Figure 3. The ppins∆A_12-21 vaccine induced Foxp3⁺ CD25⁺ Treg cells.

Splenic lymphocytes of untreated (group 1, n = 3), pCI/ppins-primed (group 2, n = 3) or ppins∆A_12-21-vaccinated/ppins-primed (group 3, n = 3) PD-L1^−/− mice were isolated 20 days after the injection of pCI/ppins, stained for surface CD4 and CD25 and intracellular Foxp3 expression and analysed by FCM. The actual percentage of Foxp3⁺ (a) and Foxp3⁺ CD25⁺ (b) Treg cells in gated CD4⁺ T cell populations ± SD of a representative experiment (out of two experiments performed) is shown (left panels). Statistically significant differences between the group 1 and group 3 or group 2 and group 3 were determined using the unpaired student’s t-test. P values of <0.05 (*), <0.01 (**) and <0.001 (***) were considered statistically significant. As example for the underlying flow cytometric analysis, Dot Plots from a representative mouse per group are shown (right panels).