Induction of apoptosis in A549 pulmonary cells by two Paracoccidioides brasiliensis samples

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Characterization of Paracoccidioides brasiliensis PbDfg5p, a cell-wall protein implicated in filamentous growth

The dimorphic fungus Paracoccidioides brasiliensis is the causative agent of the most frequent systemic mycosis in Latin America. In humans, infection starts by inhalation of fungal propagules, which reach the pulmonary epithelium and differentiate into the yeast parasitic phase. Here we describe the characterization of a Dfg5p ((d) under bar efective for (f) under bar ilamentous (g) under bar rowth) homologue of P. brasiliensis, a predictable cell wall protein, first identified in Saccharomyces cerevisiae. The protein, the cDNA and genomic sequences were analysed. The cloned cDNA was expressed in Escherichia coli and the purified rPbDfg5p was used to obtain polyclonal antibodies. Immunoelectron microscopy and biochemical studies demonstrated the presence of PbDfg5p in the fungal cell wall. Enzymatic treatments identified PbDfg5p as a beta-glucan linked protein that undergoes N -glycosylation. The rPbDfg5p bound to extracellular matrix components, indicating that those interactions could be important for initial steps leading to P. brasiliensis attachment and colonization of host tissues. The P. brasiliensis dfg5 nucleotide and deduced protein, PbDfg5p, sequences reported in this paper had been submitted to the GenBank database under Accession Nos AY307855 (cDNA) and DQ534495 (genomic). Copyright (C) 2007 John Wiley & Sons, Ltd.

The malate synthase of Paracoccidioides brasiliensis is a linked surface protein that behaves as an anchorless adhesin

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Enolase from Paracoccidioides brasiliensis: isolation and identification as a fibronectin-binding protein

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Interactions of Paracoccidioides brasiliensis with host cells: recent advances

Host-fungal interactions are inherently complex and dynamic. In order to identify new microbial targets and develop more effective anti-fungal therapies, it is important to understand the cellular and molecular mechanisms of disease. Paracoccidioidomycosis provokes a variety of clinical symptoms, and Paracoccidioides brasiliensis can reach many tissues, but primarily attacks the lungs. The ability of the pathogen to interact with the host surface structures is essential to further colonization, invasion, and growth. Epithelial cells may represent the first host barrier or the preferential site of entry of the fungus. For this reason, interactions between P. brasiliensis and Vero/A549 epithelial cells were evaluated, with an emphasis on the adherence, induction of cytoskeletal alterations, and differential signaling activity of the various surface molecules. The adhesion to and invasion of epithelial cells by P. brasiliensis may represent strategies employed to thwart the initial host immune response, and may help in the subsequent dissemination of the pathogen throughout the body.

Surface-expressed enolase contributes to the adhesion of Paracoccidioides brasiliensis to host cells

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparative transcriptome analysis of Paracoccidioides brasiliensis during in vitro adhesion to type I collagen and fibronectin: identification of potential adhesins

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Differential gene expression analysis of Paracoccidioides brasiliensis during keratinocyte infection

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Differential antibody isotype expression to the major Paracoccidioides brasiliensis antigen in juvenile and adult form paracoccidioidomycosis

We investigated the relationship between antibody response to the major Paracoccidioides brasiliensis antigen, a 43-kDa glycoprotein, and the two paracoccidioidomycosis (PCM) clinical presentations, the juvenile and the adult forms. Total immunoglobulin G (IgG), IgG isotypes, and IgA anti-gp43 antibodies were determined by enzyme-linked immunosorbent assay in patients' sera. Juvenile PCM patients had higher (P =.003) IgG anti-gp43 levels than adult form patients. IgG1 subclass levels, however, were comparable between the two clinical forms. Patients with the juvenile form had higher (P <.001) IgG4, but lower(P =.03) IgG2 levels than patients with the adult form. The IgG4 isotype, regulated by interleukin 4, was found in all juvenile form patients but in only 12% of the adult form patients. In contrast, high levels of the IgG2 isotype, regulated by interferon-gamma, were found in 41% of the adult PCM patients, mainly those with a more benign disease, but in only 12% of the juvenile patients. IgG3 was either absent or detected at low levels. These results demonstrate, for the first time, specific IgG4 antibodies in the humoral immune response of patients with an endemic deep mycosis and suggest that the switch to the IgG subclasses in PCM is regulated by the patients' T-helper subset (Th-l or Th-2) dominant cytokine profile. A possible role for IgG4 in the immunopathogenesis of the juvenile, more severe form of the disease is discussed. Finally, IgA was found mainly in adult form patients, probably as a result of the chronic mucosal antigenic stimulation characteristic of this form. (C) Elsevier, Paris.