Effect of the addition of IL-4 plus anti-IL–12 MoAb on the development of Tc2 clones derived from CD8⁺ T cells of HIV-seronegative patients. Purified CD8⁺ cells (10⁶/mL) from PBMC of three HIV-seronegative patients were preactivated with insolubilized anti-CD3 MoAb in the absence (□) or in the presence of IL-4 (4 ng/mL) plus anti-IL–12 MoAb (1 μg/mL) (▪). After 5 days, T-cell blasts were cloned in limiting numbers, as described in Materials and Methods. Supernatants of CD8⁺ T-cell clones (118 generated from unconditioned and 139 from IL-4 plus anti-IL–12 MoAb-conditioned cultures), obtained as described in the legend to Fig 1, were assayed for cytokine content, as described in Materials and Methods. The percentages of the two groups of clones producing IFN-γ, IL-4, and IL-5 (upper panel) or showing the Tc1/Tc0/Tc2 profile of cytokine production (lower panel), are reported.