Treatment with CI A23187 or A23187 with adjunct cytokines enhances T-cell allosensitizing capacity of HL-60 cells. HL-60 cells (5 × 10⁵/well) were cultured in 24-well plates in 2 mL CM (Untreated) or CM supplemented with rhGM-CSF (20 ng/mL, GM-CSF), rhIFN-γ (1000 U/mL, IFN-γ) or combined rhGM-CSF plus rhIFN-γ, each of these conditions with or without CI A23187 (180 ng/mL). HL-60 cells were harvested 72 hours later, washed three times in CM, γ-irradiated (30 Gy), and cocultured at various HL-60:T-cell ratios with freshly prepared allogeneic human T lymphocytes (1 × 10⁵/well) in triplicate 96-well tissue culture plate wells in 200 μL final volume CM. Cells were maintained in culture for 96 hours, pulsed with 1 μCi [³H]-TdR, harvested 18 hours later, and [³H]-TdR incorporation assessed by liquid scintillation spectrometry. Ordinate displays [³H]-TdR incorporation as thousands of CPM per well during the final 18-hour culture period; abscissa displays ratio of APC:T cells. Not shown: irradiated HL-60 cells alone, regardless of treatment, generated < 750 cpm when seeded at 20,000 cells per well; T cells alone generated < 250 cpm. Bars indicate SEM from triplicate wells.