RESUMO
Exoantigens (exo) from Leptomonas seymouri and Crithidia fasciculata were used in an enzyme linked immunosorbent assay (ELISA), showing 100% reactivity with sera from visceral leishmaniasis (VL) cases, and no reactivity with American tegumentary leishmaniasis (ATL) ones. Our results have indicated that these exoantigens can be applied in the discrimination of VL and ATL cases.
Assuntos
Antígenos de Protozoários/sangue , Crithidia fasciculata/imunologia , Leishmania donovani/imunologia , Leishmaniose Cutânea/diagnóstico , Leishmaniose Visceral/diagnóstico , Trypanosomatina/imunologia , Anticorpos Antiprotozoários/sangue , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoglobulina G/sangue , Leishmaniose Cutânea/parasitologia , Leishmaniose Visceral/parasitologiaRESUMO
We investigated whether ELISA using crude antigens from insect and plant trypanosomatids, which are non-pathogenic and easily cultivated in large scale, has the same positivity data as Leishmania (Leishmania) chagasi, the etiological agent of human visceral leishmaniasis (VL) or canine leishmaniasis (CanL), or as Trypanosoma cruzi, the etiological agent of Chagas disease (CD). The antigens from Crithidia fasciculata, Crithidia luciliae, and Leptomonas seymouri showed 100% cross-reactivity with VL and CanL samples, with no statistically titers differences from L. (L.) chagasi, however, 34% (17/50) of VL samples revealed higher titers using the insect trypanosomatids than the homologous antigen. On the other hand, antigens from Strigomonas culicis, Angomonas deanei, and Phytomonas serpens showed low cross-reactivity with VL and CanL samples. The sera from patients with American tegumentary leishmaniasis showed low levels of cross-reactivity with all trypanosomatids investigated, even with L. (L) chagasi, without titers dissimilarity among them. These parasites were also worthless as antigen source for detection of CD cases, which required homologous antigens to reach 100% positivity. This study showed, by ELISA, that crude extract of Crithidia and Leptomonas have epitopes similar to L. (L.) chagasi, which supports the idea of using them as antigens source for the serodiagnosis of visceral leishmaniasis.
Assuntos
Antígenos de Protozoários/imunologia , Crithidia/imunologia , Epitopos/imunologia , Leishmaniose Visceral/diagnóstico , Trypanosoma cruzi/imunologia , Trypanosomatina/imunologia , Animais , Antígenos de Protozoários/química , Doença de Chagas/imunologia , Doença de Chagas/parasitologia , Crithidia/química , Reações Cruzadas , Cães , Epitopos/química , Humanos , Soros Imunes/química , Leishmania donovani/química , Leishmania donovani/imunologia , Leishmania mexicana/química , Leishmania mexicana/imunologia , Leishmaniose Cutânea/imunologia , Leishmaniose Cutânea/parasitologia , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , Masculino , Trypanosoma cruzi/química , Trypanosomatina/químicaRESUMO
The genus Phytomonas includes parasites that are etiological agents of important plant diseases, especially in Central and South America. These parasites are transmitted to plants via the bite of an infected phytophagous hemipteran. Despite the economic impact of these parasites, many basic questions regarding the genus Phytomonas remain unanswered, such as the mechanism by which the parasites cope with the immune response of the insect vector. In this report, using a model of systemic infection, we describe the function of Oncopeltus fasciatus hemocytes in the immune response towards the tomato parasite Phytomonas serpens. Hemocytes respond to infection by trapping parasites in nodular structures and phagocytizing the parasites. In electron microscopy of hemocytes, parasites were located inside vacuoles, which appear fused with lysosomes. The parasites reached the O. fasciatus salivary glands at least six hours post-infection. After 72 hours post-infection, many parasites were attached to the salivary gland outer surface. Thus, the cellular responses did not kill all the parasites.
