Digestion of killed Paracoccidioides brasiliensis by neutrophils.

Section of Immunology I, Instituto de Biomedicina, Central University of Venezuela, Caracas.
Mycopathologia (Impact Factor: 1.49). 05/1989; 106(1):53-8. DOI: 10.1007/BF00436927
Source: PubMed

ABSTRACT We previously described an in vitro assay showing that neutrophils (PMNs) from patients with paracoccidioidomycosis (PARA) have a specific digestive deficiency against suspensions of live Paracoccidioides brasiliensis. We now report that this defect is equally detectable against autoclaved, but not Amphotericin B-killed P. brasiliensis. The use of autoclaved suspensions facilitates the use of our in vitro assay. It might allow the development of an in vitro intradermal test for digestion of fungi. Differential digestive ability of phagocytes against live (or autoclaved) and Amphotericin-B killed fungi is of conceptual interest. It may be relevant in understanding therapeutic effect of Amphotericin B.

  • [Show abstract] [Hide abstract]
    ABSTRACT: To perform in-vitro studies with Paracoccidioides brasiliensis yeast cells it is necessary to avoid the presence of clumps of cells while maintaining their integrity. Because of the multiple budding type of growth, the bud cells are always attached to the mother cell and the yeast cells keep growing, resulting in the formation of large clumps. In order to obtain free cells, the cultures are usually sonicated. The present study shows that sonication induces lesions in a significant number of cells, as evaluated by labelling of the cells with acridine orange and Janus green vital dyes. In some cases labelling was initially observed in only one cell of the clump; however, the other cells also became labelled after a few minutes. These observations were confirmed by scanning and transmission electron microscopy of treated cells. Colony forming units (c.f.u.) on BHI plates also confirmed the decrease in cell viability following sonication.
    Medical Mycology 03/2004; 42(1):43-9. · 1.98 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Paracoccidioidomycosis (Pmycosis) is one of the most common deep mycoses in many regions of Latin America, particularly in Brazil. Microscopically, it shows granulomatous inflammatory reaction with giant cells, macrophages, lymphocytes, plasma cells, polymorphonuclear neutrophilic leukocytes, and eosinophils. The purpose of this study was to assess the distribution of inflammatory cells in oral Pmycosis. Fifteen cases of oral Pmycosis were studied by immunohistochemistry for the presence of macrophages, CD4(+) and CD8(+) lymphocytes, CD20(+), CD15(+), and S100(+) cells. Macrophages were the main cells in well-organized granulomas and non-granulomatous areas. The CD4 phenotype was predominant in well-organized granulomas and a balance between CD4(+) and CD8(+) cells was observed in non-granulomatous areas. Dendritic, S100(+) cells were found mainly in the epithelium, in subepithelial connective tissue, and at the periphery of organized granulomas. CD15(+) cells were concentrated mainly in areas of intraepithelial microabscess and ulceration. Macrophages and T cells are the predominant cells in oral Pmycosis. Well-organized granulomas contain fewer yeast particles, indicating a more effective host immune response. Better understanding of the histopathological changes in oral Pmycosis might help determine treatment, severity and systemic involvement of the disease.
    Oral Diseases 08/2007; 13(4):434-9. · 2.38 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Paracoccidioidomycosis, caused by the dimorphic fungus Paracoccidioides brasiliensis, is the most prevalent systemic mycosis of Latin America, with Brazil accounting for 80% of the reported cases. The great number of neutrophils found in P. brasiliensis granulomas demonstrates the importance of polymorphonuclear neutrophils (PMN) cells during this mycotic infection. It has been found that neutrophils from healthy human donors can ingest and kill the fungus through a typical phagocytic process. The present work tests the phagocytic ability of neutrophils collected from patients that had had and were considered cured of paracoccidioidomycosis. Transmission electron microscopy and cytochemical studies indicate that patients' neutrophils eventually degenerate during phagocytosis of P. brasiliensis. Endogen peroxidase and NAD(P)H-oxidase are activated during the process showing that the respiratory burst and the neutrophil degranulation are triggered by the attachment of the yeast cells. Apparently these processes are not enough to kill P. brasiliensis. Although fungicidal activity can be determined by colony forming unit (CFU) counting, qualitative data suggest, as noted, that neutrophils from patients with treated paracoccidioidomycosis degenerate during the phagocytosis process. Hence, this work demonstrates the existence of a functional neutrophil deficiency against P. brasiliensis in susceptible individuals. The exact origin of this susceptibility is still to be determined in further studies.
    Medical Mycology 06/2008; 46(3):241-9. · 1.98 Impact Factor