CD28 expression by adoptively transferred HIV-specific CD8⁺ T-cell clones is associated with IL-2 secretion after stimulation by specific Ag. (A) Expression of CD28 on the HIV-specific CD8⁺ T-cell clone before infusion (left histogram) for patient 7707 (A*0301/QVPLRPMTYK-HIV-NEF). Whole PBMCs were obtained at day 3 after the 2nd infusion and stained with specific pentamer (A*0301/QVPLRPMTYK-HIV-NEF). The expression of CD28 ex vivo on pentamer⁺ T cells is shown (plot to the right of the histogram). Cells were stimulated with specific peptide (QVPLRPMTYK) and pentamer⁺CD8⁺ T cells analyzed for the surface expression of CD28 and intracellular production of IFNγ, TNFα, and IL-2 (rightmost plots). (B) The same analysis was performed on whole PBMCs obtained at day 112 after transfer of the HIV-specific clone into patient 7707. (C) Data on PBMCs that were obtained on day 21 after the first infusion from patient 7703 (B*0801/GEIYKRWII-HIV-GAG) are shown. Analysis for pentamer⁺CD28⁺ and CD28⁻ subpopulations are shown individually. (D) Data for patients 7701 and 7702 (B*0801/GEIYKRWII-HIV-GAG) are shown on PBMC that were obtained 14 days after the first infusion (7701), 7 and 112 days after the second infusion (7702), after stimulation with the cognate peptide (GEIYKRWII). Pentamer⁻CD8⁺ T cells in the same assays did not produce IFNγ, TNFα, or IL-2 (not shown).