Preliminary Study On Immunogenicity Of Enterovirus 68 Virus-like Particles

Enterovirus 68(EV-D68)is a member of the small RNA virus family(Picromaviradae),a member of the enterovirus D group,which was first isolated and identified in 1962.Since 2005,outbreaks and epidemics of EV-D68-related diseases have occurred in many parts of the world.Infection with children with EV-D68 can cause a variety of respiratory diseases such as pharyngitis and bronchitis,which can lead to pneumonia and respiratory failure in severe cases.EV-D68 seriously endangers public health,and there is still no effective vaccine for the prevention and treatment of related diseases caused by EV-D68.Vaccines are the most effective measures to control and prevent infectious diseases.Virus-like particles(VLPs)are composed of a structural protein or a variety of structural proteins of a virus without a viral genome.It is a novel form of vaccine.VLPs are selfassembled to form a structure that mimics the natural virus,has a virus-like immunogenicity and can effectively activate the body's natural and acquired immune responses;but because it does not contain the viral genome,it does not replicate in vivo,VLPs It is relatively safer than a live vaccine.Since the introduction of recombinant hepatitis B vaccine,VLPs have attracted widespread attention and have become a hot spot in vaccine research and development.The insect baculovirus expression system is a commonly used system for expressing and preparing VLPs.In this paper,EV-D68-VLPs were prepared based on the insect baculovirus expression system(Bac-to-Bac).By optimizing the parameters such as harvest time and multiplicity of infection(MOI)of EV-D68-VLPs,the MOI was determined to be 0.2,and the expression of EV-D68-VLPs was relatively high at 72 h after infection.The VLPs prepared by sucrose density gradient centrifugation(30%,40%,50%)were identified by Western Blotting and transmission electron microscopy(TEM).The results showed that EV-D68-VLPs were successfully prepared.The immunogenicity of EV-D68-VLPs was evaluated using the BALB/c mouse model.The three-needle immunization strategy,EV-D68-VLPs,induced higher anti-EV-D68 neutralizing antibodies in mice.After increasing the immunization dose,the titer of the neutralizing antibody is increased,showing a good dose-effect relationship.In addition,the addition of an aluminum hydroxide adjuvant helped to increase the neutralizing antibody titer in the same dose group.In summary,this paper successfully prepared immunogenic EV-D68-VLPs using the insect rod expression system.This provides a technical method and basis for the future development of EV-D68 vaccine.