TCDD causes apoptosis of Foxp3-CD4+ T cells but not Tregs.

Foxp3-GFP mice were HSV-1 infected and sacrificed on day 8 pi. A, Induction of in vitro apoptosis by different concentrations of TCDD on Foxp3-CD4+ T cells but not on Foxp3+CD4+ T cells. Cells isolated from spleens and DLNs of HSV-1 infected mice were cultured ex vivo in the presence of RPMI or RPMI with different concentrations of TCDD for 5 hours and thereafter stained for Annexin-V, representative FACS plots showing Annexin-V expression on gated CD4+ T cells. B, Representative FACS plots of Foxp3+CD4+ T cells in splenocytes and DLN cells from HSV-1 infected mice treated in vitro with different concentrations of TCDD for 5 hours. C, Bar diagram showing the percentages of Annexin V+Foxp3-CD4+, Annexin V+Foxp3+CD4+ and Foxp3+CD4+ under the indicated conditions in the DLN is shown. Data are representative of 3 independent experiments. Data were analyzed using one-way ANOVA test with Dunett's post hoc test settings and show mean values ± SEM (n = 12). P≤0.001(***), P≤0.01(**), P≤0.05(*).