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Updated: Aug 9, 2026
07:42
Activation of Apoptosis by Cytoplasmic Microinjection of Cytochrome c
Published on: June 29, 2011
Apoptosis induction by glucuronoxylomannan of Cryptococcus neoformans
L S Chiapello1, M P Aoki, H R Rubinstein
1Micología, Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
Medical Mycology
|September 11, 2003
Summary
Glucuronoxylomannan (GXM) from Cryptococcus neoformans induces apoptosis, or programmed cell death, in rat lymphocytes. This GXM-induced apoptosis may contribute to the immunosuppression seen in cryptococcosis infections.
Area of Science:
- Immunology
- Cell Biology
- Microbiology
Background:
- Cryptococcus neoformans is a fungal pathogen causing cryptococcosis.
- Glucuronoxylomannan (GXM) is the primary component of the C. neoformans capsule.
- The immunosuppressive mechanisms of cryptococcosis are not fully understood.
Purpose of the Study:
- To investigate the in vitro and in vivo effects of GXM on lymphocyte apoptosis.
- To determine if GXM contributes to the immunosuppression observed during C. neoformans infection.
Main Methods:
- Spleen mononuclear cells (Smc) from normal rats were treated with GXM.
- DNA content and fragmentation were analyzed using propidium iodide staining and gel electrophoresis.
- Terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) assay was used to detect apoptotic cells.
- Apoptosis was also assessed in lung and spleen tissues from rats infected with C. neoformans.
Main Results:
- GXM treatment increased hypodiploidy and DNA fragmentation in rat Smc.
- GXM-treated T-cell receptor (TCR+) cells showed increased hypodiploidy.
- TUNEL labeling revealed a high number of apoptotic cells in GXM-treated Smc.
- Infected rats exhibited significant apoptosis in lung and spleen tissues.
Conclusions:
- GXM induces apoptosis in lymphocytes in vitro.
- GXM-induced apoptosis is a potential mechanism of immunosuppression in C. neoformans infection.
- Programmed cell death mediated by GXM may play a role in the pathogenesis of cryptococcosis.
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