[24] Gene names of Vβ, Jβ and Vα are according to the Immunogenetics (IMGT) gene name nomenclature for Immunoglobulin (Ig) and T cell Receptor (TR) of mice.[25-27] Student’s t-test with Bonferroni correction was used for each statistical analysis. P-values less than 0·05 divided by the number of comparisons were considered statistically significant. We have reported that CD122 could be used as a marker for CD8+ Treg cells.[10] However, CD122 is also a classical marker for CD8+ memory T cells[17];

therefore, CD8+ CD122+ Selleckchem BVD-523 cells could contain both memory and regulatory T cells. Dai et al.[16] reported that PD-1 expression defines subpopulations of CD8+ CD122+ cells. They showed that CD8+CD122+ PD-1+ cells mainly produced IL-10 in vitro,

and that they suppressed rejection of allogeneic skin grafts in vivo. On the basis of these data, the authors concluded that PD-1+ cells in the CD8+ CD122+ population are real regulatory cells. We found that CD49d (integrin-α4 chain) divides CD8+ CD122+ cells into two populations (CD122+ CD49dlow cells and CD122+ CD49dhigh cells, Fig. 1a). Expression of CD49d in CD8+ CD122+ cells mostly correlated with that of PD-1 (Fig. 1b). CD8+ CD122+ CD49dhigh cells, but not CD8+ CD122+ CD49dlow cells, produced IL-10 in vitro when stimulated with an anti-CD3 antibody (Fig. 1c). This CD8+ CD122+ CD49dhigh cell RG7204 clinical trial subset was sustained until the mice were at least 20 weeks of age (Fig. 1d). On the basis of these results, subsequent experiments focused on CD8+ CD122+ CD49dhigh cells rather than CD8+ CD122+CD49dlow cells, and their TCR diversity was compared with that of CD8+ CD122− selleck compound cells (conventional, naive T cells). We compared TCR Vβ usage of CD8+ CD122+ C-D49dhigh cells and CD8+ CD122+ CD49dlow cells with that of CD8+ CD122− cells. Cells were stained with a panel of each Vβ-specific antibody, and the percentage of cells that used each Vβ was determined using flow cytometric analysis. In the spleens of wild-type mice, no statistically significant differences were observed

in the percentage of each Vβ+ cell in the three populations (Fig. 2a). However, in mesenteric lymph nodes (MLNs), the percentage of Vβ13+ cells was significantly higher in CD8+ CD122+ CD49dhigh cells (10%) than in CD8+ C-D122− cells (4%, P < 0·01) or CD8+ CD122+ CD49dlow cells (5%, P < 0·01), suggesting an increase in CD8+ CD122+ CD49dhigh Vβ13+ cells in MLNs (Fig. 2b). Immunoscope analysis of CDR3 regions of TCRs showed different patterns among CD8+ CD122+ CD49dhigh cells, CD8+ CD122+ CD49dlow cells and CD8+ CD122− cells Next, we examined TCR diversity of the CD8+ T-cell populations using immunoscope analysis (Figs. 3a,b). The results showed several skewed peaks that were not observed in CD8+ CD122− cells, but that were apparent in CD8+ CD122+ CD49dhigh cells. There were also several skewed peaks in CD8+ CD122+ CD49dlow cells.