Assuntos
Hemócitos/parasitologia , Heterópteros/imunologia , Trypanosomatina/imunologia , Animais , Hemócitos/imunologia , Hemócitos/patologia , Heterópteros/parasitologia , Interações Hospedeiro-Parasita , Imunidade Celular , Fagocitose , Glândulas Salivares/parasitologiaRESUMO
Mice infected with Trypanosoma cruzi, the agent of Chagas disease, rapidly develop anemia and thrombocytopenia. These effects are partially promoted by the parasite trans-sialidase (TS), which is shed in the blood and depletes sialic acid from the platelets, inducing accelerated platelet clearance and causing thrombocytopenia during the acute phase of disease. Here, we demonstrate that oral immunization of C57BL/6 mice with Phytomonas serpens, a phytoflagellate parasite that shares common antigens with T. cruzi but has no TS activity, reduces parasite burden and prevents thrombocytopenia and leukopenia. Immunization also reduces platelet loss after intraperitoneal injection of TS. In addition, passive transfer of immune sera raised in mice against P. serpens prevented platelet clearance. Thus, oral exposure to P. serpens attenuates the progression of thrombocytopenia induced by TS from T. cruzi. These findings are not only important for the understanding of the pathogenesis of T. cruzi infection but also for developing novel approaches of intervention in Chagas disease.
Assuntos
Doença de Chagas/imunologia , Leucopenia/imunologia , Trombocitopenia/imunologia , Trypanosoma cruzi/imunologia , Trypanosomatina/imunologia , Doença Aguda , Animais , Plaquetas/citologia , Plaquetas/imunologia , Plaquetas/metabolismo , Doença de Chagas/parasitologia , Feminino , Glicoproteínas/imunologia , Glicoproteínas/metabolismo , Interações Hospedeiro-Parasita/imunologia , Imunização/métodos , Solanum lycopersicum/parasitologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ácido N-Acetilneuramínico/imunologia , Ácido N-Acetilneuramínico/metabolismo , Neuraminidase/imunologia , Neuraminidase/metabolismo , Contagem de Plaquetas , Trypanosoma cruzi/enzimologia , Trypanosoma cruzi/fisiologiaRESUMO
The innate immune system is evolutionary and ancient and is the pivotal line of the host defense system to protect against invading pathogens and abnormal self-derived components. Cellular and molecular components are involved in recognition and effector mechanisms for a successful innate immune response. The complement lectin pathway (CLP) was discovered in 1990. These new components at the complement world are very efficient. Mannan-binding lectin (MBL) and ficolin not only recognize many molecular patterns of pathogens rapidly to activate complement but also display several strategies to evade innate immunity. Many studies have shown a relation between the deficit of complement factors and susceptibility to infection. The recently discovered CLP was shown to be important in host defense against protozoan microbes. Although the recognition of pathogen-associated molecular patterns by MBL and Ficolins reveal efficient complement activations, an increase in deficiency of complement factors and diversity of parasite strategies of immune evasion demonstrate the unsuccessful effort to control the infection. In the present paper, we will discuss basic aspects of complement activation, the structure of the lectin pathway components, genetic deficiency of complement factors, and new therapeutic opportunities to target the complement system to control infection.
