Objective   To study the influence of microenvironment created by dissoluble cytokines derived from hepatocellular carcinoma cells (HCCs) on the functional status of mitochondria in dendritic cells (DCs) in order to investigate the mechanisms of tumor

immune escape.    Methods   CD14

+

monocytes

which were isolated with immune magnetic beads from fresh peripheral blood of healthy human

were then cultured in RPMI1640/10% FBS supplemented with 100 ng/ml rhGM-CSF and 100 ng/ml rhIL-4 for 7 d to develop into immature DCs (imDCs). Maturation was induced by addition of 20 ng/ml rhTNF-α to imDCs for another 3 d of culture. Acquired imDCs and mDCs were respectively co-cultured with human HCCs for 48 h in Transwell chamber. These treated cells were investigated for mitochondrial membrane potential

   enzyme activity  and intracellular Ca

2+

concentration ([Ca

2+

]

in

) in the cytoplasma by immune fluorescence and MTT assay. Those untreated cells served as  control.    Results   After co-cultured with HCCs

flow cytometry showed that the mitochondrial membrane potentials of imDCs and mDCs were respectively decreased from （659.991±17.052）and（473.741±11.676）to（482.681±7.935）and（407.189±5.051）(P0.05)

[Ca

2+

]

in

of imDCs and mDCs were respectively increased from （427.983±3.358）and（232.587±3.815）to（517.308±0.249）and（413.062±2.981）(P0.05

P0.01). MTT assay showed that the enzyme activities of mitochondrions of imDCs and mDCs were respectively decreased from （0.764±0.089） and （0.708±0.019）to（0.291±0.019）and（0.218±0.019）(P0.01).    Conclusion   HCCs might suppress immune function of DCs by inhibiting functional status of mitochondrion.