Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 224
Filter
1.
Mem. Inst. Oswaldo Cruz ; 115: e200067, 2020. graf
Article in English | LILACS, SES-SP | ID: biblio-1135224

ABSTRACT

BACKGROUND Unfortunately, no any vaccine against leishmaniasis has been developed for human use. Therefore, a vaccine based on total Leishmania antigens could be a good and economic approach; and there are different methodologies to obtain these antigens. However, it is unknown whether the method to obtain the antigens affects the integrity and immune response caused by them. OBJECTIVES to compare the protein profile and immune response generated by total L. amazonensis antigens (TLA) produced by different methods, as well as to analyse the immune response and protection by a first-generation vaccine formulated with sonicated TLA (sTLA) and polyinosinic:polycytidylic acid [Poly (I:C)]. METHODS TLA were obtained by four different methodologies and their integrity and immune response were evaluated. Finally, sTLA was formulated with Poly (I:C) and their protective immune response was measured. FINDINGS sTLA presented a conserved protein profile and induced a strong immune response. In addition, Poly (I:C) improved the immune response generated by sTLA. Finally, sTLA + Poly (I:C) formulation provided partial protection against L. amazonensis infection. MAIN CONCLUSIONS The protein profile and immune response depend on the methodology used to obtain the antigens. Also, the formulation sTLA + Poly (I:C) provides partial protection against cutaneous leishmaniasis in mice.


Subject(s)
Humans , Animals , Mice , Protozoan Vaccines/immunology , Leishmaniasis, Cutaneous/immunology , Leishmaniasis, Cutaneous/prevention & control , Toll-Like Receptor 3/immunology , Leishmaniasis Vaccines , Leishmania , Mice, Inbred BALB C , Antigens, Protozoan/immunology
2.
Rev. Soc. Bras. Med. Trop ; 52: e20170450, 2019. tab, graf
Article in English | LILACS | ID: biblio-1041567

ABSTRACT

Abstract INTRODUCTION: Rapid diagnostic tests (RDTs) for detecting Plasmodium antigens have become increasingly common worldwide. We aimed to evaluate the accuracy of the Immuno-Rapid Malaria Pf/Pv RDT in detecting Plasmodium vivax infection compared to standard thick blood smear (TBS) under microscopy. METHODS: Hundred and eighty-one febrile patients from the hospital's regular admissions were assessed using TBS and RDT in a blinded experiment. RESULTS: RDT showed a sensitivity of 98.9%, specificity of 100%, and accuracy of 99.5% for P. vivax infection when compared to TBS. CONCLUSIONS: The RDT is highly accurate, making it a valuable diagnostic tool for P. vivax infection.


Subject(s)
Humans , Male , Female , Adult , Plasmodium falciparum/immunology , Plasmodium vivax/immunology , Malaria, Vivax/diagnosis , Malaria, Falciparum/diagnosis , Diagnostic Tests, Routine/methods , Antigens, Protozoan/immunology , Brazil , Prospective Studies , Sensitivity and Specificity
3.
Rev. Soc. Bras. Med. Trop ; 52: e20180537, 2019. tab, graf
Article in English | LILACS | ID: biblio-990433

ABSTRACT

Abstract INTRODUCTION: Elimination of malaria in areas of interrupted transmission warrants careful case assessment to avoid the reintroduction of this disease. Occasional malaria cases are reported among visitors of the Atlantic Forest area of Brazil, while data on residents of this area are scarce. METHODS: A sectional study was carried out to examine 324 individuals living in a municipality where autochthonous cases were detected. RESULTS: Asymptomatic Plasmodium infections were detected in 2.8% of the individuals by polymerase chain reaction (PCR), with one case of P. falciparum (0.3%), two cases of P. vivax (0.6%), and six cases of P. malariae (1.9%). The thick blood smears were negative in all individuals. Serological tests performed in 314 subjects were reactive in 11.1%, with 3.5% for P. falciparum and 7.7% for P. vivax. A subsample of 42 reactive individuals for any Plasmodium species showed P. malariae in 30.9% of specimens. Individuals who entered the Atlantic Forest region were 2.7 times more likely to exhibit reactive serology for P. vivax compared with individuals who did not enter this region (p<0.05). Children <15 years had a higher chance of reactive serology for P. falciparum and P. vivax than individuals ≥15 years of age (p<0.05). Individuals living in the Paraiso district had a higher chance of reactive serology for P. vivax compared to other districts (p<0.05). No associations were found between sex, past exposure to malaria, or serological response to antibodies of any Plasmodium species. CONCLUSIONS: The implications of these results for the elimination of malaria were discussed.


