RESUMO
Formation of inflammatory lesions, one of the pathologic consequences of infection with Trypanosoma cruzi, involves intricate cell-cell interactions in which cell adhesion molecules (CAMs) are involved. Sera from 56 Chagas' disease patients grouped according to disease severity were studied for the presence of soluble intercellular adhesion molecule-1 (s-ICAM-1), soluble endothelial selectin (s-E-selectin), soluble vascular cell adhesion molecule-1 (s-VCAM-1), soluble platelet selectin (s-P-selectin), and s-CD44 were studied to determine if they could be used alone or in different combinations as markers for specific diagnostic procedures. Comparisons were made between congenitally, acutely, and chronically infected patients and aged-matched, noninfected individuals, as well as between patients with chronic Chagas' disease grouped according to the severity of their heart-related pathology. No differences in levels of s-CAMs were detected between sera from children with congenital T. cruzi infection and sera from noninfected infants born from chagasic mothers. In contrast, titers of s-ICAM-1, s-VCAM-1, s-selectin, and s-CD44 but not s-P-selectin were significantly increased in sera from patients during the acute phase of infection with T. cruzi. Titers of s-VCAM-1 and s-P-selectin were increased in chronically infected patients. A positive association with disease severity in sera from patients with chronic disease was observed for the levels of s-P-selectin. In contrast, we found no association between clinical symptoms and levels of s-VCAM-1. Patients with chronic disease with severe cardiopathy also showed diminished levels of s-CD44 in comparison with healthy controls or patients with mild disease. The results are discussed in the context of pathology of Chagas' disease.
Assuntos
Moléculas de Adesão Celular/sangue , Doença de Chagas/patologia , Doença Aguda , Adolescente , Adulto , Idoso , Moléculas de Adesão Celular/química , Doença de Chagas/sangue , Doença de Chagas/congênito , Doença Crônica , Selectina E/sangue , Selectina E/química , Humanos , Receptores de Hialuronatos/sangue , Receptores de Hialuronatos/química , Lactente , Molécula 1 de Adesão Intercelular/sangue , Molécula 1 de Adesão Intercelular/química , Pessoa de Meia-Idade , Selectina-P/sangue , Selectina-P/química , Índice de Gravidade de Doença , Solubilidade , Molécula 1 de Adesão de Célula Vascular/sangue , Molécula 1 de Adesão de Célula Vascular/químicaRESUMO
La enfermedad de Chagas se asocia con diversos trastornos inmunológicos. La participación del sistema inmune del huésped infectado en la resistencia a Trypanosoma cruzi es bien conocida, no así su papel patogénico. En esta dinámica, las citoquinas juegan un papel fundamental ya que su actividad determina el inicio, duración y composición de la respuesta inmune. El interferón-gamma (IFN-t) es la citoquina más relacionada con la resistencia a T. cruzi dada su capacidad para activar a los macrófagos cuya actividad tripanocida se correlaciona con la producción de especies reactivas del oxígeno (ROS) y óxido nítrico (NO). Otras citoquinas como las interleuquinas 4 (IL-4) y 10 (IL-10) y el factor de crecimiento y transformación beta (TGF-ß) inhibirían los efectos del IFN-t durante la infección con T. cruzi, ya que desactivan la capacidad tripanocida de macrófagos e inhiben la liberación de NO. Durante la infección con T. cruzi, el factor de necrosis tumoral alfa (TNF-a) se ha asociado tanto a la resistencia como al desarrollo de patología mientras que las interleuquinas 1 (IL-1) y 6 (IL-6) se han relacionado con alteraciones del endotelio vascular responsables del espasmo microvascular observado en la miocardiopatía chagásica. Diversas citoquinas inducen la expresión de moléculas de adhesión que contribuirían al desarrollo de las procesos inflamatorios a través de las interacciones celulares del sistema inmune y de éste con las células blanco de los tejidos. En la infección aguda con distintas cepas de T. cruzi se demostró la expresión de la molécula de adhesión intercelular 1 (ICAM-1) en miocardiocitos y leucocitos inflamatorios en forma paralela a la producción de citoquinas proinflamatorias. Los resultados descriptos en modelos experimentales muestran que la infección con T. cruzi induce la producción de citoquinas cuyas actividades biológicas regulan la resistencia al parásito y posiblemente la patología de la forma crónica de la enfermedad de Chagas. Más aún, el delicado balance entre citoquinas determinaría el curso de la infección ya que los mismos mecanismo involucrados en la resistencia participarían en el desarrollo de patología y la enfermedad se apoyaría en una alteración del equilibrio regulatorio de la respuesta inmune
Assuntos
