An Envelope-Modified Tetravalent Dengue Virus-Like-Particle Vaccine Has Implications for Flavivirus Vaccine Design

Abstract

Dengue viruses (DENV) infect 50 to 100 million people each year. The spread of DENV-associated infections is one of the most serious public health problems worldwide, as there is no widely available vaccine or specific therapeutic for DENV infections. To address this, we developed a novel tetravalent dengue vaccine by utilizing virus-like particles (VLPs). We created recombinant DENV1 to -4 (DENV1-4) VLPs by coexpressing precursor membrane (prM) and envelope (E) proteins, with an F108A mutation in the fusion loop structure of E to increase the production of VLPs in mammalian cells. Immunization with DENV1-4 VLPs as individual, monovalent vaccines elicited strong neutralization activity against each DENV serotype in mice. For use as a tetravalent vaccine, DENV1-4 VLPs elicited high levels of neutralization activity against all four serotypes simultaneously. The neutralization antibody responses induced by the VLPs were significantly higher than those with DNA or recombinant E protein immunization. Moreover, antibody-dependent enhancement (ADE) was not observed against any serotype at a 1:10 serum dilution. We also demonstrated that the Zika virus (ZIKV) VLP production level was enhanced by introducing the same F108A mutation into the ZIKV envelope protein. Taken together, these results suggest that our strategy for DENV VLP production is applicable to other flavivirus VLP vaccine development, due to the similarity in viral structures, and they describe the promising development of an effective tetravalent vaccine against the prevalent flavivirus. Dengue virus poses one of the most serious public health problems worldwide, and the incidence of diseases caused by the virus has increased dramatically. Despite decades of effort, there is no effective treatment against dengue. A safe and potent vaccine against dengue is still needed. We developed a novel tetravalent dengue vaccine by using virus-like particles (VLPs), which are noninfectious because they lack the viral genome. Previous attempts of other groups to use dengue VLPs resulted in generally poor yields. We found that a critical amino acid mutation in the envelope protein enhances the production of VLPs. Our tetravalent vaccine elicited potent neutralizing antibody responses against all four DENV serotypes. Our findings can also be applied to vaccine development against other flaviviruses, such as Zika virus or West Nile virus.

Defeat Dengue and Zika Viruses With a One-Two Punch of Vaccine and Vector Blockade

“…The same issue must be dealt with for DNA or RNA vaccines that incorporate prM and E genes in order to make virus like particles in vivo (Beckett et al, 2011;Porter et al, 2012;Richner et al, 2017a). Similarly, in vitro produced virus like particle vaccines will not be ideal unless the immature virus-like particle can be eliminated through procedures such as exogenous Furin cleavage, but how to produce enough immunogens is another problem even more complicated to deal with (Urakami et al, 2017). Therefore, the exact effect and ratio of "pr" antibodies elicited by these vaccines have to be determined during development.…”

Virus-Like Particle Systems for Vaccine Development against Viruses in the Flaviviridae Family

“…In the past two decades, a number of DENV VLPs have been evaluated as vaccine candidates [69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84]. Of which, tetravalent DENV VLP vaccines, recently developed and currently in preclinical testing, possess several features that confer safety, immunogenicity, and production advantages that ideally fulfilled the requirements for a successful DENV vaccine development [81][82][83][84]. Generated by the co-expression of all four DENV serotypes' envelope proteins, these VLPs have mosaic tetravalent constructs, as opposed to many live-attenuated vaccine candidates that are mixture of monovalent vaccines against each of the four serotypes.…”

Production of dengue virus-like particles serotype-3 in silkworm larvae and their ability to elicit a humoral immune response in mice

“…VLPs are self-assembled particles, which consist of viral structural proteins. They can imitate the conformation of a genuine native virus without genomic DNA or RNA, thus making them a viable option to live-attenuated vaccines (Urakami et al 2017).…”