Natural killer (NK) cells are part of the innate immune system. NK cells can attack, damage and kill bacteria and viruses when activated by IL-12 and activated NK cells can recognize and kill tumor cells. D-fraction, a polysaccharide extract from Maitake mushroom fruiting body (Grifola frondosa,) is known to activate macrophages, dendritic cells and T cells and can inhibit tumor cells.
The present study was designed to further study the effect of D-fraction on mouse NK cells and on mammary tumors in mice. The conclusion was that D-fraction increases the ability of NK cells to kill other cells by activating macrophages (a type of white cell) that produces IL-12, a cytokine.
The authors did numerous assays at intervals following the administration of D-fraction to mice with cancer. The results of the assays showed that D-fraction enhanced the macrophage production of IL-12.
NK cell activity against tumor cells was increased by the macrophage produced IL-12. This results in increased ability to fight tumor cells, bacteria and viruses.
CONCLUSION: The authors believe that D-fraction increases the NK cytotoxic activity by increasing the macrophage production of IL-12. They believe that the above study provides information that D-fraction Grifolia could be used for immunostimulation of NK cells in cancer patients.
NOTE: D-fraction increases IL-12 production. IL-12 increases anti-tumor immune response by increasing CD8 T cell proliferation and increasing tumor cell apoptosis. Read more about natural killer (NK) cell activity in aging.
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