Rescue of the highly virulent classical swine fever virus strain "Koslov" from cloned cDNA and first insights into genome variations relevant for virulence

TY - JOUR

T1 - Rescue of the highly virulent classical swine fever virus strain "Koslov" from cloned cDNA and first insights into genome variations relevant for virulence

AU - Fahnøe, Ulrik

AU - Pedersen, Anders Gorm

AU - Risager, Peter Christian

AU - Nielsen, Jens

AU - Belsham, Graham J

AU - Höper, Dirk

AU - Beer, Martin

AU - Rasmussen, Thomas Bruun

N1 - Copyright © 2014 Elsevier Inc. All rights reserved.

PY - 2014/11/1

Y1 - 2014/11/1

N2 - Classical swine fever virus (CSFV) strain "Koslov" is highly virulent with a mortality rate of up to 100% in pigs. In this study, we modified non-functional cDNAs generated from the blood of Koslov virus infected pigs by site-directed mutagenesis, removing non-synonymous mutations step-by-step, thereby producing genomes encoding the consensus amino acid sequence. Viruses rescued from the construct corresponding to the inferred parental form were highly virulent, when tested in pigs, with infected animals displaying pronounced clinical symptoms leading to high mortality. The reconstruction therefore gave rise to a functional cDNA corresponding to the highly virulent Koslov strain of CSFV. It could be demonstrated that two single amino acid changes (S763L and P968H) in the surface structural protein E2 resulted in attenuation in the porcine infection system while another single amino acid change within the nonstructural protein NS3 (D2183G) reduced virus growth within cells in vitro.

AB - Classical swine fever virus (CSFV) strain "Koslov" is highly virulent with a mortality rate of up to 100% in pigs. In this study, we modified non-functional cDNAs generated from the blood of Koslov virus infected pigs by site-directed mutagenesis, removing non-synonymous mutations step-by-step, thereby producing genomes encoding the consensus amino acid sequence. Viruses rescued from the construct corresponding to the inferred parental form were highly virulent, when tested in pigs, with infected animals displaying pronounced clinical symptoms leading to high mortality. The reconstruction therefore gave rise to a functional cDNA corresponding to the highly virulent Koslov strain of CSFV. It could be demonstrated that two single amino acid changes (S763L and P968H) in the surface structural protein E2 resulted in attenuation in the porcine infection system while another single amino acid change within the nonstructural protein NS3 (D2183G) reduced virus growth within cells in vitro.

KW - Animals

KW - Cell Line

KW - Classical Swine Fever/mortality

KW - Classical swine fever virus/pathogenicity

KW - Cloning, Molecular

KW - DNA, Complementary/genetics

KW - Genetic Variation

KW - Genome, Viral

KW - Kidney/cytology

KW - Swine

KW - Time Factors

KW - Virulence

U2 - 10.1016/j.virol.2014.08.021

DO - 10.1016/j.virol.2014.08.021

M3 - Journal article

C2 - 25240324

SN - 0042-6822

VL - 468-470

SP - 379

EP - 387

JO - Virology

JF - Virology

ER -