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1.
Trends Parasitol ; 37(3): 214-225, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33436314

RESUMO

Trypanosoma cruzi, the protozoan agent of Chagas' disease, displays a complex population structure made up of multiple strains showing a diverse ecoepidemiological distribution. Parasite genetic variability may be associated with disease outcome, hence stressing the need to develop methods for T. cruzi typing in vivo. Serological typing methods that exploit the presence of host antibodies raised against polymorphic parasite antigens emerge as an appealing approach to address this issue. These techniques are robust, simple, cost-effective, and are not curtailed by methodological/biological limitations intrinsic to available genotyping methods. Here, we critically assess the progress towards T. cruzi serotyping and discuss the opportunity provided by high-throughput immunomics to improve this field.


Assuntos
Parasitologia/métodos , Testes Sorológicos/normas , Trypanosoma cruzi/classificação , Animais , Doença de Chagas/parasitologia , Humanos , Testes Sorológicos/economia , Testes Sorológicos/tendências , Especificidade da Espécie , Trypanosoma cruzi/imunologia
2.
PLoS Negl Trop Dis ; 14(12): e0008932, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33332357

RESUMO

BACKGROUND: Chagas disease is a neglected zoonosis of growing concern in the southern US, caused by the parasite Trypanosoma cruzi. We genotyped parasites in a large cohort of PCR positive dogs to shed light on parasite transmission cycles and assess potential relationships between parasite diversity and serological test performance. METHODOLOGY/PRINCIPAL FINDINGS: We used a metabarcoding approach based on deep sequencing of T. cruzi mini-exon marker to assess parasite diversity. Phylogenetic analysis of 178 sequences from 40 dogs confirmed the presence of T. cruzi discrete typing unit (DTU) TcI and TcIV, as well as TcII, TcV and TcVI for the first time in US dogs. Infections with multiple DTUs occurred in 38% of the dogs. These data indicate a greater genetic diversity of T. cruzi than previously detected in the US. Comparison of T. cruzi sequence diversity indicated that highly similar T. cruzi strains from these DTUs circulate in hosts and vectors in Louisiana, indicating that they are involved in a shared T. cruzi parasite transmission cycle. However, TcIV and TcV were sampled more frequently in vectors, while TcII and TcVI were sampled more frequently in dogs. CONCLUSIONS/SIGNIFICANCE: These observations point to ecological host-fitting being a dominant mechanism involved in the diversification of T. cruzi-host associations. Dogs with negative, discordant or confirmed positive T. cruzi serology harbored TcI parasites with different mini-exon sequences, which strongly supports the hypothesis that parasite genetic diversity is a key factor affecting serological test performance. Thus, the identification of conserved parasite antigens should be a high priority for the improvement of current serological tests.


Assuntos
Doença de Chagas/veterinária , Éxons/genética , Variação Genética , Trypanosoma cruzi/genética , Animais , Doença de Chagas/epidemiologia , Doença de Chagas/parasitologia , Doença de Chagas/transmissão , Estudos de Coortes , Cães , Genótipo , Humanos , Louisiana/epidemiologia , Filogenia , Testes Sorológicos/veterinária , Trypanosoma cruzi/imunologia , Trypanosoma cruzi/fisiologia , Zoonoses
3.
PLoS Negl Trop Dis ; 14(9): e0008667, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32986710

RESUMO

Digestive and cardiodigestive forms of Chagas' disease are observed in 2% to 27% of the patients, depending on their geographic location, Trypanosoma cruzi strain and immunopathological responses. The aim of this work was to evaluate the role of NOD2 innate immune receptor in the pathogenesis of the digestive system in Chagas' disease. Patients with digestive form of the disease showed lower mRNA expression of NOD2, higher expression of RIP2 and α-defensin 6, compared to indeterminate form, detected by Real-time PCR in peripheral blood mononuclear cells. In addition, there was a negative correlation between the expression of NOD2 and the degree of dilation of the esophagus, sigmoid and rectum in those patients. The infection of NOD2-/- mice with T. cruzi strain isolated from the digestive patient induced a decrease in intestinal motility. Histopathological analysis of the colon and jejunum of NOD2-/- and wild type C57BL/6 animals revealed discrete inflammatory foci during the acute phase of infection. Interestingly, during the chronic phase of the infection there was inflammation and hypertrophy of the longitudinal and circular muscular layer more pronounced in the colon and jejunum from NOD2-/- animals, when compared to wild type C57BL/6 mice. Together, our results suggest that NOD2 plays a protective role against the development of digestive form of Chagas' disease.


