title: Reproduction of PMWS in immunostimulated SPF piglets transfected with infectious cloned genomic DNA of type 2 porcine circovirus.
abstract: Postweaning multisystemic wasting syndrome (PMWS) is a recently emerged disease affecting pigs. Type 2 porcine circovirus (PCV2) has been associated with this syndrome although other factors are required in association with this virus for PMWS expression. The aim of this study was to investigate whether general immunostimulation (injections of keyhole limpet hemocyanin emulsified in incomplete Freund adjuvant and of thioglycollate medium) could strengthen the severity of PMWS in six-week-old specific-pathogen-free (SPF) piglets transfected with pure tandem-cloned PCV2 DNA by the intramuscular route. Non-immunostimulated piglets transfected with the viral clone did not present clinical signs but only mild pathological microlesions characteristic of PMWS. These piglets seroconverted and high viral genome loads and infectious titers were detected in the lymphoid organs at the end of the trial. Mild-to-moderate forms of PMWS were generally observed in the immunostimulated transfected piglets, as well as one severe form for a piglet (8003) which died. These piglets with mild-to-moderate forms had higher DNA loads than the transfected-only animals. Thus, viral replication was enhanced by immunostimulation. This is the first time that clinical PMWS has been reported in an SPF immunostimulated piglet infected with a pure inoculum consisting of tandem-cloned PCV2 DNA. This result confirms that PCV2 is the agent of PMWS and that immunostimulation could enhance PMWS in SPF piglets transfected with a PCV2 DNA clone.
authors.affiliation: French Agency for Food Safety (AFSSA), Unit of Viral Genetics and Biosafety, BP 53, 22440 Ploufragan, France. b.grasland@ploufragan.afssa.fr
authors.forename: Béatrice
authors.initials: B
authors.lastname: Grasland
authors.forename: Christophe
authors.initials: C
authors.lastname: Loizel
authors.forename: Philippe
authors.initials: P
authors.lastname: Blanchard
authors.forename: Aurélie
authors.initials: A
authors.lastname: Oger
authors.forename: Anne-Cécile
authors.initials: AC
authors.lastname: Nignol
authors.forename: Laurent
authors.initials: L
authors.lastname: Bigarré
authors.forename: Hervé
authors.initials: H
authors.lastname: Morvan
authors.forename: Roland
authors.initials: R
authors.lastname: Cariolet
authors.forename: André
authors.initials: A
authors.lastname: Jestin
mesh_terms: D000818:Animals; D000914:Antibodies, Viral; D000956:Antigens, Viral; D018173:Circoviridae Infections / Q000276:immunology / Q000662:veterinary*; D017925:Circovirus / Q000235:genetics* / Q000472:pathogenicity*; D004279:DNA, Viral; D007114:Immunization; D013047:Specific Pathogen-Free Organisms; D013552:Swine; D013553:Swine Diseases / Q000276:immunology*; D014162:Transfection / Q000379:methods; D019562:Viral Load; D014779:Virus Replication; D019282:Wasting Syndrome / Q000276:immunology / Q000662:veterinary* / Q000821:virology
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D004279:DNA, Viral