Assuntos
Lectina de Ligação a Manose da Via do Complemento , Evasão da Resposta Imune , Trypanosomatina/imunologia , Ativação do Complemento , Suscetibilidade a Doenças/imunologia , Predisposição Genética para Doença , Glicoproteínas/sangue , Glicoproteínas/imunologia , Haplótipos , Humanos , Lectinas/sangue , Lectinas/imunologia , Malária/genética , Malária/imunologia , Lectina de Ligação a Manose/genética , Lectina de Ligação a Manose/imunologia , Serina Proteases Associadas a Proteína de Ligação a Manose/genética , Serina Proteases Associadas a Proteína de Ligação a Manose/imunologiaRESUMO
Proteins containing repetitive amino acid domains are widespread in all life forms. In parasitic organisms, proteins containing repeats play important roles such as cell adhesion and invasion and immune evasion. Therefore, extracellular and intracellular parasites are expected to be under different selective pressures regarding the repetitive content in their genomes. Here, we investigated whether there is a bias in the repetitive content found in the predicted proteomes of 6 exclusively extracellular and 17 obligate intracellular protozoan parasites, as well as 4 free-living protists. We also attempted to correlate the results with the distinct ecological niches they occupy and with distinct protein functions. We found that intracellular parasites have higher repetitive content in their proteomes than do extracellular parasites and free-living protists. In intracellular parasites, these repetitive proteins are located mainly at the parasite surface or are secreted and are enriched in amino acids known to be part of N- and O-glycosylation sites. Furthermore, in intracellular parasites, the developmental stages that are able to invade host cells express a higher proportion of proteins with perfect repeats relative to other life cycle stages, and these proteins have molecular functions associated with cell invasion. In contrast, in extracellular parasites, degenerate repetitive motifs are enriched in proteins that are likely to play roles in evading host immune response. Altogether, our results support the hypothesis that both the ability to invade host cells and to escape the host immune response may have shaped the expansion and maintenance of perfect and degenerate repeats in the genomes of intra- and extracellular parasites.
Assuntos
Alveolados/genética , Amebozoários/genética , Diplomonadida/genética , Proteínas de Protozoários/genética , Trypanosomatina/genética , Alveolados/imunologia , Amebozoários/imunologia , Animais , Diplomonadida/imunologia , Interações Hospedeiro-Parasita , Humanos , Evasão da Resposta Imune/genética , Processamento de Proteína Pós-Traducional , Proteoma/química , Proteoma/genética , Proteoma/metabolismo , Proteínas de Protozoários/química , Proteínas de Protozoários/metabolismo , Sequências Repetitivas de Aminoácidos , Trypanosomatina/imunologiaRESUMO
Monoxenous trypanosomatids usually have an invertebrate as the only host in their life cycles, however, they have been found repeatedly in plants and/or mammals. To succeed in colonizing a vertebrate host, the parasite must quickly adapt to drastic changes in the environment (e.g. temperature), which reflect the conditions found in the insect and mammalian hosts. Leishmanolysin is a metalloprotease ubiquitously distributed in trypanosomatids, playing a myriad of functions. In Herpetomonas samuelpessoai, an insect trypanosomatid, the leishmanolysin-like molecule was implicated in the nutrition and insect adhesion. Herein, we showed that leishmanolysin expression is equally expressed in H. samuelpessoai parasites submitted to insect (26 °C) and mammalian (37 °C) temperatures. Also, the parasites grown in both temperatures interacted at similar rates with macrophages. Finally, we showed that leishmanolysin is involved in crucial steps in the interaction of H. samuelpessoai cells with macrophages, since the treatment with either anti-leishmanolysin antibodies or metalloprotease inhibitor 1,10-phenanthroline significantly reduced the association index. Similarly, the treatment of the macrophages with purified leishmanolysin promoted a powerful reduction in the association index, suggesting the direct involvement of macrophage receptors. These results suggest that H. samuelpessoai leishmanolysin molecules are not modulated by temperature and are involved in the interaction with mammalian cells.
Assuntos
Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/imunologia , Metaloendopeptidases/metabolismo , Trypanosomatina/imunologia , Fatores de Virulência/metabolismo , Animais , Adesão Celular , Células Cultivadas , Feminino , Interações Hospedeiro-Parasita , Macrófagos Peritoneais/parasitologia , Metaloendopeptidases/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Temperatura , Trypanosomatina/patogenicidade , Fatores de Virulência/imunologiaRESUMO
This work reports for the first time the identification and immunolocalization, by confocal and conventional indirect immunofluorescence, of m3G epitopes present in ribonucleoproteins of the following trypanosomatids: Trypanosoma cruzi epimastigotes of three different strains, Blastocrithidia ssp., and Leishmania major promastigotes. The identity of these epitopes and hence the specificity of the anti-m3G monoclonal antibody were ascertained through competition reaction with 7-methylguanosine that blocks the Ig binding sites, abolishing the fluorescence in all the parasites tested and showing a specific perinuclear localization of the snRNPs, which suggests their nuclear reimport in the parasites. Using an immunoprecipitation technique, it was also possible to confirm the presence of the trimethylguanosine epitopes in trypanosomatids.