Subject(s)
Humans , Male , Female , Adult , Aged , Aged, 80 and over , Malaria, Vivax/diagnosis , Malaria, Vivax/transmission , Malaria, Falciparum/diagnosis , Malaria, Falciparum/transmission , Brazil/epidemiology , Enzyme-Linked Immunosorbent Assay , Polymerase Chain Reaction , Cross-Sectional Studies , DNA, Protozoan/analysis , Malaria, Vivax/epidemiology , Malaria, Falciparum/epidemiology , Asymptomatic Infections/epidemiology , Antigens, Protozoan/immunology
4.
Arq. bras. cardiol ; 110(4): 348-353, Apr. 2018. tab, graf
Article in English | LILACS | ID: biblio-888059

ABSTRACT

Abstract Background: Vimentin is a main structural protein of the cell, a component of intermediate cell filaments and immersed in cytoplasm. Vimentin is mimicked by some bacterial proteins and anti-vimentin antibodies occur in autoimmune cardiac disease, as rheumatic fever. In this work we studied vimentin distribution on LLC-MK2 cells infected with T. cruzi and anti-vimentin antibodies in sera from several clinical pictures of Chagas' disease or American Trypanosomiasis, in order to elucidate any vimentin involvement in the humoral response of this pathology. Objective: We standardized an indirect immunofluorescence assay (IFI) to determine sub cellular expression in either parasites and host cells, and ELISA to evaluate anti-vimentin antibodies in sera fron chagasic patients. Methods: We analyzed the distribution of vimentin in culture cells using indirect fluorescent assays, using as external controls anti-T. cruzi sera, derived from chronic infected patients for identification of the parasites in the same model. After infection and growth of T.cruzi amastigotes, those cells express larger amounts of vimentin, with heavy staining of cytoplasm outside the parasitophorous vacuole and some particle shadowing patterns, suggesting that vimentin are associated with cell cytoplasm. Anti-vimentin antibodies were present in most American trypanosomiasis samples, but notably, they are much more present in acute (76, 9%) or clinical defined syndromes, especially cardiac disease (87, 9%). Paradoxically, they were relatively infrequent in asymptomatic (25%) infected patients, which had a clearly positive serological reaction to parasite antigens, but had low frequency of anti-vimentin antibodies, similar to controls (2,5%). Conclusion: Our current data revealed that anti-vimentin antibodies induced during T. cruzi infection could be a marker of active disease in the host and its levels could also justify drug therapy in American Trypanosomiasis chronic infection, as a large group of asymptomatic patients would be submitted to treatment with frequent adverse reactions of the available drugs. Anti-vimentin antibodies could be a marker of cardiac muscle cell damage, appearing in American Trypanosomiasis patients during active muscle cell damage.


Resumo Fundamento: A Vimentina é uma proteína estrutural importante da célula, um componente dos filamentos celulares intermediários e imersa no citoplasma. Algumas proteínas bacterianas imitam a Vimentina e anticorpos anti-vimentina ocorrem em doenças cardíacas auto-imunes, como a febre reumática. Neste trabalho, estudamos a distribuição de vimentina em células LLC-MK2 infectadas com T. Cruzi e anticorpos anti-vimentina em soros de várias imagens clínicas da doença de Chagas ou tripanossomíases americanas, a fim de elucidar qualquer implicação da vimentina na resposta humoral desta patologia. Objetivo: padronizamos um teste de imunofluorescência indireta (IFI) para determinar a expressão subcelular em parasitas e células hospedeiras, e ELISA para testar anticorpos anti-vimentina em soros de pacientes chagásicos. Métodos: analisamos a distribuição de vimentina em células de cultura usando ensaios fluorescentes indiretos, utilizando como controles externos soros anti-T. Cruzi, derivados de pacientes com infecção crônica para a identificação de parasitas no mesmo modelo. Após a infecção e o crescimento de amastigotas de T. Cruzi, essas células expressam grandes quantidades de vimentina, com forte coloração do citoplasma fora da vacuola parasitófora e alguns padrões de sombreamento das partículas, sugerindo que a vimentina está associada ao citoplasma da célula. Os anticorpos anti-vimentina estavam presentes na maioria das amostras americanas de tripanossomíases, mas estão notavelmente mais presentes em síndromes agudas ou clinicamente definidas (76,9%), especialmente em doenças cardíacas (87,9%). Paradoxalmente, eram relativamente infrequentes em pacientes infectados assintomáticos (25%), que apresentavam uma reação sorológica claramente positiva aos antígenos parasitas, mas apresentavam baixa frequência de anticorpos anti-vimentina, semelhante aos controles (2,5%). Conclusão: Nossos dados atuais revelaram que os anticorpos anti-vimentina induzidos durante a infecção por T. Cruzi poderiam ser um marcador de doença ativa no hospedeiro e seus níveis também poderiam justificar o tratamento farmacológico em infecção crônica com tripanossomíase americana, uma vez que um grande grupo de pacientes assintomáticos seria submetido a tratamento com reações adversas frequentes aos medicamentos disponíveis. Os anticorpos anti-vimentina poderiam ser um marcador de danos nas células do músculo cardíaco, que aparece em pacientes com tripanossomíase americana durante o dano das células musculares ativas.


