| Herpes simplex keratitis (HSK) is caused by ocular infection with virus 1(HSV-1). The epithelial disease is believed is to result primarily from viral toxicity, Immune effectors are pathogenically central to the second form of herpetic corneal infections-stromal keratitis. Necrotizing steomal keratitis is the more severe form, Complications of this disorder include corneal melting, glaucoma and irreversible corneal scarring which often leads to blindness. HSV-1 produce not only a primary infection but also latent and recurrent infections, antiviral therapy does not reduce subsequent recurrences. Similarly, treatment of recurrent infectious can decrease the severity of the disease and daily suppressive therapy can decrease both symptomatic and asymptomatic recurrence. Human HSK is usually the sequal to recurrent infection following reactivation from latency. The pathogenesis of human HSK remains poorly understood, since vaccines that effectively control HSV remain nonexistent, and antiviral therapy has limited usefulness against recurrent infection, new approaches are needed to deal with HSK. As the incidence of herpes continues to increase in the population, and as new strains of the virus resistant to chemotherapy continue to emerge, so does the need for a safe and effective vaccine. More recently, advances in molecular biology have allowed the development of novel vaccine. The ideal prophylactic vaccine would, therefore, prevent not only the acute disease produced by infection, the source of virus responsible for recurrent infections. DNA vaccine represents a novel approach to both vaccine and immune therapeutic development. The in vivo administration of naked DNA molecules encoding selected viral antigens is a potential mean of mimicking the de novo production of correctly folded antigens, without the risks associated with the use of infectious agents. Concerning herpesvirus infections, several reports have mow described the use of plasmid DNAs encoding herpesvirus proteins to induce a protective immunity in mice. The glycoprotein B is attractive choices for subunit vaccines because they are targets for both humoral and cell mediated immunity, gB also has a high degree of identity comparing HSV-1 and HSV-2, therefore, may provide protection against both HSV-1 and HSV-2. Further, there is an even higher degree of conservation between strains of the same virus type. gB systemic vaccination was previously shown to reduce both establishment of latency and HSV recurrences, and i. m. injection of pRP-RSV-gB1s DNA was proven effective in preventing latency in mice. Recombinant baculoviuses were used to express gB, when this glycoprotein was used as vaccine, it induced high levels of protective immunity against lethal viral challenge in BALB/C mice. Immunopurified gB and truncated form of this glycoprotein has been used to induce protective immune responses in mice and other animal model. The goal of the present study was to asses the efficacy of HSV-1 glycoprotein B DNA vaccine. In this study we construct the HSV-1 glycoprotein B DNA vaccine that would be used to prevent and treat herpes simplex keratitis, and to evaluate the possibility of designing HSV-1 gene vaccine with HSV gB gene. The whole encoding sequence of the glycoprotein B is amplified from HSV-1 SM44 DNA genome by polymerase chain reaction (PCR), and then is directionally cloned into eukaryotic expression vector pcDNA3, the recombinant vector pcDNA-gB is confirmed by the restriction endonuclease analysis,PCR and sequence analysis. The ELISA, neutralization assay and the challenge test were employed to evaluate immune response of the mice that were inoculated triply with pcDNA-gB. The results which are Double-enzyme digestion and analysis of the recombinant vector pcDNA-gB shows two bands, one is HSV-1 gB gene (2.7kb), the other is linear pcDNA3 (5.4kb); HSV-1 gB gene is cloned by pcDNA-gB as template; sequence analysis shows orientation is right and the rate of homology is 99.5% compared with GeneBank. The inoculated mice...
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