In vivo persistence of HIV-specific CD8⁺ T-cell clones isolated from CD28-expressing CD8⁺ T-cell lines. (A shaded area) The percentage of pentamer⁺CD8⁺ T cells (x-axis) detected in PBMCs collected −7 days (+/−2 days), immediately before and after infusions are shown for 5 (7701, 7702, 7703, 7705, and 7707) of 7 infused HIV-specific CD8⁺ T-cell clones that showed persistence for ≥ 21 days after the first infusion. Persistence was calculated as the last time point at which pentamer⁺CD8⁺ T cells were 2 times background levels or > 0.1%. (A nonshaded area) The percentage of pentamer⁺CD8⁺ T cells after each infusion and up to 112 days after the first infusion is shown for the same patients. (B) Two patients (7704 and 7709) that showed a rapid disappearance of the infused clones within 3 days of both infusions are shown.