RESUMO
The goal of the current study was to investigate whether cruzipain, a major Trypanosoma cruzi antigen, is able to induce in mice an autoimmune response and skeletal muscle damage. We demonstrate that immunization with cruzipain triggers immunoglobulin G antibody binding to a 210-kDa antigen from a syngeneic skeletal muscle extract. The absorption of immune sera with purified myosin completely eliminated this reactivity, confirming that the protein identified is really myosin. We also found that spleen cells from immunized mice proliferated in response to a skeletal muscle extract rich in myosin and to purified myosin. Cells from control mice did not proliferate against any of the antigens tested. In addition, we observed an increase in plasma creatine kinase activity, a biochemical marker of muscle damage. Histological studies showed inflammatory infiltrates and myopathic changes in skeletal muscle of immunized animals. Electromyographic studies of these mice revealed changes such as are found in inflammatory or necrotic myopathy. Altogether, our results suggest that this experimental model provides strong evidence for a pathogenic role of anticruzipain immune response in the development of muscle tissue damage.
Assuntos
Autoimunidade/efeitos dos fármacos , Cisteína Endopeptidases/farmacologia , Músculo Esquelético/imunologia , Músculo Esquelético/patologia , Animais , Autoanticorpos/sangue , Autoanticorpos/imunologia , Autoantígenos/imunologia , Creatina Quinase/sangue , Eletromiografia , Feminino , Imunização , Camundongos , Camundongos Endogâmicos BALB C , Monócitos/patologia , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/fisiopatologia , Miosinas/imunologia , Miosinas/metabolismo , Proteínas de Protozoários , Baço/imunologia , Baço/patologiaRESUMO
This paper shows that human antibodies specific for exoantigens of pI 4.5 (Eas 4.5), released by the blood forms of the parasite, obtained from chagasic patients sera by immunoabsorption react with cruzipain, the major cysteinyl proteinase of Trypanosoma cruzi. Sera from mice immunized with Eas 4.5 also recognize cruzipain. In addition, mouse antisera to cruzipain were reactive with Eas 4.5 as well as with total antigens excreted by culture-trypomastigotes. This reactivity was inhibited by cruzipain as revealed by enzyme-linked immunosorbent assay (ELISA). Furthermore, it was observed by immunoblot that the exoantigens recognized by mouse antisera to cruzipain have molecular weights between 50 and 60 kDa and human antibodies specific for Eas 4.5 recognize cruzipain with apparent molecular weight of 50 kDa. These findings suggest the presence of cruzipain in Eas and the subsequent release of this enzyme by the parasite.
Assuntos
Anticorpos Antiprotozoários/análise , Doença de Chagas/imunologia , Cisteína Endopeptidases/imunologia , Trypanosoma cruzi/imunologia , Animais , Western Blotting , Doença de Chagas/sangue , Ensaio de Imunoadsorção Enzimática , Humanos , Técnicas de Imunoadsorção , Camundongos , Proteínas de ProtozoáriosRESUMO
Several reports have described polyclonal activation in mice acutely infected with Trypanosoma cruzi. The aim of this work was to analyse the participation of one T. cruzi antigenic fraction in this immunological event. The antigen selected was FI, an antigenic fraction of pI 7-9 obtained from T. cruzi cytosol separated by isoelectricfocusing. FI is constituted by molecules with molecular weights of around 60 and 20 KDa. The authors assayed the ability of this antigenic fraction to induce polyclonal activation of spleen mononuclear cells from normal (NSMC) BALB/c mice. NSMC showed a marked lymphoproliferative response measured by 3H-thymidine incorporation after 3 days of culture in presence of FI. The values reached by FI-stimulated cells were 10 times higher than the controls (non-stimulated cells). This effect was dose-dependent. Furthermore, the authors observed that a purified T-cell population in the presence of adherent cells was unaffected by FI. Additionally, in a culture of NSMC, FI stimulated the proliferation of B cells as observed by the increase of the percentage of B220+ cells determined by FACS using FITC-conjugated anti-mouse B220. The authors noticed that the percentage of B220+Ly1+(CD5) populations in the presence of FI did not change with respect to the control (non-stimulated cells), indicating that FI expanded both conventional and CD5+ B cells. The isotypic pattern of the antibodies produced after 6 days of culture of NSMC in the presence of FI was predominantly IgM, which reacted with highly conserved antigens such as actin, myosin, myoglobin, thyroglobulin and carbonic anhydrase, but did not react with FI. A slight increase of IgG1 and IgG3 with respect to the control was observed but no changes on the levels of IgG2 was noticed. These results indicate that FI promotes activation, proliferation and differentiation in antibody-secreting cells of normal murine B lymphocytes.
