Publications by authors named "Yara M Gomes"

19 Publications

  • Page 1 of 1

Benznidazole: Hero or villain of cellular immune response in chronic Chagas disease patients?

Immunobiology 2021 01 4;226(1):152046. Epub 2020 Dec 4.

Instituto Aggeu Magalhães - IAM/Fiocruz, Recife, PE, Brazil. Electronic address:

Although the treatment of chronic Chagas disease (CCD) patients with Benznidazole (Bz) is still controversial, its use may prevent or delay the progression of the disease to the most severe forms. One of the main factors that can influence the effectiveness of the treatment is the possible cooperation between drug effect and the host immune response. Herein, we evaluated the immune response of peripheral blood mononuclear cells (PBMCs) infected with Trypanosoma cruzi and submitted to Bz treatment. Blood samples of CCD patients (n = 7) and non-infected individuals (n = 6) were drawn to obtain PBMCs. After cell culture, the supernatants were harvested and stored, and the cell analyzed by flow cytometer. The results showed that Bz positively regulated the molecular process of cell activation (CD80) and antigen presentation (HLA-DR), increased phagocytosis receptor and macrophage activation (CD64), and did not induce an exacerbated immune response. In conclusion, these results highlight the relevance of using Bz that, despite not being a true hero, it is also not a villain, as it presents a wide range of pharmacological/immunological response interactions, important for the immune balance in the clinical progression of CCD.
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http://dx.doi.org/10.1016/j.imbio.2020.152046DOI Listing
January 2021

Acute Chagas disease in Brazil from 2001 to 2018: A nationwide spatiotemporal analysis.

PLoS Negl Trop Dis 2020 08 3;14(8):e0008445. Epub 2020 Aug 3.

Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Salvador, Bahia, Brazil.

Background: In Brazil, acute Chagas disease (ACD) surveillance involves mandatory notification, which allows for population-based epidemiological studies. We conducted a nationwide population-based ecological analysis of the spatiotemporal patterns of ACD notifications in Brazil using secondary surveillance data obtained from the Notifiable Diseases Information System (SINAN) maintained by Brazilian Ministry of Health.

Methodology/principal Findings: In this nationwide population-based ecological all cases of ACD reported in Brazil between 2001 and 2018 were included. Epidemiological characteristics and time trends were analyzed through joinpoint regression models and spatial distribution using microregions as the unit of analysis. A total of 5,184 cases of ACD were recorded during the period under study. The annual incidence rate in Brazil was 0.16 per 100,000 inhabitants/year. Three statistically significant changes in time trends were identified: a rapid increase prior to 2005 (Period 1), a stable drop from 2005 to 2009 (Period 2), followed by another increasing trend after 2009 (Period 3). Higher frequencies were noted in males and females in the North (all three periods) and in females in Northeast (Periods 1 and 2) macroregions, as well as in individuals aged between 20-64 years in the Northeast, and children, adolescents and the elderly in the North macroregion. Vectorial transmission was the main route reported during Period 1, while oral transmission was found to increase significantly in the North during the other periods. Spatiotemporal distribution was heterogeneous in Brazil over time. Despite regional differences, over time cases of ACD decreased significantly nationwide. An increasing trend was noted in the North (especially after 2007), and significant decreases occurred after 2008 among all microregions other than those in the North, especially those in the Northeast and Central-West macroregions.

Conclusions/significance: In light of the newly identified epidemiological profile of CD transmission in Brazil, we emphasize the need for strategically integrated entomological and health surveillance actions.
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http://dx.doi.org/10.1371/journal.pntd.0008445DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7425982PMC
August 2020

Performance of recombinant chimeric proteins in the serological diagnosis of Trypanosoma cruzi infection in dogs.

PLoS Negl Trop Dis 2019 06 26;13(6):e0007545. Epub 2019 Jun 26.

Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Salvador, Bahia, Brazil.

