Tregs limit T-lymphocyte activation within MCMV-infected brains.

Activation of CD8+ and CD4+ T-cells was evaluated based on flow cytometric analysis using PE-Cy5-labeled inducible co-stimulatory molecule (ICOS) Abs. (A) Representative contour plots show the percentage of CD8+ T-cells expressing the activation marker ICOS from infected, untreated, as well as DTx-treated animals at the indicated time points. (B) Data presented show the mean fluorescent intensity (MFI) of ICOS expression on CD8+ T-cells (mean ±SD) between groups. **p <0.001 DTx- versus DTx+ MCMV-infected at 7 & 30 dpi and ***p<0.0002 at 14 dpi. (C) Pooled data presents the mean fluorescent intensity (MFI) of ICOS expression on CD4+ T-cells (mean ±SD) between groups. **p <0.001 DTx- versus DTx+ MCMV-infected at 14 & 30 dpi. (D) The number of ICOS+CD8+ T-cells in infected brains with and without DTx treatment at the indicated time points is shown. (E) The number of ICOS+CD4+ T-cells in infected brains with and without DTx treatment at the indicated time points is shown. **p < 0.001 DTx- versus DTx+ animals