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.

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.

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.