Background: Dogs are considered sentinels in areas of Trypanosoma cruzi transmission risk to humans. ELISA is generally the method of choice for diagnosing T. cruzi exposure in dogs, but its performance substantially depends on the antigenic matrix employed. In previous studies, our group has developed four chimeric antigens (IBMP-8.1, 8.2, 8.3, and 8.4) and evaluated their potential for diagnosing T. cruzi exposure in humans. For human sera, these chimeric antigens presented superior diagnostic performances as compared to commercial tests available in Brazil, Spain, and Argentina. Therefore, in this study we have evaluated the potential of these antigenic proteins for detection of anti-T. cruzi IgG antibodies in dog sera.

Methodology/principal Findings: The IBMP-ELISA assays were optimized by checkerboard titration. Subsequently, the diagnostic potential was validated through analysis of ROC curves and the performance of the tests was determined using double entry tables. Cross-reactivity was also evaluated for babesiosis, ehrlichiosis, dirofilariosis, anaplasmosis, and visceral leishmaniasis. Best performance was shown by IBMP-8.3 and IBMP-8.4, although all four antigens demonstrated a high diagnostic performance with 46 positive and 149 negative samples tested. IBMP-8.3 demonstrated 100% sensitivity, followed by IBMP-8.4 (96.7-100%), IBMP-8.2 (73.3-87.5%), and IBMP-8.1 (50-100%). The highest specificities were achieved with IBMP-8.2 (100%) and IBMP-8.4 (100%), followed by IBMP-8.3 (96.7-97.5%) and IBMP 8.1 (89.1-100%).

Conclusions/significance: The use of chimeric antigenic matrices in immunoassays for anti-T. cruzi IgG antibody detection in sera of infected dogs was shown to be a promising tool for veterinary diagnosis and epidemiological studies. The chimeric antigens used in this work allowed also to overcome the common hurdles related to serodiagnosis of T. cruzi infection, especially regarding variation of efficiency parameters according to different strains and cross-reactivity with other infectious diseases.
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http://dx.doi.org/10.1371/journal.pntd.0007545DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6615644PMC
June 2019

Binding capacity of mannose-binding lectin (MBL) is associated with the severity of chronic Chagas cardiomyopathy.

Parasitol Int 2018 10 24;67(5):593-596. Epub 2018 May 24.

Aggeu Magalhães Institute, IAM-FIOCRUZ, PE, Brazil. Electronic address:

Chagas disease (CD) is a global problem. Currently, it affects approximately 15 million individuals in Latin America. It is well know that the human immune response is related to different clinical manifestations. Mannose binding lectin (MBL) plays an important role in innate immunity, and it mediates the phagocytosis and complement-mediated destruction of pathogens. The binding capacity is enhanced by the oligomerization of MBL. In this study, we evaluated the serum concentration and the binding capacity of MBL in patients with chronic chagasic cardiomyopathy. A total of 77 patients with chronic CD were included with indeterminate (n = 19), mild cardiac (n = 29) and severe cardiac (n = 29) forms. The serum concentration and the binding capacity were measured using enzyme-linked immunosorbent assays (ELISA). There was no significant difference in the serum MBL levels between the groups of patients. However, we found a relationship between the binding capacity and the groups studied. Our results suggest that binding capacity of MBL could be an indicator of clinical manifestation in Chronic Chagas cardiomyopathy. Furthermore, combined with the Mannose Binding Index results in a useful clinical tool for management of Chronic Chagas Patients.
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http://dx.doi.org/10.1016/j.parint.2018.05.009DOI Listing
October 2018

Genetic susceptibility to chronic Chagas disease: an overview of single nucleotide polymorphisms of cytokine genes.

Cytokine 2012 Aug 15;59(2):203-8. Epub 2012 May 15.

Department of Immunology, Centro de Pesquisas Aggeu Magalhães, Recife, Brazil.

