Virus-like particles of chimeric recombinant porcine circovirus type 2 as antigen vehicle carrying foreign epitopes.

Huawei Zhang,Ping Qian,Xiangmin Li,Lifeng Liu,Huanchun Chen,Suhong Qian

doi:10.3390/v6124839

Abstract

Virus-like particles (VLPs) of chimeric porcine circovirus type 2 (PCV2) were generated by replacing the nuclear localization signal (NLS; at 1–39 aa) of PCV2 capsid protein (Cap) with classical swine fever virus (CSFV) T-cell epitope (1446–1460 aa), CSFV B-cell epitope (693–716 aa) and CSFV T-cell epitope conjugated with B-cell epitope. The recombinant proteins were expressed using the baculovirus expression system and detected by immunoblotting and indirect immunofluorescence assay. The abilities to form PCV2 VLPs were confirmed by transmission electron microscopy. Immunogenicities of the three recombinant proteins were evaluated in mice. Our Results indicated that Cap protein NLS deletion or substitution with CSFV epitopes did not affect the VLPs assembly. Three chimeric Cap proteins could form VLPs and induce efficient humoral and cellular immunity against PCV2 and CSFV in mice. Results show that PCV2 VLPs can be used as an efficient antigen carrier for delivery of foreign epitopes, and a potential novel vaccine.

Highlights

Classical swine fever (CSF) caused by CSF virus (CSFV) is a highly contagious and devastating disease of swine worldwide [1,2]
We evaluated the potential of porcine circovirus type 2 (PCV2) Virus-like particles (VLPs) as a vessel for carrying foreign epitopes
Baculovirus expression system has been extensively applied into research and production of subunit vaccines, for VLPs [30]

Summary

Introduction

Classical swine fever (CSF) caused by CSF virus (CSFV) is a highly contagious and devastating disease of swine worldwide [1,2]. This protein contains sequential neutralizing epitopes and has been used as the main component in the design of CSFV–DIVA vaccines [7]. The amino acid sequence (CKEDYRYAISSTNEIGLLGAGGLT) of the E2 glycoprotein (693–716 aa) is one of the major epitopes with neutralizing activity [8,9,10,11]. Previous studies suggested that this major epitopes can completely or partially protect pigs against CSFV [11,12]. The amino acid residues (1446–1460) of the non-structural protein NS3 (KHKVRNEVMVHWFDD) contains a specific helper T-cell epitope and a CTL epitope and play important roles in humoral and cellular immunity [8,9,12]

Methods

Results

Conclusion