['To investigate the effect of hepatoma cells on up-regulation of programmed cell death-1 (PD-1), and the function of PD-1 on T cells.', 'HepG2 or HepG2.2.1.5 cells were co-cultured with a lymphoma cell line-Jurkat cells. PD-1 expression was detected by flow cytometry. IL-2, INF-gamma and IL-10 in culture supernatant were detected by enzyme-linked immunosorbent assay (ELISA). Cytotoxic action of T cells was determined by MTT reduction assay-direct mononuclear cell cytotoxicity assay.', 'The PD-1 expression on Jurkat cells increased by 16.17% +/- 2.5% and 17.43% +/- 2.2% after HepG2 or HepG2.2.1.5 cells were co-cultured for 48 h. The levels of IL-2, INF-gamma and IL-10 in the culture supernatant were 202.9 +/- 53.0 pg/mL, 88.6 +/- 4.6 pg/mL and 63.7 +/- 13.4 pg/mL respectively, which were significantly higher than those (102.9 +/- 53 pg/mL, 39.3 +/- 4.2 pg/mL, and 34.6 +/-13.7 pg/mL) in the control group (P < 0.05). The OD value for MTT assay in the blocking group (0.29 +/- 0.06) was significantly higher than that (0.19 +/- 0.09) in the control group (P < 0.05).'] Do hepatoma cells up-regulate expression of programmed cell death-1 on T cells?