Development of a Viral-Like Particle Candidate Vaccine Against Novel Variant Infectious Bursal Disease Virus.

Yulong Wang,Yanping Zhang,Kai Li,Aijing Liu,Qing Pan,Nan Jiang,Changjun Liu,Li Gao,Yulong Gao,Xinxin Niu,Wenying Zhang,Linjin Fan,Xiaomei Wang,Xiaole Qi,Hongyu Cui

doi:10.3390/vaccines9020142

Abstract

Infectious bursal disease (IBD), an immunosuppressive disease of young chickens, is caused by infectious bursal disease virus (IBDV). Novel variant IBDV (nVarIBDV), a virus that can evade immune protection against very virulent IBDV (vvIBDV), is becoming a threat to the poultry industry. Therefore, nVarIBDV-specific vaccine is much needed for nVarIBDV control. In this study, the VP2 protein of SHG19 (a representative strain of nVarIBDV) was successfully expressed using an Escherichia coli expression system and further purified via ammonium sulfate precipitation and size-exclusion chromatography. The purified protein SHG19-VP2-466 could self-assemble into 25-nm virus-like particle (VLP). Subsequently, the immunogenicity and protective effect of the SHG19-VLP vaccine were evaluated using animal experiments, which indicated that the SHG19-VLP vaccine elicited neutralization antibodies and provided 100% protection against the nVarIBDV. Furthermore, the protective efficacy of the SHG19-VLP vaccine against the vvIBDV was evaluated. Although the SHG19-VLP vaccine induced a comparatively lower vvIBDV-specific neutralization antibody titer, it provided good protection against the lethal vvIBDV. In summary, the SHG19-VLP candidate vaccine could provide complete immune protection against the homologous nVarIBDV as well as the heterologous vvIBDV. This study is of significance to the comprehensive prevention and control of the recent atypical IBD epidemic.

Highlights

Infectious bursal disease (IBD) caused by infectious bursal disease virus (IBDV) is an important immunosuppressive disease, responsible for enormous economic losses in the poultry industry worldwide [1]
The purified protein was examined via Transmission Electron Microscopy (TEM), and virus-like particle (VLP) with a diameter of about 25 nm were observed (Figure 1e)
Due to the antigenicity mismatch, some very virulent IBDV (vvIBDV) vaccines such as attenuated vaccine [27], viral-like particle vaccine [25], and combined vaccine [22] could not provide 100% protection against bursal lesion caused by nVarIBDV [22,25], resulting in the continuous spread of nVarIBDV in immunized flocks [22,25], which has become a huge threat to the development of poultry industry

Summary

Introduction

Infectious bursal disease (IBD) caused by infectious bursal disease virus (IBDV) is an important immunosuppressive disease, responsible for enormous economic losses in the poultry industry worldwide [1]. IBDV is a non-enveloped virus, and a member of Avibirnavirus genus of the family birnaviridae. The segment A encodes a non-structural protein VP5 [3] and a polyprotein (pVP2-VP4-VP3), which can be further self-cleaved into the precursor of VP2 (pVP2), VP4, and VP3 [4]. During the process of IBDV maturation, the mature VP2 (441 residues) (amino acid [aa] 1-441) can be generated from the self-cleavage of pVP2 (aa 1-512), where its C-terminal (aa 442-512) of pVP2 end can be truncated [5,6].

Methods

Results

Conclusion