Increased proliferation of CD4⁺ T-lymphocytes in the infected brains following Treg depletion.

(A) Brain tissue from MCMV-infected, Foxp3-DTR transgenic mice was collected at 7, 14, and 30 dpi. Brain-infiltrating leukocytes were isolated and stained for flow cytometry with PE-Cy5-conjugated Abs specific for CD45, PE-Cy7-labeled for CD4-e-F 450, and Ki67 FITC–conjugated Abs. Isotype Abs for Ki67 FITC were used as gating control. Contour plots showing the proliferation frequency of CD4+ T-cells from infected, untreated (-DTx), and DTx-treated (+DTx) animals at the indicated time points are representative of 2 independent experiments. (B) Pooled data show percentage proliferation of CD4+ T-cells (mean ±SD) in infected brains with and without treatment at the indicated time points. ***p < 0.0001 DTx- versus DTx+ MCMV-infected at 14 dpi. **p < 0.001 DTx- versus DTx+ MCMV-infected at 30 dpi. (C) The number of proliferating CD4+ T-cells in infected brains of animals with and without DTx treatment at the indicated time points is shown. **p < 0.001 DTx- versus DTx+ MCMV-infected animals