Assuntos
Doença de Chagas/imunologia , Proteína Adaptadora de Sinalização NOD2/genética , Proteína Adaptadora de Sinalização NOD2/imunologia , Proteína Adaptadora de Sinalização NOD2/metabolismo , Trypanosoma cruzi/imunologia , Adolescente , Adulto , Idoso , Animais , Brasil , Doença de Chagas/patologia , Colo/microbiologia , Colo/patologia , Modelos Animais de Doenças , Feminino , Humanos , Imunidade Inata , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Proteína Serina-Treonina Quinase 2 de Interação com Receptor/genética , Proteína Serina-Treonina Quinase 2 de Interação com Receptor/metabolismo , Adulto Jovem , alfa-Defensinas/genética , alfa-Defensinas/metabolismo
4.
PLoS Negl Trop Dis ; 14(9): e0008608, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32925918

RESUMO

The receptor Signaling Lymphocyte-Activation Molecule Family 1 (SLAMF1) controls susceptibility to Infection by the lethal Trypanosoma cruzi Y strain. To elucidate whether genetic diversity of the parasite was related with disease susceptibility, we further analyzed the role of SLAMF1 using 6 different Trypanosoma cruzi strains including Y. The interaction of SLAMF1 receptor with T. cruzi was evidenced by fluorescence microscopy, flow cytometry and quantitative PCR. All the strains, except VFRA, showed a decrease in parasite load in infected macrophages in Slamf1-/- compared to BALB/c. In macrophages gene expression NADPH oxidase (NOX2), and reactive oxygen species (ROS) production increased in Slamf1-/- compared to BALB/c in 5 out of 6 strains. However, Slamf1-/-macrophages infected with VFRA strain exhibited a divergent behavior, with higher parasite load, lower NOX2 expression and ROS production compared to BALB/c. Parasitological and immunological studies in vivo with Y strain showed that in the absence of SLAMF1 the immune response protected mice from the otherwise lethal Y infection favoring a proinflammatory response likely involving CD4, CD8, dendritic cells and classically activated macrophages. In the case of VFRA, no major changes were observed in the absence of SLAMF1. Thus, the results suggest that the T. cruzi affects SLAMF1-dependent ROS production, controlling parasite replication in macrophages and affecting survival in mice in a strain-dependent manner. Further studies will focus in the identification of parasite molecules involved in SLAMF1 interaction to explain the immunopathogenesis of the disease.


Assuntos
Macrófagos/parasitologia , Espécies Reativas de Oxigênio/metabolismo , Membro 1 da Família de Moléculas de Sinalização da Ativação Linfocitária/genética , Membro 1 da Família de Moléculas de Sinalização da Ativação Linfocitária/metabolismo , Trypanosoma cruzi/imunologia , Animais , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Linhagem Celular , Doença de Chagas/imunologia , Chlorocebus aethiops , Células Dendríticas/imunologia , Suscetibilidade a Doenças/imunologia , Células HEK293 , Coração/parasitologia , Humanos , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Miocárdio/patologia , NADPH Oxidase 2/genética , NADPH Oxidase 2/metabolismo , Carga Parasitária , Células Vero
5.
Mem Inst Oswaldo Cruz ; 115: e200214, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32725060

RESUMO

BACKGROUND Chagas disease, resulting from Trypanosoma cruzi infections, continues to be a health concern mainly in Latin American countries where the parasite is endemic. The laboratory diagnosis of a chronic infection is determined through serological assays for antibodies against T. cruzi and several tests are available that differ in key components, formats and methodologies. To date, no single test meets the criteria of a gold standard. The situation is further complicated by the difficulties associated with performance comparisons between different immunoassays or methodologies executed at different times and geographical areas. OBJECTIVE To improve the diagnosis of Chagas disease, the WHO coordinated the development of two International Biological Reference Standards for antibodies against anti-T. cruzi: NIBSC 09/186 and NIBSC 09/188 that respectively represent geographical regions with the highest prevalence of TcII and TcI lineages of the parasite. METHODS The principle goal of this study was to verify the behavior of these standards when assayed by several commercially available serological tests that employ different methods to capture and detect human anti-T. cruzi antibodies. FINDINGS AND MAIN CONCLUSIONS The results reinforce the recommendation that these standards be considered for performance evaluations of commercialised immunoassays and should be an integral step in the development of new test components or assay paradigms.


Assuntos
Doença de Chagas/diagnóstico , Testes Sorológicos/normas , Trypanosoma cruzi/isolamento & purificação , Anticorpos Antiprotozoários/sangue , Doença de Chagas/parasitologia , Humanos , Imunoensaio/métodos , Padrões de Referência , Testes Sorológicos/métodos , Trypanosoma cruzi/imunologia , Organização Mundial da Saúde
6.
PLoS Negl Trop Dis ; 14(6): e0008414, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32574175

