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

Author(s)

da Silva, Marcelo Barbosa ^[1] ; Thomaz, Luciana ^[1] ; Marques, Alexandre Ferreira ^[1] ; Svidzinski, Artur E. ^[1] ; Nosanchuk, Josh D. ^{[2, 3]} ; Casadevall, Arturo ^{[2, 3]} ; Travassos, Luiz R. ^[4] ; Taborda, Carlos P. ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Ciencias Biomed, Dept Microbiol, Hosp Clin, Fac Med, Lab Micol Med LIM53, BR-05508 Sao Paulo - Brazil

^[2] Albert Einstein Coll Med, Dept Med, New York, NY - USA

^[3] Albert Einstein Coll Med, Dept Microbiol & Immunol, New York, NY - USA

^[4] Univ Fed Sao Paulo, Dept Microbiol Imunol & Parasitol, Sao Paulo - Brazil

• Document type: Journal article
• Source: Memórias do Instituto Oswaldo Cruz; v. 104, n. 4, p. 644-648, JUL 2009.
• Web of Science Citations: 18

Abstract

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. (AU)

• FAPESP's process: 06/50634-2 - Peptides and peptidases: biological activities in infectious diseases and cancer
• Grantee: Luiz Rodolpho Raja Gabaglia Travassos
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 07/07588-2 - Efficacy and biological function of monoclonal antibodies against cell wall and exoantigens from Paracoccidioides brasiliensis
• Grantee: Carlos Pelleschi Taborda
• Support Opportunities: Regular Research Grants
• FAPESP's process: 05/02776-0 - Peptido-polysaccharide from Pseudallescheria boydii, Scedosporium prolificans and Histoplasma capsulatum: purification, characterization, humoral and cellular immune responses and pathogenesis
• Grantee: Carlos Pelleschi Taborda
• Support Opportunities: Regular Research Grants