Regulatory mechanism of fucoidan-mix AG in intestinal mucosal immune cells

Abstract

Abstract Fucoidan is a series of natural sulfated polysaccharides contained in brown sea algae, and their beneficial physiological activities such as anti-tumor, anti-virus and immune regulatory effects have been reported. In previous studies, we proved that fucoidans derived from Cladosiphon okamuranus (C. okamuranus) and Undaria pinnatifida effectively improved anti-tumor immunity and tumor vaccine efficiency in combination with an Agaricus blazei mycelium extract. It is thought that the fucoidan-agaricus mix (named fucoidan-mix AG) stimulate innate immune cells to activate intestinal and mucosal immune reaction, but actual target immune tissues and cells by fucoidan have not been evidenced yet. In this study, we investigated action mechanisms of fucoidan in regulation of mucosal immune activities. At first, immune cells were isolated from Payer’s patches, mesenteric lymph node (MLN) and intestinal epithelia of Balb/c mice, then stained with fluorophore-labeled fucoidan. As the results, it was revealed that fucoidan directly interact with lymphocytes besides dendritic cells and macrophages existing in these intestinal immune tissues. Furthermore, immune cells from Payer’s patches and MLN stimulated with fucoidan from C. okamuranus and fucoidan-mix AG produced more TNF-α, IL-12 and Th1 cytokine IFN-γ. The production of an immunosuppressive cytokine IL-10 also was augmented in the fucoidan-treated immune cells, which suggesting that fucoidan balanced immune system to prevent occurrence of excessive reaction. In addition, it was newly proved that fucoidan directly stimulated T lymphocytes to induce enhanced IFN-γ production.