Figure 1.

The acute response to T. gondii results in the transient loss of Treg cells.

WT mice (five animals per group) were infected intraperitoneally with an average of 20 T. gondii strain ME49 cysts per mouse, and (A) the frequency of Treg cells defined as CD4+Foxp3+ cells was analyzed in the spleen of the infected and control (d0) mice at the indicated number of days post-infection. (B) Foxp3 expression levels were analyzed in splenocytes (left graph), isolated CD4+ T cells (central graph), or sort-purified CD4+Foxp3+ T cells (right) isolated from naïve or T. gondii infected mice (day 7 post infection) by real-time PCR. All the data were normalized to the expression level seen in sort-purified CD4+CD44-Foxp3- naïve T cells. The data shown are the mean ± SD. (C) WT mice were infected orally with an average of 20 T. gondii strain ME49 cysts per mouse, and the frequency of Treg cells was analyzed in the spleen of the infected mice at the indicated number of days post-infection. (D) Average frequency of Foxp3+ cells in the spleens of mice infected intraperitoneally (filled circles) or orally (open circles). (E) Absolute quantification of Treg cells in the spleens of mice infected intraperitoneally (filled circles) or orally (open circles) with the parasite. The data shown are representative of five independent experiments. (F). Absolute quantification of CD4+ and CD4+IFN-γ+ T cells in the spleens of naïve (d0) and T. gondii infected mice (d7). The data shown are representative of at least six independent experiments. * P< 0.05; ** P< 0.01.