CD127 expression by spleen, PLN, and BM CD8 cells. (A,B) CD127 phenotype. Single-cell suspensions were prepared from spleen, PLN, and BM of untreated B6 mice. In some experiments, cells from individual mice were stained with anti-CD8 cychrome, anti-CD44 PE plus either control FITC or anti-CD127 FITC mAb, and analyzed by flow cytometry. In other experiments, purified spleen and BM cells were pooled from 8 to 10 mice and CD8⁺ cells were purified before CD127 staining. No differences were observed in the 2 sets of experiments. Representative staining profiles of spleen, PLN, and BM samples, after gating on CD8⁺ cells (A) and percentages of CD127⁺ cells within CD44^high and CD44^int/low CD8 cells from spleen, PLN, and BM (B). In (A), the scales on x-axis and y-axis are logarithmic, in arbitrary units. The numbers represent the percentages of CD127⁺ cells in the right quadrant within CD44^high (top panels) and CD44^int/low (bottom panels) CD8 cells. Mean fluorescence intensity of cells in the right quadrant is indicated in parentheses. In panel B, individual values are represented, as well as the average of each group (horizontal bar). (C) Modulation of CD127 after culture with IL-15 and IL-7. Purified CD8⁺ cells (5 × 10⁴ cells/well) from BM and spleen of untreated B6 mice were cultured for 3 days in the presence of medium, IL-15, or IL-7, as indicated. At the end of incubation, the percentages of CD127⁺ cells within PI⁻ CD44^high and CD44^int/low cells were determined. One representative experiment is shown of 3. For each experiment, BM and spleen cells were pooled from 8 to 10 mice. Differences between BM and spleen were similar in the 3 experiments and not statistically significant (average difference never > 20% for any cytokine concentration).