In vitro effects of IFN-γ on AML cells. (A) AML cells were cultured at 2 × 106 cells/mL with either 100 U/mL rmIFN-γ or 10 ng/mL rmIL-12. Control AML cells were cultured in RPMI alone. After 48 hours, cells were harvested and stained as described in Materials and Methods. In all panels, solid histograms represent the expression of the indicated markers by AML cells cultured in RPMI alone. A total of 10,000 cells were analyzed by FACS for each sample. (B) AML cells were cultured at 4 × 105 cells/well in U-bottomed 96-well plates in the presence of 100 U/mL rmIFN-γ or 10 ng/mL rmIL-12. 3H thymidine (1 μCi/well) was added during the last 20 hours of culture. Results are representative of 2 independent experiments and are shown as the mean ± SD of 8 cultures. (C) AML cells were cultured as described in (A). After 48 hours, cells were harvested and their viability was assessed by trypan blue exclusion. Results are representative of 2 independent experiments and are shown as the mean ± SD of triplicate culture.
