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The in vitro susceptibility of Fonsecaea pedrosoi to activated macrophages
S Rozental1, C S Alviano, W de Souza
1Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brasil.
Abstract:
Light and electron microscopy were used to analyze in vitro the interaction of Fonsecaea pedrosoi with in vivo activated-macrophages. Adherence of the fungi to the surface of activated macrophages triggers the respiratory burst as revealed by reduction of nitroblue tetrazolium. Transmission electron microscopy revealed NAD(PO)H-oxidase activity in the portions of the macrophage plasma of membrane that were in contact with the fungus as well as within phagocytic vacuoles. Activated macrophages failed to kill ingested fungi, but they showed a fungistatic activity delaying germ tube and hyphae formation.
Insights
Activated macrophages engulf Fonsecaea pedrosoi, initiating a respiratory burst. While unable to kill the fungi, macrophages exhibit fungistatic activity, delaying fungal growth.
Area of Science:
- Mycology
- Immunology
- Cell Biology
Background:
- Fonsecaea pedrosoi is a fungus causing chromoblastomycosis.
- Macrophages are key immune cells involved in fungal infections.
Purpose of the Study:
- To investigate the in vitro interaction between Fonsecaea pedrosoi and activated macrophages.
- To elucidate the mechanisms of macrophage response to fungal invasion.
Main Methods:
- Light and electron microscopy were employed.
- Nitroblue tetrazolium reduction assay was used to detect respiratory burst.
- NAD(PO)H-oxidase activity was localized using transmission electron microscopy.
Main Results:
- Fungal adherence to activated macrophages triggered the respiratory burst.
- NAD(PO)H-oxidase activity was observed in macrophage membranes and phagocytic vacuoles.
- Activated macrophages demonstrated fungistatic activity, inhibiting fungal growth and development.
Conclusions:
- Activated macrophages mount a defense against Fonsecaea pedrosoi.
- The respiratory burst and NAD(PO)H-oxidase activity are involved in this interaction.
- Macrophages limit fungal proliferation but do not achieve complete fungal clearance.