Porcine circovirus type 2 (PCV2) is a single-stranded circular DNA virus infecting dom
estic pigs worldwide. Interaction of this virus with the immune system apparently modulat
es the immune r
esponse of the host. In the pr
esent study, the implication of different components of PCV2 in the modulation of the immune r
esponse of the host were inv
estigated by using PCV2 viral-like particl
es (VLPs) and 16 novel oligodeoxyribonucleotid
es containing CpG motifs (CpG-ODNs) based on the PCV2 genomic sequence. The role of th
ese viral components was studied by evaluating the cytokine profil
es (IFN-
es/204e.gif" alt="greek small letter alpha" title="greek small letter alpha" border="0">, IFN-γ, IL-10, IL-2 and IL-12) on porcine peripheral mononuclear cell (PBMC) and bone marrow-derived dendritic cell (BMDC) cultur
es. Also, the effect of PCV2 and its elements were examined in recall antigen (pseudorabi
es virus, PRV) r
espons
es. While PCV2 was a potent inducer of IL-10 by PBMCs, such effect was not observed using CpG-ODNs or VLPs. However, IFN-γ and IL-2 production by recall antigen was repr
essed in pr
esence of PCV2 and most of the studied CpG-ODNs. VLPs did not have such repr
essive effect. In BMDC cultur
es, PCV2 and most of CpG-ODNs were able to inhibit IFN-
es/204e.gif" alt="greek small letter alpha" title="greek small letter alpha" border="0"> secretion induced by PRV. Inter
estingly, CpG-ODNs with inhibitory effect were located within the PCV2 Rep gene. Additionally, PCV2 virus was a very strong IL-12 inducer in BMDC cultur
es. Whereas, IFN-
es/204e.gif" alt="greek small letter alpha" title="greek small letter alpha" border="0"> 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 r
esponse upon PCV2 infection seems to depend on the fine balance between the regulatory elements pr
esent in viral DNA and structural protein within the host immune system.