| Summary: | 碩士 === 國立東華大學 === 生物技術研究所 === 96 === Dioscorins are the major storage proteins in the yam tubers. Recent studies show that they induce the secretion of proinflammatory cytokine IL-6, IL1-β and TNF-α via TLR-4 signal transduction pathway in both macrophages in vitro and spleen cells ex vivo. They also stimulate the proliferation of spleen cells and enhance the phagocytic activity of macrophages. The aim of this study was to elucidate the effect of different dioscorin proteins isolated from two yam varieties, Tainong No. 1 (TN1-dioscorins) and Japanese yam (Dj-dioscorins), on the immune
activities of mice. Dj-dioscorins, like TN1-dioscorins, could induce expression of the proinflammatory cytokine IL1-β and IFN-α, and
stimulate phagocytosis of RAW264.7. However, the immunomodulatory activities of Dj-dioscorins in vivo were different from those of TN1-dioscorins. Intraperitoneal injection of the TN1-dioscorins in mice stimulated the phagocytosis effect of bone marrow cells, spleen cells, and
thymic cells against E. coli. In contrast, the Dj-dioscorins had no effect on stimulation of phagocytosis of the lymphoid cells. The T and B cells in bone marrow and spleen cells isolated from Dj-dioscorins injected mice have higher proliferative responses to mitogen ConA and LPS, suggesting that Dj-dioscorins could stimulate the activation of both T cells and B cells
in these tissues. Only the B cells but not the T cells in thymic cells responded to Dj-dioscorins. In contrast, the lymphoid cells from
TN1-dioscorins injected mice were not roliferated in response to ConA or LPS. Furthermore, Dj-dioscorins-treated mice enhanced the proliferation of CD4+, CD8+, Tim3+ (Th1 cells), and Tim1+ (Th2 cells) cells in spleen cells but not in thymic cells, and CD19+ cells in both spleen cells and thymic cells, whereas TN1-dioscorins in vivo only slightly stimulated the proliferation of Th1 and Th2 cells in spleen cells. Supplement of 12.5 or 50 μg/mL Dj-dioscorins in the lymphoid cells isolated from Dj-dioscorins primed mice induced the cell proliferation of both spleen cells and thymic
cells ex vivo. Supplement of TN1-dioscorins, however, could not induce the cell proliferation of both spleen cells and thymic cells. Taken together, the results suggest that TN1-dioscorins and Dj-dioscorins exhibit two distinct
immunomodulatory activities. TN1-dioscorins have higher ability than Dj-dioscorins to stimulate the phagocytic activity of the lymphoid cells,
whereas Dj-dioscorins posses more ability than TN1-dioscorins to enhance the proliferation of the lymphoid cells
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