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1.
Oncotarget ; 8(35): 58003-58020, 2017 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-28938533

RESUMO

Prophylactic and/or therapeutic vaccines have an important potential to control Trypanosoma cruzi (T. cruzi)infection. The involvement of regulatory/suppressor immune cells after an immunization treatment and T. cruzi infection has never been addressed. Here we show that a new trans-sialidase-based immunogen (TSf) was able to confer protection, correlating not only with beneficial changes in effector immune parameters, but also influencing populations of cells related to immune control. Regarding the effector response, mice immunized with TSf showed a TS-specific antibody response, significant delayed-type hypersensitivity (DTH) reactivity and increased production of IFN-γ by CD8+ splenocytes. After a challenge with T. cruzi, TSf-immunized mice showed 90% survival and low parasitemia as compared with 40% survival and high parasitemia in PBS-immunized mice. In relation to the regulatory/suppressor arm of the immune system, after T. cruzi infection TSf-immunized mice showed an increase in spleen CD4+ Foxp3+ regulatory T cells (Treg) as compared to PBS-inoculated and infected mice. Moreover, although T. cruzi infection elicited a notable increase in myeloid derived suppressor cells (MDSC) in the spleen of PBS-inoculated mice, TSf-immunized mice showed a significantly lower increase of MDSC. Results presented herein highlight the need of studying the immune response as a whole when a vaccine candidate is rationally tested.

2.
Trop Med Int Health ; 21(12): 1545-1551, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27699992

RESUMO

OBJECTIVE: Autoantibodies cross-reacting with the ß1 adrenergic receptor (anti-ß1AR and anti-p2ß) and cardiac myosin antigens (anti-B13) have been related to the pathogenesis of chronic Chagas heart disease (CCHD). Studies exploring their levels in different stages are scarce. We aimed to evaluate the relationship of these autoantibodies with the clinical profile of chronic patients, especially regarding their classificatory accuracy in severe presentation with heart failure. METHODS AND RESULTS: We conducted a cross-sectional study of 155 T. cruzi-seropositive patients and 26 age- and gender-matched healthy controls. They were categorised in three stages of CCHD. Serum antibodies were measured by specific immunoassays. Symptomatic individuals showed increased levels of anti-ß1AR and anti-B13, while anti-p2ß antibodies were similar between groups. A composite logistic regression model including anti-B13, anti-ß1AR antibody levels and age was able to predict systolic heart failure yielding an area under the curve of 83% (sensitivity of 67% and specificity of 89%). CONCLUSIONS: In our study, anti-ß1AR and anti-B13 antibodies were higher in individuals with chronic Chagas heart disease stage III, mainly in those with dilated cardiomyopathy associated with systolic heart failure. Logistic regression analysis showed that both antibodies were good predictors of severe CCHD. As well as being involved in disease progression, anti-ß1AR and anti-B13 antibodies may be used as a serum marker of poor prognosis in terms of heart compromise.


Assuntos
Autoanticorpos/sangue , Miosinas Cardíacas/imunologia , Cardiomiopatia Chagásica/imunologia , Insuficiência Cardíaca/etiologia , Receptores Adrenérgicos beta 1/imunologia , Trypanosoma cruzi/imunologia , Adulto , Idoso , Área Sob a Curva , Cardiomiopatia Chagásica/sangue , Cardiomiopatia Chagásica/parasitologia , Doença de Chagas , Estudos Transversais , Progressão da Doença , Feminino , Insuficiência Cardíaca/imunologia , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Prognóstico , Índice de Gravidade de Doença
3.
Infect Genet Evol ; 43: 123-9, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27208806

RESUMO

Different DNA markers to genotype Trypanosoma cruzi are now available. However, due to the low quantity of parasites present in biological samples, DNA markers with high copy number like kinetoplast minicircles are needed. The aim of this study was to complete a DNA assay called minicircle lineage specific-PCR (MLS-PCR) previously developed to genotype the T. cruzi DTUs TcV and TcVI, in order to genotype DTUs TcI and TcII and to improve TcVI detection. We screened kinetoplast minicircle hypervariable sequences from cloned PCR products from reference strains belonging to the mentioned DTUs using specific kDNA probes. With the four highly specific sequences selected, we designed primers to be used in the MLS-PCR to directly genotype T. cruzi from biological samples. High specificity and sensitivity were obtained when we evaluated the new approach for TcI, TcII, TcV and TcVI genotyping in twenty two T. cruzi reference strains. Afterward, we compared it with hybridization tests using specific kDNA probes in 32 blood samples from chronic chagasic patients from North Eastern Argentina. With both tests we were able to genotype 94% of the samples and the concordance between them was very good (kappa=0.855). The most frequent T. cruzi DTUs detected were TcV and TcVI, followed by TcII and much lower TcI. A unique T. cruzi DTU was detected in 18 samples meantime more than one in the remaining; being TcV and TcVI the most frequent association. A high percentage of mixed detections were obtained with both assays and its impact was discussed.


Assuntos
Doença de Chagas/diagnóstico , DNA de Cinetoplasto/genética , Tipagem de Sequências Multilocus/métodos , Trypanosoma cruzi/genética , Argentina , Variação Genética , Genótipo , Humanos , Reação em Cadeia da Polimerase/métodos , Sensibilidade e Especificidade , Análise de Sequência de DNA/métodos , Trypanosoma cruzi/isolamento & purificação
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