Subject(s)
Humans , Animals , Trypanosoma cruzi/immunology , Vimentin/immunology , Antibodies, Protozoan/immunology , Chagas Disease/immunology , Antigens, Protozoan/immunology , Reference Values , Enzyme-Linked Immunosorbent Assay/methods , Antibodies, Protozoan/analysis , Cells, Cultured , Analysis of Variance , Statistics, Nonparametric , Fluorescent Antibody Technique, Indirect/methods , Macaca mulatta , Antigens, Protozoan/analysis
5.
Mem. Inst. Oswaldo Cruz ; 112(12): 850-856, Dec. 2017. tab, graf
Article in English | LILACS | ID: biblio-1040565

ABSTRACT

BACKGROUND The surface of infected red blood cells (iRBCs) has been widely investigated because of the molecular complexity and pathogenesis mechanisms involved. Asymptomatic individuals are important in the field because they can perpetuate transmission as natural reservoirs and present a challenge for diagnosing malaria because of their low levels of circulating parasites. Recent studies of iRBC antibody recognition have shown that responses are quantitatively similar in symptomatic and asymptomatic infections, but no studies have characterised the plasmodial proteins targeted by this response. OBJECTIVES Our main objective was to identify Plasmodium falciparum proteins associated with iRBC ghosts recognised by antibodies in the sera of symptomatic and asymptomatic individuals in the Brazilian Amazon. METHODS We collected symptomatic and asymptomatic sera from patients residing in the Brazilian Amazon and P. falciparum iRBC ghosts to identify the proteins involved in natural antibody recognition by 2D-electrophoresis, western blotting, and high- resolution mass spectrometry. FINDINGS 2D gel-based immunoproteome analysis using symptomatic and asymptomatic sera identified 11 proteins with at least one unique peptide, such as chaperones HSP70-1 and HSP70-x, which likely are components of the secretion machinery/PTEX translocon. PfEMP1 is involved in antigenic variation in symptomatic infections and we found putative membrane proteins whose functions are unknown. MAIN FINDINGS Our results suggest a potential role of old and new proteins, such as antigenic variation proteins, iRBC remodelling, and membrane proteins, with no assigned functions related to the immune response against P. falciparum, providing insights into the pathogenesis, erythrocyte remodelling, and secretion machinery important for alternative diagnosis and/or malaria therapy.


Subject(s)
Humans , Plasmodium falciparum/immunology , Antibodies, Protozoan/genetics , Erythrocyte Membrane/parasitology , Antigens, Protozoan/genetics , Plasmodium falciparum/genetics , Mass Spectrometry , Antibodies, Protozoan/immunology , Electrophoresis, Gel, Two-Dimensional , Blotting, Western , Proteomics , Erythrocyte Membrane/immunology , Asymptomatic Infections , Antigens, Protozoan/immunology
6.
Rev. Soc. Bras. Med. Trop ; 50(6): 788-794, Nov.-Dec. 2017. tab, graf
Article in English | LILACS | ID: biblio-897029

ABSTRACT

Abstract INTRODUCTION: The production of the Montenegro antigen for skin test poses difficulties regarding quality control. Here, we propose that certain animal models reproducing a similar immune response to humans may be used in the quality control of Montenegro antigen production. METHODS: Fifteen Cavia porcellus (guinea pigs) were immunized with Leishmania amazonensis or Leishmania braziliensis , and, after 30 days, they were skin tested with standard Montenegro antigen. To validate C. porcellus as an animal model for skin tests, eighteen Mesocricetus auratus (hamsters) were infected with L. amazonensis or L. braziliensis , and, after 45 days, they were skin tested with standard Montenegro antigen. RESULTS: Cavia porcellus immunized with L. amazonensis or L. braziliensis , and hamsters infected with the same species presented induration reactions when skin tested with standard Montenegro antigen 48-72h after the test. CONCLUSIONS: The comparison between immunization methods and immune response from the two animal species validated C. porcellus as a good model for Montenegro skin test, and the model showed strong potential as an in vivo model in the quality control of the production of Montenegro antigen.


Subject(s)
Animals , Male , Leishmania braziliensis/immunology , Intradermal Tests/standards , Leishmaniasis, Cutaneous/diagnosis , Models, Animal , Antigens, Protozoan/biosynthesis , Antigens, Protozoan/immunology , Quality Control , Predictive Value of Tests , Sensitivity and Specificity , Leishmania/immunology
8.
Rev. Soc. Bras. Med. Trop ; 49(4): 398-407, July-Aug. 2016. tab, graf
Article in English | LILACS | ID: lil-792794

ABSTRACT

Abstract: Visceral leishmaniasis (VL) is one of the most important tropical diseases worldwide. Although chemotherapy has been widely used to treat this disease, problems related to the development of parasite resistance and side effects associated with the compounds used have been noted. Hence, alternative approaches for VL control are desirable. Some methods, such as vector control and culling of infected dogs, are insufficiently effective, with the latter not ethically recommended. The development of vaccines to prevent VL is a feasible and desirable measure for disease control; for example, some vaccines designed to protect dogs against VL have recently been brought to market. These vaccines are based on the combination of parasite fractions or recombinant proteins with adjuvants that are able to induce cellular immune responses; however, their partial efficacy and the absence of a vaccine to protect against human leishmaniasis underline the need for characterization of new vaccine candidates. This review presents recent advances in control measures for VL based on vaccine development, describing extensively studied antigens, as well as new antigenic proteins recently identified using immuno-proteomic techniques.