Chagas disease is a parasitic infection that is a significant public health problem in Latin America. The mechanisms responsible for susceptibility to the infection and the mechanisms involved in the development of cardiac and digestive forms of chronic Chagas disease remain poorly understood. However, there is growing evidence that differences in susceptibility in endemic areas may be attributable to host genetic factors. The aim of this overview was to analyze the genetic susceptibility to human Chagas disease, particularly that of single nucleotide polymorphisms of cytokine genes. A review of the literature was conducted on the following databases: PubMed/MEDLINE and Scopus. The search strategy included using the following terms: "Cytokines", "Single Nucleotide Polymorphisms" and "Chagas Disease". After screening 25 citations from the databases, 19 studies were selected for the overview. A critical analysis of the data presented in the articles suggests that genetic susceptibility to Chagas disease and chronic Chagas cardiomyopathy is highly influenced by the complexity of the immune response of the host. Follow-up studies based on other populations where Chagas disease is endemic (with distinct ethnic and genetic backgrounds) need to be conducted. These should use a large sample population so as to establish what cytokine genes are involved in susceptibility to and/or progression of the disease.
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http://dx.doi.org/10.1016/j.cyto.2012.04.035DOI Listing
August 2012

Characterization of novel Leishmania infantum recombinant proteins encoded by genes from five families with distinct capacities for serodiagnosis of canine and human visceral leishmaniasis.

Am J Trop Med Hyg 2011 Dec;85(6):1025-34

Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.

To expand the available panel of recombinant proteins that can be useful for identifying Leishmania-infected dogs and for diagnosing human visceral leishmaniasis (VL), we selected recombinant antigens from L. infantum, cDNA, and genomic libraries by using pools of serum samples from infected dogs and humans. The selected DNA fragments encoded homologs of a cytoplasmic heat-shock protein 70, a kinesin, a polyubiquitin, and two novel hypothetical proteins. Histidine-tagged recombinant proteins were produced after subcloning these DNA fragments and evaluated by using an enzyme-linked immunosorbent assays with panels of canine and human serum samples. The enzyme-linked immunosorbent assays with different recombinant proteins had different sensitivities (67.4-93.0% and 36.4-97.2%) and specificities (76.1-100% and 90.4-97.3%) when tested with serum samples from Leishmania-infected dogs and human patients with VL. Overall, no single recombinant antigen was sufficient to serodiagnosis all canine or human VL cases.
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http://dx.doi.org/10.4269/ajtmh.2011.11-0102DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3225146PMC
December 2011

Immunoglobulin M antibodies against CRA and FRA recombinant antigens of Trypanosoma cruzi in chronic chagasic patients.

Hum Immunol 2011 May 1;72(5):402-5. Epub 2011 Mar 1.

Departamento de Imunologia, Centro de Pesquisas Aggeu Magalhães/Fiocruz, Recife, Brazil.

Previous works of our research group have demonstrated aspects of the humoral immune response of chronic Chagas disease using the cytoplasmatic repetitive antigen (CRA) and the flagellar repetitive antigen (FRA) of Trypanosoma cruzi. The aim of this work was to analyze the presence of specific immunoglobulin M (IgM) antibodies in chronic chagasic patients using these recombinant antigens of T. cruzi. The positivity of IgM in chronic chagasic patients against CRA and FRA antigens was determined by indirect enzyme-linked immunosorbent assay. We reported no statistical significant differences between the levels of IgM for both recombinant antigens and the different chronic clinical forms of Chagas disease. However, a small proportion of chronic chagasic patients analyzed in this study was positive for this antibody isotype. The findings of this study indicate that the IgM antibodies cannot be used to elucidate the differences in the profile of humoral immune response among chronic chagasic patients with different clinical forms using the CRA and FRA recombinant antigens of T. cruzi.
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http://dx.doi.org/10.1016/j.humimm.2011.02.015DOI Listing
May 2011

Increased levels of IgA antibodies against CRA and FRA recombinant antigens of Trypanosoma cruzi differentiate digestive forms of Chagas disease.

Hum Immunol 2010 Oct 24;71(10):964-7. Epub 2010 Jul 24.

