Expression of monocyte chemoattractant protein-1 and macrophage inflammatory protein-1 in porcine circovirus 2-induced granulomatous inflammation.

The expression of monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1 (MIP-1) in granulomatous inflammation of lymph nodes was determined in 1-day-old piglets inoculated intranasally with porcine circovirus 2 (PCV2). The methods used were reverse transcription-polymerase chain reaction (RT-PCR), granulomatous lesion scoring, and in-situ hybridization. Maximum MCP-1 expression and MIP-1 expression were observed at 17 and 21 days post-inoculation (dpi), respectively. Granulomatous lesions of maximum severity were observed somewhat later (28 dpi). A close cell to cell relation between PCV2 and the two cytokines in serial sections from lymph nodes suggested that their induction was a direct response to PCV2. The results provide evidence of the ability of MCP-1 and MIP-1 to induce granulomatous inflammation in vivo.