Intracellular IFN-γ staining in cultured T cells. CB and AB mononuclear cells were cultured over 6 days with anti-CD3 MoAb (1:5,000 diluted OKT3 immune ascities) and IL-2 (20 U/mL). Preculture and on day 6, cells were harvested separating CD4⁺ and CD8⁺ T cells by positive selection, stimulated, and stained for intracellular IFN-γ production capability as described.2 Representative histograms of preculture (plain line) and day 6 (bold line) CB (A) and AB (B) T cells are shown with percentages of positive cells.