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Pulmonary paracoccidioidomycosis in immunized mice
J Defaveri1, M T Rezkallah-Iwasso, M F Franco
1Department of Pathology, School of Medicine, UNESP, Botucatu, Brazil.
Mycopathologia
|July 1, 1992
Summary
Immunization against Paracoccidioidomycosis in mice reduced fungal load and infection spread. This resistance was linked to delayed-type hypersensitivity reactions, suggesting a potential therapeutic avenue.
Area of Science:
- Mycology
- Immunology
- Pathology
Background:
- Paracoccidioidomycosis is a systemic fungal infection endemic in Latin America.
- Understanding the host immune response is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the role of prior immunization in the host's response to Paracoccidioides brasiliensis infection.
- To analyze the histopathological changes, fungal burden, and immune responses in immunized versus non-immunized mice.
Main Methods:
- Induction of Paracoccidioidomycosis in immunized (IM) and non-immunized (NI) mice.
- Serial investigation of histopathology, fungal counts, and cellular (footpad test, macrophage inhibition factor assay) and humoral (immunodiffusion test) immune responses.
- Evaluation of delayed-type hypersensitivity reactions.
Main Results:
- Immunized mice exhibited reduced fungal burden and milder pulmonary inflammation compared to non-immunized mice.
- Histopathology in IM mice showed macrophagic-lymphocytic alveolitis resembling hypersensitivity pneumonitis, which correlated with reduced fungal spread.
- A decrease in footpad test indices in IM mice post-infection suggested lymphocyte trapping in the lungs.
Conclusions:
- The lesional pattern in IM mice indicates a hypersensitivity pneumonitis-like reaction effective in controlling infection.
- Pulmonary resistance against P. brasiliensis appears to be associated with local and systemic delayed-type hypersensitivity.