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1.
J Parasitol ; 100(1): 73-8, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24147835

RESUMO

Diseases such as leishmaniases are important causes of morbidity and mortality in Brazil, and their diagnoses need to be improved. The use of monoclonal antibodies has ensured high specificity to immunodiagnosis. The development of an immunosensor, coupling a monoclonal antibody to a bioelectronic device capable of quickly detecting Leishmania sp. antigens both qualitatively and quantitatively, is a promising alternative for the diagnosis of leishmaniasis due to its high specificity, low cost, and portability, compared with conventional methods. The present work was aimed at developing an immunosensor-based assay for detecting Leishmania infantum antigens in tissues of infected hosts. Four hybridomas producing monoclonal antibodies against L. infantum had their specificity confirmed by enzyme-linked immunosorbent assay. These antibodies were immobilized on a gold surface, covered with a thin film of 2-aminoethanethiol (cysteamine) and glutaraldehyde, blocked with glycine, and placed into contact with extracts of L. infantum -infected and noninfected control hamster spleens. The assay was able to detect 1.8 × 10(4) amastigotes/g of infected tissue. These results demonstrated that this assay may be useful for quantifying L. infantum amastigotes in organs of experimental animals for studies on pathogenesis and immunity and that it is a promising tool for the development of a diagnostic method, based on antigen detection, of human and dog visceral leishmaniasis.


Assuntos
Anticorpos Monoclonais , Antígenos de Protozoários/isolamento & purificação , Leishmania infantum/imunologia , Leishmaniose Visceral/diagnóstico , Baço/parasitologia , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Antiprotozoários/imunologia , Especificidade de Anticorpos , Técnicas Biossensoriais/métodos , Cricetinae , Ensaio de Imunoadsorção Enzimática , Imunoglobulina G/imunologia , Leishmania infantum/isolamento & purificação , Mesocricetus , Camundongos , Camundongos Endogâmicos BALB C , Organismos Livres de Patógenos Específicos , Baço/imunologia
2.
Parasite Immunol ; 35(5-6): 188-93, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23398517

RESUMO

Infections with Trichuris trichiura and other trichurid nematodes have been reported to display protective effects against atopy, allergic and autoimmune diseases. The aims of the present study were to investigate the immunomodulatory properties of T. trichiura adult worm extract (TtE) and its fractions (TtEFs) on the production of cytokines by peripheral blood mononuclear cells and to identify their proteinaceous components. Fourteen TtEFs were obtained by ion exchange chromatography and tested for effects on cytokine production by peripheral blood mononuclear cells. The molecular constituents of the six most active fractions were evaluated using nano-LC/mass spectrometry. The homology between T. trichiura and the related nematode Trichinella spiralis was used to identify 12 proteins in TtEFs. Among those identified, fructose biphosphate aldolase, a homologue of macrophage migration inhibitory factor and heat-shock protein 70 may contribute to the immunomodulatory effects of TtEFs. The identification of such proteins could lead to the development of novel drugs for the therapy of allergic and other inflammatory diseases.


Assuntos
Citocinas/sangue , Proteínas de Helminto/imunologia , Leucócitos Mononucleares/imunologia , Trichuris/imunologia , Adulto , Animais , Criança , Cromatografia por Troca Iônica , Frutose-Bifosfato Aldolase/química , Frutose-Bifosfato Aldolase/imunologia , Proteínas de Choque Térmico HSP70/imunologia , Proteínas de Helminto/química , Humanos , Proteômica , Trichinella spiralis/química , Tricuríase/imunologia , Tricuríase/parasitologia , Trichuris/química , Adulto Jovem
3.
J Parasitol ; 97(6): 1080-4, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21740247

RESUMO

Toxoplasmosis is a cosmopolitan protozoan infection. Data regarding risk factors for the post-natal acquisition of Toxoplasma gondii infection in childhood are limited. We conducted a serological survey for T. gondii IgG antibodies and associated risk factors in 1,217 children 4-11-yr-old from Salvador, Brazil, using a commercial ELISA kit; antibodies were found in 17.5% of the children. Age (OR  =  2.18; 95% CI: 1.50-3.17) and maternal schooling level (OR  =  0.62; 95% CI: 0.42-0.92) were negatively associated with infection. A greater number of siblings (OR  =  1.53; 95% CI: 1.12-2.09), cat at home (OR  =  1.54; 95% CI: 1.06-2.24), house with non-treated piped water (OR  =  2.54; 95% CI: 1.22-5.31), and the absence of a flush toilet at home (OR  =  1.45; 95% CI: 1.04-2.01) were positively associated with T. gondii infection. Our data suggest that low socioeconomic levels and poor hygiene habits are important factors in favoring T. gondii infection.


