Measurement of CD4⁺CD25⁺Foxp3⁺ Tregs in the liver of PGK and PGK.142T vector-treated mice. Mice were injected with vehicle, PGK, or PGK.142T. (A) At the indicated times, mice were killed and the frequency of CD4⁺CD25⁺Foxp3⁺ Tregs in the liver was determined by FACS analysis. Data are expressed as the mean ± SD. A representative 3 experiments is shown, n = 3/group (n = 9/vector), except for vehicle injected (n = 17). (B) Representative dot plot gated on CD4⁺ cells is presented for each group at 3 weeks postinjection. The percentage of CD4⁺CD25⁺Foxp3⁺ Tregs is reported in the top right quadrant. CTLA-4 expression is shown gating on CD4⁺CD25⁺Foxp3⁺ Tregs or CD4⁺Foxp3⁻ T cells.