Moléculas de Adesão Celular , Doença de Chagas/metabolismo , Suécia , Trypanosoma cruzi/imunologia , Trypanosoma cruzi/patogenicidade , ArgentinaRESUMO
La enfermedad de Chagas se asocia con diversos trastornos inmunológicos. La participación del sistema inmune del huésped infectado en la resistencia a Trypanosoma cruzi es bien conocida, no así su papel patogénico. En esta dinámica, las citoquinas juegan un papel fundamental ya que su actividad determina el inicio, duración y composición de la respuesta inmune. El interferón-gamma (IFN-t) es la citoquina más relacionada con la resistencia a T. cruzi dada su capacidad para activar a los macrófagos cuya actividad tripanocida se correlaciona con la producción de especies reactivas del oxígeno (ROS) y óxido nítrico (NO). Otras citoquinas como las interleuquinas 4 (IL-4) y 10 (IL-10) y el factor de crecimiento y transformación beta (TGF-ß) inhibirían los efectos del IFN-t durante la infección con T. cruzi, ya que desactivan la capacidad tripanocida de macrófagos e inhiben la liberación de NO. Durante la infección con T. cruzi, el factor de necrosis tumoral alfa (TNF-a) se ha asociado tanto a la resistencia como al desarrollo de patología mientras que las interleuquinas 1 (IL-1) y 6 (IL-6) se han relacionado con alteraciones del endotelio vascular responsables del espasmo microvascular observado en la miocardiopatía chagásica. Diversas citoquinas inducen la expresión de moléculas de adhesión que contribuirían al desarrollo de las procesos inflamatorios a través de las interacciones celulares del sistema inmune y de éste con las células blanco de los tejidos. En la infección aguda con distintas cepas de T. cruzi se demostró la expresión de la molécula de adhesión intercelular 1 (ICAM-1) en miocardiocitos y leucocitos inflamatorios en forma paralela a la producción de citoquinas proinflamatorias. Los resultados descriptos en modelos experimentales muestran que la infección con T. cruzi induce la producción de citoquinas cuyas actividades biológicas regulan la resistencia al parásito y posiblemente la patología de la forma crónica de la enfermedad de Chagas. Más aún, el delicado balance entre citoquinas determinaría el curso de la infección ya que los mismos mecanismo involucrados en la resistencia participarían en el desarrollo de patología y la enfermedad se apoyaría en una alteración del equilibrio regulatorio de la respuesta inmune (AU)
Assuntos
Trypanosoma cruzi/imunologia , Trypanosoma cruzi/patogenicidade , Doença de Chagas/metabolismo , Moléculas de Adesão Celular , Suécia , ArgentinaRESUMO
Chagas disease is associated with several immunological alterations. Although resistance against infection with Trypanosoma cruzi has been shown to be influenced by the immune system, its participation in the development of the disease remains unclear. In this regard, cytokines play a fundamental role since they are involved in the regulation of hemopoiesis, lymphopoiesis and affect the function of all cell types involved in an immune response. Interferon gamma (IFN-gamma) has been extensively involved as a protective lymphokine against T. cruzi. Macrophages activated by IFN-gamma result in the release of reactive oxygen metabolites (ROS) and nitric oxide (NO). On the other hand, interleukin 4 (IL-4), interleukin 10 (IL-10) and transforming growth factor beta (TGF-beta) are able to down-regulate the intracellular control of T. cruzi infection by IFN-gamma-activated macrophages, to inhibit NO release and to down-regulate the activity of the TH1 subset of cells (IFN-gamma producers). While TNF-alpha has been implicated in the resistance as well as in the generation of tissue damage, interleukin 6 (IL-6) and interleukin 1 (IL-1) are associated with a variety of alterations in endothelial cell function which may be responsible for the microvascular spasm seen in chagasic myocardiopathy. Several cytokines, including IFN-gamma, IL-1 alpha, IL-6 and TNF-alpha have been shown to modulate the expression of adhesion molecules which participate in inflammatory process by recruitment of lymphocytes into inflammatory sites, contributing to the progression of the local inflammatory reaction in chagasic cardiomyopathy. Thus, it has been shown that acute infection with different strains of T. cruzi induced enhanced expression of ICAM-1 not only on infiltrating leukocytes but also on sarcolemma of cardiocytes and paralleled the production of proinflammatory cytokines. Experimental infection with T. cruzi induces cytokine production which in time modulates the resistance against the parasite and probably the development of chronic Chagas disease. Therefore, it can be postulated that an alteration in quantity and/or quality of cytokine production may be the cause of chronic Chagas disease.
