Figure 1. CD25⁺ cell depletion enhances immune responses in all strains.

(A) Experimental scheme representing the protocol of treatment and immunization: i.v. injection with anti-CD25Ab or control Ab on day −1, i.d. immunization with PAg plus adjuvant on days 0 and 15, and mice sacrifice on day 24. This protocol was applied to six to 8 week old male NOD, C57BL/6 and BALB/c mice. (B) Foxp3⁺ CD4⁺ and CD25⁺ Foxp3⁺ CD4⁺ T cell depletion efficiency tested 48 h after anti-CD25 Ab treatment measured by Flow cytometry. (C) PSBP-specific IgG1 and IgG2a-c levels measured in serum samples on day 24 by ELISA as described in Materials and Methods. (D) Gating strategy used to evaluate absolute numbers of effector (CD62L^lowCD44^hi) T cells and Treg (CD4⁺ Foxp3⁺) cells in draining LN from individual NOD, C57BL/6 and BALB/c mice in steady state conditions (without treatment) or on day 24 of the experimental protocol. Data are shown as mean ± SEM, n = 6 mice per group and representative of two independent experiments. The p values were obtained using one-way ANOVA followed by Bonferroni post-hoc analysis.