Assuntos
Antígenos de Protozoários/imunologia , Linfócitos B/imunologia , Ativação Linfocitária , Trypanosoma cruzi/imunologia , Animais , Formação de Anticorpos , Camundongos , Camundongos Endogâmicos BALB C , Linfócitos T/imunologiaRESUMO
Exoantigens of pI 4.5 (Ea 4.5) of T. cruzi released to the circulation of infected mice are able to induce partial protective immune response in mice (F. Cerbán et al. 1991, International Archives of Allergy and Applied Immunology 96, 35-40). In order to analyze the participation of cellular immunity in the parasitemia control, we i.d. immunized mice with Ea 4.5 plus Bordetella pertussis as adjuvant. The role of immune cells in protective immunity was examined by adoptive transfer experiments. The immune lymph node cells (LNC) transferred the capacity to control the parasitemia, since it was observed that the normal recipients of immune LNC, which were afterward infected, presented a significant decrease in parasite levels with respect to the animals receiving LNC from control mice. This capacity was absent in the spleen cells. In addition, polystyrene nonadherent cells from immune LNC transferred the capacity to control T. cruzi infection. It was observed that Ig+ cells and enriched T cells from immunized mice are able to control the parasitemia. To define epitopes of Ea 4.5 able to stimulate protective immunity, the levels of parasitemia were examined in mice immunized with Ea 4.5 untreated or treated with sodium metaperiodate. These animals presented similar levels of parasitemia and in both cases they are significantly lower than the parasitemias of the control animals, suggesting that the most relevant epitopes for the protective immune response that control the beginning of the infection are not carbohydrates. Later, on Day 30 postinfection only the animals immunized with untreated Ea 4.5 maintained a significant decrease in parasite levels.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Antígenos de Protozoários/imunologia , Doença de Chagas/prevenção & controle , Imunoterapia Adotiva , Linfonodos/imunologia , Trypanosoma cruzi/imunologia , Animais , Linfócitos B/imunologia , Doença de Chagas/imunologia , Epitopos/imunologia , Imunidade Celular , Imunização , Linfonodos/citologia , Camundongos , Camundongos Endogâmicos BALB C , Linfócitos T/imunologiaRESUMO
The aim of this work was to study the reactivity of chagasic patient sera against a panel of natural antigens and its relationship with the immune response against T. cruzi acidic antigens. The presence of IgG and IgM antibodies reactive with myosin, myoglobin, actin and thyroglobulin was investigated in sera with positive serology for Chagas' disease classified into groups (G) I, n = 7, with normal electrocardiogram (ECG) and no signs or symptoms of the disease; GII, n = 7, with ECG abnormalities but without cardiomegaly and GIII, n = 7, with cardiomegaly and congestive heart failure. Healthy individual sera were analyzed in parallel as controls. In the three groups of chagasic patients, a high proportion of sera exhibited an enhancement of IgG response anti actin ranging from 71 to 100%. IgM against this antigen was found positive in GI, 21%; GII and GIII, 57%. The antibodies binding to myosin and myoglobin were mainly of IgM type. When myosin was assayed, the frequency of reactive sera was gradually diminished as heart involvement increased: GI 57%, GII 28% and GIII 14%. Only IgG antibodies against thyroglobulin were detected in the three groups of chagasic patients ranging from 43 to 86%. IgG natural antibodies showed to be polyreactive, since a diminished reactivity against each one of the natural antigens assayed and against T. cruzi acidic antigens (FIV) was observed in the sera absorbed with any of the selected antigens irrespective of the absorbing ones. Moreover, the antibodies against FIV parasite's antigens purified by immunoabsorption showed a similar reactivity with FIV, myosin and actin, and a slight lower reactivity with thyroglobulin. These results indicate that in chagasic patients, the specific humoral response against FIV is associated with an increase of the natural autoantibodies along with their polyspecificity.