RESUMO

Chemokine receptor type 3 (CXCR3) plays an important role in CD8+ T cells migration during intracellular infections, such as Trypanosoma cruzi. In addition to chemotaxis, CXCR3 receptor has been described as important to the interaction between antigen-presenting cells and effector cells. We hypothesized that CXCR3 is fundamental to T. cruzi-specific CD8+ T cell activation, migration and effector function. Anti-CXCR3 neutralizing antibody administration to acutely T. cruzi-infected mice decreased the number of specific CD8+ T cells in the spleen, and those cells had impaired in activation and cytokine production but unaltered proliferative response. In addition, anti-CXCR3-treated mice showed decreased frequency of CD8+ T cells in the heart and numbers of plasmacytoid dendritic cells in spleen and lymph node. As CD8+ T cells interacted with plasmacytoid dendritic cells during infection by T. cruzi, we suggest that anti-CXCR3 treatment lowers the quantity of plasmacytoid dendritic cells, which may contribute to impair the prime of CD8+ T cells. Understanding which molecules and mechanisms guide CD8+ T cell activation and migration might be a key to vaccine development against Chagas disease as those cells play an important role in T. cruzi infection control.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Doença de Chagas/imunologia , Quimiocinas/metabolismo , Células Dendríticas/imunologia , Ativação Linfocitária/imunologia , Receptores CXCR3/metabolismo , Trypanosoma cruzi/imunologia , Animais , Movimento Celular , Doença de Chagas/parasitologia , Citoplasma/metabolismo , Citoplasma/parasitologia , Modelos Animais de Doenças , Feminino , Coração , Controle de Infecções , Camundongos , Camundongos Endogâmicos C57BL , Baço/imunologia
7.
PLoS One ; 15(5): e0232829, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32379842

RESUMO

The diagnosis of American tegumentary leishmaniasis (ATL) still requires the design of more effective tools. Leishmania (Viannia) braziliensis is the causal agent of the 90% of Argentinean ATL cases. Considering the current knowledge, an ELISA based crude antigen (CA) for the diagnosis was designed. Ninety-nine subjects diagnosed as ATL, 27 as no-ATL, and 84 donors from non-ATL-endemic areas were included in this study. The current ATL diagnosis was based four techniques, dermal smear microscopic examination (parasitological test), PCR, Leishmanin skin test, and clinical records. We obtained CA extracts from promastigotes and amastigotes from macrophage cultures of different zymodemes of endemic Leishmania species circulating in the study area. Crude antigens from the 'local' main zymodeme of L. (V.) braziliensis showed the highest reactivity against anti-Leishmania antibodies compared to the other included species. The CA of amastigotes of this zymodeme was 3.4 fold more reactive than promastigotes one. Moreover, amastigote-membrane CA (MCA) were 3.6 fold more reactive than the soluble antigens. The MCA-ELISA reached a sensitivity and specificity of 98% (CI = 94.7%-100%) and 63.6% (53.9-73.1), respectively. When anti-Trypanosoma cruzi reactive sera were excluded, the specificity reached 98.4% (94.4-100), while the sensitivity was similar, with a positive predictive value (PV) of 98.6% (94.6-100) and negative PV of 96.3% (91.6-100). The performance of the MCA-ELISA results strongly contribute to the final diagnostic decision, since a non-reactive serological result almost discards the suspected ATL, because of its high negative PV. The developed MCA-ELISA showed a high diagnostic performance, which makes it a good candidate for ATL diagnosis, for seroprevalence studies, or for monitoring treatments efficacy.


Assuntos
Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/imunologia , Membrana Celular/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Leishmania braziliensis/imunologia , Leishmaniose Cutânea/diagnóstico , Afinidade de Anticorpos , Especificidade de Anticorpos , Argentina/epidemiologia , Doadores de Sangue , Doenças Endêmicas , Humanos , Leishmania braziliensis/crescimento & desenvolvimento , Leishmaniose Cutânea/sangue , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/parasitologia , Leishmaniose Mucocutânea/sangue , Leishmaniose Mucocutânea/diagnóstico , Leishmaniose Mucocutânea/parasitologia , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Estudos Soroepidemiológicos , Trypanosoma cruzi/imunologia
8.
J Parasitol ; 106(3): 323-333, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32369594

RESUMO

Benznidazole and nifurtimox are the only drugs specifically approved for the treatment of Chagas disease. Both compounds are given orally in tablets, but occasionally are ineffective and cause adverse effects. Benznidazole, the first-line treatment in many countries, is a compound with low solubility in water that is administered at high doses for long periods of time. To improve its solubility, we developed a new liquid formulation on the basis of solid dispersions (SD) using the amphiphilic polymer poloxamer 407. Herein we present data on its trypanocidal performance in mouse models of acute and chronic Trypanosoma cruzi infection. SD at doses of 60 or 15 mg/kg per day given with different administration schedules were compared with the commercial formulation (CF; 50 mg/kg per day) and vehicle. The SD performance was assessed by direct parasitemia, total anti-T. cruzi antibodies, and parasitic burden in tissues after 4 or 6 mo posttreatment. The efficacy of the SD was equivalent to the CF but without manifest side effects and hepatotoxicity. Considering our previous data on solubility, together with these on efficacy, this new liquid formulation represents a promising alternative for the treatment of Chagas disease, particularly in cases when dosing poses a challenge, as in infants.


