Figure 3. P25 cells are not preferentially recruited into the Tfr pool.

(a) P25.Rag⁺ mice have similar frequency of thymic Treg cells (6.0±0.9%) as OT-II.Rag⁺ mice (6.4±0.7%). (b) C57BL/6 mice were transferred simultaneously with 10⁷ CD4⁺ T cells from OT-II.Rag⁺ and P25.Rag⁺ mice, and subsequently immunized with either OVA_323–339BSA-IFA or Ag85B_280–294BSA-IFA in the footpad. (c) Gating strategy to determine the percentage of OT-II.Rag⁺ and P25.Rag⁺ cells within Tfh and Tfr populations in mice immunized with OVA_323–339BSA-IFA (upper panel) or Ag85B_280–294BSA-IFA (bottom panel). (d) T-cell subsets from draining LNs show that mice immunized with OVA_323–339 have a large accumulation of OVA-specific cells within the Tfh and Tconv populations while, conversely, Ag85B_280–294-immunized mice accumulate P25-specific T cells among Tfh cells (*P<0.05 and **P<0.01 using two-tailed non-parametric Mann–Whitney U-tests). We observed a very small increase of T cells specific for the immunizing antigen among the Tfr population. In all graphs, mean±s.e.m. are presented. Data are representative of three independent experiments, each with n=5.