Restimulation and expansion of generated T-cell lines. CFSE-labeled PBMCs and generated T cells (1 × 10⁶/mL) were cultured with CMV lysate-loaded autologous DCs. The CFSE staining and the expansion rate are shown in one representative donor after 7 days (LSA9). The number of divisions and the percentages of CD4⁺ and CD8⁺ T cells that underwent at least one cell division are indicated. Multiple cell division can be detected in isolated and expanded CD4⁺ and CD8⁺ T cells. In contrast, less than 13% of the unselected CD4⁺ and 17% of the unselected CD8⁺ T cells derived from the same donor dilute the CFSE dye. Differences in the degree of CFSE dilution in the selected and expanded T cells correlate with increases in cell numbers (up to 11-fold), whereas unselected PBMCs expanded marginally (up to 2.3-fold) in the same time period.