Experimental toxoplasmosis in hypoiodemic mice

The hypothesis, that hypoiodemia of goats causes such a compromise of the immune system, which during subsequent Toxoplasma gondii infections results in clinically more pronounced signs of toxoplasmosis, was verifying in laboratory mouse. Hypoiodemic mice (fed by wheat and supplied by water), normoiodemic mice (fed by wheat and supplied by water containing 1.25 mg KI/l) and the majority of standard mice (fed by commercial grain mixture containing 0.83 mg I/kg) were experimentally infected with T. gondii oocysts or tachyzoites. The susceptibility to acute T. gondii infection was evaluated according to mortality rate. As a criterion of cell-mediated immune function has been chosen the spleen-lymphocyte transformation test (LTT). We observed no difference in LTT between hypoiodemic and normoiodemic mice infected with T. gondii oocysts or tachyzoites and no difference in mortality of both infected groups. Four days after the exposure to 100 tachyzoites of T. gondii (K24 strain), all experimentally infected groups of mice showed statistically significant decrease (P = 0.004) in spleen cells responsiveness to stimulation by all mitogens used – as compared to non-infected standard mice group. Reduced responsiveness of cells was probably caused by T. gondii infection itself – the relation to iodine deficiency has not been found.