Background & objective: Cytokine-induced killer (CIK) cells have high cytotoxic activity against tumor cells. Dendritic cells (DCs) are the strongest antigen-presenting cells (APC) and could increase the cytotoxic activity of immunologic effector cells against tumor cells. This study was to investigate the changes of phenotype, proliferative activity, and in vitro and in vivo cytotoxicity of CIK cells after in vitro co-culturing with DCs.
Methods: DCs and CIK cells were prepared routinely from human peripheral blood mononuclear cells (PBMC), then CIK cells were cocultured with autologous DCs for 5 days at a stimulator-to-responder ratio of 1:10 to prepare immunologic effector DC-CIK cells. Phenotypes of DC-CIK cells were analyzed by flow cytometry; The in vitro cytotoxicity of DC-CIK cells was detected by 3H-TdR incorporation method; the in vivo antitumor activity was evaluated in BALB/c nude mice bearing A549 lung cancer.
Results: At the 14th day of culture, compared with CIK cells, DC-CIK cells got a significant increase of proliferation rate [(17.0+/-1.8) times vs. (10.9+/-2.0) times, P<0.05] and CD3+CD56+ expression rate [(36.0+/-4.2)% vs. (25.7+/-2.9)%, P<0.05], and resulted in an enhancement of cytotoxicity to A549 cells (P<0.05) in vivo. At the 51st day after inoculation of tumor cells, the inhibition rate was significantly higher in DC-CIK group than in CIK group (62.9% vs. 41.5%, P<0.05). DC-CIK cells and CIK cells showed significant inhibitory effects on the growth of transplanted tumor cells as compared with control group (P<0.01).
Conclusion: DC-CIK cells have higher proliferative activity and cytotoxicity in vitro and in vivo against lung cancer in comparison with CIK cells alone.