Assuntos
Anticorpos Monoclonais , Epitopos/isolamento & purificação , Ribonucleoproteínas Nucleares Pequenas/isolamento & purificação , Trypanosomatina/química , Animais , Anticorpos Monoclonais/imunologia , Técnica Indireta de Fluorescência para Anticorpo , Imunoprecipitação , Microscopia Confocal , Ribonucleoproteínas Nucleares Pequenas/imunologia , Trypanosomatina/genética , Trypanosomatina/imunologia , Trypanosomatina/ultraestruturaRESUMO
The present review provides an overview of recent discoveries concerning the immunological similarities between Phytomonas serpens, a tomato parasite, and human trypanosomatid pathogens, with special emphasis on peptidases. Leishmania spp. and Trypanosoma cruzi express peptidases that are well-known virulence factors, named leishmanolysin and cruzipain. P. serpens synthesizes two distinct classes of proteolytic enzymes, metallo- and cysteine-type peptidases, that share common epitopes with leishmanolysin and cruzipain, respectively. The leishmanolysin-like and cruzipain-like molecules from P. serpens participate in several biological processes including cellular growth and adhesion to the salivary glands of Oncopeltus fasciatus, a phytophagous insect experimental model. Since previous reports demonstrated that immunization of mice with P. serpens induced a partial protective immune response against T. cruzi, this plant trypanosomatid may be a suitable candidate for vaccine studies. Moreover, comparative approaches in the Trypanosomatidae family may be useful to understand kinetoplastid biology, biochemistry and evolution.
Assuntos
Cisteína Endopeptidases , Metaloendopeptidases , Peptídeo Hidrolases , Trypanosomatina/classificação , Trypanosomatina/imunologia , Animais , Cisteína Endopeptidases/imunologia , Cisteína Endopeptidases/metabolismo , Humanos , Leishmania/enzimologia , Leishmania/imunologia , Solanum lycopersicum/parasitologia , Metaloendopeptidases/imunologia , Metaloendopeptidases/metabolismo , Peptídeo Hidrolases/imunologia , Peptídeo Hidrolases/metabolismo , Doenças das Plantas/microbiologia , Proteínas de Protozoários , Trypanosoma cruzi/enzimologia , Trypanosomatina/enzimologia , Fatores de VirulênciaRESUMO
We have previously demonstrated that Phytomonas serpens, a tomato parasite, shares antigens with Trypanosoma cruzi, the protozoa that causes Chagas' disease. These antigens are recognized by human sera and induce protective immunity in Balb/c mice. In the present study, inducible nitric oxide synthase (iNOS) knockout (KO) mice and C57BL/6 mice treated with the nitric oxide inhibitor, aminoguanidine (AG, 50 mg kg(-1)) infected with T. cruzi, were used to demonstrate the role of nitric oxide (NO) to host protection against T. cruzi infection achieved by oral immunization with live P. serpens. A reduction in parasitaemia and an increase in survival were observed in C57BL/6 infected mice and previously immunized with P. serpens, when compared to non-immunized mice. iNOS (KO) mice immunized and C57BL/6 immunized and treated with AG presented parasitaemia and mortality rates comparable to those of infected and non-immunized mice. By itself, immunization with P. serpens did not induce inflammation in the myocardium, but C57BL/6 mice so immunized showed fewer amastigotes nests in the heart following an acute T. cruzi infection than those in non-immunized mice. These results suggest that protective immunity against T. cruzi infection induced by immunization with P. serpens is dependent upon enhanced NO production during the acute phase of T. cruzi infection.