Assuntos
Anticorpos Antiprotozoários/imunologia , Especificidade de Anticorpos , Cardiomiopatia Chagásica/imunologia , Doença de Chagas/imunologia , Trypanosoma cruzi/imunologia , Actinas/imunologia , Adulto , Animais , Autoanticorpos/imunologia , Autoantígenos/imunologia , Cardiomegalia , Insuficiência Cardíaca , Humanos , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Mioglobina/imunologia , Miosinas/imunologia , Tireoglobulina/imunologiaRESUMO
Assuntos
Anticorpos Antiprotozoários/análise , Doença de Chagas/imunologia , Grupos Raciais , Trypanosoma cruzi/imunologia , Animais , Especificidade de Anticorpos , Antígenos de Protozoários/imunologia , Cardiomiopatia Chagásica/imunologia , Doença de Chagas/genética , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Isotipos de Imunoglobulinas/análise , Indígenas Sul-Americanos , MasculinoRESUMO
This paper deals with the enhancement of natural antibodies in mice immunized with a previously purified exoantigen of Trypanosoma cruzi from infected mouse plasma by isoelectric focusing, called Ea 4.5. A simultaneous rinse of IgG antibodies recognizing acidic sciatic nerve antigen (SNA) and other conserved antigens such as myoglobin, actin, thyroglobulin, and tubulin was observed. The highest level of antibodies was revealed when myoglobin was used as antigen in the ELISA test. Good correlation was found between the level of antibodies reactive with SNA and with highly conserved antigens. Furthermore, absorption experiments showed that a fraction of antibodies binding SNA are polyreactive and also react with the highly conserved antigens. The histological studies of sciatic nerve, heart and skeletal muscle performed 1 month after the last immunization revealed no modifications with respect to the control animals. Based on these and a previous result [1], indicating that injection of Ea 4.5 induced in mice a partial protection against T. cruzi, the possibility exists that a percentage of antibodies induced by Ea 4.5 may correspond to the natural autoantibody type and take part in protective and/or pathogenic effects.
Assuntos
Antígenos de Protozoários/imunologia , Autoanticorpos/biossíntese , Autoanticorpos/imunologia , Trypanosoma cruzi/imunologia , Animais , Anticorpos Antiprotozoários/biossíntese , Anticorpos Antiprotozoários/imunologia , Ensaio de Imunoadsorção Enzimática , Imunoglobulina G/biossíntese , Imunoglobulina G/imunologia , Focalização Isoelétrica , Camundongos , Camundongos Endogâmicos BALB CRESUMO
The aim of this work was to study whether Trypanosoma cruzi infection could elicit humoral immune response to the well-defined parasite antigen acidic fraction separated from T. cruzi cytosol by isoelectric focusing and designated fraction IV (FIV) and whether this response could account for some of the autoreactive immune response against peripheral nerve components. Chagasic patients with positive serology for Chagas' disease were classified as group I (n = 12) with normal electrocardiograms (ECG) and no signs of disease, group II (n = 12) with ECG abnormalities but without cardiomegaly, and group III (n = 12) with cardiomegaly and congestive heart failure. Sera from patients in group II showed the highest frequency of positive reactivity against FIV. Ninety-two percent had titers higher than 1/400 while the percentage for groups I and III was 50%. The autoreactive response against human sciatic nerve saline extract (SNS) was studied. The binding of IgG to SNS was positive in groups I (58%), II (66%), and III (75%) patients. The treatment of SNS with periodate diminished the ability of antigens to fix IgG from these chagasic patients. Absorption studies were performed to investigate whether FIV and SNS could have cross-reactive epitopes. Preabsorption of positive sera with FIV inhibited 48-69% of samples' reactivity against antigen. In contrast, preabsorption of positive sera with SNS inhibited only 12-23% of samples' reactivity against antigen. Overall, these results suggest that FIV-T. cruzi and sciatic nerve components possess some epitopes, possibly of a carbohydrate nature, in common. Thus, infection in Chagas' disease could overcome the tolerance to self components and could lead to autoimmunity.
