A novel lectin with potent immunomodulatory activity isolated from both fruiting bodies and cultured mycelia of the edible mushroom Volvariella volvacea

A novel lectin has been purified from the fruiting bodies as well as cultured mycelia of the edible mushroom Volvariella volvacea. The lectin, designated as VVL, was a homodimeric protein with a molecular weight of 32 kDa as demonstrated by gel filtration and SDS-PAGE. VVL had no carbohydrate moiety, and its hemagglutinating activity was inhibited by thyroglobulin but not by simple carbohydrates such as monomeric or dimeric sugars. The immunomodulatory activity of VVL was demonstrated by its potent stimulatory activity toward murine splenic lymphocytes. VVL was also found to markedly enhance the transcriptional expression of interleukin-2 and interferon-γ by reverse transcriptase-polymerase chain reaction. As revealed by its N-terminal amino acid sequence, VVL possessed a molecular structure distinct from other immunomodulatory proteins previously reported in the same fungus.