[Enhancement of resistance of mice Toxoplasma gondii by 2 polysaccharides beta 1-3, beta 1-6 (PSAT and Scleroglucan)].

The protective effect of PSAT and Scleroglucan (beta 1-3, beta 1-6 polysaccharides), has been studied in mice infected with different strains of Toxoplasma gondii (RH, attenuated RH or Prugniaud strains). Intramuscular or intravenous administration of PSAT before infection of mice by the attenuated RH strain, resulted in a significant enhancement of survival: 100% of survival in the treated group, compared to 33% in controls and 50% in mice pretreated with Scleroglucan (10 mg/kg, intravenously). In contrast, there was no difference in the survival rate between the group treated with PSAT (1 mg/kg, IV) and the control in mice infected with the virulent RH strain: all mice died between day 7 and day 8. In mice infected with 15 cysts of the Prugniaud strain a decrease in the chemiluminescence (CL) of peritoneal macrophages and of the number of cysts in the brain of mice were observed in mice treated either with PSAT (1 mg/kg, IM) or scleroglucan (10 mg/kg, IM).