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

 

[PubMed - as supplied by publisher]

Serum inoculation for elimination of PRRS from a farrow-to-finish farm

Acta Vet Hung. 2015 Sep;63(3):389-399.

Serum inoculation as a possibility for elimination of porcine reproductive and respiratory syndrome (PRRS) from a farrow-to-finish pig farm.

Štukelj M1, Plut J1, Toplak I2.

Author information

• 1Institute for the Health Care of Pigs, University of Ljubljana , Gerbičeva 60, 1000 Ljubljana , Slovenia.
• 2Institute for Microbiology and Parasitology, Veterinary Faculty, University of Ljubljana , Gerbičeva 60, 1000 Ljubljana , Slovenia.

Abstract

The large heterogeneity among porcine reproductive and respiratory syndrome virus (PRRSV) isolates is probably the main obstacle to its effective control using current commercial vaccines. Intentionally exposing all breeding pigs to PRRSV circulating on the farm could eliminate porcine reproductive and respiratory syndrome (PRRS) from the herd. The objective of this study was to eliminate PRRS from a farrow-to-finish pig farm by serum inoculation. The owner was acquainted with the strict biosecurity measures. Breeding pigs were immunised with serum, which was obtained from PRRSV-positive weaners from the same farm. The percent of antibody high positive breeding pigs decreased six months after serum inoculation, while 34 months after serum inoculation no more antibody high positive pigs were detected and 56.8% of breeding pigs and all other categories were free of antibodies. In the breeding herd no virus was detected during all testing while PRRSV circulated in 2-month-old weaners until 12 months after serum inoculation. Later all tested samples from weaners, growers and fatteners were negative. Herd closure and the adoption of strict biosecurity measures are essential. Serum inoculation of the breeding herd proved to be a successful measure for eliminating PRRS from this farrow-to-finish farm.

KEYWORDS: 

PRRS; Porcine; elimination; immunisation; serum inoculation

PMID:

 

26551429

 

[PubMed - as supplied by publisher]