Assuntos
Cardiomiopatia Chagásica/imunologia , Doença de Chagas/imunologia , Doenças do Sistema Nervoso/imunologia , Nervo Isquiático/imunologia , Trypanosoma cruzi/imunologia , Adulto , Animais , Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/imunologia , Autoanticorpos/análise , Autoantígenos/imunologia , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Epitopos/análise , Humanos , Immunoblotting , Imunoglobulina G/sangueRESUMO
We studied the reactivity of IgG isotypes detected in sera from chronic Chagas' disease patients with a Trypanosoma cruzi cytosol acidic antigenic fraction (F IV) and parasite epimastigote forms (EPI). All patients studied had positive serology for Chagas' disease, with normal electrocardiogram (Group I), abnormal ECG without cardiomegaly (Group II), and abnormal ECG with cardiomegaly (Group III). The highest levels of antibodies were observed in sera from Group II patients. A high prevalence of IgG1 and IgG3, low levels of IgG2, and IgG4 isotypes against EPI were found in sera from all groups by ELISA. When the F IV was used as antigen, IgG1 was the main antibody isotype detected by ELISA in all groups of patients. The antigenic recognition patterns by IgG1 among the different clinical groups by immunoblotting of F IV revealed some differences. The sera from Group I recognized antigens of F IV of 80, 53, and 43 kDa. Sera from Group III recognized mainly one antigenic band of 43 kDa. Finally, sera from Group II showed greater diversity of binding by IgG1, detecting between one and six bands in the 80 and 30 kDa ranges.
Assuntos
Cardiomiopatia Chagásica/imunologia , Doença de Chagas/imunologia , Adulto , Animais , Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/sangue , Ensaio de Imunoadsorção Enzimática , Humanos , Immunoblotting , Imunoglobulina G/sangue , Isotipos de Imunoglobulinas/sangue , Trypanosoma cruzi/imunologiaRESUMO
The humoral and cellular immune responses as well as the resistance to infection with bloodstream forms of T. cruzi were studied in mice immunized with acidic antigenic fractions from parasite cytosol, F III and F IV, plus Bordetella pertussis as adjuvant. The immunization with F III induced positive ITH and DTH responses to homologous antigens. In mice immunized with F IV, the ITH was negative and four out of six animals presented positive DTH reactions. In both groups of mice the analysis of IgG against T. cruzi showed that the major isotype elicited was IgG1. Specific IgE was also detected in sera from F III immunized mice, thus confirming the presence of homocytotropic antibodies. The parasitemias reached by F III and F IV immunized mice after challenge were lower than those of the controls showing in this way a partial protection against the acute infection. The histological studies of heart and skeletal muscle performed two months after the infection revealed variable mononuclear infiltration in all infected mice despite immunization.
