Fig. 3.

Cell division of subsets of CD8⁺CD127⁺ and CD8⁺CD127⁻ T cells. Isolated CD8⁺CD127⁺ and CD8⁺CD127⁻ T cells were cultured with media only (Ctl) and cells incubated with PHA (2.5 μg ml⁻¹), PHA + IL-4 (1, 10 or 100 ng ml⁻¹) or PHA + IL-15 (10 ng ml⁻¹) or PHA + IL-2 (1, 10 or 100 units ml⁻¹). Representative dot plots (y-axis, CD8⁺: x-axis, CFSE) of cell division profiles of CD8⁺ T cell subsets are shown: (A) CD127⁺CD45RA⁺, (B) CD127⁺CD45RA⁻, (C) CD127⁻CD45RA⁺ and (D) CD127⁻CD45RA⁻. The CFSE^lo cells (shown in hatched boxes) have undergone the maximum number of detectable divisions. The cytokine concentrations shown here include IL-4 (100 ng ml⁻¹), IL-15 (10 ng ml⁻¹) and IL-2 (100 units ml⁻¹). In addition, the proportion of CFSE^lo cells from experiments in six individuals is summarized in bar graphs. Statistically significant changes in the proportion of CFSE^lo cells are indicated with a ‘‡’ compared with unstimulated controls (Ctl) or ‘*’ when comparing PHA + IL-4 (paired Student's t-test, P < 0.05), IL-15 or IL-2 to PHA alone.