title: Antigenic and genetic variations of the 15 kD nucleocapsid protein of porcine reproductive and respiratory syndrome virus isolates.
abstract: The antigenic variability of the 15 kD nucleocapsid protein of porcine reproductive and respiratory syndrome (PRRS) virus was characterized with a panel of 24 monoclonal antibodies (MAbs) raised against the American PRRS virus isolate ISU-P. Five continuous epitopes designated EpORF7-A through E were revealed by the reactivity pattern of these MAbs with 67 American field isolates, two modified-live vaccine viruses, and the European Lelystad virus as determined by the indirect immnofluorescence assay and Western immunoblotting and confirmed by additivity and blocking enzyme-linked immunosorbent assays. The reactivity pattern of isolates in the IFA permitted their subdivision into 4 American antigenic groups which represented 84.1, 11.6, 2.9 and 1.4% of viruses tested. The antigenic variation among isolates was correlated to single, group specific nucleotide substitutions and mediated by a combination of at least 4 of the 5 epitopes. EpORF7-A was conserved in all American isolates and the Lelystad virus which constituted a separate antigenic group. Consequently, monoclonal antibodies specific for EpORF7-A may prove useful as the antigenic basis for a universal diagnostic test for the PRRS virus. EpORF7-C, D and E were only present in the American isolates tested.
authors.affiliation: Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, USA.
authors.forename: L
authors.initials: L
authors.lastname: Yang
authors.forename: K J
authors.initials: KJ
authors.lastname: Yoon
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.forename: J J
authors.initials: JJ
authors.lastname: Zimmerman
authors.forename: M L
authors.initials: ML
authors.lastname: Frey
authors.forename: K M
authors.initials: KM
authors.lastname: Harmon
authors.forename: K B
authors.initials: KB
authors.lastname: Platt
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000914:Antibodies, Viral / Q000276:immunology; D000940:Antigenic Variation / Q000276:immunology*; D000956:Antigens, Viral / Q000276:immunology; D001483:Base Sequence; D002460:Cell Line; D004279:DNA, Viral; D018985:Epitopes, B-Lymphocyte / Q000276:immunology; D014644:Genetic Variation; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins / Q000235:genetics* / Q000276:immunology*; D016366:Open Reading Frames; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics* / Q000276:immunology* / Q000302:isolation & purification; D012689:Sequence Homology, Nucleic Acid; D013552:Swine
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000956:Antigens, Viral; D004279:DNA, Viral; D018985:Epitopes, B-Lymphocyte; D019590:Nucleocapsid Proteins