Assuntos
Doença de Chagas/tratamento farmacológico , Excipientes/uso terapêutico , Nitroimidazóis/uso terapêutico , Poloxâmero/uso terapêutico , Tripanossomicidas/uso terapêutico , Doença Aguda , Animais , Anticorpos Antiprotozoários/sangue , Aspartato Aminotransferases/sangue , Doença Crônica , Modelos Animais de Doenças , Feminino , Coração/parasitologia , Camundongos , Miocárdio/patologia , Parasitemia , Músculo Quadríceps/parasitologia , Músculo Quadríceps/patologia , Distribuição Aleatória , Reação em Cadeia da Polimerase em Tempo Real , Trypanosoma cruzi/imunologia
9.
PLoS Negl Trop Dis ; 14(4): e0007717, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32302312

RESUMO

BACKGROUND: The long term and complex nature of Chagas disease in humans has restricted studies on vaccine feasibility. Animal models also have limitations due to technical difficulties in monitoring the extremely low parasite burden that is characteristic of chronic stage infections. Advances in imaging technology offer alternative approaches that circumvent these problems. Here, we describe the use of highly sensitive whole body in vivo imaging to assess the efficacy of recombinant viral vector vaccines and benznidazole-cured infections to protect mice from challenge with Trypanosoma cruzi. METHODOLOGY/PRINCIPAL FINDINGS: Mice were infected with T. cruzi strains modified to express a red-shifted luciferase reporter. Using bioluminescence imaging, we assessed the degree of immunity to re-infection conferred after benznidazole-cure. Those infected for 14 days or more, prior to the onset of benznidazole treatment, were highly protected from challenge with both homologous and heterologous strains. There was a >99% reduction in parasite burden, with parasites frequently undetectable after homologous challenge. This level of protection was considerably greater than that achieved with recombinant vaccines. It was also independent of the route of infection or size of the challenge inoculum, and was long-lasting, with no significant diminution in immunity after almost a year. When the primary infection was benznidazole-treated after 4 days (before completion of the first cycle of intracellular infection), the degree of protection was much reduced, an outcome associated with a minimal T. cruzi-specific IFN-γ+ T cell response. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that a protective Chagas disease vaccine must have the ability to eliminate parasites before they reach organs/tissues, such as the GI tract, where once established, they become largely refractory to the induced immune response.


Assuntos
Doença de Chagas/imunologia , Doença de Chagas/prevenção & controle , Imunidade Heteróloga , Vacinas Protozoárias/imunologia , Trypanosoma cruzi/imunologia , Vacinação/métodos , Animais , Modelos Animais de Doenças , Feminino , Camundongos Endogâmicos BALB C , Vacinas Protozoárias/administração & dosagem , Vacinas de Subunidades/administração & dosagem , Vacinas de Subunidades/imunologia , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologia
10.
Sci Rep ; 10(1): 5294, 2020 03 24.
Artigo em Inglês | MEDLINE | ID: mdl-32210339

RESUMO

The detection of pathogen-specific antibodies remains a cornerstone of clinical diagnostics. Yet, many test exhibit undesirable performance or are completely lacking. Given this, we developed serum epitope repertoire analysis (SERA), a method to rapidly discover conserved, pathogen-specific antigens and their epitopes, and applied it to develop an assay for Chagas disease caused by the protozoan parasite Trypanosoma cruzi. Antibody binding peptide motifs were identified from 28 Chagas repertoires using a bacterial display random 12-mer peptide library and next-generation sequencing (NGS). Thirty-three motifs were selected and mapped to candidate Chagas antigens. In a blinded validation set (n = 72), 30/30 Chagas were positive, 30/30 non-Chagas were negative, and 1/12 Leishmania sp. was positive. After unblinding, a Leishmania cross-reactive epitope was identified and removed from the panel. The Chagas assay exhibited 100% sensitivity (30/30) and specificity (90/90) in a second blinded validation set including individuals with other parasitic infections. Amongst additional epitope repertoires with unknown Chagas serostatus, assay specificity was 99.8% (998/1000). Thus, the Chagas assay achieved a combined sensitivity and specificity equivalent or superior to diagnostic algorithms that rely on three separate tests to achieve high specificity. NGS-based serology via SERA provides an effective approach to discover antigenic epitopes and develop high performance multiplex serological assays.