Subject(s)
Humans , Animals , Dogs , Antibodies, Protozoan/immunology , Protozoan Vaccines/immunology , Leishmania/immunology , Leishmaniasis, Visceral/prevention & control , Antigens, Protozoan/immunology , Protozoan Proteins/immunology , Leishmania/classification
9.
Mem. Inst. Oswaldo Cruz ; 111(6): 365-371, June 2016. tab, graf
Article in English | LILACS | ID: lil-784247

ABSTRACT

This study aimed to evaluate well-documented diagnostic antigens, named B13, 1F8 and JL7 recombinant proteins, as potential markers of seroconversion in treated chagasic patients. Prospective study, involving 203 patients treated with benznidazole, was conducted from endemic areas of northern Argentina. Follow-up was possible in 107 out of them and blood samples were taken for serology and PCR assays before and 2, 3, 6, 12, 24 and 36 months after treatment initiation. Reactivity against Trypanosoma cruzi lysate and recombinant antigens was measured by ELISA. The rate of decrease of antibody titers showed nonlinear kinetics with an abrupt drop within the first three months after initiation of treatment for all studied antigens, followed by a plateau displaying a low decay until the end of follow-up. At this point, anti-B13, anti-1F8 and anti-JL7 titers were relatively close to the cut-off line, while anti-T. cruzi antibodies still remained positive. At baseline, 60.8% (45/74) of analysed patients tested positive for parasite DNA by PCR and during the follow-up period in 34 out of 45 positive samples (75.5%) could not be detected T. cruzi DNA. Our results suggest that these antigens might be useful as early markers for monitoring antiparasitic treatment in chronic Chagas disease.


Subject(s)
Humans , Male , Female , Adult , Middle Aged , Young Adult , Antibodies, Protozoan/blood , Chagas Disease/drug therapy , Nitroimidazoles/therapeutic use , Trypanocidal Agents/therapeutic use , Antigens, Protozoan/immunology , Argentina , Chagas Disease/blood , Chronic Disease , Cohort Studies , Enzyme-Linked Immunosorbent Assay , Follow-Up Studies , Prospective Studies , Time Factors
10.
Mem. Inst. Oswaldo Cruz ; 110(8): 945-955, Dec. 2015. graf
Article in English | LILACS | ID: lil-769829

ABSTRACT

Asymptomatic Plasmodium infection carriers represent a major threat to malaria control worldwide as they are silent natural reservoirs and do not seek medical care. There are no standard criteria for asymptomaticPlasmodium infection; therefore, its diagnosis relies on the presence of the parasite during a specific period of symptomless infection. The antiparasitic immune response can result in reducedPlasmodium sp. load with control of disease manifestations, which leads to asymptomatic infection. Both the innate and adaptive immune responses seem to play major roles in asymptomatic Plasmodiuminfection; T regulatory cell activity (through the production of interleukin-10 and transforming growth factor-β) and B-cells (with a broad antibody response) both play prominent roles. Furthermore, molecules involved in the haem detoxification pathway (such as haptoglobin and haeme oxygenase-1) and iron metabolism (ferritin and activated c-Jun N-terminal kinase) have emerged in recent years as potential biomarkers and thus are helping to unravel the immune response underlying asymptomatic Plasmodium infection. The acquisition of large data sets and the use of robust statistical tools, including network analysis, associated with well-designed malaria studies will likely help elucidate the immune mechanisms responsible for asymptomatic infection.


Subject(s)
Humans , Asymptomatic Infections , Antigens, Protozoan/immunology , Carrier State/immunology , Malaria, Falciparum/immunology , Malaria, Vivax/immunology , Plasmodium/immunology , Adaptive Immunity/physiology , Biomarkers , Carrier State/parasitology , Disease Reservoirs/parasitology , Ferritins/immunology , Haptoglobins/immunology , Heme Oxygenase-1/immunology , Immunity, Innate/physiology , /immunology , JNK Mitogen-Activated Protein Kinases/immunology , Malaria, Falciparum/prevention & control , Malaria, Vivax/prevention & control , Parasitemia/immunology , Plasmodium/isolation & purification , Transforming Growth Factor beta/immunology
11.
Mem. Inst. Oswaldo Cruz ; 110(6): 732-738, Sept. 2015. tab, graf
Article in English | LILACS | ID: lil-763098

ABSTRACT

The aim of this study was to evaluate an enzyme-linked immunoassay with recombinant rhoptry protein 2 (ELISA-rROP2) for its ability to detectToxoplasma gondii ROP2-specific IgG in samples from pregnant women. The study included 236 samples that were divided into groups according to serological screening profiles for toxoplasmosis: unexposed (n = 65), probable acute infection (n = 48), possible acute infection (n = 58) and exposed to the parasite (n = 65). When an indirect immunofluorescence assay forT. gondii-specific IgG was considered as a reference test, the ELISA-rROP2 had a sensitivity of 61.8%, specificity of 62.8%, predictive positive value of 76.6% and predictive negative value of 45.4% (p = 0.0002). The ELISA-rROP2 reacted with 62.5% of the samples from pregnant women with probable acute infection and 40% of the samples from pregnant women with previous exposure (p = 0.0180). Seropositivity was observed in 50/57 (87.7%) pregnant women with possible infection. The results underscored that T. gondii rROP2 is recognised by specific IgG antibodies in both the acute and chronic phases of toxoplasmosis acquired during pregnancy. However, the sensitivity of the ELISA-rROP2 was higher in the pregnant women with probable and possible acute infections and IgM reactivity.