Assuntos
Doença de Chagas/imunologia , Citocinas/fisiologia , Trypanosoma cruzi/imunologia , Animais , Cardiomiopatia Chagásica/imunologia , Cardiomiopatia Chagásica/patologia , Doença de Chagas/patologia , Endotélio Vascular/patologia , Humanos , Imunidade Inata , Ativação de Macrófagos , Óxido Nítrico/biossíntese , Linfócitos T Auxiliares-Indutores/classificação , Linfócitos T Auxiliares-Indutores/imunologiaRESUMO
We analyzed the biological role of nitric oxide (NO) during murine Trypanosoma cruzi infection. Infection of mice with T. cruzi markedly increased NO synthesis. Administration of N-nitro-L-arginine methyl-esther (L-NAME) intraperitoneally or intragastrically diminished endogenous NO synthesis and resistance of mice to acute infection with three biologically different strains of T. cruzi. Mice protected against challenge with T. cruzi by transfer of T-cell-enriched populations from chronically infected animals, showed higher serum nitrate levels than controls non-transferred, or transferred, with T cells from non-immune mice. Administration of L-NAME abrogated transfer of resistance, suggesting NO participation in this process. Depletion of T cells from the transferred population abolished both protection and NO3- increase. On the contrary, mice chronically infected with T. cruzi showed no increased parasitemia or death upon treatment with L-NAME. The NO donor drug S-nitroso-acetyl-penicillamine was able to kill tissue culture or bloodstream trypomastigotes in vitro at biologically relevant concentrations. Conversely, NO appeared not to play a role in formation of inflammatory foci during T. cruzi infection, since infected mice treated with L-NAME showed no reduced inflammation.
Assuntos
Doença de Chagas/imunologia , Doença de Chagas/patologia , Óxido Nítrico/fisiologia , Doença Aguda , Animais , Doença de Chagas/prevenção & controle , Doença Crônica , Imunidade Inata , Camundongos , Camundongos Endogâmicos BALB C , Óxido Nítrico/imunologia , Óxido Nítrico/metabolismo , Linfócitos T/imunologia , Linfócitos T/patologia , Trypanosoma cruzi/imunologiaRESUMO
We analysed the production of nitric oxide (NO) intermediates by cells from BALB/c mice infected with either virulent (Tulahuén or RA) or avirulent (CA-1) strains of Trypanosoma cruzi. Peritoneal or spleen cells from mice infected with T. cruzi released NO when incubated without further stimuli. Cells from mice during the acute stage of infection accumulated higher levels of inducible NO synthase mRNA and produced both, before and after lypopolysaccharide stimulation, higher amounts of NO than cells from mice chronically infected with T. cruzi. NO synthesis showed similar kinetics in connection with all three strains of T. cruzi, but cells from mice inbred with the Tulahuén or RA strains released higher levels of IFN-gamma, an activator of the NO pathways, than cells from mice infected with the CA-1 strain. In vivo administration of L-Ng-monomethyl-L-arginine (L-NMMA), a competitive inhibitor of NO synthase, increased the susceptibility of mice to T. cruzi. We conclude that infection with T. cruzi induces NO production, and suggest that NO plays a role in the resistance against the parasite.
Assuntos
Doença de Chagas/metabolismo , Óxido Nítrico/biossíntese , Aminoácido Oxirredutases/metabolismo , Animais , Arginina/análogos & derivados , Arginina/farmacologia , Sequência de Bases , Primers do DNA , Modelos Animais de Doenças , Feminino , Interferon gama/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Óxido Nítrico/antagonistas & inibidores , Óxido Nítrico Sintase , Cavidade Peritoneal/citologia , RNA Mensageiro/metabolismo , Baço/citologia , Trypanosoma cruzi/patogenicidade , Virulência/efeitos dos fármacos , ômega-N-MetilargininaRESUMO
We studied the effect of in vivo administration of anti-gamma-IFN and anti-IL-4 monoclonal antibodies on the resistance of mice against myotropic and reticulotropic strains of Trypanosoma cruzi. Anti-gamma-IFN treatment augmented the susceptibility of mice when infected with the reticulotropic RA and Tulahuén strains of T. cruzi but did not alter the course of infection with the myotropic CA-I strain of the parasite. In vivo administration of anti-IL-4 enhanced the resistance of mice when infected with either Tulahuén or RA strains but did not affect the course of parasitemia when infected with CA-I. The possible biological relevance of these observations is discussed.