Assuntos
Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/imunologia , Doença de Chagas/sangue , Doença de Chagas/diagnóstico , Epitopos/imunologia , Trypanosoma cruzi/imunologia , Adulto , Anticorpos Antiprotozoários/sangue , Doença de Chagas/imunologia , Doença de Chagas/parasitologia , Feminino , Humanos , Masculino , Biblioteca de Peptídeos
11.
J Leukoc Biol ; 107(4): 695-706, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32202341

RESUMO

In secondary lymphoid organs, pathogen-derived and endogenous danger molecules are recognized by pattern recognition receptors, leading to adaptive proinflammatory immune responses. This conceptual rule does not apply directly to the liver, as hepatic immune cells tolerate gut-derived bacterial molecules from the flora. Therefore, the recognition of danger and proinflammatory stimuli differs between the periphery and the liver. However, the tolerant nature of the liver must be overcome in the case of infections or cancer, for example. The central paradigm is the basis for danger recognition and the balance between inflammation and tolerance in the liver. Here, we observed functional integration, with activated peripheral T lymphocytes playing a role in the induction of a proinflammatory environment in the liver in the presence of Trypanosoma cruzi antigens. When only parasite extract was orally administered, it led to the up-regulation of hepatic tolerance markers, but oral treatment plus adoptively transferred activated splenic T lymphocytes led to a proinflammatory response. Moreover, treated/recipient mice showed increased levels of TNF, IFN-γ, IL-6, and CCL2 in the liver and increased numbers of effector and/or effector memory T lymphocytes and F4/80+ cells. There was a reduction in FoxP3+ Treg cells, NKT cells, and γδ T lymphocytes with increased liver damage in the presence of activated peripheral T cells. Our results show that the induction of a proinflammatory liver response against T. cruzi danger molecules is at least partially dependent on cooperation with activated peripheral T cells.


Assuntos
Antígenos de Protozoários/imunologia , Inflamação/patologia , Fígado/patologia , Ativação Linfocitária/imunologia , Linfócitos T/imunologia , Trypanosoma cruzi/imunologia , Transferência Adotiva , Animais , Antígeno B7-H1/metabolismo , Antígeno CTLA-4/metabolismo , Doença de Chagas/imunologia , Doença de Chagas/parasitologia , Citocinas/metabolismo , Linfócitos Intraepiteliais/imunologia , Macrófagos do Fígado/imunologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Células T Matadoras Naturais/imunologia , Parasitos/imunologia , Receptor de Morte Celular Programada 1/metabolismo , Linfócitos T/parasitologia , Linfócitos T Reguladores/imunologia
12.
MMWR Morb Mortal Wkly Rep ; 69(7): 193-195, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32078594

RESUMO

On December 13, 2017, the Missouri Department of Health and Senior Services (MDHSS) was notified of a suspected case of Chagas disease in a Missouri woman. The patient had donated blood, and laboratory screening revealed antibodies to Trypanosoma cruzi, the parasite that causes Chagas disease. Evaluation by physicians found no clinical symptoms consistent with Chagas disease. The patient had no travel history that would have suggested a significant risk for Chagas disease risk and had no occupational exposure to the disease agent. She had never received a blood transfusion or organ transplant. Confirmatory testing of the patient's serum at CDC for T. cruzi antibody was consistent with infection. These findings raise the possibility that the exposure to T. cruzi occurred locally (autochthonously) in Missouri. Although the insect vector for the parasite T. cruzi, triatomines (commonly known as "kissing bugs"), has been identified previously in Missouri, no locally acquired human cases of Chagas disease have been identified in the state. Health care providers and public health professionals should be aware of the possibility of locally acquired Chagas disease in the southern United States.


Assuntos
Doença de Chagas/diagnóstico , Anticorpos Antiprotozoários/isolamento & purificação , Doadores de Sangue , Doença de Chagas/transmissão , Feminino , Humanos , Pessoa de Meia-Idade , Missouri , Trypanosoma cruzi/imunologia
13.
J Immunol ; 204(6): 1571-1581, 2020 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-32060134

RESUMO

T cell-mediated immune response plays a crucial role in controlling Trypanosoma cruzi infection and parasite burden, but it is also involved in the clinical onset and progression of chronic Chagas' disease. Therefore, the study of T cells is central to the understanding of the immune response against the parasite and its implications for the infected organism. The complexity of the parasite-host interactions hampers the identification and characterization of T cell-activating epitopes. We approached this issue by combining in silico and in vitro methods to interrogate patients' T cells specificity. Fifty T. cruzi peptides predicted to bind a broad range of class I and II HLA molecules were selected for in vitro screening against PBMC samples from a cohort of chronic Chagas' disease patients, using IFN-γ secretion as a readout. Seven of these peptides were shown to activate this type of T cell response, and four out of these contain class I and II epitopes that, to our knowledge, are first described in this study. The remaining three contain sequences that had been previously demonstrated to induce CD8+ T cell response in Chagas' disease patients, or bind HLA-A*02:01, but are, in this study, demonstrated to engage CD4+ T cells. We also assessed the degree of differentiation of activated T cells and looked into the HLA variants that might restrict the recognition of these peptides in the context of human T. cruzi infection.


