Phenotype of in vitro cultured and activated CTLs. (A) CTLs were harvested on day 16 of in vitro cell culture. Flow cytometric analysis of CTLs was performed. Cells were gated on CD8 expression. CTLs displayed an activated and effector memory phenotype. (B) Lysis of C1498FFDsR target or irrelevant tumor target, EL-4, was performed with CTLs 16 days after in vitro culture for 5 hours. CTLs were capable of killing the AML target but not the EL-4 cells in vitro. Error bars represent SD.