title: Porcine circovirus type 2 (PCV2) viral components immunomodulate recall antigen responses.
abstract: Porcine circovirus type 2 (PCV2) is a single-stranded circular DNA virus infecting domestic pigs worldwide. Interaction of this virus with the immune system apparently modulates the immune response of the host. In the present study, the implication of different components of PCV2 in the modulation of the immune response of the host were investigated by using PCV2 viral-like particles (VLPs) and 16 novel oligodeoxyribonucleotides containing CpG motifs (CpG-ODNs) based on the PCV2 genomic sequence. The role of these viral components was studied by evaluating the cytokine profiles (IFN-alpha, IFN-gamma, IL-10, IL-2 and IL-12) on porcine peripheral mononuclear cell (PBMC) and bone marrow-derived dendritic cell (BMDC) cultures. Also, the effect of PCV2 and its elements were examined in recall antigen (pseudorabies virus, PRV) responses. While PCV2 was a potent inducer of IL-10 by PBMCs, such effect was not observed using CpG-ODNs or VLPs. However, IFN-gamma and IL-2 production by recall antigen was repressed in presence of PCV2 and most of the studied CpG-ODNs. VLPs did not have such repressive effect. In BMDC cultures, PCV2 and most of CpG-ODNs were able to inhibit IFN-alpha secretion induced by PRV. Interestingly, CpG-ODNs with inhibitory effect were located within the PCV2 Rep gene. Additionally, PCV2 virus was a very strong IL-12 inducer in BMDC cultures. Whereas, IFN-alpha modulation on BMDC after PCV2 VLP treatment was neglectable, PCV2 VLPs were potent IL-12 inducers. Our data shows that PCV2 viral elements can distinctly regulate cytokine production depending on the cell population studied. Thus, the final immune response upon PCV2 infection seems to depend on the fine balance between the regulatory elements present in viral DNA and structural protein within the host immune system.
authors.affiliation: Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain. Tuija.Kekarainen@cresa.uab.es
authors.forename: Tuija
authors.initials: T
authors.lastname: Kekarainen
authors.forename: Maria
authors.initials: M
authors.lastname: Montoya
authors.forename: Javier
authors.initials: J
authors.lastname: Dominguez
authors.forename: Enric
authors.initials: E
authors.lastname: Mateu
authors.forename: Joaquim
authors.initials: J
authors.lastname: Segalés
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000276:immunology*; D018173:Circoviridae Infections / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D017925:Circovirus / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D016679:Genome, Viral; D011558:Herpesvirus 1, Suid / Q000276:immunology; D007155:Immunologic Factors / Q000276:immunology*; D016898:Interferon-alpha / Q000276:immunology; D007371:Interferon-gamma / Q000276:immunology; D016753:Interleukin-10 / Q000276:immunology; D018664:Interleukin-12 / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000276:immunology; D009838:Oligodeoxyribonucleotides / Q000276:immunology; D053570:Porcine Postweaning Multisystemic Wasting Syndrome / Q000276:immunology* / Q000821:virology*; D022421:Pseudorabies Vaccines / Q000276:immunology; D013552:Swine
chemical_list: D000956:Antigens, Viral; C408982:CPG-oligonucleotide; D007155:Immunologic Factors; D016898:Interferon-alpha; D009838:Oligodeoxyribonucleotides; D022421:Pseudorabies Vaccines; D016753:Interleukin-10; D018664:Interleukin-12; D007371:Interferon-gamma