Assuntos
Antígenos de Protozoários/imunologia , Linfócitos T CD4-Positivos/imunologia , Cardiomiopatia Chagásica/imunologia , Epitopos de Linfócito T/imunologia , Trypanosoma cruzi/imunologia , Antígenos de Protozoários/metabolismo , Argentina , Linfócitos T CD4-Positivos/metabolismo , Diferenciação Celular/imunologia , Cardiomiopatia Chagásica/sangue , Cardiomiopatia Chagásica/parasitologia , Simulação por Computador , ELISPOT , Epitopos de Linfócito T/metabolismo , Feminino , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Antígenos de Histocompatibilidade Classe II/imunologia , Antígenos de Histocompatibilidade Classe II/metabolismo , Humanos , Imunidade Celular , Memória Imunológica , Testes de Liberação de Interferon-gama , Ativação Linfocitária , Masculino , Trypanosoma cruzi/metabolismo
14.
Am J Trop Med Hyg ; 102(4): 800-803, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32100675

RESUMO

Chagas is a neglected disease endemic in Latin America. Vector transmission control had been aggressively performed. Recent entomological surveillance in Brazil has revealed natural infection rates ranging from 0.40% to 0.52%. Although serological surveys are complex to develop, they are important for disease control. In this study, we validated the use of saliva in ELISA commercial kits with a cohort of 100 patients with Chagas disease followed at Hospital das Clinicas in São Paulo, Brazil, and 50 healthy controls. Five ELISA kits for detecting antibodies against Trypanosoma cruzi were tested. The best discrimination between Chagas patients and controls was observed with the Wiener kit, which yielded a sensitivity of 97% and a specificity of 100%. Our findings reveal that the use of saliva may be an alternative to large-scale screening surveys in detecting T. cruzi antibodies; it is a noninvasive sample collection method potentially key to large-scale screening in children.


Assuntos
Anticorpos Antiprotozoários/análise , Doença de Chagas/diagnóstico , Doenças Endêmicas , Ensaio de Imunoadsorção Enzimática/métodos , Saliva/imunologia , Trypanosoma cruzi/imunologia , Brasil/epidemiologia , Estudos de Casos e Controles , Doença de Chagas/epidemiologia , Estudos de Coortes , Humanos , Sensibilidade e Especificidade , Estudos Soroepidemiológicos
15.
Biochim Biophys Acta Mol Basis Dis ; 1866(5): 165707, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32004621

RESUMO

Current understanding of key cellular pathways, which are activated by the interaction between T. cruzi and host immunity, is crucial for controlling T. cruzi infection and also for limiting the development of the immunopathological symptoms of Chagas´ disease. Here, we focus on recent advances in the knowledge of modulation of innate receptors such as TLRs and NLRs, especially NLRP3, by T. cruzi in different cells of the immune system. On the other hand, the modulation of macrophage activation may be instrumental in allowing parasite persistence and long-term host survival. In this sense, we discuss the importance of the metabolism of two amino acids: L-arginine and tryptophan, and evaluate the role of iNOS, arginase and IDO enzymes in the regulation of innate and adaptive immune response during this infection; and, finally, we also discuss how T. cruzi exploits the AhR, mTOR and Wnt signaling pathways to promote their intracellular replication in macrophages, thus evading the host's immune response.


Assuntos
Doença de Chagas/imunologia , Interações Hospedeiro-Parasita/imunologia , Transdução de Sinais/imunologia , Trypanosoma cruzi/imunologia , Imunidade Adaptativa , Animais , Antígenos de Protozoários/imunologia , Antígenos de Protozoários/metabolismo , Arginina/imunologia , Arginina/metabolismo , Caspase 1/metabolismo , Doença de Chagas/parasitologia , Modelos Animais de Doenças , Vetores de Doenças , Humanos , Imunidade Inata , Indolamina-Pirrol 2,3,-Dioxigenase/metabolismo , Ativação de Macrófagos , Macrófagos/imunologia , Macrófagos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Receptores de Hidrocarboneto Arílico/metabolismo , Receptores Toll-Like/metabolismo , Triatoma/imunologia , Triatoma/parasitologia , Trypanosoma cruzi/metabolismo , Triptofano/imunologia , Triptofano/metabolismo
16.
Infect Immun ; 88(4)2020 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-31907197

