T Helper 17 Cells Promote Cytotoxic T Cell Activation in Tumor Immunity

Natalia, M.O. et al. 2009. Immunity 31: 787-798.

Speaker: 陳奐勻                                                         Time: 14:10~15:00, Mar 31, 2010

Commentator: 張 堯 老師                                               Place: Room 601

Abstract:

After being activated by professional antigen-presenting cells, CD4⁺ T cells, differentiate into different lineages of helper T (Th) cells that are characterized by distinct developmental regulation and biological functions. Th17 cells, in particular through the production of IL‑17 and IL‑17F, have recently been identified as a new lineage of effector Th cells and shown to be important in immune responses to infectious agents, as well as in various immune diseases. Th17 cells have been found in various human tumors but its function has been a controversial subject. In this study, the authors first analyzed tumor development in IL-17-deficient mice by using a poorly immunogenic B16-F10 melanoma that colonizes the lung. Moreover, they used adoptive transfer of Th17 cells in several tumor prevention and treatment models. These results indicate that Th17 cells play a protective role against tumors. Furthermore, they found that Th17 cells triggered a strong CD8⁺ T cell response against the tumor. Th17 cell therapy promoted dendritic cell infiltration into tumor tissues and presentation of tumor antigens in the tumor-draining lymph nodes. Compared to Th1 cells, Th17 cells strongly induced CCL20 expression in the tumor tissues and CCR6 deficiency abrogated the antitumor effects of Th17 cells. Collectively, these results suggest that Th17 cells participate in antitumor immunity by facilitating T cell recruitment to the tumor site and promote the activation of tumor-specific CD8⁺ T cells. These findings reveal a new avenue for developing Th17 cell-based therapy for tumors or chronic viral infections.

References:

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2. Dong, C. (2008). TH17 cells in development: An updated view of their molecular identity and genetic programming. Nat. Rev. Immunol. 8, 337–348.