Immunopotentiating activity of the water-soluble lignin rich fraction prepared from LEM--the extract of the solid culture medium of Lentinus edodes mycelia.

The water-soluble lignin in LEM (the extract of the solid culture medium of Lentinus edodes mycelia) has been known to have antiviral and immunopotentiating activities in vivo and in vitro. The water-soluble lignin rich fraction (JLS-18) was prepared from LEM using ultrafiltration and hydrophobic column chromatography. JLS-18 showed about 70 times higher antiviral activity than LEM in vitro. JLS-18 activated the cytotoxicity of NK cells and macrophages, and activated T cells in vitro. JLS-18 also induced interleukin 6 (IL-6) secretion from human leukocytes infected with Sendai virus in vitro. These data showed that JLS-18, the water-soluble rich fraction of LEM, had antiviral and immunopotentiating activities.