title: The Cholera Toxin B Subunit (CTB) Fused to the Porcine Arterivirus Matrix M and GP5 Envelope Proteins Fails to Enhance the GP5-Specific Antibody Response in Pigs Immunized with Adenovectors.
abstract: The porcine reproductive and respiratory syndrome virus (PRRSV) is an arterivirus of the Arteriviridae family. As the current commercial vaccines are incompletely protective effective against PRRSV infection, we developed a vaccine strategy using replicating but non-disseminating adenovectors (rAdVs) expressing the PRRSV M matrix protein in fusion with the neutralizing major epitope-carrying GP5 envelope protein (Roques et al. in Vet Res 44:17, 2013). Although production of GP5-specific antibodies (Abs) was observed, no PRRSV-specific neutralizing Abs (NAbs) were induced in pigs given the rAdVs expressing M-GP5 or M-GP5m (GP5m being a mutant form of GP5). Nevertheless, partial protection was observed in the M-GP5m-rAdV-inoculated pigs experimentally infected with PRRSV. Here, we determined the impact of the cholera toxin B subunit (CTB, known for its adjuvant effect) in fusion with the C-terminus of M-GP5m on the Ab response to PRRSV. Three-week-old pigs were immunized twice both intramuscularly and intranasally at 3-week intervals with rAdV-expressing the green fluorescent protein (rAdV-GFP), rAdV-M-GP5m, or rAdV-M-GP5m-CTB. Pigs immunized with rAdV-M-GP5m showed a high level of serum GP5-specific Abs (as determined by an indirect ELISA). In contrast, CTB in fusion with M-GP5m had an unexpected severe negative impact on GP5-specific Ab production. PRRSV-specific NAbs could not be detected in any pigs of all groups.
authors: Department of Biological Sciences, University of Québec at Montréal, Succursale Centre-Ville, P.O. Box 8888, Montreal, QC, H3C 3P8, Canada.
authors: Elodie
authors: E
authors: Roques
authors: Martin
authors: M
authors: Lessard
authors: Denis
authors: D
authors: Archambault
mesh_terms: D000256:Adenoviridae; D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology*; D018018:Arterivirus / Q000235:genetics / Q000276:immunology*; D002772:Cholera Toxin / Q000235:genetics / Q000276:immunology*; D007114:Immunization; D013552:Swine; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology*; D014763:Viral Matrix Proteins / Q000235:genetics / Q000276:immunology*; D014765:Viral Vaccines / Q000235:genetics / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D014759:Viral Envelope Proteins; D014763:Viral Matrix Proteins; D014765:Viral Vaccines; D002772:Cholera Toxin