Antitumor T-cell responses. Intracellular IFN-γ production by (A) CD4+ cells and (B) CD8+ cells. On day 4 posttreatment, splenocytes from the treated mice were cocultured with either media, irradiated BL3750 or H11 cells for 24 hours, and was in the presence of monensin for the last 5 to 6 hours. Intracellular IFN-γ were assayed by flow cytometry and results were gated on CD3+ cells; indicated are the proportion of IFN-γ+ cells as a percentage of total lymphocytes.