Assuntos
Doença de Chagas/prevenção & controle , Imunoterapia Ativa , Óxido Nítrico Sintase/fisiologia , Óxido Nítrico/fisiologia , Trypanosoma cruzi/imunologia , Trypanosomatina/imunologia , Administração Oral , Animais , Sangue/parasitologia , Doença de Chagas/genética , Coração/parasitologia , Camundongos , Camundongos Knockout , Miocárdio/patologia , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase Tipo IIRESUMO
The immune cross-reactivity between Trypanosoma cruzi, the protozoan that causes Chagas' disease, and Phytomonas serpens, a trypanosomatid that infects tomatoes, was studied. Sera from patients with Chagas' disease presented a strong reactivity with P. serpens antigens by conventional serological assays such as indirect immunofluorescence (IIF) and direct agglutination test (DAT), confirmed after cross-absorption experiments. The results show that this protozoan is highly immunogenic and that rabbit and mouse hyperimmune serum raised against T. cruzi or P. serpens was able to recognize both T. cruzi and P. serpens antigens in immunofluorescence and agglutination assays. The antigenic cross-reactivity between T. cruzi and P. serpens was also demonstrated in vivo. BALB/c mice immunized by the intraperitoneal or oral route with P. serpens and later challenged with a lethal inoculum of T. cruzi blood forms showed a significant decrease in parasitemia and increase in survival compared to controls. A practical implication of these findings is that the ingestion by humans or animals of living plant trypanosomatids present in naturally infected edible fruits could potentially prime the immune response to T. cruzi antigens and interfere with the development of T. cruzi infection.
Assuntos
Antígenos de Protozoários/imunologia , Doença de Chagas/imunologia , Trypanosoma cruzi/imunologia , Trypanosomatina/imunologia , Testes de Aglutinação , Animais , Doença de Chagas/parasitologia , Doença de Chagas/prevenção & controle , Reações Cruzadas/imunologia , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Imunização , Solanum lycopersicum/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Parasitemia , Coelhos , Análise de SobrevidaRESUMO
Leishmania metacyclogenesis is associated with changes in morphology, gene expression, and structural alterations of the lipophosphoglycan (LPG), the promastigote most abundant surface glycolipid. Purification of metacyclics is accomplished using lectins or monoclonal antibodies (MAbs) that exploit stage-specific differences in the LPG. Besides, LPG displays extensive interspecies polymorphisms and is synthesized by promastigotes of all species investigated to date. In this work we studied the species- and stage-specificity of two MAbs (3A1-La and LuCa-D5) used to purify metacyclics of Leishmania amazonensis. Their ability to recognize different members of the Trypanosomatidae family was tested by direct agglutination, indirect immunofluorescence, and dot-blot analysis of LPG. We found that both MAbs were highly selective for L. amazonensis: 3A1-La recognized only promastigotes and LuCa-D5 labeled amastigote and promastigote stages of this species. These MAbs might be useful for Leishmania typing.
Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Antiprotozoários/imunologia , Especificidade de Anticorpos , Leishmania/classificação , Leishmania/crescimento & desenvolvimento , Testes de Aglutinação , Animais , Anticorpos Monoclonais/biossíntese , Anticorpos Antiprotozoários/biossíntese , Imunofluorescência , Glicoesfingolipídeos/imunologia , Humanos , Immunoblotting , Leishmania/imunologia , Estágios do Ciclo de Vida , Camundongos , Camundongos Endogâmicos BALB C , Especificidade da Espécie , Trypanosomatina/classificação , Trypanosomatina/imunologiaAssuntos
Doença de Chagas/parasitologia , Infecções por Protozoários/parasitologia , Trypanosoma cruzi/genética , Trypanosomatina/genética , Animais , Antiprotozoários/uso terapêutico , Doença de Chagas/tratamento farmacológico , Doença de Chagas/prevenção & controle , Suscetibilidade a Doenças , Resistência a Medicamentos , Humanos , Insetos Vetores/imunologia , Insetos Vetores/parasitologia , Infecções por Protozoários/tratamento farmacológico , Infecções por Protozoários/prevenção & controle , Vacinas Protozoárias , Trypanosoma cruzi/imunologia , Trypanosomatina/imunologiaRESUMO
Promastigote forms of Phytomonas serpens, Leptomonas samueli, and Leishmania tarentolae express cytoskeletal giant proteins with apparent molecular masses of 3,500 kDa (Ps 3500), 2,500 kDa (Ls 2500), and 1,200 kDa (Lt 1200), respectively. Polyclonal antibodies to Lt 1200 and to Ps 3500 specifically recognize similar polypeptides of the same genera of parasite. In addition to reacting with giant polypeptides of the Leptomonas species, anti-Ls 2500 also cross reacts with Ps 3500, and with a 500-kDa polypeptide of Leishmania. Confocal immunofluorescence and immunogold electron microscopy showed major differences in topological distribution of these three proteins, though they partially share a common localization at the anterior end of the cell body skeleton. Furthermore, Ps 3500, Ls 2500, and Lt 1200 are in vivo phosphorylated at serine and threonine residues, whereas, in vitro phosphorylation of cytoskeletal fractions reveal that only Ps 3500 and Ls 2500 are phosphorylated. Heat treatment (100 degrees C) of high salt cytoskeletal extracts demonstrates that Ps 3500 and Ls 2500 remain stable in solution, whereas Lt 1200 is denatured. Kinase assays with immunocomplexes of heat-treated giant proteins show that only Ps 3500 and Ls 2500 are phosphorylated. These results demonstrate the existence of a novel class of megadalton phosphoproteins in promastigote forms of trypanosomatids that appear to be genera specific with distinct cytoskeletal functions. In addition, there is also evidence that Ps 3500 and Ls 2500, in contrast to Lt 1200, seem to be autophosphorylating serine and threonine protein kinases, suggesting that they might play regulatory roles in the cytoskeletal organization.
Assuntos
Proteínas do Citoesqueleto/metabolismo , Leishmania/metabolismo , Proteínas de Protozoários/metabolismo , Trypanosomatina/metabolismo , Animais , Antígenos de Protozoários/análise , Técnicas de Cultura de Células , Proteínas do Citoesqueleto/imunologia , Citoesqueleto/metabolismo , Citoesqueleto/ultraestrutura , Immunoblotting , Leishmania/imunologia , Leishmania/ultraestrutura , Microscopia Confocal , Microscopia Imunoeletrônica , Peso Molecular , Fosforilação , Fosfosserina/metabolismo , Fosfotreonina/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas de Protozoários/imunologia , Trypanosomatina/imunologia , Trypanosomatina/ultraestruturaAssuntos
Ectoparasitoses/parasitologia , Dermatoses Faciais/parasitologia , Trypanosomatina/isolamento & purificação , Animais , Ectoparasitoses/epidemiologia , Ectoparasitoses/imunologia , Dermatoses Faciais/epidemiologia , Dermatoses Faciais/imunologia , Humanos , Imunocompetência , Masculino , Martinica/epidemiologia , Pessoa de Meia-Idade , Trypanosomatina/imunologiaRESUMO
Apoptosis, a form of programmed cell death (PCD), has been described as essential for normal organogenesis and tissue development, as well as for the proper function of cell-renewal systems in adult organisms. Apoptosis is also pivotal in the pathogenesis of several different diseases. In this paper we discuss, from two different points of view, the role of apoptosis in parasitic diseases. The description of apoptotic death in three different species of heteroxenic trypanosomatids is reviewed, and considerations on the phylogenesis of apoptosis and on the eventual role of PCD on their mechanism of pathogenesis are made. From a different perspective, an increasing body of evidence is making clear that regulation of host cell apoptosis is an important factor on the definition of a host-pathogen interaction. As an example, the molecular mechanisms by which Trypanosoma cruzi is able to induce apoptosis in immunocompetent cells, in a murine model of Chagas' disease, and the consequences of this phenomenon on the outcome of the experimental disease are discussed.
