Abstract: Objective To study the cytotoxicity and inducing apoptosis effects of dendritic cells(DC)co-cultured with cytokine induced killer(CIK)cells against colon cancer cells lines LOVO.Methods Mononuclear cells were extracted from health adult peripheral blood.The cells were used to induce DC and CIK respectively with different cytokines, and after DC maturing these two kinds of cells were co-cultured.The proliferation activity of CIK cells were observed by cell counting method, the cytotoxicity was detected by MTT assay, transmission electron microscopy was used to observe the apoptosis of tumor cells, and the expression of FasL in effective cells was determined by Western Blotting method.Results DCs could advance the proliferation activity of CIK cells, and the killing activity of DC-CIK cells was significant higher than those of CIK cells alone at different effector-target ratios.Transmission electron microscopy showed that DC-CIK could induce colon cells to apoptosis, and quantity expression of FasL on effective cells could be observed.Conclusion DC cells could obviously enhance the proliferation and cytotoxicity of CIK cells, one of the mechanisms of cytotoxic activity in DC-CIK cells is displayed by Fas/FasL pathway.

Key words: Dendritic cell, CIK cell, Apoptosis, Fas/FasL