Assuntos
Reações Antígeno-Anticorpo/imunologia , Antígenos de Protozoários/imunologia , Citosol/imunologia , Imunização , Trypanosoma cruzi/imunologia , Animais , Anticorpos Antiprotozoários/sangue , Doença de Chagas/imunologia , Doença de Chagas/parasitologia , Doença de Chagas/patologia , Hipersensibilidade Tardia/imunologia , Hipersensibilidade Tardia/parasitologia , Hipersensibilidade Tardia/patologia , Hipersensibilidade Imediata/imunologia , Hipersensibilidade Imediata/parasitologia , Hipersensibilidade Imediata/patologia , Imunização/métodos , Imunoglobulina G/sangue , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Músculos/patologia , Miocárdio/patologia , Testes CutâneosRESUMO
In a previous work we demonstrated that Trypanosoma cruzi exoantigens of pI 4.5 (Ea 4.5), whose most important epitopes are glucidic, are able to induce a partially protective immune response in mice. To ascertain the involvement of antibody isotypes in this protection, we immunized mice with Ea 4.5 plus Bordetella pertussis as adjuvant. The analysis of immune response by skin test revealed the occurrence of specific immediate type hypersensitivity on Day 15 after the last immunization. By ELISA and using Ea 4.5 as antigen, specific IgG1 antibody was detected. When formaldehyde-fixed epimastigotes were used as antigen, binding of IgG1 and IgG2 was observed. Trypomastigotes incubated for 1 hr at 33 degrees C with the immune sera and then injected in normal syngeneic mice produced a significantly lower parasitemia than trypomastigotes incubated with the control sera. This capacity of anti-Ea 4.5 sera was resistant to 56 degrees C for 2 hr and was diminished after the absorption of immune sera with the carbohydrate moiety of Ea 4.5. The assay with the immune IgG1 and IgG2, separated through protein A-Sepharose affinity chromatography, showed that IgG1 retains most of this capacity. Purified immune IgG1 revealed two antigenic bands of molecular weight between 50 and 55 kDa in SDS-PAGE of Ea 4.5.
Assuntos
Anticorpos Antiprotozoários/biossíntese , Antígenos de Protozoários/imunologia , Doença de Chagas/imunologia , Imunoglobulina G/biossíntese , Trypanosoma cruzi/imunologia , Animais , Antígenos de Protozoários/química , Imunização , Ponto Isoelétrico , Camundongos , Camundongos Endogâmicos BALB C , Peso MolecularRESUMO
Exoantigens (Ea) of Trypanosoma cruzi released in blood during the acute phase of experimental murine infection and recognized as antigens by sera from chagasic patients were grouped into two zones: one zone of pI 4-5 (Ea4-5), which had components of 35 kDa, 50 kDa and slightly higher than 100 kDa, MW, and another zone, of pI 6-7 (Ea 6-7), with Ea of 50 kDa, 66-80 kDa and higher than 100 kDa. Immunization of mice with Ea4-5 or Ea6-7 prior to infection induced a protective immune response, as judged by levels of parasitaemia which were significantly lower than those of controls. Analysis of the immune response by skin test revealed that both groups of Ea induced immediate type hypersensitivity, the values of which were higher in animals immunized with Ea4-5. These antigens also induced specific cellular immunity (delayed-type hypersensitivity). There was a direct correlation between intensity of reactivity and the drop in the number of blood forms of parasites in these animals. Antibodies able to fix the epimastigote surface were also detected by ELISA and the immunofluorescence test in mice immunized with Ea4-5 or Ea6-7. There were no qualitative or quantitative differences in the antibody induced by the two groups of Ea; the main isotypes of these antibodies which recognized Ea expressed on the parasite surface were IgG1 and IgG2.
Assuntos
Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/imunologia , Doença de Chagas/imunologia , Trypanosoma cruzi/imunologia , Animais , Anticorpos Antiprotozoários/biossíntese , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Hipersensibilidade Tardia , Hipersensibilidade Imediata , Imunização , Imunoglobulina G/biossíntese , Imunoglobulina G/imunologia , Focalização Isoelétrica , Masculino , Camundongos , Camundongos Endogâmicos BALB CRESUMO
The capacity of Trypanosoma rangeli antigens to induce immune response in mice was analyzed and the course of the infection was studied in immunized animals challenged with virulent forms of T. cruzi. BALB/c mice were immunized with supernatant of disrupted epimastigotes of T. rangeli and with epimastigotes (EPI) of T. rangeli fixed with glutaraldehyde. Both of the antigens were emulsified with incomplete Freund's adjuvant (IFrAdj). All of the animals received T. cruzi Tulahuen antigens in the footpad and the skin reactivity was later studied. The mice that received EPI with or without IFrAdj showed significantly higher skin reactivity than controls, both in Arthus (3 hr) and delayed type hypersensitivity (24 hr) reactions. Furthermore, the mice immunized with T. rangeli developed antibodies against T. cruzi detectable through hemagglutination and immunofluorescence tests. When the animals were challenged with trypomastigotes of T. cruzi, only the groups immunized with EPI-IFrAdj had significantly lower parasitemias and greater survival against infection than controls. These results suggest that T. rangeli can induce humoral and cellular immune response against T. cruzi and attenuate the acute period of the infection produced by this parasite. This is the first time that partial resistance to T. cruzi in T. rangeli-immunized mice is reported. These findings may provide a useful tool for future studies directed at the immunoprevention of Chagas' disease.
