- 學位論文
豬生殖與呼吸綜合症病毒與豬第二型環狀病毒接種後豬隻週邊血液單核球之先天性免疫基因表現
Expression of Genes Associated with Innate Immunity in Peripheral Blood Mononuclear Cells from Pigs Co-infected with Porcine Reproductive and Respiratory Syndrome Virus and Porcine Circovirus Type 2
摘要
豬生殖與呼吸綜合症病毒（PRRSV)與豬環狀病毒第二型（PCV2）是引起世界養豬業嚴重經濟損失的兩種主要病原體。研究發現豬隻合併感染PRRSV和PCV2是相當常見的，這兩種病毒在宿主內的交互作用可能是嚴重發病的關鍵，但其確切的交互作用機制目前仍有待闡明。在本研究中，自單獨感染PRRSV或PCV2及合併感染兩者之豬隻血液萃取週邊血液單核細胞（PBMCs），分析其與先天性免疫相關的信號分子如類鐸受體其mRNA的表現量，使用即時定量聚合酶鏈鎖反應方法檢測。`在PRRSV 及 PCV2共同感染的豬隻體內，可觀察到CD14mRNA的表現量增 加，相反地 ，A20、Bcl-3、FoxP3、IRAK-M、RANTES及SAMR1的表現量則會降低；這可能會造成當豬隻混和感染PRRSV及PCV2時，前發炎性細胞激素 表現量的增加。另外，由IRF-1及IRF-3表現量的抑制可推論干擾素的表現也會受到抑制，使得混和感染的豬隻其體內的PCV2病毒複製能力較單獨感染者佳。
並列摘要
Porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) are the two major pathogens, causing most severe economic losses in swine industry worldwide. Field and experimental studies have shown that co-infection of PRRSV and PCV2 in pigs were quite common and thus the interactions between both viruses in the host might be critical to the pathogenesis of the disease. The exact interaction mechanisms are unknown and remained to be elucidated. In this study, the expression of cytokine mRNA as well as Toll like receptor signaling molecules associated with innate immunity in peripheral blood mononuclear cells (PBMCs) from pigs infected with PRRSV and/or PCV2 were investigated. Cytokine mRNA and TLR signaling molecule expression were determined by quantitative real-time polymerase chain reaction. Co-infection of pigs with PRRSV and PCV2 led to up-regulated expression of IL-1β and IL-10 mRNA and down-regulated expression of TNF-α and IL-6 in PBMCs of pigs co-infected with PRRSV and PCV2. An increased expression of CD14 mRNA was noticed in pigs co-infected with PRRSV and PCV2. In contrast, there were down-regulated expression of A20, Bcl-3, FoxP3, IRAK-M, RANTES and SAMR1 and that might contribute to the increased expression of proinflammatory cytokines in pigs co-infected with PRRSV and PCV2. A down-regulated expression of IRF-1 and IRF-3 might also suppress the expression of IFNs that leads to the enhanced replication of PCV2 in pigs co-infected with PRRSV and PCV2.