Assuntos
Anticorpos Antiprotozoários/sangue , Toxoplasma/imunologia , Toxoplasmose/epidemiologia , Toxoplasmose/transmissão , Animais , Brasil , Doenças do Gato/parasitologia , Doenças do Gato/transmissão , Gatos , Criança , Pré-Escolar , Humanos , Higiene/normas , Imunoglobulina G/sangue , Modelos Logísticos , Análise Multivariada , Oocistos , Fatores de Risco , Estudos Soroepidemiológicos , Fatores Socioeconômicos , Inquéritos e Questionários , Toxoplasmose Animal/transmissão , População Urbana
4.
Parasite Immunol ; 32(4): 259-66, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20398226

RESUMO

This work aimed at investigating the lipid profile of zoonotic visceral leishmaniasis (VL) patients' sera and the effect of lipoproteins on the in vitro production of tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, IL-10 and IL-12 by Leishmania infantum-infected and uninfected macrophages. Lipids were quantified in 26 VL patients' sera and 26 healthy controls from a VL endemic area. The patients' sera had higher triglyceride and very low density lipoprotein (VLDL) levels, and much lower apolipoprotein A1, total cholesterol, low density lipoprotein (LDL) and high density lipoprotein (HDL) levels than the control sera. Lipoprotein fractions were obtained by ultracentrifugation of sera. The addition of LDL and HDL to Leishmania-infected and uninfected macrophages, in physiological concentrations, enhanced the production of IL-6 and IL-10, but not of IL-12. LDL stimulated the production of TNF-alpha only in infected macrophages, whereas HDL stimulated the production of lower amounts of TNF-alpha in both infected and uninfected macrophages. VLDL stimulated only the production of IL-10. It is proposed herein that LDL may influence the development of VL by promoting the production of TNF-alpha by infected macrophages. A decrease in plasma LDL in some VL patients (to 20 mg/mL or less); however, would tend to reduce the production of TNF-alpha and therefore to limit the development of immune-mediated pathology, not withstanding the fact that it would perhaps increase the permissiveness of macrophages to Leishmania growth.


Assuntos
Leishmaniose Visceral/imunologia , Leishmaniose Visceral/patologia , Lipídeos/sangue , Lipoproteínas/sangue , Macrófagos/imunologia , Macrófagos/parasitologia , Adulto , Animais , Criança , Pré-Escolar , Citocinas/metabolismo , Feminino , Humanos , Lactente , Lipoproteínas/isolamento & purificação , Masculino , Ultracentrifugação , Adulto Jovem
5.
Parasite Immunol ; 30(10): 515-24, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18665902

RESUMO

The aim of this study was to identify splenic immuno-inflammatory patterns associated with natural infection by Leishmania chagasi. Spleen samples were obtained from 72 stray dogs from an endemic area of visceral leishmaniasis. The animals were grouped into four categories as follows: (i) potentially resistant to visceral leishmaniasis, with a positive leishmanin skin test result, and negative splenic culture for Leishmania parasites (ii) potentially susceptible to visceral leishmaniasis, with a negative leishmanin skin test and positive splenic culture for Leishmania (iii) infected with undefined susceptibility status, with a positive leishmanin skin test and positive splenic culture for Leishmania, and (iv) noninfected, with a negative leishmanin skin test, negative splenic culture for Leishmania, and negative serology for anti-Leishmania antibodies. Histopathological analyses showed that there was a higher frequency of perisplenitis (18/25, P < 0.0001), granuloma (7/25, P = 0.0102), structural disorganization (14/25, P < 0.0001), and atrophy of the lymphoid follicles (20/25, P = 0.0036) and of the marginal zone (15/25, P = 0.0025) in the potentially susceptible group than in the other groups. The data presented here show changes in the white pulp of the spleen that are associated with naturally acquired visceral leishmaniasis.


