A Novel Lectin with Antiproliferative and HIV-1 Reverse Transcriptase Inhibitory Activities from Dried Fruiting Bodies of the Monkey Head Mushroom<i>Hericium erinaceum</i>

A lectin designated as Hericium erinaceum agglutinin (HEA) was isolated from dried fruiting bodies of the mushroom Hericium erinaceum with a chromatographic procedure which entailed DEAE-cellulose, CM-cellulose, Q-Sepharose, and FPLC Superdex 75. Its molecular mass was estimated to be 51 kDa and its N-terminal amino acid sequences was distinctly different from those of other isolated mushroom lectins. The hemagglutinating activity of HEA was inhibited at the minimum concentration of 12.5 mM by inulin. The lectin was stable at pH 1.9-12.1 and at temperatures up to 70 degrees C, but was inhibited by Hg(2+), Cu(2+), and Fe(3+) ions. The lectin exhibited potent mitogenic activity toward mouse splenocytes, and demonstrated antiproliferative activity toward hepatoma (HepG2) and breast cancer (MCF7) cells with an IC(50) of 56.1 microM and 76.5 microM, respectively. It manifested HIV-1 reverse transcriptase inhibitory activity with an IC(50) of 31.7 microM. The lectin exhibited potent mitogenic activity toward murine splenocytes but was devoid of antifungal activity.