Assuntos
Doença de Chagas/imunologia , Interferon gama/antagonistas & inibidores , Interleucina-4/antagonistas & inibidores , Trypanosoma cruzi/imunologia , Animais , Anticorpos Monoclonais/administração & dosagem , Doença de Chagas/parasitologia , Doença de Chagas/prevenção & controle , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Especificidade da Espécie , Trypanosoma cruzi/patogenicidadeRESUMO
Effector mechanisms of resistance exerted by T cells from BALB/c mice chronically infected with Trypanosoma cruzi, Tulahuén strain, were studied. Spleen cells from chronically infected mice (Chro-SC) prestimulated with heat-killed trypomastigotes (HKT) and/or IL-2 destroyed PHA-labeled p-815 mastocytoma cells, HKT-pulsed macrophages, and normal peritoneal macrophages. However, HKT-stimulated Chro-SC did not affect the infectivity of free bloodstream forms of the parasite. Upon HKT stimulation, Chro-SC or their culture supernatant activated peritoneal macrophages for the destruction of intracellular amastigotes. The effect was abolished after Thy 1.2+ cell depletion. The addition of Cyclosporin A (CyA), which blocks T-cell activation, during HKT-stimulation of Chro-SC, diminished their ability to activate the trypanocidal activity of macrophages. CyA also inhibited the production of both macrophage-activating factors and interferon-gamma by HKT-stimulated Chro-SC. CyA administration to recipients of nylon-wool nonadherent spleen cells from chronically infected mice inhibited their adoptively acquired resistance against T. cruzi, suggesting that the conferred resistance depended on the effect of specifically activated cells. When administered during the chronic stage of the infection, CyA abrogated the antigen-specific delayed type hypersensitivity response but increased the levels of anti-T. cruzi IgG antibodies. Neither parasitemia, tissular parasitism in myocardium or skeletal muscle, nor mortality were detected after CyA treatment, suggesting the presence of a CyA nonsensitive mechanism(s) in the control of T. cruzi during the chronic phase of the infection.
Assuntos
Doença de Chagas/imunologia , Linfócitos T/imunologia , Trypanosoma cruzi/imunologia , Animais , Células Cultivadas , Ciclosporinas/farmacologia , Imunoglobulina G/análise , Interferon gama/biossíntese , Interleucina-2/farmacologia , Ativação Linfocitária , Ativação de Macrófagos , Macrófagos/imunologia , Macrófagos/parasitologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Baço/imunologia , Trypanosoma cruzi/crescimento & desenvolvimentoAssuntos
Anticorpos Antiprotozoários/biossíntese , Doença de Chagas/imunologia , Trypanosoma cruzi/imunologia , Animais , Citotoxicidade Celular Dependente de Anticorpos , Humanos , Tolerância Imunológica , Imunidade Celular , Interferon gama , Linfocinas/fisiologia , Camundongos , Fagócitos/parasitologia , Trypanosoma cruzi/isolamento & purificaçãoRESUMO
Release of reactive oxygen species (ROS) by cells from BALB/c mice was studied during the acute stage of the infection with 50 bloodstream forms of Trypanosoma cruzi, Tulahuén strain. Production of ROS by spleen and peritoneal cells was evaluated by chemiluminescence using luminol as enhancer (CL-Lum). Three to four weeks after infection, CL-Lum response after the addition of opsonized zymosan to spleen and peritoneal cells from infected mice was 13 and 98 times, respectively, above the levels obtained with cells from noninfected mice. The kinetics of this hyperactivity was similar to that of the parasitemia. Both reached maximal values on the third to fourth weeks and decreased at 7 weeks postinfection. During this hyperactivation stage, spleen and peritoneal cells from infected mice showed a "spontaneous" CL-Lum response (without any stimulus added in vitro) absent in noninfected mice. Both, "spontaneous" and zymosan stimulated CL-Lum responses were inhibited by 100 microM azide and by 0.8 microM superoxide dismutase, suggesting the involvement of hemoproteins and superoxide anion in the measured responses. Moreover, spleen cells from acutely infected mice displayed a hyperactivity in the CL-Lum response when recombinant interferon-gamma was added in vitro. Supernatants of spleen cells from both normal or infected mice, stimulated in vitro with concanavalin A, contained similar levels of interferon and were equally able to stimulate the trypanocidal activity of normal macrophages. These results suggest that mediators of activation of phagocytic cells can be produced during acute T. cruzi infection. In addition, phagocytic cells from acutely infected mice were activated in vivo and were hyperactive to the in vitro stimulation.
