Gliotoxin belongs to the epipolythiodioxopiperazine class of secondary metabolites. These compounds show a diverse range of biological activity including antimicrobial, antifungal and antiviral properties. They also display potent in vitro and in vivo immunomodulating activity. 2. Their properties resulted in a number of early studies designed to exploit their possible chemotherapeutic value, although the general toxicity of most members of this class has precluded clinical use. 3. Most recently, their selective immunosuppressive properties have led to the possibility of ex vivo treatment of tissue to selectively remove immune cells responsible for tissue rejection. The mode of action of gliotoxin appears to be via covalent interaction to proteins through mixed disulphide formation and gliotoxin has been shown to inhibit a number of thiol requiring enzymes. 4. Gliotoxin is also a potent inducer of apoptotic cell death in a number of cells. Gliotoxin and other members of this class of toxins may be produced in vivo during the course of fungal infections and contribute to the aetiology of the disease.