RESUMO

Chagas disease, caused by Trypanosoma cruzi, is a major public health issue. Limitations in immune responses to natural T. cruzi infection usually result in parasite persistence with significant complications. A safe, effective, and reliable vaccine would reduce the threat of T. cruzi infections; however, no suitable vaccine is currently available due to a lack of understanding of the requirements for induction of fully protective immunity. We established a T. cruzi strain expressing green fluorescent protein (GFP) under the control of dihydrofolate reductase degradation domain (DDD) with a hemagglutinin (HA) tag, GFP-DDDHA, which was induced by trimethoprim-lactate (TMP-lactate), which results in the death of intracellular parasites. This attenuated strain induces very strong protection against reinfection. Using this GFP-DDDHA strain, we investigated the mechanisms underlying the protective immune response in mice. Immunization with this strain led to a response that included high levels of gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α), as well as a rapid expansion of effector and memory T cells in the spleen. More CD8+ T cells differentiate to memory cells following GFP-DDDHA infection than after infection with a wild-type (WT) strain. The GFP-DDDHA strain also provides cross-protection against another T. cruzi isolate. IFN-γ is important in mediating the protection, as IFN-γ knockout (KO) mice failed to acquire protection when infected with the GFP-DDDHA strain. Immune cells demonstrated earlier and stronger protective responses in immunized mice after reinfection with T. cruzi than those in naive mice. Adoptive transfers with several types of immune cells or with serum revealed that several branches of the immune system mediated protection. A combination of serum and natural killer cells provided the most effective protection against infection in these transfer experiments.


Assuntos
Doença de Chagas/prevenção & controle , Vacinas Protozoárias/imunologia , Subpopulações de Linfócitos T/imunologia , Trypanosoma cruzi/imunologia , Animais , Doença de Chagas/imunologia , Modelos Animais de Doenças , Imunidade Celular , Fatores Imunológicos/metabolismo , Interferon gama/metabolismo , Camundongos , Vacinas Protozoárias/administração & dosagem , Fator de Necrose Tumoral alfa/metabolismo , Vacinas Atenuadas/administração & dosagem , Vacinas Atenuadas/imunologia
17.
Biochim Biophys Acta Mol Basis Dis ; 1866(5): 165692, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-31972227

RESUMO

Many important pathogen-host interactions rely on highly specific carbohydrate binding events. In the case of the protozoan Trypanosoma cruzi, the causative agent of Chagas disease, glycointeractions involving sialic acid (SA) residues are pivotal for parasite infectivity, escape from immune surveillance and pathogenesis. Though unable to synthesize SA de novo, T. cruzi displays a unique trans-Sialidase (TS) enzyme, which is able to cleave terminal SA residues from host donor glycoconjugates and transfer them onto parasite surface mucins, thus generating protective/adhesive structures. In addition, this parasite sheds TS into the bloodstream, as a way of modifying the surface SA signature, and thereby the signaling/functional properties of mammalian host target cells on its own advantage. Here, we discuss the pathogenic aspects of T. cruzi TS: its molecular adaptations, the multiplicity of interactions in which it is involved during infections, and the array of novel and appealing targets for intervention in Chagas disease provided by TS-remodeled sialoglycophenotypes.


Assuntos
Doença de Chagas/imunologia , Glicoproteínas/metabolismo , Interações Hospedeiro-Parasita/imunologia , Neuraminidase/metabolismo , Polissacarídeos/imunologia , Proteínas de Protozoários/metabolismo , Trypanosoma cruzi/patogenicidade , Animais , Doença de Chagas/parasitologia , Glicoproteínas/imunologia , Humanos , Evasão da Resposta Imune , Neuraminidase/imunologia , Polissacarídeos/química , Polissacarídeos/metabolismo , Proteínas de Protozoários/imunologia , Ácidos Siálicos/química , Ácidos Siálicos/imunologia , Ácidos Siálicos/metabolismo , Trypanosoma cruzi/enzimologia , Trypanosoma cruzi/imunologia , Fatores de Virulência/imunologia , Fatores de Virulência/metabolismo
18.
Biochim Biophys Acta Mol Basis Dis ; 1866(5): 165706, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-31987839

RESUMO

Host resistance during infection with Trypanosoma cruzi, and other protozoans, is dependent on a balanced immune response. Robust immunity against these pathogens requires of the concerted action of many innate and adaptive cell populations including macrophages, neutrophils, dendritic cells, CD4+, and CD8+ T cells and B cells among others. Indeed, during most protozoan infections only a balanced production of inflammatory (TH1) and anti-inflammatory (TH2/regulatory) cytokines will allow the control of parasite spreading without compromising host tissue integrity. The description of TH17 cells, a novel effector helper T cell lineage that produced IL-17 as signature cytokine, prompted the revision of our knowledge about the mechanisms that mediate protection and immunopathology during protozoan infections. In this manuscript we discuss the general features of IL-17 mediated immune responses as well as the cellular sources, effector mechanisms and overall role of IL-17 in the immune response to T. cruzi and other protozoan infections.