Assuntos
Doença de Chagas/fisiopatologia , Oxigênio/metabolismo , Doença Aguda , Animais , Azidas/farmacologia , Concanavalina A/farmacologia , Citotoxicidade Imunológica , Radicais Livres , Imunidade Celular , Interferon gama/farmacologia , Medições Luminescentes , Ativação de Macrófagos , Camundongos , Camundongos Endogâmicos BALB C , Cavidade Peritoneal/citologia , Proteínas Recombinantes , Baço/citologia , Superóxido Dismutase/farmacologia , Trypanosoma cruzi , Zimosan/farmacologiaRESUMO
Cellular populations involved in resistance against T. cruzi infection were characterized from mice chronically infected with the parasite. Mice transfused with spleen cells (SC), nylon-wool-non-adherent spleen cells (NWNA) or sera from mice chronically infected with T. cruzi, showed an enhanced resistance against challenge with the parasite. The protective activity of NWNA but not of SC was completely abrogated by treatment with anti-Thy1.2 monoclonal antibodies (mAb) and complement (C). Pretreatment of NWNA cells from chronically infected mice with either anti-L3T4 or anti-Lyt 2.2 mAb partially reduced the transfer of resistance. When both L3T4+ and Lyt2.2+ cells were depleted from NWNA populations, transfer of resistance was abolished. These results appear to indicate that L3T4+, Lyt2.2+ T cell subsets and non-T cells are involved in the immunity to T. cruzi.
Assuntos
Doença de Chagas/imunologia , Baço/citologia , Linfócitos T/imunologia , Animais , Imunidade Celular , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Baço/imunologiaRESUMO
Diferentes fracciones subcelulares de epimastigotes de T.cruzi fueron ensayadas en su capacidad de inducir protección o agresión en animales experimentales. La fracción flagelar (F) tuvo las mejores propiedades protectoras, sin efectos agresivos sobre los tejidos. Se prepararon varios anticuerpos monoclonales contra esta fracción. Dos de ellos, FCH-F8-1 y 4, mostraron capacidad de neutralizar la infectividad de tripomastigotes sanguíneos, de producir la lisis mediada por complemento de tripomastigotes de cultivo y de reconocer antígenos de la superfície de ambas formas epi y tripomastigotes. El anticuerpo FCH-F8-1, reconoce por inmunoprecipitación, una proteína de 85 kDa en tripomastigotes, mientras que en "blotting" reaccionó con una molécula de 43 kDa, en ambas formas del parásito. El otro anticuerpo, FCH-F8-4 reaccionó por esta última técnica, con varias proteínas de peso molecular entre 50 y 150 kDa, en epimastigotes y sólo con dos (15 y 48 kDa) en tripomastigotes. Ratones inmunizados con antígenos purificados por cromatografia de afinidad usando FCH-F8-4, fueron protegidos contra el desafio de formas infectantes. En una biblioteca de ADNc de epimastigotes de T. cruzi construída en el vector I gt11 se detectaron varios clones, tres con FCH-F8-4 y dos con FCH-F8-1. Dos clones, uno de cada grupo fueron estudiados, y (FCH-F8-1) 1 y (FCH-F8-4) 1. El tamaño de los insertos para ambos fue de 150 pares de bases y utilizados como sondas detectaron ARNm de epimastigotes de 3,5 y 5,0...