Assuntos
Apoptose/fisiologia , Doenças Parasitárias/imunologia , Trypanosomatina/fisiologia , Animais , Trypanosomatina/imunologiaRESUMO
This article reviews current concepts of the biology of Endotrypanum spp. Data summarized here on parasite classification and taxonomic divergence found among these haemoflagellates come from our studies of molecular characterization of Endotrypanum stocks (representing an heterogenous population of reference strains and isolates from the Brazilian Amazon region) and from scientific literature. Using numerical zymotaxonomy we have demonstrated genetic diversity among these parasites. The molecular trees obtained revealed that there are, at least, three groups (distinct species?) of Endotrypanum, which are distributed in Central and South America. In concordance with this classification of the parasites there are further newer molecular data obtained using distinct markers. Moreover, comparative studies (based on the molecular genetics of the organisms) have shown the phylogenetic relationships between some Endotrypanum and related kinetoplastid lineages.
Assuntos
Bichos-Preguiça/parasitologia , Trypanosomatina/classificação , Trypanosomatina/isolamento & purificação , Animais , Anticorpos Antiprotozoários/análise , DNA de Protozoário/análise , Trypanosomatina/genética , Trypanosomatina/imunologiaRESUMO
Apoptosis, a form of programmed cell death (PCD), has been described as essential for normal organogenesis and tissue development, as well as for the proper function of cell-renewal systems in adult organisms. Apoptosis is also pivotal in the pathogenesis of several different diseases. In this paper we discuss, from two different points of view, the role of apoptosis in parasitic diseases. The description of apoptotic death in three different species of heteroxenic trypanosomatids is reviewed, and considerations on the phylogenesis of apoptosis and on the eventual role of PCD on their mechanism of pathogenesis are made. From a different perspective, an increasing body of evidence is making clear that regulation of host cell apoptosis is an important factor on the definition of a host-pathogen interaction. As an example, the molecular mechanisms by which Trypanosoma cruzi is able to induce apoptosis in immunocompetent cells, in a murine model of Chagas' disease, and the consequences of this phenomenon on the outcome of the experimental disease are discussed.
Assuntos
Animais , Apoptose/fisiologia , Doenças Parasitárias/fisiopatologia , Trypanosomatina/fisiologia , Trypanosomatina/imunologiaRESUMO
We have characterized glycoinositol phospholipids (GIPLs) from three strains of the trypanosomatid parasites Endotrypanum schaudinni and Endotrypanum monterogeii. Methanolysis of the intact GIPLs liberated methyl esters of tetracosanoic acid, docosanoic acid, octadecanoic acid and hexadecanoic acid and C20 and C21 phytosphingosines. Phosphoinositol oligosaccharides were released from the GIPLs by mild base treatment, and their structures were determined by compositional analysis, fast-atom-bombardment MS and NMR spectroscopy. Similar compounds were detected in all three strains, although their relative proportions varied. The predominant components in E. schaudinni strain LV59 and E. monterogeii LV88 were Galpbeta1-3Galpbeta1-3Manalpha1-3Manalpha1-4G lcNalpha1-6Ins-1-P and Arapbeta1-2Ga lpbeta1-3Galpbeta1-3Manalpha1-3Manalpha1-4Glc Nalpha1-6Ins-1-P, and the major phosphoinositol oligosaccharide in E. schaudinni LV58 was the hybrid-type GIPL Manalpha1-2(EtNP-6)Manalpha1-6(Galpbeta1-3Man alpha1-3)Manalpha1-4GlcN alpha1-6Ins-1-P (where EtNP is ethanolamine phosphate). Several minor oligosaccharides containing additional galactose and/or arabinose residues were also detected.