Recognition and killing of SNT 16 by LMP2-specific CD8⁺ T-cell clones through HLA A2 and A24. (A) CD8⁺ clones specific for endogenously processed LMP2-derived peptides FLYALALLLL and TYGPVFMCL were cocultured for 18 hours with 10⁵ target cells (gray and black bars indicate 5000 and 10 000 CD8⁺effectors per well, respectively). HLA-matched and -mismatched LCLs were positive and negative controls, respectively. Other controls included SNT 16 and CD8⁺ effectors cultured alone to assess spontaneous IFN-γ release. Error bars indicate 1 SD from the mean. Results are representative of those seen in 3 separate experiments. Supernatant IFN-γ was quantitated by ELISA. Relative to the maximal values seen using the same target cells preloaded with 5μM cognate peptide, recognition of the unmanipulated cells were as follows: FLY (SNT 16 = 14%, LCL = 26%), TYG (SNT 16 = 5%, LCL = 15%). (B) Lysis of SNT 16 and LCL targets by the LMP2-specific FLY and TYG CD8⁺ clones shown in panel A. Five-hour ⁵¹Chromium-release assays were conducted with SNT 16, HLA class I–matched and –mismatched LCL targets. Spontaneous release of ⁵¹Cr was < 30% of maximum release. Results are expressed as the percentage of specific chromium release from the target cells at the indicated effector-to-target ratios. Gray lines indicate results after preincubation for 1 hour with 5μM cognate peptide. Results are representative of those seen in 3 different experiments. Error bars indicate 1 SD from the mean.