Combination Treatment of Stereotactic Body Radiation Therapy and Immature Dendritic Cell Vaccination for Augmentation of Local and Systemic Effects / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The purpose of this study was to investigate the efficacy of stereotactic body radiation therapy (SBRT) as a tumor-associated antigen (TAA) presentation method for dendritic cell (DC) sensitization and evaluate its effect in combination with immunotherapy using an intratumoral injection of immature DCs (iDCs). MATERIALS AND METHODS: CT-26 colon carcinoma cell was used as a cancer cell line. Annexin V staining and phagocytosis assays were performed to determine the appropriate radiation dose and incubation time to generate TAAs. BALB/c mice were used for in vivo experiments. Cancer cells were injected into the right legs and left flanks to generate primary and metastatic tumors, respectively. The mice were subjected to radiation therapy (RT) alone, intradermal injection of electroporated DCs alone, or RT in combination with iDC intratumoral injection (RT/iDC). Tumor growth measurement and survival rate analysis were performed. Enzyme-linked immunospot and cytotoxicity assays were performed to observe the effect of different treatments on the immune system. RESULTS: Annexin V staining and phagocytosis assays showed that 15 Gy radiation dose and 48 hours of incubation was appropriate for subsequent experiments. Maximum DC sensitization and T-cell stimulation was observed with RT as compared to other TAA preparation methods. In vivo assays revealed statistically significant delay in the growth of both primary and metastatic tumors in the RT/iDC group. The overall survival rate was the highest in the RT/iDC group. CONCLUSION: The combination of SBRT and iDC vaccination may enhance treatment effects. Clinical trials and further studies are warranted in the future.

Optimization of Isolation Processing of Monocytes from Peripheral Blood Mononuclear Cells and Differentiation into Dendritic Cells / 대한수혈학회지

BACKGROUND: Rescently, the immunotherapy against infectious disease and cancer is being actively studied, and high yield of pure CD14+ monocytes is a key of concern. In this study, we optimized the percoll gradient method to increase the purity and yield of monocytes from peripheral mononuclear cells. METHODS: We separated mononuclear cells (MNC) from healthy donors, and monocytes from MNC were separated with the various density of percoll gradient. After centrifugation, we determined the most efficient density of the percoll gradient to get the highest yield and purity of monocytes. We also obtained monocytes by the plastic absorption method. Monocytes were differentiated into dendritic cells (DC) and the efficacy of differentiation to DC is confirmed and compared by morphological characteristics and using a flowcytometer. RESULTS: The purity of monocytes was 51.3+/-8.3% by the 35% percoll gradient method and the purity was improved to 82.9+/-4.2% with 100% of yield by repeating the same method. Therefore, the yield of mature dendritic cells was 3.6+/-0.9% of the total input MNC by the 35% percoll repetition method, which was 1.7 times higher than the plastic adherent method (2.1+/-0.5%). CONCLUSION: This study shows a cost-effective method to isolate CD14+ monocytes and these cells demonstrate high differentiation rate to DC. This process will be valuable for obtaining a sufficient number of DC.