| HSV-2is a ubiquitous sexual transmitted virus and its infection is related with manydiseases such as congenital malformation, abortion and cervical cancer etc. Due to the factthat drug-resistant HSV strains are often encountered in the clinical nowadays, it isnecessary to develop new, kind of antiviral drugs against HSV virus.Defensins, a kind of endogenous cationic polypeptide, possess a broad spectrum ofantimicroorganism activity with less toxic effects and are expected to be developed into anew generation of antibacterial or antiviral drugs. According to the diversities of expressionand intramolecular disulfide bonds, mammal defensins are divided into α、β and θ3types.Six human alpha defensins have been found until now. Human α-defensin5(HD-5), whichwas primitively found in the granules of enteric Paneth cells and lately detected to beexpressed in the female genital tract mucosa, is presumed to have stronger antimicrobialability endowed by evolution upon environmental pressures. Therefore, HD-5has a goodprospect of development and application in the prevention and treatment of bacterial andviral infections. However, the effect of HD-5against HSV-2lacks of thoroughly studies.In this study, by application of virus particle preparation, cell culture, cytopathic effect(CPE) observation, CCK-8assy and establishment of guinea pig genital herpes model, thein vitro and in vivo effects of HD-5polypeptide against HSV-2infection and the relatedmechanism were investigated. The main results and conclusions are as follows:(1) The replication and preparation of HSV-2virus with the titer of TCID50=10-3.8was successfully achieved.(2) No obvious cytotoxic effect of HD-5was found in the cultured vero cells withinthe concentration of100μg/ml.(3) Even at the concentration of100μg/ml, HD-5polypeptide displayed negativehemolytic reactions with erythrocytes. (4) When HD-5was added before or simultaneously with HSV-2infection, itcould significantly inhibit the HSV-2virus to infect vero cells cultured in vitro. At aconcentration of100μg/ml, the protective rates of HD-5against HSV-2adhesion andinvasion reached83.6±4.3%and89.4±3.3%, while there was no significantinhibitive effect of HD-5when it was added2hours after HSV-2infection(P>0.05).These results indicate that HD-5has significant antiviral activity against HSV-2invitro, probably by disruption of virus adhesion and invasion.(5) The antiviral activity of HD-5was markedly reduced in the culture systemcontained with high concentration of serum, and further study revealed that a certainamount of albumin and fetuin could significantly inhibit the antiviral activity of HD-5,suggesting that the presence of serum can interfere with the anti-viral activity of HD-5,which is partly due to the nospecific binding of albumin and the fetuin to HD-5.(6) The animal model of female guinea pigs with genitalias infected with HSV-2wereestablished. HD-5polypeptide given through vagina could significantly improve the livingconditions and survival probability of guinea pigs infected with HSV-2. Compared withvirus control group, the symptom score of genital infection of HD-5treatment group wassignificantly lower (P<0.05). These results imply that in vivo application of HD-5by localadministration can also display a significant anti-HSV-2activity. |
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