TLR2/MyD88/NF-κB signalling pathway regulates IL-8 production in porcine alveolar macrophages infected with porcine circovirus 2.

Porcine circovirus 2 (PCV2) is the primary cause of post-weaning multisystemic wasting syndrome, in which it stimulates a strong IL-8 response that is associated with chronic inflammation as well as lesions in the lymphoid organs. However, the mechanism underlying PCV2-induced IL-8 production is still unclear. In the present study, we demonstrated that increased IL-8 expression during PCV2 infection depends on Toll-like receptor (TLR2), but not TLR4 or TLR9 signalling pathways in porcine alveolar macrophages. Moreover, we found that impairment of the MyD88/NF-κB signalling pathway by MyD88 knockdown or NF-κB inhibitors markedly decreased PCV2-induced IL-8 secretion. These results suggest that PCV2 induces IL-8 secretion via the TLR2/MyD88/NF-κB signalling pathway. Therefore, it is important to elucidate the molecular mechanisms of the PCV2-induced inflammatory response.