| Budget Amount *help |
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2011: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2010: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2009: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
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| Research Abstract |
Tumor cells are considered' altered self' because they accumulate genetic mutations and acquire features that enable them to evade immune surveillance. The generation of tumor-directed cytotoxic T lymphocytes is considered crucial for the induction of anti-tumor immunity. To activate these CD8 T cells, antigen presenting cells(APCs) must initially acquire tumor cell-associated antigens. The major source of tumor antigens is dead tumor cells, but little is known about how APCs in draining lymph nodes acquire and crosspresent these antigens. Here we show that CD169^+macrophages phagocytose dead tumor cells transported via lymphatic flow and subsequently crossprime CD8 T cells. Subcutaneous immunization with irradiated tumor cells protects mice from syngenic tumor. However, tumor antigen-specific CD8 T cell activation and subsequent anti-tumor immunity are severely impaired in mice depleted with CD169^+macrophages. Neither migratory dendritic cells(DCs) nor lymph node-resident conventional DCs are essential for the crosspresentation of tumor antigens. Thus, we have identified lymph node CD169^+macrophages as a novel APC subset dominating early activation of tumor antigen-specific CD8 T cells.
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