Allogeneic CTL clones define antigens restricted to renal cells or to renal and colon tumors. CTL G16 and B4 were cloned from MLTC-1 on CD8⁺ T lymphocytes of healthy donor 860 and the HLA class Ia–matched RCC line MZ1257-RCC. (A,D) CTL-mediated cytolysis was tested against MZ1257-RCC (▪), MZ1257-LCL (▴), and K562 (○) in 4-hour ⁵¹Cr-release assays. Results are given as percentage of specific lysis at indicated E/T ratios. (B,E) HLA class I restriction of CTLs reactive against MZ1257-RCC was identified by adding different anti-HLA mAbs in 20-hour IFN-γ ELISPOT assays. (C,F) Cross-reactivity pattern of CTLs observed in 20-hour IFN-γ spot assays against allogeneic target cell lines expressing HLA-A2 for CTL G16 and HLA-B7 for CTL B4, respectively. Results shown are representative of at least 20 different targets tested per CTL. Spot assays were plated with 5000 CTLs/well in triplicates.