Effect of CD161 on CD4⁺CD28^nullT-cell clones in the presence of IL-12.

CD161 on CD4⁺CD28^null T-cell clones can be induced by IL-12. CD4⁺CD28^null and CD4⁺CD28⁺ T-cell clones were cultured in the presence (solid line) or absence (dotted line) of 10 ng/mL IL-12 and tested for the expression of the IL-12–responsive gene, CD161, by flow cytometry. CD161 was up-regulated on CD4⁺CD28^null (panel A) but not CD4⁺CD28⁺ (panel B) T-cell clones. The expression of CD158b (panel C) and CD4 (panel D) on CD4⁺CD28^null T-cell clones was not significantly changed by exposure to IL-12. Representative histograms of 3 experiments are shown. In all histograms, the shaded area represents staining with an isotype control mAb.