Subject(s)
Female , Humans , Pregnancy , Antigens, Protozoan/immunology , Enzyme-Linked Immunosorbent Assay/methods , Immunoglobulin G/blood , Membrane Proteins/immunology , Pregnancy Complications, Parasitic/diagnosis , Protozoan Proteins/immunology , Toxoplasmosis/diagnosis , Antigens, Protozoan/blood , Confidence Intervals , Enzyme-Linked Immunosorbent Assay/standards , Fluorescent Antibody Technique, Indirect , Immunoglobulin G/isolation & purification , Immunoglobulin M/blood , Immunoglobulin M/isolation & purification , Inventions/standards , Membrane Proteins/genetics , Predictive Value of Tests , Pregnancy Complications, Parasitic/blood , Pregnancy Complications, Parasitic/immunology , Protozoan Proteins/genetics , Recombinant Proteins , Reference Standards , Sensitivity and Specificity , Toxoplasma/immunology , Toxoplasmosis/blood , Toxoplasmosis/immunology
12.
Mem. Inst. Oswaldo Cruz ; 110(4): 500-506, 09/06/2015. tab, graf
Article in English | LILACS | ID: lil-748873

ABSTRACT

Re-infections with Trypanosoma cruzi are an aggravating factor for Chagas disease morbidity. The Colombian strain of T. cruzi represents multiclonal populations formed by clonally propagating organisms with different tropisms and degrees of virulence. In the present study, the influence of successive inoculations with clones of the Colombian strain, exhibiting different degrees of virulence, on chronic myocarditis and the humoral and cellular immune responses (Col-C1 high virulence, Col-C8 medium virulence and Col-C5 low virulence) were demonstrated. Mice from three groups with a single infection were evaluated during the acute (14th-30th day) and chronic phases for 175 days. An immunofluorescence assay, ELISA and delayed type hypersensitivity (DTH) cutaneous test were also performed. Mice with a triple infection were studied on the 115th-175th days following first inoculation. The levels of IgM and IgG2a were higher in the animals with a triple infection. DTH showed a higher intensity in the inflammatory infiltrate based on the morphometric analysis during a 48 h period of the triple infection and at 24 h with a single infection. The histopathology of the heart demonstrated significant exacerbation of cardiac inflammatory lesions confirmed by the morphometric test. The humoral responses indicate a reaction to the triple infection, even with clones of the same strain.


Subject(s)
Animals , Mice , Chagas Disease/parasitology , Myocarditis/parasitology , Trypanosoma cruzi/pathogenicity , Antigens, Protozoan/immunology , Chronic Disease , Cloning, Molecular , Chagas Disease/pathology , Enzyme-Linked Immunosorbent Assay , Immunity, Cellular/immunology , Myocarditis/pathology , Parasitemia/immunology , Trypanosoma cruzi/genetics , Trypanosoma cruzi/immunology , Virulence/immunology
13.
Rev. bras. parasitol. vet ; 24(2): 148-154, Apr-Jun/2015. graf
Article in English | LILACS | ID: lil-750757

ABSTRACT

Neosporosis is a disease caused by the protozoon Neospora caninum that leads to significant economic losses in many countries. In the present study, we report on use of the recombinant protein NcSRS2 of N. caninum expressed in Pichia pastoris in an indirect immunoenzymatic assay (ELISA) for diagnosing neosporosis infection in sheep and dogs. We observed that the ELISA test yielded specificity of 94.5% and sensitivity of 100% for sheep and specificity of 93.3% and sensitivity of 100% for dogs. We observed that the sensitivity was higher than shown by the indirect fluorescent antibody test, and this was confirmed by means of Western blot. The results from this study suggest that the recombinant protein expressed in P. pastoris is a suitable antigen for use in immunodiagnosis to detect N. caninum in two important species exposed to this parasitosis.


A neosporose é uma doença causada pelo protozoário Neospora caninum que leva a perdas econômicas importantes em muitos países. No presente estudo, é descrita a utilização da proteína recombinante NcSRS2 de N. caninum expressa em Pichia pastoris em um ensaio imunoenzimático indireto (ELISA) para o diagnóstico de infecção por Neospora em ovelhas e cães. Observou-se, que utilizando-se um ELISA, o teste produziu uma especificidade de 94,5% e uma sensibilidade de 100% para ovinos; e uma especificidade de 93,3% e sensibilidade de 100% para cães. Uma maior sensibilidade foi observada em relação à IFI que foi confirmada por Western blot. Os resultados deste estudo sugerem que a proteína recombinante expressa em P. pastoris é bom antígeno para ser utilizado no diagnóstico imunológico para detectar N. caninum em duas espécies importantes expostas a esta parasitose.


