title: Dissociation of porcine reproductive and respiratory syndrome virus neutralization from antibodies specific to major envelope protein surface epitopes.
abstract: Glycoprotein 5 (GP5) and membrane (M) protein are the major proteins in the envelope of porcine reproductive and respiratory syndrome virus (PRRSV). Although viral neutralization epitopes are reported in GP5 and M of type 2 PRRSV, their significance as targets of porcine humoral immunity is not well described. Thus, we constructed recombinant polypeptides containing ectodomain neutralization epitopes to examine their involvement in porcine antibody neutralization and antiviral immunity. PRRSV infection elicited ectodomain-specific antibodies, whose titers did not correlate with the neutralizing antibody (NA) response. Ectodomain-specific antibodies from PRRSV-neutralizing serum bound virus but did not neutralize infectivity. Furthermore, immunization of pigs with ectodomain polypeptides raised specific antibodies and provided partial protection without a detectable NA response. Finally the polypeptides did not block infection of porcine macrophages. These results suggest that the GP5/M ectodomain peptide epitopes are accessible for host antibody recognition, but are not associated with antibody-mediated virus neutralization.
authors.affiliation: Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, MN 55108, USA.
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Michael P
authors.initials: MP
authors.lastname: Murtaugh
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D057134:Antibodies, Neutralizing / Q000096:biosynthesis; D000914:Antibodies, Viral / Q000096:biosynthesis; D000915:Antibody Affinity; D000918:Antibody Specificity; D000956:Antigens, Viral / Q000235:genetics; D000939:Epitopes / Q000235:genetics; D005260:Female; D007114:Immunization; D016676:Macrophages, Alveolar / Q000276:immunology / Q000821:virology; D008297:Male; D008969:Molecular Sequence Data; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D034421:Sus scrofa; D013552:Swine; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology; D014763:Viral Matrix Proteins / Q000235:genetics / Q000276:immunology
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D000956:Antigens, Viral; D000939:Epitopes; C525999:M protein, porcine reproductive and respiratory syndrome virus; D014759:Viral Envelope Proteins; D014763:Viral Matrix Proteins; C114789:glycoprotein 5, PRRSV