Elimination of antigen-specific CTLs by κaAPCs is strongly ratio dependent. CTLs were cocultured with unloaded (circles), Mart-1–loaded (squares), and CMVpp65-loaded (triangles) CBs or κaAPCs. Closed symbols represents CTLs cocultured with CBs, whereas open symbols indicate CTLs cocultured with κaAPCs. Different bead-CTL ratios are indicated at the x-axis. Numbers of viable CTLs; (% viable cells = (% treated cells × 100%)/% untreated cells were determined by Annexin V and PI staining 48 hours following initiation of cocultures. One representative experiment of 3 is shown.