title: Vectored vaccines to protect against PRRSV.
abstract: PRRSV is the causative agent of the most important infectious disease affecting swine herds worldwide, producing great economic losses. Commercially available vaccines are only partially effective in protection against PRRSV. Moreover, modified live vaccines may allow virus shedding, and could revert generating virulent phenotypes. Therefore, new efficient vaccines are required. Vaccines based on recombinant virus genomes (virus vectored vaccines) against PRRSV could represent a safe alternative for the generation of modified live vaccines. In this paper, current vectored vaccines to protect against PRRSV are revised, including those based on pseudorabies virus, poxvirus, adenovirus, and virus replicons. Special attention has been provided to the use of transmissible gastroenteritis virus (TGEV) as vector for the expression of PRRSV antigens. This vector has the capability of expressing high levels of heterologous genes, is a potent interferon-α inducer, and presents antigens in mucosal surfaces, eliciting both secretory and systemic immunity. A TGEV derived vector (rTGEV) was generated, expressing PRRSV wild type or modified GP5 and M proteins, described as the main inducers of neutralizing antibodies and cellular immune response, respectively. Protection experiments showed that vaccinated animals developed a faster and stronger humoral immune response than the non-vaccinated ones. Partial protection in challenged animals was observed, as vaccinated pigs showed decreased lung damage when compared with the non-vaccinated ones. Nevertheless, the level of neutralizing antibodies was low, what may explain the limited protection observed. Several strategies are proposed to improve current rTGEV vectors expressing PRRSV antigens.
authors.affiliation: Centro Nacional de Biotecnología, CSIC, Department of Molecular and Cell Biology, Campus Universidad Autónoma de Madrid, Darwin 3, 28049 Madrid, Spain.
authors.forename: Jazmina L G
authors.initials: JL
authors.lastname: Cruz
authors.forename: Sonia
authors.initials: S
authors.lastname: Zúñiga
authors.forename: Martina
authors.initials: M
authors.lastname: Bécares
authors.forename: Isabel
authors.initials: I
authors.lastname: Sola
authors.forename: Juan E
authors.initials: JE
authors.lastname: Ceriani
authors.forename: Sandra
authors.initials: S
authors.lastname: Juanola
authors.forename: Juan
authors.initials: J
authors.lastname: Plana
authors.forename: Luis
authors.initials: L
authors.lastname: Enjuanes
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D005822:Genetic Vectors; D008168:Lung / Q000473:pathology; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology / Q000517:prevention & control*; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics / Q000276:immunology*; D013552:Swine; D005760:Transmissible gastroenteritis virus / Q000235:genetics*; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology; D014765:Viral Vaccines / Q000235:genetics / Q000276:immunology*
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D014614:Vaccines, Synthetic; D014765:Viral Vaccines