Polyclonal EBNA1-specific IFN-γ CD8⁺ T cells are capable of recognizing and killing endogenously expressed EBNA1-presenting B cells. Polyclonal EBNA1-specific T cells were generated from healthy PBMCs using the 14-day peptide pool expansion protocol. On day 14, the cells were restimulated with the EBNA1 peptide pool and live sorted for IFN-γ–producing CD8⁺ T cells using PerCP-labeled anti–human CD8 monoclonal antibody, FITC-labeled anti–human CD14 monoclonal antibody, and PE-labeled IFN-γ detection antibody/IFN-γ catch reagent. (A) Flow cytometry live sort of IFN-γ⁺ CD8⁺ T cells and IFN-γ⁻ CD8⁺ T cells. The percentage of the cells within each quadrant is shown. Cells were gated on CD14-negative lymphocyte population. (B) Five-hour ⁵¹Cr release assay comparing the sorted IFN-γ⁺ CD8⁺ T cells and IFN-γ⁻ CD8⁺ T cells using autologous LCL and K562 as targets. Samples were tested in duplicate with an effector/target ratio of 20:1. Error bars represent SEM.