the effect of vitamin d3 alone and mixed with ifn-γ on tachyzoites of toxoplasma gondii (rh strain) proliferation and nitric oxide (no) production in infected macrophages of balb/c mice

introduction: toxoplasma gondii is an obligatory interacelullar parasite that infects nucleated cells in its intermediate hosts. the aim of the present study was to determine the effect of vitamin d3 on the multiplication of t. gondii in peritoneal macrophage of balb/c mice and nitric oxide production by macrophages.  methods: according to usage of vitamin d3 (one dose or seven doses) and infγ in vitro and in vivo, this study was divided into four experiments. in all experiments, the macrophages were col­lected from peritoneum and cultured in rpmi-1640. then the supernatants were collected after 24 h and their nitric oxide was measure. after 96 h, the macrophages were collected and stained and the number of tachyzoites was measured.  results: the first experiment (the mice were infected with tachyzoites and after 2 h, got one dosevita­min d3 intraperitonealy) showed the best results. the mean of tachyzoites per macrophages was 2.37, and mean ± sd of nitric oxide was 187.8 ± 9. discussion: high-level production of nitric oxide may be related to the only one injection of vita­min d3. the injection in long time might suppress the immune system.