The Effect of Novel Selenopolysaccharide Isolated from Lentinula edodes Mycelium on Human T Lymphocytes Activation, Proliferation, and Cytokines Synthesis

Polysaccharides isolated from Lentinula edodes are bioactive compounds with immunomodulatory properties. In our previous studies from L. edodes mycelium, we have isolated a selenium(Se)-enriched fraction (named Se-Le-30), a mixture of linear 1,4-α-glucan and linear 1,3-β- and 1,6-β-glucans. In this study, we analyzed the effects of Se-Le-30 on the activation and proliferation of human T lymphocytes stimulated by anti-CD3 and anti-CD3/CD28 antibodies (Abs) and on the production of cytokines by peripheral blood mononuclear cells (PBMCs). Se-Le-30 had effects on T cell proliferation induced by Abs against CD3 and CD28. It significantly inhibited the proliferation of CD3-stimulated CD4(+) and CD8(+) T cells and enhanced the proliferation of CD4(+) T cells stimulated with anti-CD3/CD28 Ab. Moreover, Se-Le-30 downregulated the number of CD3-stimulated CD4(+)CD69(+) cells, CD4(+)CD25(+) cells, as well as CD8(+)CD25(+) cells, and upregulated the expression of CD25 marker on CD4+ and CD8+ T cells activated with anti-CD3/CD28 Abs. Furthermore, Se-Le-30 enhanced the synthesis of IFN-γ by the unstimulated and anti-CD3/CD28-stimulated PBMCs, inhibited synthesis of IL-2 and IL-4 by CD3-stimulated cells, and augmented the synthesis of IL-6 and IL-10 by unstimulated, CD3-stimulated, and CD3/CD28-stimulated PBMCs. Together, we demonstrated that Se-Le-30 exerts immunomodulatory effects on human T lymphocytes. These observations are of importance for the prospective use of Se-Le-30 in research or as a therapeutic compound.