Resistance of melanized yeast cells of Paracoccidioides brasiliensis to antimicrobial oxidants and inhibition of phagocytosis using carbohydrates and monoclonal antibody to CD18

Paracoccidioides brasiliensis , a thermal dimorphic fungal pathogen, produces a melanin-like pigment in vitro and in vivo. We investigated the involvement of carbohydrates and monoclonal antibody to CD18, on phagocytosis inhibition, involving macrophage receptors and the resistance of melanized fung...

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Bibliographic Details
Published in:Memórias do Instituto Oswaldo Cruz 2009-07, Vol.104 (4), p.644-648
Main Authors: da Silva, Marcelo Barbosa, Thomaz, Luciana, Marques, Alexandre Ferreira, Svidzinski, Artur E, Nosanchuk, Josh D, Casadevall, Arturo, Travassos, Luiz R, Taborda, Carlos P
Format: Article
Language:English
Subjects:
Animals
anti-CD18 antibody
Antibodies, Monoclonal - pharmacology
Antifungal Agents - pharmacology
Antimicrobial agents
antimicrobial oxidants
Carbohydrates - pharmacology
CD18 Antigens - drug effects
Macrophages - microbiology
melanin
melanin - P. brasiliensis - antimicrobial oxidants - anti-CD18 antibody
Melanins - biosynthesis
Mice
Mice, Inbred BALB C
Oxidants - pharmacology
P. brasiliensis
Paracoccidioides - drug effects
Paracoccidioides - metabolism
Paracoccidioides - pathogenicity
Paracoccidioides brasiliensis
PARASITOLOGY
Phagocytosis
TROPICAL MEDICINE
Virulence Factors - physiology
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Summary:Paracoccidioides brasiliensis , a thermal dimorphic fungal pathogen, produces a melanin-like pigment in vitro and in vivo. We investigated the involvement of carbohydrates and monoclonal antibody to CD18, on phagocytosis inhibition, involving macrophage receptors and the resistance of melanized fungal cells to chemically generated nitric oxide (NO), reactive oxygen species (ROS), hypochlorite and H2O2. Our results demonstrate that melanized yeast cells were more resistant than nonmelanized yeast cells to chemically generated NO, ROS, hypochlorite and H2O2, in vitro. Phagocytosis of melanized yeast cells was virtually abolished when mannan, N-acetyl glucosamine and anti-CD18 antibody were added together in this system. Intratracheal infection of BALB/c mice, with melanized yeast cells, resulted in higher lung colony forming units, when compared to nonmelanized yeast cells. Therefore, melanin is a virulence factor of P. brasiliensis.
ISSN:1678-8060
0074-0276
1678-8060
0074-0276
DOI:10.1590/s0074-02762009000400019