RESUMO
SUMMARYParacoccidioidomycosis (PCM), caused by Paracoccidioides spp, is an important endemic mycosis in Latin America. There are two recognized Paracoccidioides species, P. brasiliensis and P. lutzii, based on phylogenetic differences; however, the pathogenesis and disease manifestations of both are indistinguishable at present. Approximately 1,853 (~51,2%) of 3,583 confirmed deaths in Brazil due to systemic mycoses from 1996-2006 were caused by PCM. Antifungal treatment is required for patients with PCM. The initial treatment lasts from two to six months and sulfa derivatives, amphotericin B, azoles and terbinafine are used in clinical practice; however, despite prolonged therapy, relapses are still a problem. An effective Th1-biased cellular immune response is essential to control the disease, which can be induced by exogenous antigens or modulated by prophylactic or therapeutic vaccines. Stimulation of B cells or passive transference of monoclonal antibodies are also important means that may be used to improve the efficacy of paracoccidioidomycosis treatment in the future. This review critically details major challenges facing the development of a vaccine to combat PCM.
RESUMOA paracoccidioidomicose (PCM), causada por Paracoccidioides spp, é importante micose endêmica na América Latina. Com base em diferenças filogenéticas, existem duas espécies reconhecidas de Paracoccidioides, P. brasiliensis e P. lutzii, no entanto, a patogênese e as manifestações clínicas de ambas são indistinguíveis atualmente. Aproximadamente 1853 (~51,2%) de 3583 mortes confirmadas, atribuídas a micoses sistêmicas de 1996-2006, no Brasil foram causadas por PCM. Tratamento antifúngico é necessário para pacientes com PCM. O tratamento inicial dura de dois a seis meses e derivados de sulfa, anfotericina B, azóis e terbinafina são utilizados na prática clínica; no entanto, apesar da terapêutica prolongada, as recaídas ainda são um problema. Uma resposta imune celular eficaz, tendendo a Th1, é essencial para controlar a doença que pode ser induzida por antígenos exógenos, ou moduladas por vacinas profiláticas ou terapêuticas. A estimulação de células B ou a transferência passiva de anticorpos monoclonais também são meios importantes que podem ser utilizados para melhorar a eficácia do tratamento da paracoccidioidomicose no futuro. Esta revisão detalha criticamente os principais desafios que o desenvolvimento de uma vacina para combater a PCM enfrenta.
Assuntos
Animais , Humanos , Camundongos , Antígenos de Fungos/imunologia , Vacinas Fúngicas/imunologia , Paracoccidioides/imunologia , Paracoccidioidomicose/terapia , Vacinas de DNA/imunologia , Antígenos de Neoplasias/imunologia , Glicoproteínas/imunologia , Paracoccidioidomicose/imunologia , Fragmentos de Peptídeos/imunologiaRESUMO
Utilizando-se 3 amostras de leveduras psicrofóbicas: Torulopsis pintolopesii, Torulopsis bovina e Candida slooffii foram realizadas experiências visando a determinação dos possíveis fatores condicionantes da especificidade destas leveduras para determinados hospedeiros. Estes fatores parecem estar relacionados às exigências nutritivas das amostras, apresentando interesse no estudo da associação ecológica. Não foram detectados fatores estomacais determinantes da especificidade para o hospedeiro, observada em algumas amostras, embora não estejam excluídos fatores nutricionais presentes em áreas mais distais do trato digestivo. Alguns resultados sobre a viabilidade de leveduras em presença de soros animais sugerem que fatores séricos podem ser importantes na fixação de microrganismos nos animais hospedeiros.
RESUMO
We have characterized, in the Paracoccidioides brasiliensis yeast phase, an exocellular SH-dependent serine proteinase activity against Abz-MKRLTL-EDDnp and analogous fluorescent-quenched peptides, and showed that it is also active against constituents of the basement membrane in vitro. In the present study, we separated the components of P. brasiliensis culture filtrates by electrophoresis and demonstrated that the serine-thiol exocellular proteinase has a diffuse and heterogeneous migration by SDS-PAGE, localizing in a region between 69 and 43 kDa. The hydrolytic activity was demonstrable after SDS-PAGE using buffered agarose overlays of Abz-MKALTLQ-EDDnp, following incubation at 37oC, and detection of fluorescent bands with a UV transilluminator. Hydrolysis was more intense when incubation was carried out at basic pH, and was completely inhibited with 2.5 mM PMSF and partially with sodium 7-hydroxymercuribenzoate (2.5 mM p-HMB), suggesting its serine-thiol nature. A proteolytic band with similar characteristics was observed in conventional gelatin zymograms, but could not be correlated with a silver-stained component. Detection of the serine-thiol proteinase in substrate gels after SDS-PAGE provides a useful way of monitoring purification of the basement membrane degrading enzyme
Assuntos
Membrana Basal/metabolismo , Eletroforese em Gel de Poliacrilamida , Paracoccidioides/enzimologia , Serina Proteases/metabolismo , Eletroforese em Gel de Ágar , Serina Proteases/químicaRESUMO
Antibodies from Chagasic patients (Ch), bound to a column of immobilized purified glycoprotein 25-kDa antigen of Trypanosoma cruzi epimastigotes (gp25), were partially lytic (70% lysis at 50 microng/ml) to cultured metacyclic trypomastigotes (Y strain) in a complement-mediated reaction (alternative pathway). Antibodies (Ch) eluted with galactose from a melibiose-Agarose column reacted in ELISA titration plates with gp25, whole cells of metacyclic trypomastigotes (Y strain), and less intensely with aqueous extracts of either T. cruzi (CL- 14 strain) or Herpetomonas muscarum. Agglutination of rabbit erythrocytes by anti-Gal antibodies from Chagasic patients or normal human sera (NHS) was inhibited by galactose and alfa- but not ß- anomeric galactosides. Anti-Gal antibodies (Ch or NHS) were lytic to metacyclic trypomastigotes in complement-mediated reactions. Agglutination of rabbit red cells by a serum sample from a T. cruzi-infected Rhesus monkey was inhibited by laminin. This serum was also lytic to metacyclic forms of T. cruzi (Y strain) involving the alternative complement pathway (70% lysis at 1:20 final dilution). These results open the possibility of using anti-Gal antibodies for protection against infection by virulent T. cruzi
Assuntos
Humanos , Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários , Doença de Chagas/imunologia , Galactose , Glicoproteínas/imunologia , Imunidade InataRESUMO
Malignant transformation is accompanied by changes in cell-matrix interations. Upon transfection with EJ-ras oncogene, transformed fibroblasts, acquired a migratory phenotype towards laminin-1. The increase in integrin expression was responsible for the migratory activity of transformed fibroblasts. In addition alpha(6)beta(1) integrins, both galectin-3 and an unidentified laminin-binding polypeptide had their expression pattern altered upon transformation. Here, we review these two classes of laminin-binding proteins and their possible roles in cell-laminin interactions.