Our results show that production of IL-12 as well as expression of activation markers by APCs was significantly impaired in 3d mice infected with T. gondii. Intriguingly, the IFNγ levels were similar in the sera, splenocyte cultures and peritoneal cavity, when comparing 3d and WT mice at day 8 post-infection with T. gondii. This evidence concerns the gene IFNG and infection.