Boosting high-intensity focused ultrasoundinduced anti-tumor immunity using a sparse-scan strategy that can more effectively promote dendritic cell maturation | Liu et al. Journal of Translational Medicine 2010 8 7 http content 8 1 7 JOURNAL OF TRANSLATIONAL MEDICINE RESEARCH Open Access Boosting high-intensity focused ultrasound-induced anti-tumor immunity using a sparse-scan strategy that can more effectively promote dendritic cell maturation Fang Liu1 Zhenlin Hu1 Lei Qiu1 Chun Hui2 Chao Li2 Pei Zhong3 Junping Zhang1 Abstract Background The conventional treatment protocol in high-intensity focused ultrasound HIFU therapy utilizes a dense-scan strategy to produce closely packed thermal lesions aiming at eradicating as much tumor mass as possible. However this strategy is not most effective in terms of inducing a systemic anti-tumor immunity so that it cannot provide efficient micro-metastatic control and long-term tumor resistance. We have previously provided evidence that HIFU may enhance systemic anti-tumor immunity by in situ activation of dendritic cells DCs inside HIFU-treated tumor tissue. The present study was conducted to test the feasibility of a sparse-scan strategy to boost HIFU-induced anti-tumor immune response by more effectively promoting DC maturation. Methods An experimental HIFU system was set up to perform tumor ablation experiments in subcutaneous implanted MC-38 and B16 tumor with dense- or sparse-scan strategy to produce closely-packed or separated thermal lesions. DCs infiltration into HIFU-treated tumor tissues was detected by immunohistochemistry and flow cytometry. DCs maturation was evaluated by IL-12 IL-10 production and CD80 CD86 expression after co-culture with tumor cells treated with different HIFU. HIFU-induced anti-tumor immune response was evaluated by detecting growth-retarding effects on distant re-challenged tumor and tumor-specific IFN-y-secreting cells in HIFU-treated mice. Results HIFU exposure raised temperature up to 80 degrees centigrade at beam focus within 4 s in experimental tumors and led to formation of a well-defined thermal lesion. The .