Assuntos
Camundongos , Animais , Anticorpos Monoclonais , Antígenos de Protozoários/isolamento & purificação , Doença de Chagas/imunologia , Trypanosoma cruzi/imunologia , Vacinas Sintéticas/imunologia , Citotoxicidade Imunológica , Camundongos Endogâmicos BALB C , Fragmentos de Peptídeos/imunologia , Mapeamento de PeptídeosRESUMO
Diferentes fracciones subcelulares de epimastigotes de T.cruzi fueron ensayadas en su capacidad de inducir protección o agresión en animales experimentales. La fracción flagelar (F) tuvo las mejores propiedades protectoras, sin efectos agresivos sobre los tejidos. Se prepararon varios anticuerpos monoclonales contra esta fracción. Dos de ellos, FCH-F8-1 y 4, mostraron capacidad de neutralizar la infectividad de tripomastigotes sanguíneos, de producir la lisis mediada por complemento de tripomastigotes de cultivo y de reconocer antígenos de la superfície de ambas formas epi y tripomastigotes. El anticuerpo FCH-F8-1, reconoce por inmunoprecipitación, una proteína de 85 kDa en tripomastigotes, mientras que en "blotting" reaccionó con una molécula de 43 kDa, en ambas formas del parásito. El otro anticuerpo, FCH-F8-4 reaccionó por esta última técnica, con varias proteínas de peso molecular entre 50 y 150 kDa, en epimastigotes y sólo con dos (15 y 48 kDa) en tripomastigotes. Ratones inmunizados con antígenos purificados por cromatografia de afinidad usando FCH-F8-4, fueron protegidos contra el desafio de formas infectantes. En una biblioteca de ADNc de epimastigotes de T. cruzi construída en el vector I gt11 se detectaron varios clones, tres con FCH-F8-4 y dos con FCH-F8-1. Dos clones, uno de cada grupo fueron estudiados, y (FCH-F8-1) 1 y (FCH-F8-4) 1. El tamaño de los insertos para ambos fue de 150 pares de bases y utilizados como sondas detectaron ARNm de epimastigotes de 3,5 y 5,0... (AU)
Assuntos
Camundongos , Animais , Doença de Chagas/imunologia , Vacinas Sintéticas/imunologia , Trypanosoma cruzi/imunologia , Antígenos de Protozoários/isolamento & purificação , Anticorpos Monoclonais/diagnóstico , Citotoxicidade Imunológica , Fragmentos de Peptídeos/imunologia , Mapeamento de Peptídeos , Camundongos Endogâmicos BALB CRESUMO
Subcellular fractions of T. cruzi epimastigotes (Epi) were studied for their capability to induce protective or aggressive effects in animals. The flagellar fraction (F) showed the best immunoprotective properties without tissular aggression. Monoclonal antibodies were raised against F. Two of them, FCH-F8-1 and 4, were able to neutralize the infectivity of bloodstream forms, to mediate lysis by complement of cell culture derived[trypomastigotes (Tripo) and to recognize the surface of Tripo and Epi. FCH-F8-1 reacted with a 85 kDa protein from Tripo (assayed by immunoprecipitation) and with peptides of 43 kDa on Epi and Tripo (tested by immunoblotting). FCH-F8-4 recognized several proteins ranging from 50 to 150 kDa on Epi and two molecules of 15 and 48 kDa on Tripo. Mice immunized with antigens purified by affinity chromatography by using FCH-F8-4 were protected against the infection. Several recombinant clones were detected on a cDNA lambda gt11 expression library constructed from T. cruzi Epi (Tulahuén strain): three with FCH-F8-4 and two with FCH-F8-1. One clone recognized by each monoclonal antibody was studied gamma (FCH-F8-1) 1 and gamma (FCH-F8-4) 1. Both inserts were of 150 base pairs each; they detected a 3.5 and 5.0 kilobases Epi mRNA, respectively. Both inserts were sequenced, and the amino acid sequences were inferred. gamma (FCH-F8-4) 1 codified for a 19 aa peptide, PAFLGCSSRFSGSFSGVEP, and gamma (FCH-F8-1) 1 for a 29 aa peptide EFLERGRISCORHSYTSYTSCSDEHNVTPFC. The whole 19 aa peptide was synthesized. This peptide (SP4) inhibited the ELISA reactivity against the parasite of chronically infected and F immunized mouse sera.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Anticorpos Monoclonais , Antígenos de Protozoários/imunologia , Doença de Chagas/imunologia , Vacinas Protozoárias/imunologia , Trypanosoma cruzi/imunologia , Animais , Antígenos de Protozoários/isolamento & purificação , Citotoxicidade Imunológica , Camundongos , Camundongos Endogâmicos BALB C , Fragmentos de Peptídeos/imunologia , Mapeamento de PeptídeosRESUMO
