Stimulation, inhibition and death of macrophages infected with Trichophyton rubrum

Trichophyton rubrum is the most common pathogen causing dermatophytosis, accounting for approximately 80% of the reported cases of onychomycosis. Since 90% of the chronic dermatophyte infections are caused by T. rubrum, it is likely that this pathogen must have evolved mechanisms that evade or suppr...

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Bibliographic Details
Published in:Microbes and infection 2006-02, Vol.8 (2), p.372-379
Main Authors: Campos, M.R.M., Russo, M., Gomes, E., Almeida, S.R.
Format: Article
Language:English
Subjects:
Animals
Biological and medical sciences
Cell Death
Cytokines - metabolism
Dermatophytes
Female
Fundamental and applied biological sciences. Psychology
Human mycoses
Humans
Infectious diseases
Interleukin-10 - metabolism
Macrophage
Macrophage Activation - immunology
Macrophages - immunology
Macrophages - microbiology
Macrophages, Peritoneal - immunology
Macrophages, Peritoneal - microbiology
Medical sciences
Mice
Microbiology
Miscellaneous
Mycology
Mycoses
Mycoses of the skin
Phagocytosis
Trichophyton - growth & development
Trichophyton - pathogenicity
Trichophyton rubrum
Tumor Necrosis Factor-alpha - metabolism
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Summary:Trichophyton rubrum is the most common pathogen causing dermatophytosis, accounting for approximately 80% of the reported cases of onychomycosis. Since 90% of the chronic dermatophyte infections are caused by T. rubrum, it is likely that this pathogen must have evolved mechanisms that evade or suppress cell-mediated immunity. Several reports have highlighted the participation of phagocytes in the immune defense against fungi; however, few studies have addressed the role of these cells in dermatophytosis. In this study, we investigated the interactions of resident and peritoneal macrophages with T. rubrum. We show here that the interaction of T. rubrum conidia with resident macrophages results in the production of TNF-α and IL-10 but not IL-12 and nitric oxide. Infected macrophages down-regulated the expression of co-stimulatory molecules (CD80 and CD54). We also show that phagocytosis of T. rubrum conidia is inhibited by the addition of fungal exoantigens or mannan. Cytotoxicity assays indicated that after 8 h of conidia ingestion macrophage viability decreased drastically. Electron microscopy revealed that the ingested conidia grow and differentiate into hyphae inside macrophages leading to rupture of the macrophage membrane.
ISSN:1286-4579
1769-714X
DOI:10.1016/j.micinf.2005.07.028