Toxoplasma Gondii In Fibroblasts Research Articles

Inhibition of growth of Toxoplasma gondii by qinghaosu and derivatives

The antimalarial compound qinghaosu (artemisinin) was tested in vitro for the ability to inhibit plaque formation by Toxoplasma gondii in fibroblasts. Qinghaosu at 0.4 microgram/ml for 5 days eliminated all plaques and microscopic foci of T. gondii. At 1.3 micrograms/ml for 14 days, qinghaosu completely eliminated T. gondii. Pretreatment of host cells or T. gondii with qinghaosu had no effect on T. gondii growth. There was no apparent toxicity to human fibroblasts in long-term studies. Of the six qinghaosu derivatives tested, dihydroqinghaosu, 1-propyl-ether-qinghaosu, and 1-butyl-ether-qinghaosu were comparable to qinghaosu. Ethyl-ether-qinghaosu (arteether) and sec-butyl-ether-qinghaosu were more effective. Methyl-ether-qinghaosu (artemether) was the most effective, with a potency approximately 10-fold greater than that of qinghaosu.

Beta interferon inhibits Toxoplasma gondii growth in human monocyte-derived macrophages

Gamma interferon (IFN-gamma) previously has been shown to block the replication of Toxoplasma gondii in fibroblasts by the induction of indoleamine 2,3-dioxygenase (IDO) activity. IFN-beta also is known to induce IDO activity in monocyte-derived macrophages, but its ability to block the growth of T. gondii has not been demonstrated. We found not only that the combination of IFN-beta and lipopolysaccharide induced greater IDO activity in monocyte-derived macrophages than did IFN-beta alone but that this combination also was effective in inhibiting the growth of T. gondii. In addition, the inhibition was reversed by the addition of exogenous tryptophan, thus demonstrating that a mechanism by which IFN-beta inhibited T. gondii replication was by the induction of IDO.

Interferon gamma and the growth of Toxoplasma gondii in fibroblasts

Interferon gamma and the growth of Toxoplasma gondii in fibroblasts