title: Immunization with DNA vaccines containing porcine reproductive and respiratory syndrome virus open reading frames 5, 6, and 7 may be related to the exacerbation of clinical disease after an experimental challenge.
abstract: Pigs were immunized with DNA plasmids containing different open reading frames (ORFs) of a porcine reproductive and respiratory syndrome virus (PRRSV) genotype I strain. One group was injected with three inoculations of ORF7, a second group was immunized with three inoculations of plasmids containing ORF5 and ORF6, and a third group was kept as controls. Later, +21 days after the last inoculation, animals were challenged with the homologous strain. After the challenge, PRRSV-specific interferon (IFN)-γ-secreting cells and anti-PRRSV IgG antibodies developed faster in DNA vaccinated pigs (p<0.05). However, DNA-immunized pigs showed an exacerbation of the disease compared to the unvaccinated challenged pigs. The data suggest that previous immunization with DNA vaccines against glycoprotein 5 and/or matrix protein of PRRSV, as well as nucleoprotein but to a lesser degree, could result in an exacerbation of the clinical course in terms of fever upon challenge.
authors: Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain. ivan.diaz@cresa.uab.cat
authors: Ivan
authors: I
authors: Díaz
authors: Llilianne
authors: L
authors: Ganges
authors: Iván
authors: I
authors: Galindo-Cardiel
authors: Joan
authors: J
authors: Tarradas
authors: Belén
authors: B
authors: Alvarez
authors: Cristina
authors: C
authors: Lorca-Oró
authors: Joan
authors: J
authors: Pujols
authors: Mariona
authors: M
authors: Gimeno
authors: Laila
authors: L
authors: Darwich
authors: Mariano
authors: M
authors: Domingo
authors: Javier
authors: J
authors: Domínguez
authors: Enric
authors: E
authors: Mateu
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D000956:Antigens, Viral / Q000235:genetics / Q000276:immunology*; D007114:Immunization / Q000379:methods*; D007074:Immunoglobulin G / Q000097:blood; D007371:Interferon-gamma / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000276:immunology; D016366:Open Reading Frames; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology* / Q000473:pathology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics / Q000276:immunology*; D012720:Severity of Illness Index; D013552:Swine; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D007074:Immunoglobulin G; D019444:Vaccines, DNA; D007371:Interferon-gamma