Effect of anti-CD25 mAb treatment on Treg compartment and on anti-mycobacterial Th1 responses.

<p>(A) Mice received, at days −2 and 11, i.p. injections of PBS or of 1 mg of the control rat IgG (CRL-1912) or of anti-CD25 mAb (PC61). At day 0, mice were immunized s.c. with 1×10⁶ CFU of BCG. (B) At day 21, percentages of FoxP3⁺ cells within CD4⁺ T cell splenocytes were determined. Results represent mean±SD obtained in individually studied mice (<i>n</i> = 3). * = statistically significant, as determined by Anova test, <i>p</i><0.001. (C) Frequency of IFN-γ producing T splenocytes in response to TB10.3 or TB10.4 in mice immunized by BCG and treated with anti-CD25 mAb. At day 21 post-immunization, serial dilutions of splenocytes from mice (<i>n</i> = 6), unvaccinated or immunized with BCG and injected with PBS, control IgG or PC61 mAb, as described in (A), were stimulated <i>in vitro</i> with 10 µg/ml of TB10.3:74–88 (left) or TB10.4:74–88 (right) to determine the frequency of specific CD4⁺ IFN-γ-producing T cells by ELISPOT. Horizontal bars and the boxes indicate the mean values and SD, respectively. Whiskers show the smallest and the largest values. * or ** = statistically significant, as determined by Student's <i>t</i> test, <i>p</i><0.02 or 0.01, respectively. <i>Ns</i> = no significant difference.