possession of a single flagellum and a subpellicular microtubule cytoskeleton. The flagellum is more than an organelle for motility; its position and polarity along with the sub-pellicular cytoskeleton enables the morphogenesis of a distinct flagellar pocket and the flagellar basal body is responsible for positioning and segregating the kinetoplast--the mitochondrial genome. Recent work has highlighted the molecules and morphogenesis of these cytoskeletal/flagellum structures and how dynamic events, occurring in the flagellar pocket and kinetoplast, are critical for host-parasite interactions.
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Affiliation(s)
- Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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Luhrs KA, Fouts DL, Manning JE. Immunization with recombinant paraflagellar rod protein induces protective immunity against Trypanosoma cruzi infection. Vaccine 2003; 21:3058-69. [PMID: 12798650 DOI: 10.1016/s0264-410x(03)00108-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the present study, we have produced recombinant paraflagellar rod proteins (PFR) and report their use for successful vaccination of mice against Trypanosoma cruzi. This protection is associated with a highly polarized type 1 cytokine production profile. Additionally, we have analyzed the gene sequence encoding PFR-2 to determine the degree of conservation among seven highly diverse strains of T. cruzi, and found it to be highly conserved. The results presented here indicate that the PFR antigens are highly conserved, and immunization with rPFR-1, PFR-2, or an equimolar mix of the PFR-1, -2, and -3 proteins provides protective immunity against Trypanosoma cruzi.
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Affiliation(s)
- Keith A Luhrs
- Department of Molecular Biology and Biochemistry, 3205 McGaugh Hall, University of California, Irvine, CA 92697, USA
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