title: Heterogeneous antigenic properties of the porcine reproductive and respiratory syndrome virus nucleocapsid.
abstract: Porcine reproductive and respiratory syndrome virus (PRRSV) is an arterivirus responsible for a widespread contagious disease of domestic pigs with high economic impact. Switzerland is one of the rare PRRSV-free countries in Europe, although sporadic outbreaks have occurred in the past. The PRRSV isolate IVI-1173 from the short outbreak in Switzerland in 2012 was entirely sequenced, and a functional full-length cDNA clone was constructed. Genetic and antigenic characterization of IVI-1173 revealed the importance of amino acid 90 of the nucleocapsid protein N as part of a conformational epitope. IVI-1173 was not detected by SDOW17, a monoclonal antibody against N widely used to detect PRRSV-infected cells. Substitution of alanine at position 90 of N [N(A90)] with a threonine [N(T90)] restored reactivity of vIVI1173-N(T90) to SDOW17 completely. The relevance of this amino acid for the conformational SDOW17 epitope of PRRSV N was further confirmed by the opposite substitution in a functional cDNA clone of the genotype 2 isolate RVB-581. Finally, N proteins from ten genotype 1 strains differing from threonine at position 90 were analysed for reactivity with SDOW17. N(A90) totally disrupted or severely affected the epitope in 7 out of 8 strains tested. Based on these findings, 225 genotype 1 strains were screened for the prevalence of N(A90). N(A90) is rare in classical subtype 1 and in subtype 3 strains, but is frequent in Russian subtype 1 (70%) and in subtype 2 (45%) isolates. In conclusion, this study highlights the variable antigenic properties of N among genotype 1 PRRSV strains.
authors.affiliation: The Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland.|Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.
authors.forename: Julie C F
authors.initials: JC
authors.lastname: Rappe
authors.affiliation: The Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland.
authors.forename: Obdulio
authors.initials: O
authors.lastname: García-Nicolás
authors.affiliation: The Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland.
authors.forename: Franziska
authors.initials: F
authors.lastname: Flückiger
authors.affiliation: The Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland.|Office for Consumer Protection, Canton Aargau, Obere Vorstadt 14, 5000, Aarau, Switzerland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Thür
authors.affiliation: The Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland.
authors.forename: Martin A
authors.initials: MA
authors.lastname: Hofmann
authors.affiliation: The Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland.|Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
authors.forename: Artur
authors.initials: A
authors.lastname: Summerfield
authors.affiliation: The Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland. nicolas.ruggli@ivi.admin.ch.
authors.forename: Nicolas
authors.identifier: 0000-0002-7679-6290
authors.initials: N
authors.lastname: Ruggli
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology; D000956:Antigens, Viral / Q000235:genetics / Q000276:immunology*; D004196:Disease Outbreaks / Q000662:veterinary; D000939:Epitopes / Q000235:genetics / Q000276:immunology; D005260:Female; D005434:Flow Cytometry / Q000662:veterinary; D005455:Fluorescent Antibody Technique / Q000662:veterinary; D008297:Male; D019251:Nucleocapsid / Q000235:genetics / Q000276:immunology*; D010802:Phylogeny; D019318:Porcine Reproductive and Respiratory Syndrome / Q000453:epidemiology / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics / Q000276:immunology*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA / Q000662:veterinary; D013552:Swine; D013557:Switzerland / Q000453:epidemiology
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D000939:Epitopes