Comparative study on anti-tumor immune response of autologous cytokine-induced killer (CIK) cells, dendritic cells-CIK (DC-CIK), and semi-allogeneic DC-CIK

Background and Objective: Cytokine-induced killer (CIK) cells and autologous dendritic cells-CIK (DC- CIK) cells co-cultured with autologous dendritic cells (DCs) and CIK cells are commonly used for immunotherapy recently. We compared the anti-tumor immune response of CIK cells, autologous DC-CIK cells, and semi-allogeneic DC-CIK cells to explore a more effective anti-tumor adoptive immunotherapy approach. Methods: Peripheral monocytes were isolated from patients with renal carcinoma, lung cancer, or maxillary squamous cell carcinoma and their healthy adult children. Isolated cells were cultured and induced as DCs and CIK cells in vitro. CIK cells from patients were co-cultured with autologous DCs and DCs from their children respectively, generating DC-CIK cells and semi-allogeneic DC-CIK cells. The anti-tumor activities of autologous CIK cells, autologous DC-CIK cells, and semi-allogeneic DC-CIK cells were measured by LDH assay. Intracellular staining was used to test the secretion of cytokines. Flow cytometry was applied for detecting the phonotype changes of these three types of cells. Cell proliferation and cell apoptosis were detected by 5,6- carboxyfluorescein diacetate succinimidyl ester (CFSE) and Annexin V/PI respectively. Results: Compared with autologous CIK cells and DC-CIK cells, semi-allogeneic DC-CIK cells significantly enhanced the anti-tumor activity and IFN-γ secretion, reduced IL-4 secretion, increased the ratio of CD3⁺CD56⁺ cells and CD3⁺CD8⁺ cells, decreased the number of CD4⁺CD25⁺ cells, promoted cell proliferation, and lessened cell apoptosis. Conclusions: Semi-allogeneic DC-CIK cells had a stronger anti-tumor effect than did autologous CIK cells and DC-CIK cells. Our results provided experimental evidence for clinical application of DC-CIK cells.