Figure 2. CD25hi Foxp3− CD4SP TCR repertoire is enriched for Treg cell TCRs.
(A) Analysis of shared TCRα sequences among thymic CD4SP populations. Foxp3+, CD25hi GITRhi Foxp3−, or CD25lo GITRint Foxp3−, CD4SP thymocytes were sorted from TCli TCRβ-transgenic x Foxp3gfp x Tcra+/− mice and TRAV14 (Vα2) TCRα sequences obtained as previously described (Hsieh et al., 2004). Data shown is pooled from two independent experiments (Suppl. Figure 2). Each pie graph represents the TCRα sequences in the data set which were also found in at least one other thymic data set. The portion of the TCRα sequences which overlaps another data set is indicated by a different color in the pie graph, and the data set overlapped is denoted by an arrow. The number of TCRα chains which were not found in another subset was similar between the three subsets (73%, 65%, and 67% for CD25lo, CD25hi, and Foxp3+ subsets, respectively). (B) Comparison of TCRα sequences from thymic and peripheral subsets. Unique TCRα sequences from the indicated thymic CD4SP subsets which were also found in the peripheral TCR data sets are plotted on the x-axis. Each vertical bar represents the likelihood that an individual thymic TCR would be found within the peripheral Foxp3+, naïve (Foxp3− CD44lo), or memory/activated (Foxp3− CD44hi) CD4+ T cell data sets. The size of each color in the bar is calculated by the frequency of the TCR in the subset divided by the sum of the frequencies in all three subsets.