Subject(s)
Animals , Dogs , Protozoan Infections, Animal/blood , Sheep Diseases/blood , Enzyme-Linked Immunosorbent Assay , Protozoan Proteins/blood , Neospora/immunology , Dog Diseases/parasitology , Dog Diseases/blood , Antigens, Protozoan/blood , Antigens, Surface/blood , Pichia/metabolism , Protozoan Infections, Animal/diagnosis , Sheep Diseases/diagnosis , Sheep Diseases/parasitology , Sheep , Protozoan Proteins/biosynthesis , Protozoan Proteins/immunology , Dog Diseases/diagnosis , Antigens, Protozoan/biosynthesis , Antigens, Protozoan/immunology , Antigens, Surface/biosynthesis , Antigens, Surface/immunology
14.
Mem. Inst. Oswaldo Cruz ; 110(3): 445-451, 05/2015. graf
Article in English | LILACS | ID: lil-745966

ABSTRACT

Prevention of Trypanosoma cruzi infection in mammals likely depends on either prevention of the invading trypomastigotes from infecting host cells or the rapid recognition and killing of the newly infected cells by T. cruzi-specific T cells. We show here that multiple rounds of infection and cure (by drug therapy) fails to protect mice from reinfection, despite the generation of potent T cell responses. This disappointing result is similar to that obtained with many other vaccine protocols used in attempts to protect animals from T. cruzi infection. We have previously shown that immune recognition of T. cruzi infection is significantly delayed both at the systemic level and at the level of the infected host cell. The systemic delay appears to be the result of a stealth infection process that fails to trigger substantial innate recognition mechanisms while the delay at the cellular level is related to the immunodominance of highly variable gene family proteins, in particular those of the trans-sialidase family. Here we discuss how these previous studies and the new findings herein impact our thoughts on the potential of prophylactic vaccination to serve a productive role in the prevention of T. cruzi infection and Chagas disease.


Subject(s)
Animals , Female , Mice , Chagas Disease/immunology , Protozoan Vaccines/immunology , Trypanosoma cruzi/immunology , Antibodies, Protozoan/immunology , Antigens, Protozoan/immunology , Chagas Disease/parasitology , Chagas Disease/prevention & control
15.
Mem. Inst. Oswaldo Cruz ; 110(3): 414-421, 05/2015. tab, graf
Article in English | LILACS | ID: lil-745978

ABSTRACT

The aim of this review is to describe the contributions of the knowledge of T-cell responses to the understanding of the physiopathology and the responsiveness to etiological treatment during the chronic phase of Chagas disease. T-helper (Th)1 and interleukin (IL)-10 Trypanosoma cruzi-specific T-cells have been linked to the asymptomatic phase or to severe clinical forms of the disease, respectively or vice versa, depending on the T. cruzi antigen source, the patient’s location and the performed immunological assays. Parasite-specific T-cell responses are modulated after benznidazole (BZ) treatment in chronically T. cruzi-infected subjects in association with a significant decrease in T. cruzi-specific antibodies. Accumulating evidence has indicated that treatment efficacy during experimental infection with T. cruzi results from the combined action of BZ and the activation of appropriate immune responses in the host. However, strong support of this interaction in T. cruzi-infected humans remains lacking. Overall, the quality of T-cell responses might be a key factor in not only disease evolution, but also chemotherapy responsiveness. Immunological parameters are potential indicators of treatment response regardless of achievement of cure. Providing tools to monitor and provide early predictions of treatment success will allow the development of new therapeutic options.


Subject(s)
Humans , Chagas Disease/immunology , Nitroimidazoles/therapeutic use , T-Lymphocytes/immunology , Trypanocidal Agents/therapeutic use , Trypanosoma cruzi/immunology , Antigens, Protozoan/immunology , Chronic Disease , Chagas Disease/drug therapy , T-Lymphocytes/drug effects , Trypanosoma cruzi/drug effects
16.
Rev. Soc. Bras. Med. Trop ; 48(2): 188-193, mar-apr/2015. tab, graf
Article in English | LILACS | ID: lil-746220

ABSTRACT

INTRODUCTION: Various methods are used for the diagnosis of visceral leishmaniasis (VL), such as microscopic examination, culture and inoculation of laboratory animals; however, serological assays are commonly used for the detection of antibodies in serum samples with a wide range of specificity and sensitivity. METHODS: The purpose of this study was to compare three serological methods, including rA2-ELISA, the recombinant KE16 (rKE16) dipstick test and the direct agglutination test (DAT), for the detection of antibodies against VL antigens. The assays utilized 350 statistically based random serum samples from domestic dogs with clinical symptoms as well as samples from asymptomatic and healthy dogs from rural and urban areas of the Meshkinshahr district, northwestern Iran. RESULTS: Samples were assessed, and the following positive rates were obtained: 11.5% by rKE16, 26.9% by DAT and 49.8% by ELISA. The sensitivity among symptomatic dogs was 32.4% with rKE16, 100% with DAT and 52.9% with ELISA. Conversely, rA2-ELISA was less specific for asymptomatic dogs, at 46.5%, compared with DAT, at 88.9%. CONCLUSIONS : This study recommends rA2-ELISA as a parallel assay combined with DAT to detect VL infection among dogs. Further evaluations should be performed to develop an inexpensive and reliable serologic test for the detection of Leishmania infantum among infected dogs. .


