Possible mode of antiviral activity of acidic protein bound polysaccharideisolated from Ganoderma lucidum on herpes simplex viruses

Two protein bound polysaccharides, a neutral protein bound polysaccharide ( NPBP) and an acidic protein bound polysaccharide (APBP), were isolated from water soluble substances of Ganoderma lucidum by EtOH precipitation and DE AE-cellulose column chromatography. Their antiviral activities against herp es simplex virus type 1 (HSV-1) and type 2 (HSV-2) were then investigated b y plaque reduction assay. APBP exhibited more potent HSV-1 and HSV-2 antivi ral activity than NPBP with 50% effective concentration (EC50) of 300-520 m u g/ml. In order to examine the possible mode of the antiviral activity of APBP its virucidal effect, antiviral activity in preincubation, attachment and penetration assay were tested with HSV-1 and HSV-2. APBP was found to h ave a direct virucidal effect on HSV-1 and HSV-2. APBP did not induce IFN o r IFN-like materials in vitro and is not expected to induce a change from a normal state to an antiviral state. APBP in concentrations of 100 and 90 m u g/ml inhibited up to 500/u of the attachment of HSV-1 and HSV-2 to Vero c ells and was also found to prevent penetration of both types of HSV into Ve ro cells. These results show that the antiherpetic activity of APBP seems t o be related to its binding with HSV-specific glycoproteins responsible for the attachment and penetration, and APBP impedes the complex interactions of viruses with cell plasma membranes. (C) 2000 Elsevier Science Ireland Lt d. All rights reserved.