Construction And Immunogenicity Of A DNA Vaccine Expressing GE And IE63 Protein Of Varicella Zoster Virus

Varicella,also known as chickenpox,is a highly contagious disease caused by the infection with varicella zoster virus(VZV).This disease is most commonly affecting 2 to 6 years old children and usually from exposure either through direct contact with a skin lesion or through airborne spread from respiratory droplets.Primary VZV infection results in chickenpox,and the virus remains latent and may be reactivated in later life to cause herpes zoster.More than 90% people become infected with this virus before adulthood and 50% of persons living until age 85 will develop zoster.Varicella vaccine and herpes zoster vaccine are two type vaccines have been developed to protect children and young people from VZV initial infection and control the recurrence of the virus in old people,respectively.The currently marketed vaccines of this disease are live attenuated vaccines which are based on the Oka strain of VZV.After initial infection,VZV establishes lifelong latency in dorsal root ganglia,and can reactivate years to decades later when the body immunity is low.Therefore,elimination of the intracellular infection of VZV is a critical step in the control of this disease and cellular immunity may play a key role in the defence against intracellular infections.DNA vaccination is one of the most promising techniques for immunization against disease by injection with genetically engineered DNA and it has potential advantages over conventional vaccines,including the ability to induce both cellular and humoral immunity.The glycoprotein E(gE)is an envelope protein of VZV,which play a crucial role in the process of virus infection and transmission.Previous studies have demonstrated that the gE is one of the most promising candidate antigen.As far as we know,subunit vaccines based on gE can induce strong humoral immune response but cannot generate a satisfactory cellular immunity level.The immediate early 63 protein(IE63)is expressed very early in cutaneous lesions and the first viral protein detected during latency.Previous studies showed that T cell recognition of IE63 and other VZV proteins is one of the probable mechanisms involved in controlling VZV reactivation from latency.In the present study,several eukaryotic expression vectors(pcDNA3.1)of VZV gE and IE63 were constructed and enabled to express in 293 T cells and mouse muscle tissues.Co-immunization of mice with CpG(ODN1826)and plasmid DNA vaccine induce humoral and cellular immune response.These results indicate that a DNA vaccine of VZV based on gE and IE63 is an excellent vaccine candidate and should be considered for further developmental studies.