Evaluation of PCV1 as vaccine vector to express antigenic epitopes of PRRSv

Virus Res. 2015 Nov 7. pii: S0168-1702(15)30112-X. doi: 10.1016/j.virusres.2015.11.005. [Epub ahead of print]

Evaluation of the use of non-pathogenic porcine circovirus type 1 as a vaccine delivery virus vector to express antigenic epitopes of porcine reproductive and respiratory syndrome virus.

Piñeyro PE1, Kenney SP2, Giménez-Lirola LG3, Opriessnig T4, Tian D2, Heffron CL2, Meng XJ5.

Author information

• 1Department of Biomedical Sciences & Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA; Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University College of Veterinary Medicine, Ames, Iowa 5001, USA.
• 2Department of Biomedical Sciences & Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA.
• 3Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University College of Veterinary Medicine, Ames, Iowa 5001, USA.
• 4Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University College of Veterinary Medicine, Ames, Iowa 5001, USA; The Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
• 5Department of Biomedical Sciences & Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA. Electronic address: xjmeng@vt.edu.

Abstract

We previously demonstrated that the C-terminus of the capsid gene of porcine circovirus type 2 (PCV2) is an immune reactive epitope displayed on the surface of virions. Insertion of foreign epitope tags in the C-terminus produced infectious virions that elicited humoral immune responses against both PCV2 capsid and the inserted epitope tags, whereas mutation in the N terminus impaired viral replication. Since the non-pathogenic porcine circovirus type 1 (PCV1) shares similar genomic organization and significant sequence identity with pathogenic PCV2, in this study we evaluated whether PCV1 can serve as a vaccine delivery virus vector. Four different antigenic determinants of porcine reproductive and respiratory syndrome virus (PRRSV) were inserted in the C-terminus of the PCV1 capsid gene, the infectivity and immunogenicity of the resulting viruses are determined. We showed that an insertion of 12 (PRRSV-GP2 epitope II, PRRSV-GP3 epitope I, and PRRSV-GP5 epitope I), and 14 (PRRSV-GP5 epitope IV) amino acid residues did not affect PCV1 replication. We successfully rescued and characterized four chimeric PCV1 viruses expressing PRRSV linear antigenic determinants (GP2 epitope II: aa 40-51, ASPSHVGWWSFA; GP3 epitope I: aa 61-72, QAAAEAYEPGRS; GP5 epitope I: aa 35-46, SSSNLQLIYNLT; and GP5 epitope IV: aa 187-200, TPVTRVSAEQWGRP). We demonstrated that all chimeric viruses were stable and infectious in vitro and three chimeric viruses were infectious in vivo. An immunogenicity study in pigs revealed that PCV1-VR2385EPI chimeric viruses elicited neutralizing antibodies against PRRSV-VR2385. The results have important implications for further evaluating PCV1 as a potential vaccine delivery vector.

Copyright © 2015. Published by Elsevier B.V.

KEYWORDS: 

Antigenic epitopes; Porcine circovirus type 1 (PCV1); Porcine circovirus type 2 (PCV2); Porcine reproductive and respiratory syndrome virus (PRRSV); Vaccine delivery vector

PMID:

 

26555162

 

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