Assuntos
Doenças do Cão/parasitologia , Leishmania/imunologia , Leishmaniose Visceral/veterinária , Baço/patologia , Baço/parasitologia , Animais , Doenças do Cão/imunologia , Cães , Emaciação/imunologia , Emaciação/parasitologia , Granuloma/parasitologia , Granuloma/patologia , Inflamação/parasitologia , Inflamação/patologia , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia
6.
Vet Immunol Immunopathol ; 123(3-4): 251-9, 2008 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-18359091

RESUMO

Associations among parameters commonly used as markers of infection by Leishmania sp., or of susceptibility to visceral leishmaniasis, were investigated in 325 stray dogs from an area where this disease is endemic. Evidence of infection (presence of Leishmania in splenic cultures, positive leishmanin skin test (LST) or detection of anti-Leishmania antibody activity in the serum) was found in 57% of the animals. Both evidence of weight loss (chi(2)-test, P=0.0005) and presence of specific antibody activity in the serum (chi(2)-test, P<0.0001) were directly associated with positive splenic culture. The frequencies of animals with positive splenic culture were directly correlated with the intensities of antibody activity in the serum as measured by ELISA (relative risk of 3.4 for animals with moderate antibody levels and relative risk of 8.43 for animals with high-antibody levels). A negative association was observed between positive leishmanin skin test results and emaciation (chi(2), P=0.0089). Furthermore, animals with positive splenic cultures and negative leishmanin skin test results had higher levels of total serum IgG (Kruskal-Wallis test, P=0.001) and IgG2 (Kruskal-Wallis test, P=0.05) than animals with negative splenic cultures, and were more emaciated than animals with negative LST results and positive splenic cultures. The data presented herein suggest that associating these common parameters may improve their performance in predicting susceptibility to canine visceral leishmaniasis.


Assuntos
Anticorpos Antiprotozoários/imunologia , Doenças do Cão/imunologia , Doenças do Cão/parasitologia , Leishmania/imunologia , Leishmaniose Visceral/veterinária , Baço/parasitologia , Animais , Anticorpos Antiprotozoários/sangue , Especificidade de Anticorpos , Antígenos de Protozoários , Cães , Emaciação/imunologia , Emaciação/parasitologia , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , Masculino , Baço/imunologia
7.
Microb Pathog ; 40(6): 254-60, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16626930

RESUMO

Opportunistic infections, due to disease-related immunosuppression, constitute the major cause of death in American visceral leishmaniasis (AVL). Sera from these patients (AVL sera) non-specifically inhibit the in vitro proliferative response of normal human lymphocytes to lectins or antigens. In the present work, the mediation of this inhibition by IgG, immune complexes and low- or very low-density lipoproteins was studied. AVL serum fractions containing proteins with the molecular weight of IgG, and IgG, purified from AVL sera by anion exchange chromatography, did not suppress the lymphoproliferation. Most of the suppressive activity of AVL sera was associated with a fraction containing molecules with molecular weights above 430 kDa. This would be compatible with it being due to immune complexes and/or lipoproteins, and not to soluble IL-2 receptors as reported previously. However, neither of the two possibilities seem to be the case, as (1) depletion of immune complexes by protein-A followed by protein-G chromatographies did not affect the serum suppressive activity, (2) no correlation between immune complex contents and suppressive activities in individual sera was observed, and (3) plasma lipoproteins (VLDL and LDL), purified from AVL patients and from healthy individuals, had the same degree of immunosuppressive activity.


Assuntos
Complexo Antígeno-Anticorpo/imunologia , Imunoglobulina G/imunologia , Leishmaniose Visceral/imunologia , Lipoproteínas LDL/sangue , Lipoproteínas VLDL/sangue , Animais , Concanavalina A/farmacologia , Humanos , Hospedeiro Imunocomprometido , Leishmania infantum , Leishmaniose Visceral/sangue , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/imunologia , Ativação Linfocitária/efeitos dos fármacos
8.
J Biochem Biophys Methods ; 58(3): 187-93, 2004 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-15026205

RESUMO

The present work compares six biochemical methods for extraction of lipids from human serum. Although some organic solvents were good lipid extractors, they precipitated most of the total proteins and albumin. On the other hand, methodologies using Triton X-114 and silica were efficient for extraction of lipids, while sparing the protein fraction.


