Gliotoxin inhibits transformation and its cytotoxic to turkey peripheral blood lymphocytes
J L Richard1, W M Peden, P P Williams
1Mycotoxin Research, National Center for Agricultural Utilization Research, USDA/ARS, MWA, Peoria, Illinois.
Abstract:
Gliotoxin, an epipolythiodioxopiperizine mycotoxin, has been shown to be produced by, among other fungi, Aspergillus fumigatus Fresenius. This organism is the major causative agent of the respiratory disease aspergillosis in avian species, especially turkeys. Because gliotoxin has been shown to be immunosuppressive and has the potential for being involved in the pathogenesis of aspergillosis, the in vitro activity of this compound with avian lymphocytes was investigated. Immunosuppression was investigated using peripheral blood lymphocytes from turkeys in a lymphoblastogenesis assay and a cytotoxicity assay using conversion of the tetrazolium salt MTT to MTT formazan by the mitochondrial succinate dehydrogenase enzyme elaborated only by living cells. Gliotoxin appeared to have a threshold level in both tests because little or no response or stimulation was evident when cells were exposed to concentrations of the toxin below 100 ng/ml, but at 100 ng/ml, all cells appeared to be dead. Using T-2 mycotoxin as a known cytotoxic agent, the response in the MTT bioassay using turkey peripheral lymphocytes was linear with increasing concentrations of toxin. Gliotoxin may potentially cause immunosuppression in turkey poults through action on the lymphocytes or if this toxin were present in low concentrations stimulation could possibly occur.
Insights
Gliotoxin, a mycotoxin from Aspergillus fumigatus, impacts turkey lymphocytes. At concentrations above 100 ng/ml, it causes cell death, potentially contributing to avian aspergillosis.
Area of Science:
- Mycology
- Immunology
- Avian Pathology
Background:
- Gliotoxin is a mycotoxin produced by fungi like Aspergillus fumigatus.
- Aspergillus fumigatus is a primary cause of respiratory aspergillosis in avian species, particularly turkeys.
- Gliotoxin exhibits immunosuppressive properties and may play a role in aspergillosis pathogenesis.
Purpose of the Study:
- To investigate the in vitro effects of gliotoxin on avian lymphocytes.
- To assess the potential immunosuppressive and cytotoxic activities of gliotoxin in turkeys.
Main Methods:
- Utilized peripheral blood lymphocytes from turkeys.
- Conducted lymphoblastogenesis and cytotoxicity assays.
- Employed the MTT (tetrazolium salt) bioassay to measure cell viability via mitochondrial activity.
Main Results:
- Gliotoxin demonstrated a threshold effect, with minimal impact below 100 ng/ml.
- At concentrations of 100 ng/ml and above, gliotoxin caused significant cell death in turkey lymphocytes.
- The MTT bioassay showed a linear response to increasing concentrations of cytotoxic agents like T-2 mycotoxin.
Conclusions:
- Gliotoxin can induce immunosuppression in turkey poults by affecting lymphocytes.
- Low concentrations of gliotoxin might potentially stimulate lymphocytes.
- The findings highlight gliotoxin's potential role in the pathogenesis of avian aspergillosis.