Departamento de Imunologia, Instituto Aggeu Magalhães/Fiocruz, Recife, Pernambuco, Brazil.

In the chronic phase of Chagas disease, individuals infected by Trypanosoma cruzi may be asymptomatic or may present cardiac and/or digestive complications. Our aim here was to analyze the relationship between the presence of specific immunoglobulin A antibodies and the different chronic clinical forms of Chagas disease using two recombinant antigens of Trypanosoma cruzi, cytoplasmatic repetitive antigen and flagellar repetitive antigen. The association of this immunoglobulin isotype with the digestive and cardio-digestive forms of the disease determined by indirect enzyme-linked immunosorbent assay, strongly suggests that IgA antibodies against these recombinant antigens of T. cruzi can be used as an immunological marker of the digestive alterations caused by Chagas disease. The tests performed in this study show that it is possible to differentiate digestive forms of Chagas disease. The knowledge provided by these results may help physicians to manage early alterations in the digestive tract of patients with the indeterminate or cardiac forms of Chagas disease. Prospective studies, however, with follow-up of the patients that presenting with high levels of immunoglobulin A against cytoplasmatic repetitive antigen and flagellar repetitive antigen recombinant antigens, need to be conducted to confirm this hypothesis.
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http://dx.doi.org/10.1016/j.humimm.2010.07.004DOI Listing
October 2010

Diagnosis of Chagas disease: what has been achieved? What remains to be done with regard to diagnosis and follow up studies?

Mem Inst Oswaldo Cruz 2009 Jul;104 Suppl 1:115-21

Laboratório de Imunoparasitologia, Departamento de Imunologia, Centro de Pesquisas Aggeu Magalhães-Fiocruz, Recife, PE, Brasil.

In the acute phase and in the chronic forms of Chagas disease, the etiological diagnosis may be performed by detection of the parasite using direct or indirect parasitological methods and by the presence of antibodies in the serum by way of serological tests. Several techniques are easily available, ranging from the simplest wet smear preparation to immuno-enzymatic assays with recombinant antigens that will meet most diagnostic needs. Other tests under evaluation include a molecular test using polymerase chain reaction, which has shown promising results and may be used as a confirmatory test both in the acute and chronic phases of the disease. Better rapid tests are needed for diagnosis, some of which are already under evaluation. Additionally, there is a need for tools that can identify patients cured shortly after specific treatment. Other needs include a marker for prognosis and early diagnosis of congenital transmission.
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http://dx.doi.org/10.1590/s0074-02762009000900017DOI Listing
July 2009

Cellular immune response from Chagasic patients to CRA or FRA recombinant antigens of Trypanosoma cruzi.

J Clin Lab Anal 2008 ;22(2):91-8

Departamento de Imunologia, Centro de Pesquisas Aggeu Magalhães/Fiocruz, Recife-PE, Brazil.

We propose to analyze the relation between the cellular immune response of Chagas' disease patients after in vitro stimulation of peripheral blood mononuclear cells (PBMC) with recombinant antigens cytoplasmatic repetitive antigen (CRA) or flagellar repetitive antigen (FRA) of T. cruzi and the chronic clinical forms of disease. Cells were stimulated using phytohemagglutinin, CRA, FRA, or a soluble antigen of Epimastigota (Ag-Epi) for 24 hr, 72 hr, or 6 days. The proliferation of cells was evaluated after 6 days of culture by quantification of incorporated 3H-thymidine. Cytokines were measured in the supernatants obtained after 24 hr (tumor necrosis factor [TNF]-alpha and interleukin [IL]-4), 72 hr (IL-10), and 6 days (interferon [IFN]-gamma) using enzyme-linked immunosorbent assay (ELISA). Cells of the Chagas patients stimulated with the recombinant antigens exhibited higher proliferation responses compared with that of non-Chagas (NC) individuals. However, when proliferation was compared between patients with the cardiac form (CF) or indeterminate form (IF), it was not possible to establish a difference in the response. So far as the cytokines secreted in the culture supernatants after stimulation in vitro with T. cruzi antigens were concerned, the results showed that CRA, as well as Epi-Ag, were able to stimulate the production of TNF-alpha and IFN-gamma in Chagas patients as compared with NC individuals. However, the cytokine levels after stimulation with the T. cruzi antigens were not different between the patients with CF and IF. CRA was capable of inducing a T helper type 1 (Th1) immune response, with elevated production of TNF-alpha and IFN-gamma in Chagas patients that are carriers of CF and IF clinical forms.
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http://dx.doi.org/10.1002/jcla.20209DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6649253PMC
May 2008