Assuntos
Técnicas de Laboratório Clínico , Lipídeos/isolamento & purificação , Soro/química , Humanos , Lipídeos/química , Octoxinol , Polietilenoglicóis/química , Preservação Biológica , Proteínas/química , Sensibilidade e Especificidade , Dióxido de Silício/química , Solventes/química
9.
An Acad Bras Cienc ; 73(4): 547-59, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11743602

RESUMO

Chagas' disease is a major health problem in Latin America, where it constitutes one of the leading causes of heart failure. About one fourth of Trypanosoma cruzi-infected individuals develop chronic chagasic cardiomyopathy (CChC), the most severe form of the disease. CChC is histologically characterized by the presence of multifocal inflammatory infiltrates in the heart, composed mainly by mononuclear cells, usually adhered to myocytes and leading to myocytolysis, and frequently by interstitial fibrosis. The pathogenesis of CChC is still unclear, despite intense investigations both in human beings and in animal models of the disease. Although tissue parasitism is rare in the chronic phase of infection, an immune response targeted to persistent parasites or parasite antigens is suggested, by some authors, as the pathogenic mechanism of CChC. Other researchers affirm that the lack of correlation between tissue parasitism and intensity of inflammation suggests, along with the presence of autoreactive immune responses, that CChC results from the action of an autoimmune response. Herein we review reports from the literature and our own data, which together indicate, on one hand, the participation of parasite-specific immune responses and, on the other hand, clearly demonstrate the participation of heart-specific immune responses in the pathogenesis of CChC. Moreover, multiple factors may determine whether an individual in the indeterminate form of the disease will develop CChC. The mechanisms by which T. cruzi breaks immunological tolerance to heart antigens are also discussed.


Assuntos
Autoimunidade , Cardiomiopatia Chagásica/imunologia , Trypanosoma cruzi/imunologia , Animais , Cardiomiopatia Chagásica/patologia , Doença Crônica , Humanos , Hipersensibilidade Tardia/imunologia , Tolerância Imunológica , Camundongos , Fatores de Tempo
10.
Mem Inst Oswaldo Cruz ; 96(7): 997-9, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11685268

RESUMO

In this study, the ability of maxadilan and Lutzomyia longipalpis salivary gland lysate to enhance the infection of CBA mice by Leishmania major and of BALB/c mice by L. braziliensis was tested. No difference was observed between sizes of lesion in CBA mice infected with L. major and treated or not with salivary gland lysate or maxadilan, although they were injected in concentrations that induced cutaneous vasodilation. Although parasites were more frequently observed in foot pads and spleens of animals treated with maxadilan than in the animals treated with salivary gland lysate or saline, the differences were small and not statistically significant. The lesions in BALB/c mice infected with L. braziliensis and treated with maxadilan were slightly larger than in animals that received Leishmania alone. Such differences disappeared 14 weeks after infection, and were statistically significant only in one of two experiments.


Assuntos
Proteínas de Insetos/farmacologia , Leishmania/patogenicidade , Leishmaniose Cutânea/parasitologia , Psychodidae/química , Glândulas Salivares/química , Extratos de Tecidos/farmacologia , Vasodilatadores/farmacologia , Animais , Bovinos , Leishmania braziliensis/patogenicidade , Leishmania major/patogenicidade , Leishmaniose Cutânea/imunologia , Leishmaniose Cutânea/patologia , Camundongos , Camundongos Endogâmicos BALB C , Psychodidae/efeitos dos fármacos , Coelhos , Glândulas Salivares/efeitos dos fármacos
11.
Mem Inst Oswaldo Cruz ; 96(5): 679-81, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11500770

RESUMO

Positive Montenegro's skin test is a delayed type hypersensitivity reaction widely used as indicative of previous infection with Leishmania in both humans and dogs. Montenegro's antigen consists of a crude Leishmania antigen solution, usually containing thimerosal as preserving agent. In this work it is shown that a large proportion of dogs (11 out of 56) examined in an endemic area of leishmaniasis presented induration at the site of injection of a diluent containing thimerosal alone. This clearly demonstrates that thimerosal leads to a high number of false positive skin reactions in dogs and that its use in Montenegro's skin test antigenic preparations should be avoided.