Subject(s)
Animals , Dogs , Female , Male , Dog Diseases/diagnosis , Leishmania infantum/immunology , Leishmaniasis, Visceral/veterinary , Agglutination Tests/methods , Agglutination Tests/veterinary , Antibodies, Protozoan/blood , Antigens, Protozoan/immunology , Enzyme-Linked Immunosorbent Assay/veterinary , Leishmaniasis, Visceral/diagnosis , Sensitivity and Specificity
17.
Córdoba; s.n; 2015. 90 p. tab, graf.
Thesis in Spanish | LILACS | ID: biblio-831447

ABSTRACT

La giardiasis es una infección intestinal de amplia distribución mundial, que presenta manifestaciones clínicas con variaciones desde la infección asintomática, a la enfermedad aguda o crónica asociada con diarrea prolongada y severa y malabsorción de nutrientes. Su agente etiológico es el protozoario Giardia lamblia. La infección se inicia por la ingestión de quistes del parásito, presentes en agua y/o alimentos contaminados o por contacto orofecal directo. Los mecanismos a través de los cuales G. lamblia causa le enfermedad permanecen aún en discusión, pero los principales postulados incluyen tanto alteraciones morfológicas como funcionales de la mucosa intestinal a causa de la adhesión de los trofozoítos a las células epiteliales mediante el disco ventral o suctorio, que afectaría la absorción de nutrientes. El principal tratamiento es la administración de drogas antiparasitarias, muchas de las cuales han demostrado tener un amplio rango de efectos secundarios desagradable, lo cual sumado a la ocurrencia de resultados clínicos insatisfactorios y al surgimiento de cepas resistentes, ha impulsado la búsqueda de nuevas estrategias terapéuticas. Es por ello que el objetivo de esta tesis doctoral fue evaluar la actividad antigiardiásica de componentes alimentarios de origen vegetal y microbiano, como así también la interacción de los mismos con drogas antiparasitarias de uso común.


ABSTRACT: Giardiasis is an intestinal infection of worldwide distribution, presenting with clinical manifestations ranging from asymptomatic infection to acute or chronic disease associated with prolonged and severe diarrhea and malabsorption of nutrients, Its etiologic agent is the protozoan Giardia lamblia. Infection is initiated by ingestion of parasite cysts present in contaminated water and food or by direct fecal-oral contact The mechanisms through which G. lamblia causes disease will remain still under discussion, but the main tenets include both mechanical obstruction as morphological and functional alterations of the intestinal mucosa because of the adherence of trophozoites to epithelial cells by ventral disk that affect nutrient absorption. The main treatment is the administration of antiparasitic drugs, many of which have been shown to have a wide range of unpleasant side effects, which added to the occurrence of unsatisfactory clinical results and the emergence of resistant strains, has prompted the search for new therapeutic strategies.


Subject(s)
Humans , Male , Female , Antigens, Protozoan/immunology , Food Microbiology , Giardia lamblia/immunology , Giardiasis/prevention & control , Giardiasis/therapy , Antiprotozoal Agents/therapeutic use , Food Quality , Giardiasis/parasitology , Metronidazole/therapeutic use , Plants/microbiology
18.
J. bras. nefrol ; 36(4): 430-436, Oct-Dec/2014. tab, graf
Article in Portuguese | LILACS | ID: lil-731139

ABSTRACT

Introdução: Atualmente, é descrita elevada prevalência de hipovitaminose D no Lúpus Eritematoso Sistêmico (LES), a qual se associa a algumas manifestações clínicas e maior atividade inflamatória. Objetivo: Avaliar a associação entre insuficiência de vitamina D com LES e marcadores inflamatórios. Métodos: Estudo transversal, tendo sido avaliados 45 pacientes com LES e 24 controles sem a doença. Níveis de 25-hidroxivitamina D [25(OH)D] menores que 30 ng/mL foram considerados insuficientes. A atividade da doença foi avaliada pelo Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Foram avaliados, ainda, proteína C reativa ultrassensível (PCRus) e interleucina-6 (IL-6) para verificação do status inflamatório. Para avaliação do envolvimento renal, foram realizados análise de elementos anormais e sedimentoscopia urinárias (EAS), hematúria e piúria quantitativas, proteinúria e depuração de creatinina em urina de 24 horas e anti-DNA de dupla hélice sérico. Resultados: A prevalência de insuficiência de 25(OH)D foi de 55% nos pacientes lúpicos e 8% nos participantes controles (p = 0,001). A mediana da 25(OH)D foi menor nos pacientes do que no grupo controle. Os pacientes com insuficiência de 25(OH)D apresentaram níveis mais elevados de IL-6 e maior prevalência de hematúria ao EAS. Não houve correlação entre vitamina D, nefrite lúpica e SLEDAI. Conclusão: Em nosso estudo, a insuficiência de vitamina D foi mais prevalente em pacientes com LES e se associou com níveis mais elevados de IL-6 e presença de hematúria. .