Subcellular fractions of T. cruzi epimastigotes (Epi) were studied for their capability to induce protective or aggressive effects in animals. The flagellar fraction (F) showed the best immunoprotective properties without tissular aggression. Monoclonal antibodies were raised against F. Two of them, FCH-F8-1 and 4, were able to neutralize the infectivity of bloodstream forms, to mediate lysis by complement of cell culture derived[trypomastigotes (Tripo) and to recognize the surface of Tripo and Epi. FCH-F8-1 reacted with a 85 kDa protein from Tripo (assayed by immunoprecipitation) and with peptides of 43 kDa on Epi and Tripo (tested by immunoblotting). FCH-F8-4 recognized several proteins ranging from 50 to 150 kDa on Epi and two molecules of 15 and 48 kDa on Tripo. Mice immunized with antigens purified by affinity chromatography by using FCH-F8-4 were protected against the infection. Several recombinant clones were detected on a cDNA lambda gt11 expression library constructed from T. cruzi Epi (Tulahuén strain): three with FCH-F8-4 and two with FCH-F8-1. One clone recognized by each monoclonal antibody was studied gamma (FCH-F8-1) 1 and gamma (FCH-F8-4) 1. Both inserts were of 150 base pairs each; they detected a 3.5 and 5.0 kilobases Epi mRNA, respectively. Both inserts were sequenced, and the amino acid sequences were inferred. gamma (FCH-F8-4) 1 codified for a 19 aa peptide, PAFLGCSSRFSGSFSGVEP, and gamma (FCH-F8-1) 1 for a 29 aa peptide EFLERGRISCORHSYTSYTSCSDEHNVTPFC. The whole 19 aa peptide was synthesized. This peptide (SP4) inhibited the ELISA reactivity against the parasite of chronically infected and F immunized mouse sera.(ABSTRACT TRUNCATED AT 250 WORDS)
RESUMO
The humoral and cellular immune responses were studied in mice immunized with flagellar fraction (F), F plus Bordetella pertussis as adjuvant (F-Bp), and microsomal (Mc) subcellular fractions from the epimastigote forms of Trypanosoma cruzi. The immune response was studied before and after the challenge with 50 bloodstream forms of T. cruzi, Tulahuén strain. The immunization with F-Bp, but not with Mc or F and Bp separately, protected mice, in terms of parasitemia and mortality, from the challenge with the parasite. Before the challenge, levels of specific antibodies in mice immunized with F-Bp were higher than in mice immunized with F or Mc. Antibody levels 17 days after the infection were similar in the three groups of mice while nonimmunized mice reached lower levels. Early during the infection nonimmunized infected mice lacked delayed-type hypersensitivity (DTH) responses to parasite antigens and to concanavalin A (Con A). Mice immunized with F-Bp, however, presented positive DTH responses to parasite antigens and Con A both, before and after the challenge with T. cruzi. DTH reaction was transferred with spleen cells. Mice immunized with Mc behaved similarly to infected nonimmunized animals in their reactivity to parasite antigens. These results indicated striking differences between protected and nonprotected mice in humoral and cellular immune responses during experimental T. cruzi infection.
Assuntos
Anticorpos Antiprotozoários/biossíntese , Antígenos de Protozoários/imunologia , Doença de Chagas/prevenção & controle , Imunização , Trypanosoma cruzi/imunologia , Adjuvantes Imunológicos , Animais , Bordetella pertussis/imunologia , Hipersensibilidade Tardia , Imunidade Celular , Ativação Linfocitária , Masculino , Camundongos , Microssomos/imunologiaRESUMO
Infective forms of Trypanosoma cruzi were used to evaluate the complement-mediated lysis (CoML) of the parasites in the presence of anti-T. cruzi sera. Parasites released to the supernatant from infected Vero cell monolayers were used. Cultures of 1-3 x 10(6) parasites/ml were incubated for 24 h in the presence of 10 microCi/ml of 3H-uridine. Under these conditions 10(5) parasites used for each determination incorporated about 9600 dpm of the radioactive material. The release of tritium from labelled parasites after incubation with antiserum and complement correlated with the percentage of lysed parasites evaluated by optical microscopy. Normal sera from humans, a guinea pig, a rabbit, and mice were tested as complement sources. Only human sera were suitable for the evaluation of CoML in the presence of antisera, and the levels of lysis attained depended on the serum donor.
