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Programmed cell death in thymus during experimental paracoccidioidomycosis
Paula C S Souto1, Vânia N Brito, Jacy Gameiro
1Departamento de Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Cidade Universitária Zeferino Vaz s/n, Caixa Postal 6109, 13083-970 Campinas-SP, Brazil. souto@unicamp.br
Medical Microbiology and Immunology
|April 11, 2003
Summary
Systemic mycosis from Paracoccidioides brasiliensis causes thymic atrophy through programmed cell death (PCD). This damage to the thymus may explain the immunosuppression seen in paracoccidioidomycosis.
Area of Science:
- Immunology
- Pathology
- Mycology
Background:
- Systemic mycosis can lead to immunosuppression via primary lymphoid organ damage.
- Paracoccidioides brasiliensis infection causes thymus atrophy, reducing cortical area and blurring cortico-medullary boundaries.
Purpose of the Study:
- To determine if programmed cell death (PCD) causes thymic atrophy during P. brasiliensis infection.
- To investigate the ultrastructural changes in the thymus following experimental infection.
Main Methods:
- Immunohistochemistry to assess apoptotic index.
- Transmission electron microscopy to examine cellular ultrastructure.
- Experimental infection of BALB/c mice with Paracoccidioides brasiliensis.
Main Results:
- An eightfold increase in apoptotic index was observed by day 5 post-infection.
- Autophagic programmed cell death (PCD) alterations were identified via transmission electron microscopy.
- Significant thymic atrophy and loss of structural integrity were confirmed.
Conclusions:
- Programmed cell death (PCD) is a key mechanism driving thymic atrophy in paracoccidioidomycosis.
- Thymic alterations likely contribute to the immunosuppression associated with this fungal infection.
- Findings highlight the thymus as a critical target organ in P. brasiliensis infections.