ABSTRACT
In this study,a standard strain of HSV-1(strain SM44)was used to investigate the antiviral activity of the recombinant Cyanovirin-N(CV-N)against Herpes simplex virus type 1(HSV-1)in vitro and in vivo.Cytopathic effect(CPE)and MTT assays were used to evaluate the effect of CV-N on HSV-1 in Vero cells.The number of copies of HSV-DNA was detected by real-time fluorescence quantitative PCR(FQ-PCR).The results showed that CV-N had a low cytotoxicity on Vero cells with a CC50 of 359.03±0.56 μg/mL,and that it could not directly inactivate HSV-1 infectivity.CV-N not only reduced the CPE of HSV-1 when added before or after viral infection,with a 50% inhibitory concentration(IC50)with 2.26 and 30.16μg/mL respectively,but it also decreased the copies of HSV-1 DNA in infected host cells.The encephalitis model for HSV-1 infection was conducted in Kunming mice,and treated with three dosages of CV-N(0.5,5 & 10 mg/kg)which was administered intraperitoneally at 2h,3d,5d,7d post infection.The duration for the appearance of symptoms of encephalitis and the survival days were recorded and brain tissue samples were obtained for pathological examination(HEstaining).Compared with the untreated control group,in the 5mg/kg CV-N and 10mg/kg CV-N treated groups,the mice suffered light symptoms and the number of survival days were more than 9d and 14d respectively.HE staining also showed that in 5mg/kg CV-N and 10mg/kg CV-N treated groups,the brain cells did not show visible changes,except for a slight inflammation.Our results demonstrated that CV-N has pronounced antiviral activity against HSV-1 both in vitro and in vivo,and it would be a promising new candidate for anti-HSV therapeutics.
ABSTRACT
Objective To purify,renature and explore the antiviral effects of recombinant cyanovirin-N(CV-N)on herpes simplex virus type 1(HSV-1).Methods The recombinant CV-N was purified with Ni Sepharose column and renatured by dilution method.The antiviral activities of CV-N were carried out in Vero cells by observing cytopathic effect(CPE)and by using MTT colorimetric assay for vital cell rate.Results SDS-PAGE showed that the purified protein was in the position of 11KDa with only one clear band.The renatured CV-N had little cytotoxic effect on Vero cells,it could not directly inactivate HSV-1 infectivity.CV-N not only interfered in adsorption of HSV-1 to Vero cells but also inhibited HSV-1 biosynthesis in the cells,which were more effective than the positive control Acyclovir.Conclusion CV-N exhibited pronounced antiviral activities agaist HSV-1,further development of CV-N might yield novel candidates of antiviral drugs.