| Herpes simplex virus type 1 (HSV-1) and Herpes simplex virus type 2 (HSV-2) are members of the family Herpesviridae, subfamily Alphaherpesvirinae. Their genomes are relatively stable. HSV-1 and HSV-2 are common throughout the word.They produce not only primary infection but also latent and recurrent infection.And they can cause a wide range of symptoms.keratitis, acute retinal necrosis (ARNS), et al.Among eye infections, HSV is the most common cause of viral infection and infectious blindness in developed countries, with more than 90% of ocular HSV infections caused by HSV-1. Herpetic stromal keratiti(sHSK), one of the most common vision-threatening diseases, is caused by recurrent attacks of herpes simplex virus (HSV) type 1. ARNS due to infection with virus of the herpes family is the most common and most visually threatening intraocular infections. At various times throughout the life of the latently infected individual, the virus may reactivate, travel back to the eye and cause recurrent disease.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.Since vaccines that effectively control HSV remain nonexistent, and antiviral therapy has limited usefulness against recurrent infection, new approaches are needed to deal with HSV. 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 latent and recurrent infections.Types of HSV-1 vaccines include Inactivated whole or partially purified HSV-infected cell culture-derived, subunit vaccines, Gnentically-attenuated live virus vaccine, Replication-limited or replication-impaired mutant vaccine, peptide Vaccines, live vectored vaccines expressing HSV-1 antigens, and DNA vaccines. DNA vaccine represent 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. Different vaccine strategies are presented with an emphasis on subunit glycoprotein vaccines as these are the furthest along in development.Concerning herpesvirus infections, several reports have mow described the use of plasmid DNAs encoding herpesvirus glycoprotein 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.HSV-1 gB systemic vaccination was previously shown to reduce both establishment of latency and HSV recurrences, and intramuscular 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.gB is efficacious glycoprotein vaccine for protection against death,eye disease,virus replication in the eye and the establishment of latency.The goal of the present study was to asses the efficacy of HSV-1 glycoprotein B DNA vaccine. In this study we constructed the HSV-1 glycoprotein B DNA vaccine which would be used to prevent and treat herpes simplex virus infections, and to evaluate the possibility of designing HSV-1 gene vaccine with HSV gB gene. The encoding sequence of the glycoprotein B(truncated part signal peptide 39bp ) was amplified from HSV-1 SM44 DNA genome by polymerase chain reaction (PCR), and then was directionally cloned into eukaryotic expression vector pcDNA3, the pgB was confirmed by the restriction endonuclease analysis,PCR and sequence analysis. In vitro, the transfected 293 cells with pgB were analyzed by RT-PCR and Western blot,and mice splenocytes were restimulated by the supernant of transfected cells with pgB and the level of IFNγwas analyzed by ELISA assay. In vivo, ELISA, neutralization assay, DTH HSV-1 specific lymphoproliferation, cytokine assay and the challenge test were employed to evaluate immune response of the mice that were vaccinated three times at 3- week intervals with pgB. Ocular challenge with HSV-1 was done after the final vaccination.Animal model of HSK and ARNS were established. Mice surviving 28 days after challenge were inoculated with HSV-1. Both ganglia were individually explanted onto vero cell monolayers and the monolayers were monitored for 30 days for the presence of infectious virus.The result of double-enzyme digestion and analysis of the recombinant vector pgB showed two bands, one was HSV-1 gB gene (2.7kb), the other was linear pcDNA3 (5.4kb); HSV-1 gB gene was cloned by pgB as template; sequence analysis showed orientation was right and the rate of homology was 99.9% compared with different HSV-1 strains in GeneBank. RT-PCR and Western blot results for the transfected 293 cells with pgB showed that gB could express HSV-1 gB protein in mRNA and protein level, and IFN-гconcentrations in the supernant was very high compared with pcDNA3, which indicated HSV-1 gB protein expressed had biological function in vitro. The inoculated mice produced specific antibodies to HSV-1 (ELISA titer was 1: 4265, neutralization antibody titer was 1:292) .The protection of vaccinated mice from lethal intraperitoneal challenge. pgB group had the highest level of IL-2 ,IFN-г, IL-10,but the level of IL-4 was normal. humoral and cellular responses were enhanced after pgB inoculation as well as proliferation and DTH reaction.Vaccination with pgB appeared to produce sinificant protection against HSK and ARNS.The HSV-1 gB gene vaccine was constructed successfully. gB is efficacious glycoprotein vaccine for protection against death,eye disease,virus replication in the eyes and the establishment of latency. which will provide a theoretical basis in a cocktail of expressed viral glycoproteins which is likely to be an ideal vaccine in prophylaxis and therapy for herpes simplex virus 1 infections in eyes.
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