[Family screening for HBB*S gene and detection of new cases of sickle cell trait in Northeastern Brazil].

Rev Saude Publica 2008 Apr 29;42(2):234-41. Epub 2008 Feb 29.

Fundação de Hematologia e Hemoterapia de Pernambuco, Recife, PE, Brazil.

Objective: To estimate the additional number of affected individuals based on the prevalence of sickle-cell syndromes among relatives of index cases.

Methods: Cross-sectional study of relatives of a random sample of index cases identified through a neonatal screening program in Northeastern Brazil, between 2001 and 2005. The extended family trial model included 463 relatives of 21 index cases. Relatives were classified as nuclear family (NF: father, mother, and siblings); first degree extended family (N1: grandparents, uncles and aunts, and first cousins); second degree extended family (N2: children of first cousins); extended family (NA: NF+N1+N2); and extended nuclear family (NA1: NF+N1). The presence of HBB*S and other abnormal hemoglobins was confirmed by high-performance liquid chromatography. The association between the presence of HBB*S and other variables was calculated using prevalence ratios and their respective 95% confidence intervals, and differences between means were calculated using Student's t test with a 5% significance level.

Results: Of relatives, 81% had no knowledge of sickle-cell anemia and HBB*S was present in 114 family members. A total of 53.3% of the studied population was considered as of reproductive age, and 80% of HBB*S carriers had already had children. Frequency was higher among NF (69%), but was also high in N1 (22.8%). NA1 screening resulted in the detection of 69 carriers additional (a 172% increase).

Conclusions: These results indicate that family screening for the identification of sickle-cell carriers should be extended to first degree relatives.
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April 2008

Molecular variations linked to the grouping of beta- and alpha-globin genes in neonatal patients with sickle cell disease in the State of Pernambuco, Brazil.

Hemoglobin 2007 ;31(1):83-8

Fundação de Hematologia e Hemoterapia de Pernambuco, Hemope, Recife, Brasil.

Various factors have been described as phenotypic modulators of sickle cell disease, such as levels of fetal hemoglobin (Hb F), presence of alpha-thalassemia (thal), and haplotypes of the beta-globin genes. In order to characterize and determine the frequency of the betaS and betaC mutations and the prevalence of -alpha3.7-thal, 74 patients with sickle cell disease detected during neonatal screening in the State of Pernambuco, Brazil, were studied. The haplotypes of the beta gene and -alpha3.7-thal were determined using polymerase chain reaction (PCR), and specific restriction endonucleases were used to establish the polymorphic sites of the haplotypes. The results showed the high frequency of the Central African Republic (CAR) or Bantu haplotype in the State of Pernambuco, Brazil. The low frequency of the Benin haplotype recorded in this study, in comparison with other states in northeast Brazil, suggests the diversity of origins of Afro-Brazilians in this region.
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http://dx.doi.org/10.1080/03630260601057153DOI Listing
May 2007

Humoral and cellular immune responses in BALB/c and C57BL/6 mice immunized with cytoplasmic (CRA) and flagellar (FRA) recombinant repetitive antigens, in acute experimental Trypanosoma cruzi infection.

Parasitol Res 2005 Jun 27;96(3):154-61. Epub 2005 Apr 27.

Centro de Pesquisas Aggeu Magalhães/FIOCRUZ, Recife, PE, Brazil.