Assuntos
Anticorpos Antiprotozoários/sangue , Doença de Chagas/imunologia , Imunização , Trypanosoma cruzi/imunologia , Trypanosoma/imunologia , Animais , Reação de Arthus , Doença de Chagas/parasitologia , Hipersensibilidade Tardia , Camundongos , Camundongos Endogâmicos BALB C , Trypanosoma cruzi/isolamento & purificaçãoRESUMO
In this work we studied the IgG isotypes induced in mice immunized with two Trypanosoma cruzi acidic antigenic fractions (F IV and Eas 4.5) and the level of protection to a later infection with parasites. F IV is a cytosolic antigen from epimastigotes, and Eas 4.5 is an exoantigen released by trypomastigotes. The most relevant epitopes of Eas 4.5 are carbohydrates. A high prevalence of IgG1, low levels of IgG3 and no IgG2 antibodies against F IV and Eas 4.5 were found in sera obtained 2 weeks after the last antigen dose from animals immunized with F IV (group I) or Eas 4.5 (group II). Immunized mice from both groups were infected with trypomastigotes, and the parasitemias detected later on were significantly lower than in control groups (p less than 0.01, group I; p less than 0.001, group II). The amount of IgG2-specific antibodies, which was only detected using epimastigotes as antigen in ELISA, was significantly increased after the infection, but no major changes were seen in the profiles of other isotypes.
Assuntos
Antígenos de Protozoários/imunologia , Imunoglobulina G/imunologia , Isotipos de Imunoglobulinas/imunologia , Trypanosoma cruzi/imunologia , Animais , Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/administração & dosagem , Doença de Chagas/imunologia , Doença de Chagas/prevenção & controle , Ensaio de Imunoadsorção Enzimática , Epitopos/imunologia , Humanos , Imunização , Ponto Isoelétrico , Camundongos , Camundongos Endogâmicos BALB C , Trypanosoma cruzi/crescimento & desenvolvimentoRESUMO
The expression of T. cruzi electronegative antigens (FIV) on the parasite surface and their cross-reactivity with heart tissue antigens was studied. For the former purpose epimastigotes (EPI) treated with glutaraldehyde were used to absorb antibodies against surface antigens. Glutaraldehyde fixed heart tissue was used for absorption of antibodies in sera from two groups of chagasic patients with normal and altered electrocardiogram. The absorption of sera from normal electrocardiogram group with EPI significantly reduced the anti FIV activity by ELISA (p less than 0.001). The decreased reactivity was observed with the antigenic bands focused at pI about 4.5. Thus, the results indicate that chagasic patients without electrocardiographic alterations have a high percentage of antibodies reactive with T. cruzi cell surface antigens. Serum absorption with glutaraldehyde fixed heart tissue reduced the anti FIV activity from both groups of patients by ELISA and diminished the intensity of several bands focused at pI 4-6.
