T 세포 및 대식세포 기능에 대한 Silybin의 조절효과

초록

Silybin is known to be a major active flavonoid component isolated from Silybum marianum, a hepatoprotectivemedicinal plant. In this study, we examined the immunomodulatory role of silybin on T cell and macrophage-mediatedimmune responses. To do this, the proliferation of splenic lymphocytes and CD8+ CTLL-2 cells under mitogenic stim-ulation with lipopolysacharide (LPS), concanavalin (Con) A and interleukin (IL)-2 and the production of TNF-α and NO fromLPS- and IFN-γ-activated macrophages was evaluated under silybin treatment. The mitogenic proliferation of splenic lym-phocytes induced by LPS and Con A was strongly diminished by silybin in a dose-dependent manner. Moreover, the pro-liferation of CD8+ CTLL-2 cells was also negatively modulated by the compound. In contrast, silybin did not stronglysuppress the proliferation of normal splenocytes and T cell line Sup-T1 cells, indicating that the inhibitory effect of silybinmay be due to blocking only mitogenic responses of splenic lymphocytes. In addition, silybin inhibited TNF-α productionin LPS-stimulated RAW264.7 cells. Effect of silybin however was distinct, acording to NO-inducing stimuli. Thus, silybinonly blocked NO production induced by IFN-γ but not LPS and the inhibition was increased when PMA was co-treated withIFN-γ. Unlike NO inhibition, however, this compound protected the cytotoxic damage of RAW264.7 cells induced by bothLPS and IFN-γ. Therefore, our data suggest that silybin may participate in host immune responses mediated by T cells andmacrophages via regulating mitogenic proliferation, and the production of TNF-α and NO, depending on cellular stimuli.Keywords . silybin, T cell proliferation, NO release, TNF-α production

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