title: Immune response to ORF5a protein immunization is not protective against porcine reproductive and respiratory syndrome virus infection.
abstract: Porcine reproductive and respiratory syndrome virus (PRRSV) is an enveloped RNA virus responsible for PRRS in swine, a disease with globally significant animal welfare and economic concerns. There is no specific treatment and variably effective immune protection. Molecular mechanisms responsible for virulence, pathogenesis and protective immune response remain poorly understood. These factors limit progress toward development of effective measures for prevention and treatment of PRRS. A novel PRRSV ORF5a protein, encoded in an open reading frame (ORF) that overlaps the major envelope glycoprotein GP5 ORF, was recently identified. Because ORF5a is highly conserved in diverse PRRSV isolates, is a structural protein in the virion, and elicits a specific antibody response in infected pigs, we investigated its potential role in immune protection against PRRSV infection. Pigs immunized with ORF5a protein had robust serologic responses. However, the antibodies did not neutralize virus, and immunity did not protect against challenge infection. We conclude from these findings that the ORF5a antibody response is neither neutralizing nor protective.
authors.affiliation: Department of Veterinary and Biomedical Sciences, University of Minnesota, 1971 Commonwealth Avenue, St. Paul, MN 55108, USA. robin782@umn.edu
authors.forename: Sally R
authors.initials: SR
authors.lastname: Robinson
authors.forename: Marina C
authors.initials: MC
authors.lastname: Figueiredo
authors.forename: Juan E
authors.initials: JE
authors.lastname: Abrahante
authors.forename: Michael P
authors.initials: MP
authors.lastname: Murtaugh
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000276:immunology*; D002460:Cell Line; D002478:Cells, Cultured; D005260:Female; D008297:Male; D009500:Neutralization Tests; D016366:Open Reading Frames / Q000235:genetics; D019318:Porcine Reproductive and Respiratory Syndrome / Q000517:prevention & control*; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology*; D013552:Swine; D015678:Viral Structural Proteins / Q000276:immunology*; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D015678:Viral Structural Proteins; D014765:Viral Vaccines