Elimination of CMVpp65-specific CTLs by ^CMVpp65κaAPCs. (A) An example of CMVpp65-specific CTLs used throughout the experiments. CTLs were specifically stained with CMVpp65 tetramer (88.84%). Mart-1 tetramer (0.19%) served as control stain. (B) Elimination of (▓) CMVpp65- or (▒) Mart-1–specific CTLs from different donors in cocultures with CBs or κaAPCs loaded with CMVpp65 or Mart-1 peptide. Cocultures with unloaded CBs or κaAPCs served as negative controls. Numbers of viable cells (% viable cells = (% treated cells × 100%) /% untreated cells) after 48 hours of coculture are depicted (means ± SD) of 5 independent experiments.