CMV-specific T cells of recipient origin produce IFN-γ after stimulation with pp65-transfected, EBV-transformed B-cell lines. (A) Percentages of HLA-A^*0101/YSEHPTFTSQY-tetramer positive cells at day 59. IFN-γ production by CD8⁺ lymphocytes in the same sample cultured overnight with HLA-A^*0101-positive EBV cells transduced with GFP and pp65 (B), without stimulator cells (C), or with EBV cells transduced with GFP alone (D). Results are expressed as percentages of CD8⁺ cells with gates on lymphocytes (scatter) and GFP negativity (fluorescence 1) to exclude the antigen-presenting cells.