Assuntos
Doenças do Cão/diagnóstico , Leishmania/imunologia , Leishmaniose/veterinária , Conservantes Farmacêuticos/efeitos adversos , Pele/efeitos dos fármacos , Timerosal/efeitos adversos , Animais , Brasil/epidemiologia , Doenças do Cão/epidemiologia , Doenças do Cão/imunologia , Cães , Doenças Endêmicas , Reações Falso-Positivas , Hipersensibilidade/imunologia , Hipersensibilidade/veterinária , Leishmaniose/diagnóstico , Leishmaniose/epidemiologia , Pele/imunologia , Pele/patologia , Testes Cutâneos
12.
Parasite Immunol ; 23(2): 93-101, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11240900

RESUMO

To study the role of autoreactive T cells in the pathogenesis of cardiomyopathy in Chagas' disease, we generated a cell line by repeated in vitro antigenic stimulation of purified splenic CD4+ T lymphocytes from a chronically Trypanosoma cruzi-infected mouse. Cells from this line were confirmed to be CD4+ CD8- and proliferated upon stimulation with soluble heart antigens from different animal species, as well as with T. cruzi antigen, in the presence of syngeneic feeder cells. In vitro antigen stimulation of the cell line produced a Th1 cytokine profile, with high levels of IFNgamma and IL-2 and absence of IL-4, IL-5 and IL-10. The cell line also terminated the beating of fetal heart clusters in vitro when cocultured with irradiated syngeneic normal spleen cells. In situ injection of the cell line into well established heart transplants also induced the cessation of heart beating. Finally, adoptive transfer of the cell line to heart-immunized or T. cruzi-infected BALB/c nude mice caused intense heart inflammation.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Doença de Chagas/imunologia , Trypanosoma cruzi , Animais , Linhagem Celular , Doença Crônica , Técnicas de Cocultura , Modelos Animais de Doenças , Rejeição de Enxerto , Transplante de Coração , Interferon gama/análise , Interleucina-2/análise , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Nus , Miocardite/imunologia , Miocárdio/citologia , Miocárdio/imunologia , Coelhos , Ratos , Baço/imunologia
13.
Cytobios ; 104(405): 33-41, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11219729

RESUMO

In this study computational analysis was used to compile sequence alignments, construct a dendrogram and calculate physical data in order to predict potential T-cell epitopes of the Leishmania cysteine proteinase. Using multiple alignment of human and Leishmania proteinase sequences deposited on data bank sequences, it was possible to predict that the extreme C-terminus of cysteine proteinase (Cyspep, 355-444) contained three peptides (pI 361-370, pII 415-422 and pIII 431-444) with charge score, hydrophobicity and isoelectric points compatible for human leucocyte-associated antigen (HLA) class II binding. The prediction was confirmed in vitro through the ability of synthetic peptides corresponding to the predicted regions to stimulate peripheral blood mononuclear cells of patients with leishmaniasis.


Assuntos
Cisteína Endopeptidases/imunologia , Epitopos de Linfócito T/química , Leishmania/enzimologia , Algoritmos , Sequência de Aminoácidos , Animais , Bases de Dados Factuais , Humanos , Leishmania/imunologia , Leishmaniose/imunologia , Leishmaniose/patologia , Ativação Linfocitária/efeitos dos fármacos , Peptídeos/síntese química , Peptídeos/imunologia , Peptídeos/farmacologia , Alinhamento de Sequência
14.
Acta Trop ; 69(1): 75-83, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9588243

RESUMO

American visceral leishmaniasis is a main public health matter in Brazil. Since dogs have been incriminated as the main urban reservoir of AVL agent Leishmania chagasi, a cohort study aimed at understanding the dynamics of the canine infection was carried out in Jequié--an endemic community in the Northeast of Brazil. The inhabited urban and periurban areas of Jequié were divided into 140 clusters of 0.25 km2. All 1681 dogs domiciled in 34 randomly selected clusters were screened for Leishmania antibodies in an enzyme-linked immunosorbent assay. After the seropositive dogs were painlessly eliminated, a cohort of 1286 seronegative dogs was followed up for 18 months, yielding a total of 1739.7 dog-years. The overall incidence of Leishmania infection, as assessed by the detection of Leishmania antibodies in blood samples collected every six months, was 6.55 cases/100 dog-years (95% confidence interval; CI 6.04-7.26). Two subsets of clusters, with 0.70 and 1.35 relative risks of infection, were identified. The annual emigration rate was 2.26 cases/100 dog-years (95% CI 1.86-2.66). The implications of these findings for the control of American visceral leishmaniasis are discussed.