In previous studies, cytoplasmic repetitive antigen (CRA) and flagellar repetitive antigen (FRA) proteins induced specific humoral and cellular immune responses in susceptible and resistant mice in the absence of Trypanosoma cruzi infection with a significant induction of the Interferon-gamma (IFN-gamma) production in those animals. In this follow-up paper, the immunostimulatory and protective effects of these proteins were evaluated by immunizing with CRA or FRA antigens, BALB/c and C57BL/6 mice and challenging with a T. cruzi (Y strain). Both proteins induced humoral response with high levels of IgG isotypes as well as cellular immunity with high levels of IFN-gamma when compared to controls. However, the lymphocyte proliferative response was minimal. The survival rate at 30 days post-infection was significant in CRA (60%) or FRA (50%)--immunized BALB/c mice and CRA (83.3%)--immunized C57BL/6 mice. Taken as a whole these findings indicate that CRA and FRA are immunogenic and potentially important for protective immunity.
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http://dx.doi.org/10.1007/s00436-005-1336-4DOI Listing
June 2005

Elevated concentrations of CCL2 and tumor necrosis factor-alpha in chagasic cardiomyopathy.

Clin Infect Dis 2004 Apr 10;38(7):943-50. Epub 2004 Mar 10.

Departamento de Bioquimica e Imunologia, Instituto de Ciencias Biologicas, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte Mg Brasil.

Chronic myocarditis is the main pathological finding associated with Chagas disease-related morbidity. Concentrations of CCL2, CCL3, tumor necrosis factor (TNF)-alpha, and brain natriuretic peptide (BNP) were evaluated in plasma samples obtained from patients with different clinical forms of chronic chagasic cardiomyopathy. Patients with more-severe Chagas disease had elevated plasma concentrations of TNF-alpha, CCL2, and BNP, and there was a good correlation between levels of these proteins (especially TNF-alpha ) and the degree of heart dysfunction. Indeed, TNF-alpha level was an excellent predictor of heart failure. Peripheral blood mononuclear cell samples obtained from patients with mild or severe chagasic cardiomyopathy produced greater amounts of TNF-alpha and CCL2 than did those obtained from noninfected individuals. The elevation of TNF-alpha and CCL2 levels in the plasma of patients appears to be secondary to the degree of heart dysfunction, whereas spontaneous production of TNF-alpha and CCL2 by mononuclear cells is secondary not only to heart dysfunction, but also to the underlying inflammation in the heart of chagasic patients. Measurement of the TNF-alpha level could be a useful tool in the identification of patients with heart dysfunction who may benefit from further investigation and treatment.
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http://dx.doi.org/10.1086/381892DOI Listing
April 2004

Mitogenic activity of Cratylia mollis lectin on human lymphocytes.

Biologicals 2004 Mar;32(1):57-60

Universidade Federal de Pernambuco, Centro de Ciências Biológicas (CCB), Departamento de Bioquímica, Rua Prof. Nelson Chaves S/N, 50670-901 Cidade Universitária Recife-PE, Brazil.

The mitogenic effect of Cratylia mollis seed lectin preparations containing two (Cramoll 1,4) or one molecular form (Cramoll 1) showed activity similar to the well known T-cell mitogen, concanavalin A (Con A). The effect on human lymphocytes was analyzed through a colorimetric assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). Inhibition of lymphocyte proliferation with methyl-alpha-d-mannoside (both preparations) indicated that the mitogenic effect involved carbohydrate lectin binding sites.
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http://dx.doi.org/10.1016/j.biologicals.2003.12.001DOI Listing
March 2004

Antibody isotype responses in Balb/c mice immunized with the cytoplasmic repetitive antigen and flagellar repetitive antigen of Trypanosoma cruzi.

Mem Inst Oswaldo Cruz 2003 Sep 29;98(6):823-5. Epub 2003 Oct 29.

