text: FACS-based cytotoxicity assay.
  To measure cytotoxicity, EL4 thymoma target cells were loaded with 0 or 1 muM Gp33 peptide for 2 h before a 2-h coincubation with P14 CD8+ T cells at the effector-to-target ratios indicated in the figures in 96-well round-bottom plates. After the coincubation period, cells were stained with Annexin V-FITC and anti-CD8-allophycocyanin. Data analysis was performed with FlowJo software (Tree Star, Inc.); EL4 target cells (CD8-negative events) were gated, and the percentage of Annexin V+ target cells was determined. 
  