Assuntos
Doença de Chagas/imunologia , Interações Hospedeiro-Parasita/imunologia , Imunidade Celular , Interleucina-17/metabolismo , Trypanosoma cruzi/imunologia , Animais , Antígenos de Protozoários/imunologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Doença de Chagas/parasitologia , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Modelos Animais de Doenças , Humanos , Imunidade Inata , Interleucina-17/imunologia , Macrófagos/imunologia , Macrófagos/metabolismo , Neutrófilos/imunologia , Neutrófilos/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismo
19.
PLoS One ; 15(1): e0227828, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31951634

RESUMO

Trypanosoma cruzi, the protozoan agent of Chagas disease in the Americas, is comprised of six genetic lineages (TcI-TcVI) and a possible seventh (TcBat, related to TcI). Identification of T. cruzi lineages infecting reservoir mammalian species is fundamental to resolving transmission cycles. However, this is hindered by the limited sensitivity and technical complexity of parasite isolation and genotyping. An alternative approach is serology using T. cruzi lineage-specific epitopes, such as those of the trypomastigote small surface antigen (TSSA). For surveillance of T. cruzi lineage infections in mammal species from diverse Brazilian regions, we apply a novel rapid diagnostic test (RDT, Chagas Sero K-SeT), which incorporates the TSSA peptide epitope specific to TcII/V/VI (TSSApep-II/V/VI) and Protein G detection of antibodies. Chagas Sero K-SeT RDT results with sera from experimentally infected mice, from tamarin primates (Leontopithecus spp.) and from canines (Canis familiaris) were concordant with corresponding TSSApep-II/V/VI ELISAs. The Chagas Sero K-Set detected TcII/V/VI infections in Leontopithecus spp. from the Atlantic forest (n = 46), in C. familiaris (n = 16) and Thrichomys laurentius (n = 2) from Caatinga biome and Chiroptera (n = 1) from Acre, Amazonia. The Chagas Sero K-SeT RDT is directly applicable to TcII/V/VI-specific serological surveillance of T. cruzi infection in several different mammalian Orders. It can replace ELISAs and provides efficient, point-of-sampling, low-cost detection of TcII/V/VI infections, with at least equivalent sensitivity, although some mammals may be difficult to trap, and, not unexpectedly, Chagas Sero K-SeT could not recognise feline IgG. Knowledge of sylvatic hosts of T. cruzi can be expanded, new reservoir species discovered, and the ecology of transmission cycles clarified, particularly with adaptation to further mammalian Orders.


Assuntos
Doença de Chagas/veterinária , Trypanosoma cruzi/isolamento & purificação , Animais , Antígenos de Protozoários/sangue , Antígenos de Protozoários/imunologia , Brasil/epidemiologia , Gatos , Doença de Chagas/sangue , Doença de Chagas/diagnóstico , Testes Diagnósticos de Rotina , Cães , Ensaio de Imunoadsorção Enzimática , Humanos , Camundongos , Trypanosoma cruzi/imunologia
20.
Biochim Biophys Acta Mol Basis Dis ; 1866(5): 165658, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-31904415

RESUMO

Chagas disease is currently endemic to 21 Latin-American countries and has also become a global concern because of globalization and mass migration of chronically infected individuals. Prophylactic and therapeutic vaccination might contribute to control the infection and the pathology, as complement of other strategies such as vector control and chemotherapy. Ideal prophylactic vaccine would produce sterilizing immunity; however, a reduction of the parasite burden would prevent progression from Trypanosoma cruzi infection to Chagas disease. A therapeutic vaccine for Chagas disease may improve or even replace the treatment with current drugs which have several side effects and require long term treatment that frequently leads to therapeutic withdrawal. Here, we will review some aspects about sub-unit vaccines, the rationale behind the selection of the immunogen, the role of adjuvants, the advantages and limitations of DNA-based vaccines and the idea of therapeutic vaccines. One of the main limitations to advance vaccine development against Chagas disease is the high number of variables that must be considered and the lack of uniform criteria among research laboratories. To make possible comparisons, much of this review will be focused on experiments that kept many variables constant including antigen mass/doses, type of eukaryotic plasmid, DNA-delivery system, mice strain and sex, lethal and sublethal model of infection, and similar immunogenicity and efficacy assessments.


Assuntos
Antígenos de Protozoários/imunologia , Cardiomiopatia Chagásica/prevenção & controle , Vacinas Protozoárias/imunologia , Projetos de Pesquisa , Trypanosoma cruzi/imunologia , Animais , Cardiomiopatia Chagásica/imunologia , Cardiomiopatia Chagásica/parasitologia , Modelos Animais de Doenças , Feminino , Humanos , Imunogenicidade da Vacina , Masculino , Camundongos , Vacinas Protozoárias/administração & dosagem , Fatores Sexuais , Vacinas de Subunidades/administração & dosagem , Vacinas de Subunidades/imunologia
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