2020 Volume 43 Issue 4 Pages 629-638
Sparassis crispa (SC; Japanese name: Hanabiratake) is a mushroom with high β(1-3)-glucan content. We here studied the effects of SC and lactic acid bacteria-fermented SC (SCL) on innate immunity. In in vivo studies using mice, oral administration of SC or SCL enhanced the accumulation of macrophages, neutrophils, natural killer (NK) cells, and C–C chemokine receptor type 2- or phospho-Syk-expressing cells in the jejunum epithelial villi and spleen, with significantly higher cell numbers in the SCL group than in the SC group. In addition, mRNA levels of genes encoding tissue factor (TF) and tumor necrosis factor (TNF)-α were increased in monocytes/macrophages from the peritoneal cavity of mice orally administered SCL. In in vitro studies using cultured human monocytes, SC and SCL enhanced the expression of gees involved in blood coagulation and inflammation, as well as those encoding various innate immune-related factors, such as TF, TNF-α, plasminogen activator inhibitor (PAI)-1, monocyte chemotactic protein (MCP)-1, interleukin (IL)-1β, IL-8, IL-12β, and IL-17, in a dose-dependent manner. In particular, the expression levels of all these factors in monocytes were significantly higher with SCL treatment than with SC treatment. SCL significantly enhanced the phagocytosis of pH-sensitive fluorescent dye-labeled Escherichia coli by human monocytes compared to SC. The effect of SCL on phagocytosis was significantly reduced to approximately 30% by pre-digestion of SCL with β-glucanase, suggesting that β(1-3)-glucan in SCL is a major contributor to the effect. These data suggest that oral administration of SCL significantly enhances innate immunity in mice and possibly humans.