Assuntos
Doenças do Cão/epidemiologia , Leishmaniose/veterinária , Animais , Anticorpos Antiprotozoários/sangue , Brasil/epidemiologia , Reservatórios de Doenças , Doenças do Cão/imunologia , Doenças do Cão/parasitologia , Cães , Ensaio de Imunoadsorção Enzimática , Feminino , Incidência , Leishmaniose/epidemiologia , Leishmaniose/imunologia , Leishmaniose/parasitologia , Masculino
15.
Braz J Med Biol Res ; 29(11): 1479-83, 1996 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9196549

RESUMO

The humoral antibody response to Cryptosporidium was investigated in mice genetically selected for high (H) and low (L) antibody responsiveness. Groups of 4-5 mice from two different selections, general primary (GP) and general secondary (GS), were studied. Following immunization with Cryptosporidium parvum antigens, the maximum levels of IgG in the HGP (X +/- SD = 1.13 +/- 0.35, N = 5) in the HGS (0.42 +/- 0.15, N = 4) lines, and of IgM in the HGP line (0.86 +/- 0.53, N = 5) were significantly higher than those in their L counterparts (0.04 +/- 0.02, N = 5; 0.05 +/- 0.02, N = 4 and 0.24 +/- 0.07, N = 5, respectively). These findings were similar to those reported for other immunogens. However, the IgG (0.22 +/- 0.05, N = 4) and the IgM (0.33 +/- 0.08, N = 4) responses to immunization of F1 (LGP x HGP) hybrids indicated an incomplete dominance of the low response, in contrast to the incomplete dominance of the high response described for many other antigens and representing an important exception. In addition, the H, L and F1 mice did not develop detectable infections when inoculated with live Cryptosporidium oocysts, supporting the view that a reduced or zero antibody production itself is not enough to permit the establishment of Cryptosporidium infection in adult mice.


Assuntos
Afinidade de Anticorpos/imunologia , Cryptosporidium parvum/imunologia , Animais , Afinidade de Anticorpos/genética , Criptosporidiose/imunologia , Criptosporidiose/parasitologia , Suscetibilidade a Doenças , Genes Dominantes , Genes Recessivos , Camundongos
16.
Am J Trop Med Hyg ; 55(1): 39-44, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8702020

RESUMO

Jequie, a community of about 144,500 inhabitants located in the State of Bahia, Brazil, is endemic for both visceral and cutaneous leishmaniases. In the present epidemiologic study, the urban and inhabited periurban areas of the town were divided into 140 clusters of 0.25 km2 each. The seroprevalence of canine Leishmania antibodies was investigated using an enzyme-linked immunosorbent assay as a screening test since its sensitivity was significantly higher than that of an indirect immunofluorescence assay. A total of 1,681 dogs was surveyed in 34 randomly sampled clusters. The overall prevalence of Leishmania antibodies in the dog population was 23.5%, with intracluster prevalences ranging from 0% to 67%. There was no correlation of these seroprevalences with the intracluster densities of canine populations, or with the distances from individual clusters to the town center. Moreover, the Leishmania transmission did not seem to follow any clear-cut spatial pattern, since large disparities in the seroprevalences of contiguous clusters were found. Curiously, human cases of visceral leishmaniasis have never been observed in some clusters with a relatively high prevalence of canine seroprevalences. Eight parasite isolates from seropositive dogs were found to belong to the same serodeme and zymodeme as Leishmania (L.) chagasi. The implications of these findings with respect to the epidemiology and control of American visceral leishmaniasis are discussed.