Departamento de Imunologia, Centro de Pesquisas Aggeu Magalhães-Fiocruz, 50670-420 Recife, PE, Brasil.

In the present report we analyzed the levels of IgG1, IgG2a, IgG2b and IgG3 isotypes from Balb/c mice immunized with cytoplasmic repetitive antigen (CRA), and flagellar repetitive antigen (FRA) of Trypanosoma cruzi. The immunization was done by subcutaneous route three times (20 days apart) and the analysis was performed 14 days after each treatment. CRA-immunized mice produced high levels of all IgG isotypes, mainly IgG3 and IgG1. FRA-immunization elicited only high levels of IgG1.
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http://dx.doi.org/10.1590/s0074-02762003000600019DOI Listing
September 2003

Impedimetric evaluation for diagnosis of Chagas' disease: antigen-antibody interactions on metallic electrodes.

Biosens Bioelectron 2003 Nov;19(2):79-84

Laboratório de Eletroquímica, Departamento de Química Fundamental, Universidade Federal de Pernambuco, Cidade Universitária, 50670-901 Recife, PE, Brazil.

A polypeptide chain formed by recombinant antigens, cytoplasmic repetitive antigen (CRA) and flagellar repetitive antigen (FRA) (CF-Chimera) of Trypanosoma cruzi, was adsorbed on gold and platinum electrodes and investigated by electrochemical impedance spectroscopy on phosphate buffer saline solutions (PBS) containing a redox couple. It was found that the adsorption is strongly sensitive to the oxide layer on the electrode surface. In the majority of the experiments the antigens retained their activity as observed through their interaction with sera from chronic chagasic patients. The results expressed in terms of the charge transfer resistance across the interface, indicate the viability of using the impedance methodology for the development of a biosensor for serological diagnosis of Chagas' disease.
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http://dx.doi.org/10.1016/s0956-5663(03)00213-6DOI Listing
November 2003

Antibody isotype responses to egg antigens in human chronic Schistosomiasis mansoni before and after treatment.

Mem Inst Oswaldo Cruz 2002 ;97 Suppl 1:111-2

Departamento de Imunologia, Centro de Pesquisas Aggeu Magalhães, Fiocruz, Recife, PE, 50670-420, Brasil.

In the present communication we analyzed the levels of IgG1, IgG2, IgG3, IgG4 and IgE isotypes to soluble egg antigen of Schistosoma mansoni by ELISA in individuals from an endemic area for schistosomiasis in Northeast Brazil. The analysis was performed before and after treatment to evaluate the age-dependent pattern, and to identify differences in the reactivities to antigens. Our results suggest that schistosomiasis treatment would not interfere with this sort of immune response.
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http://dx.doi.org/10.1590/s0074-02762002000900022DOI Listing
February 2003

Use of the EIE-recombinant-Chagas-biomanguinhos kit to monitor cure of human Chagas' disease.

J Clin Lab Anal 2002 ;16(3):132-6

Bio-Manguinhos/Fiocruz, Rio de Janeiro, RJ, Brazil.

We used the EIE-Recombinant-Chagas-Biomanguinhos kit (EIE-Rec kit) developed by the Oswaldo Cruz Foundation, Brazil, to monitor cure of chagasic patients who were treated during the acute phase of T. cruzi infection. Treated patients were previously studied by parasitological and serological tests and classified as cured patients (CP) (n = 10), dissociated patients (DP) (n = 6), and noncured patients (NCP) (n = 6). When sera of these patients were assayed by EIE-Rec kit all sera from NCP and all sera from CP showed positive and negative reactions, respectively. These results were in full agreement with those obtained previously by the classical tests. Two DP showed a positive reaction; the remaining four displayed a negative reaction, similar to that observed in sera from nonchagasic (NCh) individuals, and could therefore be considered CP. Our results suggest that the EIE-Rec kit could be used to monitor the efficacy of Chagas' disease treatment.
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http://dx.doi.org/10.1002/jcla.10028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6807848PMC
October 2002
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