Antiviral activity of gliotoxin can be demonstrated at approximately one-tenth of the concentration which produces toxic effects in tissue culture cells and embryonated eggs.
The inhibition of picornaviruses in tissue culture varies quantitatively according to the strain of virus. Inhibition of influenza and parainfluenza viruses is found in embryonated eggs and chorioallantoic membrane pieces. No activity was found against any of the myxoviruses tested in tissue culture or against viruses containing deoxyribonucleic acid.
Gliotoxin acts on a stage in the intracellular synthesis of susceptible picornaviruses and results in inhibition of the production of virus specific proteins.
The adsorption of gliotoxin by cellsin vitro is rapid. Subsequent washing of the cells with gliotoxin-free medium does not result in a reversal of inhibition of virus synthesis.
A related compound, dethiogliotoxin, which does not contain the disulphide bridge present in gliotoxin appears to have no specific antiviral or antibiotic activity. It is suggested that the antiviral activity of gliotoxin is associated with the presence of the linked sulphur atoms in the molecule.