Trichinella spiralis infection reduces tumor growth and metastasis of B16-F10 melanoma cells.

Recently, attempts have been made to use parasites as novel candidates for live vaccine vectors against solid tumors. In this study, we examined the effects of Trichinella spiralis (T. spiralis) infection on solid tumor growth and metastasis. After oral infection with T. spiralis larvae, B16-F10 cells were injected subcutaneously and intravenously into C57BL/6 mice to evaluate tumor growth and metastatic potential, respectively. Tumor growth and lung metastases in T. spiralis infected mice were significantly reduced compared with control mice. To elucidate the mechanism of tumor reduction by parasitic infection, we conducted cytokine arrays using mouse serum. CXCL9 and CXCL10 were increased in the infection group and decreased in the infection-tumor group. However, the expression level was not changed in the infection-metastasis group compared to the infection or control-metastasis groups. Although SDF-1 and IL-4 were increased in the infection group, there was no significant change in expression in the infection-tumor group or the infection-metastasis group. Additionally, IL-4 and KC were increased in the infection-tumor group compared to the control-tumor group, but there was no difference in expression between the control-metastasis group and the infection-metastasis group. CXCL13 was significantly increased in the infection-metastasis group only. These results suggest that T. spiralis infection reduced tumor growth and metastasis through a complex transition in cytokine regulation profiles including CXCL9, CXCL10, and CXCL13.