[#2007-05] Isolation, identification and function of a novel anti-HSV-1 protein from Grifola frondosa, Chang-Qing Gu et al.

Isolation, identification and function of a novel anti-HSV-1 protein from Grifola frondosa

Gu CQ, Li JW, Chao FH, Jin M, Wang XW, Shen ZQ

Institute of Environment and Health, PR China

A novel antiviral protein was purified from an extract of Grifola frondosa ( maitake ) fruiting bodies using a procedure that included 40% ammonium sulfate precipitation and DEAE-cellulose ion exchange chromatography, and designated GFAHP. This protein inhibited herpes simplex virus type 1 (HSV-1) replication in vitro with an IC50 value of 4.1 μg/ml and a therapeutic index >29.3. Higher concentrations of GFAHP (125 and 500 μg/ml) also significantly reduced the severity of HSV-1 induced blepharitis, neovascularization, and stromal keratitis in a murine model. Topical administration of GFAHP to the mouse cornea resulted in a significant decrease in virus production (mean virus yields: 3.4 log10 PFU in the treated group and 4.19 log10 PFU in the control group). We proved that GFAHP directly inactivates HSV-1 while simultaneously inhibiting HSV-1 penetration into Vero cells. Gel electrophoresis showed that GFAHP had a molecular weight of 29.5 kDa. GFAHP was tryptic digested and analyzed from the PMF of matrix assisted desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) and nanoelectrospray ionization tandem mass spectrometry. The N-terminal sequence of GFAHP consisted of an 11 amino acid peptide, NH2-REQDNAPCGLN-COOH that did not match any known amino acid sequences, indicating that GFAHP is likely to be a novel antivirus protein. To our knowledge, this is the first report that characterizes an anti-HSV protein from G. frondosa.