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.
To read the author’s abstract of the article click on the link to the author’s title of the article.
PMID: 15706424.
Summary #163.
