ABSTRACT
The virulence of four Sporothrix schenckii isolates was compared in a murine model of sporotrichosis, together with the protein pattern of the yeast cell surface and the capacity to bind the extracellular matrix protein fibronectin. Virulence was determined by the mortality rate, fungal burden and histopathology. Two clinical isolates were more virulent for C57BL/6 mice, but no direct correlation was seen between virulence and the clinical or environmental origin of the isolates. The lowest virulence was observed for an isolate recovered from a patient with meningeal sporotrichosis. Although all isolates could effectively disseminate, the dissemination patterns were not similar. Using flow cytometry analysis, we investigated the interaction of all the strains with fibronectin, and showed that the binding capacity correlated with virulence. Western blot analysis of S. schenckii cell wall extracts revealed positive bands for fibronectin in the range of 37-92 kDa. The 70 kDa adhesin was also recognized by a protective monoclonal antibody raised against a gp70 antigen of S. schenckii (mAb P6E7). Confocal microscopy confirmed the co-localization of fibronectin and mAb P6E7 on the yeast cell surface. To our knowledge, this is the first report identifying adhesins for fibronectin on the surface of this human pathogen.
Subject(s)
Fibronectins/metabolism , Fungal Proteins/metabolism , Membrane Proteins/metabolism , Sporothrix/pathogenicity , Sporotrichosis/microbiology , Animals , Cell Adhesion , Male , Mice , Mice, Inbred C57BL , Sporothrix/isolation & purification , Sporothrix/metabolism , Sporotrichosis/pathology , VirulenceABSTRACT
A esporotricose é uma micose subcutânea de caráter crônico e de ampla distribuição mundial, cujo agente patogênico é o fungo dimórfico térmico, Sporothrix schenckii. Esse trabalho teve como principal objetivo a caracterização da atividade biológica da glicoproteína de 70 kDa (gp70), secretado pelas células leveduriformes de S. schenckii, visando à produção de anticorpos monoclonais e estudos de imunização passiva. Para atingir tais objetivos, foi produzido um hibridoma secretor de anticorpos monoclonais contra a fração de 70 kDa, denominado de AcMo P6E7. Através de ensaios de imunização passiva, foi observado que a administração do AcMo P6E7 em camundongos BALB/c foi capaz de modificar o curso da infecção experimental por S. schenckii, protegendo esses animais contra a infecção. Através de ensaios de imunofluorescência foi verificado que a gp70 está presente na superfície das células leveduriformes de S. schenckii e é uma adesina putativa para fibronectina e laminina...
Subject(s)
Animals , Mice , Antibodies, Monoclonal/immunology , Antigens, Fungal/analysis , Antigens, Fungal/immunology , Sporotrichosis/diagnosis , Sporotrichosis/genetics , Sporotrichosis/immunology , Sporotrichosis/transmission , Mycology , Sporothrix/immunology , Sporothrix/isolation & purification , Biological Assay/methods , Enzyme-Linked Immunosorbent Assay , Electrophoresis/methods , Electrophoresis , ImmunoblottingABSTRACT
The host defense mechanism in chromoblastomycosis has not been thoroughly investigated. It has been suggested that cell-mediated immunity in patients with long-standing chromoblastomycosis is somehow impaired. As a result, these individuals became unable to develop an efficient immune reaction. Many studies have shown that monocyte-derived macrophages exhibit critical activities in immunity to microorganisms. Moreover, the ability of cells from the monocytic lineage to process and present antigens, to produce cytokines, and to provide costimulatory signals confirms their pivotal role in the initiation of specific immune responses. In the present study, it was observed that monocytes from patients with a severe form of disease had a higher production of IL-10 and a lower expression of HLA-DR and costimulatory molecules when stimulated with specific antigen or LPS. Immune modulation with recombinant IL-12 or anti-IL-10 can restore the antigen-specific Th1-type immune response in chromoblastomycosis patients by up-regulating HLA-DR and costimulatory molecules in monocytes. Therefore, our data show that monocytes from patients with different clinical forms of chromoblastomycosis present distinct phenotypic and functional profiles. This observation suggests possible mechanisms that control the T cell response and influence their role in the development of pathology.