Assuntos
Doenças do Cão/epidemiologia , Leishmania infantum/isolamento & purificação , Leishmaniose Visceral/veterinária , Animais , Anticorpos Antiprotozoários/sangue , Brasil/epidemiologia , Estudos Transversais , Doenças do Cão/imunologia , Doenças do Cão/parasitologia , Cães , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Imunofluorescência/veterinária , Leishmania infantum/classificação , Leishmania infantum/imunologia , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , Masculino , Prevalência , Sensibilidade e Especificidade
17.
Parasitol Res ; 81(7): 560-4, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-7479647

RESUMO

Parasite-derived trans-sialidase (TS) activity was demonstrated in the serum and blood of Trypanosoma cruzi-infected mice. Serum TS activity levels correlated well with parasitemia in BALB/c and Swiss mice during the initial stages of the infection. However, in later stages the TS activity levels decreased despite increasing parasitemia. This coincided with the appearance of circulating TS antibodies. On the other hand, there was always a good correlation between TS activity and parasitemia in athymic nude mice. Sera from mice with high parasitemia and low TS activity inhibited TS activity in vitro. The inhibition was also observed with purified serum IgG, and it was absorbed by staphylococcal protein A, indicating that it was caused by anti-TS IgG antibodies. These antibodies inhibited the enzymatic activity of insolubilized TS, indicating that they act by interfering with the catalytic site rather than by aggregating the enzyme. The presence of inhibitory antibodies, however, did not prevent the progression of parasitemia in BALB/c mice.


Assuntos
Anticorpos Antiprotozoários/sangue , Doença de Chagas/sangue , Glicoproteínas/sangue , Neuraminidase/sangue , Trypanosoma cruzi/enzimologia , Animais , Western Blotting , Doença de Chagas/enzimologia , Doença de Chagas/imunologia , Eletroforese em Gel de Poliacrilamida , Feminino , Glicoproteínas/antagonistas & inibidores , Glicoproteínas/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/isolamento & purificação , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Neuraminidase/antagonistas & inibidores , Neuraminidase/imunologia , Parasitemia/sangue , Parasitemia/enzimologia , Parasitemia/imunologia , Fatores de Tempo , Trypanosoma cruzi/imunologia
18.
J Biol Chem ; 269(11): 7970-5, 1994 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-8132517

RESUMO

trans-Sialidase isolated from trypomastigote forms of Trypanosoma cruzi, the protozoan parasite that causes Chagas' disease, is multimeric and heterogeneous in size. We show here that limited proteolysis of tans-sialidase with papain yields a single monomeric polypeptide chain of 70 kDa that conserves full enzymatic activity on soluble and membrane-bound substrates. The papain fragment lacks most of the 12-amino acid repeats of the carboxyl-terminal domain that comprises about 50% of the native trans-sialidase. When injected into rabbits, the papain-generated fragment induces antibodies that inhibit trans-sialidase activity and trypomastigote sialylation. The repeats are also not required for the stability of the enzyme or for the correct folding during the biosynthesis in Escherichia coli, but seem essential for trans-sialidase oligomerization. We conclude that trans-sialidase is composed of two structurally and functionally independent domains.


Assuntos
Anticorpos/farmacologia , Neuraminidase/antagonistas & inibidores , Neuraminidase/metabolismo , Fragmentos de Peptídeos/imunologia , Fragmentos de Peptídeos/metabolismo , Trypanosoma cruzi/enzimologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Cromatografia de Afinidade , Primers do DNA , Immunoblotting , Cinética , Dados de Sequência Molecular , Neuraminidase/isolamento & purificação , Peptídeos/síntese química , Peptídeos/imunologia , Plasmídeos , Coelhos/imunologia , Proteínas Recombinantes/antagonistas & inibidores , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Mapeamento por Restrição , Deleção de Sequência
20.
Am J Trop Med Hyg ; 46(4): 435-9, 1992 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-1575290

RESUMO

Mouse monoclonal antibodies (MAb) were produced against antigen from epimastigote forms of the Montalvania 17 strain of Trypanosoma cruzi. Several T. cruzi-specific MAb were obtained, some of which were capable of discriminating between different T. cruzi strains.


Assuntos
Anticorpos Monoclonais/biossíntese , Antígenos de Protozoários/imunologia , Trypanosoma cruzi/imunologia , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Antiprotozoários/biossíntese , Anticorpos Antiprotozoários/imunologia , Especificidade de Anticorpos , Imunofluorescência , Immunoblotting , Técnicas Imunoenzimáticas , Ensaio Imunorradiométrico , Camundongos , Camundongos Endogâmicos BALB C , Especificidade da Espécie , Trypanosoma cruzi/isolamento & purificação
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