Introduction: Nowadays it is described a high prevalence of hypovitaminosis D in Systemic Lupus Erythematosus (SLE), which is associated with some clinical manifestations and increased inflammatory activity. Objective: To evaluate the association between vitamin D insufficiency with SLE and inflammatory markers. Methods: Cross-sectional study, in which have been evaluated 45 SLE patients and 24 controls without the disease. Levels of 25-hydroxyvitamin D [25(OH) D] less than 30 ng/mL were considered inadequate. Disease activity was assessed by the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). High sensitivity C reactive protein (hsCRP) and interleukin-6 (IL-6) were evaluated for verification of the inflammatory status. For assessment of renal involvement, analysis of abnormal elements and urinay sediment (AES), quantitative hematuria and pyuria, proteinuria and creatinine clearance in 24-hour urine and serum anti-double stranded DNA were performed. Results: The prevalence of 25(OH)D insufficiency was 55% in SLE patients and 8% in the controls participants (p = 0.001). The median of 25(OH)D was lower in patients than in controls. Patients with insufficient 25(OH)D had higher levels of IL-6 and higher prevalence of hematuria in the AES. There was no correlation between vitamin D and SLEDAI or lupus nephritis. Conclusion: In our study, vitamin D deficiency was more prevalent in patients with SLE and was associated with higher levels of IL-6 and hematuria. .


Subject(s)
Animals , Rabbits , Antigens, Protozoan/immunology , Membrane Proteins/immunology , Protein Folding , Plasmodium falciparum/immunology , Protozoan Proteins/immunology , Sarcosine/analogs & derivatives , Antibodies, Protozoan/immunology , Antigens, Protozoan/biosynthesis , Antigens, Protozoan/genetics , Antigens, Protozoan/isolation & purification , Cysteine , Chromatography, Affinity/methods , Chromatography, Ion Exchange/methods , Edetic Acid , Endotoxins , Escherichia coli , Fermentation , Gene Expression , Membrane Proteins/biosynthesis , Membrane Proteins/genetics , Membrane Proteins/isolation & purification , Nickel , Protein Structure, Tertiary , Plasmodium falciparum/genetics , Protozoan Proteins/biosynthesis , Protozoan Proteins/genetics , Protozoan Proteins/isolation & purification , Sucrose
19.
Mem. Inst. Oswaldo Cruz ; 109(5): 608-617, 19/08/2014. tab, graf
Article in English | LILACS | ID: lil-720427

ABSTRACT

Plasmodium vivax infects human erythrocytes through a major pathway that requires interaction between an apical parasite protein, the Duffy binding protein (PvDBP) and its receptor on reticulocytes, the Duffy antigen/receptor for chemokines (DARC). The importance of the interaction between PvDBP (region II, DBPII) and DARC to P. vivax infection has motivated our malaria research group at Oswaldo Cruz Foundation (state of Minas Gerais, Brazil) to conduct a number of immunoepidemiological studies to characterise the naturally acquired immunity to PvDBP in populations living in the Amazon rainforest. In this review, we provide an update on the immunology and molecular epidemiology of PvDBP in the Brazilian Amazon - an area of markedly unstable malaria transmission - and compare it with data from other parts of Latin America, as well as Asia and Oceania.


Subject(s)
Humans , Antigens, Protozoan/immunology , Malaria Vaccines/immunology , Malaria, Vivax/prevention & control , Plasmodium vivax/immunology , Protozoan Proteins/immunology , Receptors, Cell Surface/immunology , Antibodies, Protozoan/blood , Antigens, Protozoan/chemistry , Brazil , Enzyme-Linked Immunosorbent Assay , Geography, Medical , Protozoan Proteins/chemistry , Receptors, Cell Surface/chemistry
20.
Mem. Inst. Oswaldo Cruz ; 109(1): 99-107, 02/2014. tab, graf
Article in English | LILACS | ID: lil-703638

ABSTRACT

The association of single nucleotide polymorphisms (SNPs) in the interferon (IFN)-γ gene ( IFNG ) with different types of retinal scar lesions presumably caused by toxoplasmosis were investigated in a cross-sectional population-based genetic study. Ten SNPs were investigated and after Bonferroni correction, only the associations between SNPs rs2069718 and rs3181035 with retinal/retinochoroidal scar lesions type A (most severe scar lesions) and C (least severe scar lesions), respectively, remained significant. The associations of two different IFNG SNPs with two different types of retinal lesions attributable to toxoplasmosis support the hypothesis that different inflammatory mechanisms underlie the development of these lesions. The in vitro analysis of IFN-γ secretion by peripheral blood mononuclear cells stimulated with Toxoplasma gondii antigens was also investigated. The association between SNP rs2069718 and type A scar lesions revealed that differential IFN-γ levels are correlated with distinct genotypes. However, no correlation was observed with IFN-γ secretion levels and the SNP rs3181035 , which was significantly associated with type C scar lesions. Our findings strongly suggest that immunogenetic studies of individuals with congenital or postnatally acquired infection are needed to better understand the role of IFN-γ and its polymorphisms in the pathogenesis of ocular toxoplasmosis.


Subject(s)
Adult , Female , Humans , Male , Middle Aged , Choroid Diseases/parasitology , Cicatrix/parasitology , Interferon-gamma/genetics , Polymorphism, Single Nucleotide/genetics , Retinal Diseases/parasitology , Toxoplasmosis, Ocular/complications , Antigens, Protozoan/immunology , Cross-Sectional Studies , Genetic Association Studies , Genotype , Gene Frequency/immunology , Interferon-gamma , Leukocytes, Mononuclear/parasitology , Phenotype , Risk Factors , Severity of Illness Index , Socioeconomic Factors , Toxoplasmosis, Ocular/blood , Toxoplasmosis, Ocular/immunology
SELECTION OF CITATIONS
SEARCH DETAIL