FIG. 1.

Decreased IL-2 production in HCV C-expressing cells. (A) The expression of HCV C was investigated in parental Jurkat cells (Jk) and C-transfected sublines (JHC.d, JHC.g, and JHC.h) by Western blotting. The position of the molecular size marker (in kilodaltons) is indicated. (B) IL-2 synthesis was induced by triggering of surface receptors with specific antibodies (anti-CD3 and anti-CD28, left panel) or by treatment with TPA and ionomycin (right panel). The amounts of IL-2 in cell culture supernatants were determined by an ELISA at 24 h postinduction. (C) Numbers of IL-2-secreting cells were determined by flow cytometry. Cell lines were stimulated with TPA and ionomycin in the presence of monensin. After 6 h, the cells were fixed, permeabilized, and stained with a phycoerythrin-labeled Ab recognizing human IL-2. (D) Transcriptional activation of IL-2 gene in cells expressing HCV C. Control and C-expressing cell lines were transfected with a luciferase reporter plasmid driven by the IL-2 promoter. At 40 h posttransfection, the cells were stimulated with TPA and ionomycin for 6 h, and the luciferase activity, presented in relative light units (RLU), was determined. The data presented are representative of three independent experiments.