title: Boosting in planta production of antigens derived from the porcine reproductive and respiratory syndrome virus (PRRSV) and subsequent evaluation of their immunogenicity.
abstract: Porcine reproductive and respiratory syndrome (PRRS) is a disease of swine, caused by an arterivirus, the PRRS virus (PRRSV). This virus infects pigs worldwide and causes huge economic losses. Due to genetic drift, current vaccines are losing their power. Adaptable vaccines could provide a solution to this problem. This study aims at producing in planta a set of antigens derived from the PRRSV glycoproteins (GPs) to be included in a subunit vaccine. We selected the GP3, GP4 and GP5 and optimized these for production in an Arabidopsis seed platform by removing transmembrane domains (Tm) and/or adding stabilizing protein domains, such as the green fluorescent protein (GFP) and immunoglobulin (IgG) 'Fragment crystallizable' (Fc) chains. Accumulation of the GPs with and without Tm was low, reaching no more than 0.10% of total soluble protein (TSP) in homozygous seed. However, addition of stabilizing domains boosted accumulation up to a maximum of 2.74% of TSP when GFP was used, and albeit less effectively, also the Fc chains of the porcine IgG3 and murine IgG2a increased antigen accumulation, to 0.96% and 1.81% of TSP respectively, while the murine IgG3 Fc chain did not. Antigens with Tm were less susceptible to these manipulations to increase yield. All antigens were produced in the endoplasmic reticulum and accordingly, they carried high-mannose N-glycans. The immunogenicity of several of those antigens was assessed and we show that vaccination with purified antigens did elicit the production of antibodies with virus neutralizing activity in mice but not in pigs.
authors.affiliation: Department of Plant Systems Biology, VIB, Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.
authors.forename: Robin
authors.initials: R
authors.lastname: Piron
authors.affiliation: Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
authors.forename: Stefaan
authors.initials: S
authors.lastname: De Koker
authors.affiliation: Department of Plant Systems Biology, VIB, Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.
authors.forename: Annelies
authors.initials: A
authors.lastname: De Paepe
authors.affiliation: Department of Bioscience Engineering, VUB, Brussels, Belgium.
authors.forename: Julie
authors.initials: J
authors.lastname: Goossens
authors.affiliation: Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
authors.forename: Johan
authors.initials: J
authors.lastname: Grooten
authors.affiliation: Department of Virology, Parasitology and Immunology, Ghent University, Ghent, Belgium.
authors.forename: Hans
authors.initials: H
authors.lastname: Nauwynck
authors.affiliation: Department of Plant Systems Biology, VIB, Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.
authors.forename: Ann
authors.initials: A
authors.lastname: Depicker
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000096:biosynthesis / Q000276:immunology* / Q000302:isolation & purification; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D002846:Chromatography, Affinity; D004269:DNA, Bacterial / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006023:Glycoproteins / Q000276:immunology*; D006031:Glycosylation; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D011134:Polysaccharides / Q000378:metabolism; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology*; D012639:Seeds / Q000378:metabolism; D013552:Swine / Q000821:virology*
chemical_list: D000956:Antigens, Viral; D004269:DNA, Bacterial; D006023:Glycoproteins; D011134:Polysaccharides; C036483:T-DNA