Assuntos
Anticorpos Antiprotozoários/análise , Antígenos de Protozoários/imunologia , Doença de Chagas/imunologia , Miocárdio/imunologia , Trypanosoma cruzi/imunologia , Adulto , Animais , Especificidade de Anticorpos , Antígenos de Superfície/imunologia , Cardiomiopatia Chagásica/imunologia , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Epitopos/imunologia , Feminino , Interações Hospedeiro-Parasita , Humanos , MasculinoRESUMO
The autoimmune response to mouse accessory glands (MAG) was investigated in male BALB/c mice immunized with different doses of chemically modified mouse accessory glands (MMAG) and complete Freund's adjuvant (CFA). This autoimmune response was studied at several time intervals using the skin test with MAG. It was found that 5 mg of MMAG induced on the day 15 an autoimmune response detected by specific skin test at 20 min., 3 h and 24 h. The results of the immediate type hypersensitivity (ITH) were higher than those with the other skin tests. In order to study the type of immunoglobulin involved, the ITH was also analyzed by passive cutaneous anaphylaxis (PCA) at different time intervals with treated and untreated sera at 56 degrees C. The findings suggest the presence of reaginic antibodies, IgE being the major antibody as detected by enzime linked immunosorbent assay (ELISA). The MAG was subsequently fractionated using Sephandex G-100 and the fractions thus obtained (FI,FII and FIII) were used to challenge mice immunized with MMAG. It was found that FI was the only fraction which revealed an ITH similar to that revealed by MAG. The effect of infection with Trypanosoma cruzi on the autoimmune response to MAG was analyzed with different mouse groups intraperitoneally treated with 2 x 10(3) blood trypomastigotes/animal at several time intervals: namely, on days -5, 0, +5 and +10 with respect to the immunization with MMAG. The autoimmune response to MAG showed suppression when the animals received the parasites on the same day as the autoantigen.
Assuntos
Autoanticorpos/análise , Doença de Chagas/imunologia , Hipersensibilidade Imediata/imunologia , Imunoglobulina E/análise , Adjuvantes Imunológicos/administração & dosagem , Animais , Anticorpos Antiprotozoários/análise , Ensaio de Imunoadsorção Enzimática , Imunização , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Fatores de TempoRESUMO
This work describes the occurrence of anaphylactic antibodies against exoantigens of Trypanosoma cruzi in infected or immunized mice. The results obtained show that the exoantigens induce an IgE response when injected into mice with complete Freund's adjuvant or in animals infected with 10(2) trypomastigotes. Among the antigens recognized by anti-exoantigen IgE, two molecules of 27 and 45 kD were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by western blotting. Immunofluorescence analysis located some target antigens on the parasite surface.
Assuntos
Antígenos de Protozoários/imunologia , Imunoglobulina E/análise , Trypanosoma cruzi/imunologia , Anafilaxia/etiologia , Animais , Camundongos , Camundongos Endogâmicos BALB CRESUMO
This work describes the occurrence of antibodies against exoantigens of Trypanosoma cruzi in a high percentage of patients with chronic Chagas' disease. When analyzing selected groups of patients, it was observed that sera from individuals with electrocardiographic alterations showed a greater number of precipitin system and higher antibody titers than sera from patients with positive serology only. Partial characterization of exoantigens of T. cruzi was performed by isoelectric focusing and immunoblotting. Two distinct groups of antigens at pI around 5 and 6, respectively, were identified by these methods. It was also shown in absorption experiments that exoantigens of lower pI share epitopes with components of the cellular surface of epimastigotes of T. cruzi, whereas exoantigens of higher pI share epitopes with normal human heart tissue.
Assuntos
Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/análise , Miocárdio/imunologia , Trypanosoma cruzi/imunologia , Animais , Antígenos de Protozoários/imunologia , Antígenos de Superfície/análise , Epitopos/análise , Humanos , Imunoglobulina G/imunologia , Camundongos , Camundongos Endogâmicos BALB CRESUMO
In a previous work, we showed that the immunization of male rats, 3 and 12 months old, with saline extract of rat male accessory glands chemically modified (MRAG) and human serum albumin (HSA) induced a higher humoral and cellular autoimmune response in old animals than in young ones. We have also demonstrated that the facilitation of the autoimmune response is transferred by spleen total cells of 12-month-old animals. The immune response to HSA was not modified. In this work, the cellular type involved in such facilitation was analyzed. For this transference experiment, cells enriched in T and B lymphocytes and macrophages were used. The results showed that the macrophage is the main cellular type involved. However, the transference was only total with the three cellular types together. The study, performed with macrophages pulsed in vivo with MRAG-HSA and then transferred to normal recipients, indicated that although the macrophages from young and old animals were capable of presenting the antigens, the latter did this with significantly greater efficiency for the autoantigen.