Treg limit effector differentiation of CD8+ T cells activated under immunogenic conditions.

<p>A-D) 11c.OVA mice were injected with αCD25 or isotype-control mAb and 3 days later 2×10⁶ CD45.1+ OT-I T-cells transferred with or without CpG administration. Additional αCD25 or isotype-control mAb (iso) was administered every 3 days after the initial injection. At the times shown (A) or 7 days after OT-I transfer (B-F) the total number of OT-I (CD45.1⁺CD8⁺ Vα2⁺ ) T cells in spleen producing IFN-γ, TNF-α, IL-2 or co-producing IFN-γ and TNF-α was determined by ICC and a FACS-based counting assay. IL-2 production 7 days after transfer in OVA_257–264 restimulated cultures is displayed for host (CD45.-ve left quadrants) or OT-I (CD45.1+ve, right quadrants) cells. Numbers depict the proportion of host (CD45.1-ve) or OT-I cells (CD45.1+ve) staining positively for IL-2. Data shown are (A) mean ± SEM (n = 4) or (B-E) the actual cytokine producing cell numbers for each individual cytokine from individual mice pooled from at least two independent experiments. (A) **: 11c+CpG+αCD25 is greater than 11c+CpG+iso (p<0.05) and greater than 11c+αCD25 and 11c+iso (p<0.01), *11c+CpG+aCD25 and 11c+CpG+iso are greater than others (p<0.05) (one-way ANOVA, Newman-Keuls post-test. GraphPad Prism V5.03). (F) Data are representative of analyses shown in D-E.