Toxoplasma gondii is one of the most prevalent parasites, causing
toxoplasmosis in various warm-blooded animals, including humans. Because of the broad range of hosts susceptible to T. gondii, it had been postulated that a universal component of the host cell surface, such as
glycosaminoglycans (GAGs), may act as a receptor for T. gondii
infection. Carruthers et al. (Infect Immun 68:4005-4011, 2000) showed that soluble GAGs have also been shown to disrupt parasite binding to human fibroblasts. Therefore, we investigated the inhibitory effect of GAGs and their analogue
dextran sulfate (DS) on T. gondii
infection. For up to 24 h of incubation after inoculation of T. gondii, the inhibitory effect of GAGs on T. gondii
infection and growth inside the host cell was weak. In contrast, DS markedly inhibited T. gondii
infection. Moreover, low molecular weight DS particularly slowed the growth of T. gondii inside host cells. DS10 (
dextran sulfate MW 10 kDa) was the most effective agent in these in vitro experiments and was therefore tested for its inhibitory effects in animal experiments;
infection inhibition by DS10 was confirmed under these in vivo conditions. In this report, we showed that DSs, especially DS10, have the potential of a new type of
drug for
toxoplasmosis.