Cellular cytotoxicity of irradiated KG1a cells toward myeloid (U937, K562) or lymphoid (Jurkat) cell lines.

Irradiated KG1a cells were cultured for 72 hours. Cytotoxicity was measured by using a 4-hour nonradioactive LDH-release assay at the indicated E:T ratio. Untreated KG1a (■), irradiated KG1a (▪), NKL (▴), or PBL-IL2 (●) cells (used as an internal control) were co-incubated with U937 (A), K562 (B), or Jurkat (C) cells as targets. Results are the mean ± standard deviation of three independent experiments performed in triplicate. *P = 0.02 for E:T ratio of 80:1 to 10:1.