Alterations of Toxoplasma gondii induced by 2',3'-dideoxyinosine in vitro

The time-course of action of the antiviral agent 2',3'-di-deoxyinosine (ddl) against Toxoplasma gondii tachyzoites in vitro and its effects at the ultrastructural level were investigated. The very short latency of effect and high efficacy of ddl were evidenced by the fact that the drugs' effects on parasite growth occurred 2 hr after addition to the culture medium, and that an IL 90 value of 0.5 μg/ml was reached after 72 hr. Although without apparent effect on uninfected cells, ddl clearly acted on the intracellular parasites, which tended to disappear. Remaining tachyzoites were almost exclusively extracellularly located and often exhibited a clustering of mitochondria-like bodies and subsequent deep alterations of their plasma membranes, These results confirm previous findings and emphasize the potential usefulness of ddl the management of cerebral toxoplasmosis, a major health problem acquired immune deficiency syndrome patients.