CD8⁺ T cells from leukemic SJL/J mice secrete Th1 type cytokines. (A) T-1 and (B) T-2 cells were cultured at 2 × 10⁵ cells/well in the presence of PMA plus ionomycin and a feeder layer of irradiated 2 × 10⁵ syngeneic, anti-Thy 1.2 and C′-treated splenocytes. Cytokine concentrations were determined in tissue culture supernatants taken after 24 hours (IL-2) or 48 hours (IFN-γ, IL-4) of the initiation of the culture. The graphs are representative of three independent experiments. Data are shown as the mean and SD of triplicate culture.