Gliotoxin is an immunosuppressive mycotoxin produced by pathogenic strains of Aspergillus and other fungi. It inhibits 20S proteasomal chymotrypsin activity (IC50 = 10 μM), blocking the degradation of IκBα and preventing the activation of NF-κB. Gliotoxin also induces apoptosis in monocytes and dendritic cells and reduces phagocytosis by neutrophils. It also inhibits geranylgeranyltransferase I and farnesyltransferase (IC50 = 17 and 80 μM, respectively). Gliotoxin potently suppresses viral infection by Nipah and Hendra virus in vitro (IC50 = 149 and 579 nM, respectively). While gliotoxin production by fungi correlates with invasiveness, its role in aspergillosis remains unclear.
