Structural Insight into CVB3-VLP Non-Adjuvanted Vaccine

Abstract

Coxsackievirus B (CVB) enteroviruses are common pathogens that can cause acute and chronic myocarditis, dilated cardiomyopathy, aseptic meningitis, and they are hypothesized to be a causal factor in type 1 diabetes. The licensed enterovirus vaccines and those currently in clinical development are traditional inactivated or live attenuated vaccines. Even though these vaccines work well in the prevention of enterovirus diseases, new vaccine technologies, like virus-like particles (VLPs), can offer important advantages in the manufacturing and epitope engineering. We have previously produced VLPs for CVB3 and CVB1 in insect cells. Here, we describe the production of CVB3-VLPs with enhanced production yield and purity using an improved purification method consisting of tangential flow filtration and ion exchange chromatography, which is compatible with industrial scale production. We also resolved the CVB3-VLP structure by Cryo-Electron Microscopy imaging and single particle reconstruction. The VLP diameter is 30.9 nm on average, and it is similar to Coxsackievirus A VLPs and the expanded enterovirus cell-entry intermediate (the 135s particle), which is ~2 nm larger than the mature virion. High neutralizing and total IgG antibody levels, the latter being a predominantly Th2 type (IgG1) phenotype, were detected in C57BL/6J mice immunized with non-adjuvanted CVB3-VLP vaccine. The structural and immunogenic data presented here indicate the potential of this improved methodology to produce highly immunogenic enterovirus VLP-vaccines in the future.

Viruses and Type 1 Diabetes: From Enteroviruses to the Virome

“…Although the use of whole virus vaccines (live and inactivated) has proven their safety and efficacy against poliovirus [250], it is expensive, slow to develop, lacks flexibility to engineer new epitopes and is limited by the culturability of the target EV. To overcome such limitations, an alternative vaccine strategy has been explored for CVB1, 3 and 4, involving the use of empty VLPs as antigens [251][252][253][254]. Generated from recombinantly expressed viral structural proteins, VLPs resemble the native CVB capsid structure but lack the infectious RNA genome.…”

“…Thus, VLP-based vaccines can be manufactured without culturing the virus, are modified rapidly with ease and are not subject to safety concerns associated with live virus vaccines. However, it remains to be determined whether VLP-based vaccines can offer a sufficient level of immunogenicity To overcome such limitations, an alternative vaccine strategy has been explored for CVB1, 3 and 4, involving the use of empty VLPs as antigens [251][252][253][254]. Generated from recombinantly expressed viral structural proteins, VLPs resemble the native CVB capsid structure but lack the infectious RNA genome.…”

“…To overcome such limitations, an alternative vaccine strategy has been explored for CVB1, 3 and 4, involving the use of empty VLPs as antigens [ 251 , 252 , 253 , 254 ]. Generated from recombinantly expressed viral structural proteins, VLPs resemble the native CVB capsid structure but lack the infectious RNA genome.…”

Combating coxsackievirus B infections

“…139 Stable CVB1, 3, and 4 VLP vaccines have been developed [139][140][141][142] and shown to induce a strong neutralising antibody response in C57BL/6J and BALB/c mice. [139][140][141]…”

Viruses and Type 1 Diabetes: From Enteroviruses to the Virome

“…Although the use of whole virus vaccines (live and inactivated) have proven their safety and efficacy against poliovirus [246], it is expensive, slow to develop, lacks flexibility to engineer new epitopes and limited by the culturability of the target EV. To overcome such limitations, an alternative vaccine strategy has been explored for CVB1, 3 and 4, involving the use of empty VLPs as antigens [247][248][249][250]. Generated from recombinantly expressed viral structural proteins, VLPs resemble the native CVB capsid structure but lack the infectious RNA genome.…”