In vitro effects of gliotoxin, a natural proteasome inhibitor, on the infectivity and proteolytic activity of Toxoplasma gondii

Abstract.

We examined the in vitro effect of increasing gliotoxin concentrations on the infectivity of Toxoplasma gondii for NIH-3T3 murine fibroblasts and on Toxoplasma chymotrypsin-like activity, which is specific to the proteasome. Parasite penetration of host cells was not modified by a high gliotoxin concentration (1 µM), but replication was markedly decreased (approximately 50% inhibition by 0.5 µM gliotoxin). Gliotoxin reduced the chymotrypsin-like activity of the Toxoplasma proteasome, but five times less potently than in HeLa cells.