Assuntos
Anticorpos Antiprotozoários/análise , Doença de Chagas/imunologia , Trypanosoma cruzi/imunologia , Animais , Cobaias , Humanos , Camundongos , Coelhos , Radiometria , Células VeroRESUMO
The sera of three groups (I, II and III) of cattle vaccinated every three months with trivalent hydroxysaponinated commercial vaccine against aphthovirus were studied. The only difference between groups I and II was that the former received a revaccination on day 17 after the initial immunization. Groups I and II included sera from animals three months old born from vaccinated mothers. Group III consisted of the sera of adult animals (the mothers of animals in groups I and II). The animals from the three groups were bled monthly during one year. The studies were performed with pooled sera from each group. The presence of protective and neutralizing antibodies was investigated in the gammaglobulin fractions which were then separated into subclasses, by chromatography on DE-cellulose columns, in order to study their biological activity. The immunization of cattle 3 months old with commercial vaccine against aphthovirus resulted in weak primary humoral response; neutralizing antibodies could not be detected. When the animals were restimulated three weeks after the first immunization, neutralizing antibodies appeared although the response did not persist. Nevertheless, five months after the experiment was started both groups I and II showed neutralizing antibodies. (Fig. 1, 2, 3). Persistent immunity to the three virus subtypes was acquired by animals of groups I and II but not before nine months. The kinetics of protective antibodies was similar to that of neutralizing antibodies, but with higher titers. Some bleedings that did not show neutralizing activity, did show significant protective activity (Figs. 4, 5). The investigation of the neutralizing activity of the gammaglobulin subclasses obtained by chromatography revealed that there was not one single subclass responsible for this activity, but that several subclasses were involved. The gammaglobulin subclasses were analyzed by immunoelectrophoresis; proteins with alpha 2 mobility appeared, coincident with early bleedings of high neutralizing titers, although these proteins did not present neutralizing activity (Tables 1, 2). The protective and neutralizing activity was not correlated with the protein concentration of the fractions so that the increase observed may be due to a qualitative change in the antibodies.
Assuntos
Anticorpos Antivirais/biossíntese , Aphthovirus/imunologia , Animais , Animais Lactentes/imunologia , Anticorpos Antivirais/classificação , Bovinos/imunologia , Doenças dos Bovinos/imunologia , Doenças dos Bovinos/prevenção & controle , Feminino , Febre Aftosa/imunologia , Febre Aftosa/prevenção & controle , Imunidade Materno-Adquirida , Cinética , Masculino , Testes de Neutralização , Vacinação , Vacinas ViraisRESUMO
The sera of three groups (I, II and III) of cattle vaccinated every three months with trivalent hydroxysaponinated commercial vaccine against aphthovirus were studied. The only difference between groups I and II was that the former received a revaccination on day 17 after the initial immunization. Groups I and II included sera from animals three months old born from vaccinated mothers. Group III consisted of the sera of adult animals (the mothers of animals in groups I and II). The animals from the three groups were bled monthly during one year. The studies were performed with pooled sera from each group. The presence of protective and neutralizing antibodies was investigated in the gammaglobulin fractions which were then separated into subclasses, by chromatography on DE-cellulose columns, in order to study their biological activity. The immunization of cattle 3 months old with commercial vaccine against aphthovirus resulted in weak primary humoral response; neutralizing antibodies could not be detected. When the animals were restimulated three weeks after the first immunization, neutralizing antibodies appeared although the response did not persist. Nevertheless, five months after the experiment was started both groups I and II showed neutralizing antibodies. (Fig. 1, 2, 3). Persistent immunity to the three virus subtypes was acquired by animals of groups I and II but not before nine months. The kinetics of protective antibodies was similar to that of neutralizing antibodies, but with higher titers. Some bleedings that did not show neutralizing activity, did show significant protective activity (Figs. 4, 5). The investigation of the neutralizing activity of the gammaglobulin subclasses obtained by chromatography revealed that there was not one single subclass responsible for this activity, but that several subclasses were involved. The gammaglobulin subclasses were analyzed by immunoelectrophoresis; proteins with alpha 2 mobility appeared, coincident with early bleedings of high neutralizing titers, although these proteins did not present neutralizing activity (Tables 1, 2). The protective and neutralizing activity was not correlated with the protein concentration of the fractions so that the increase observed may be due to a qualitative change in the antibodies.