State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, No. 2 Yuan Ming Yuan West Road, Beijing 100193, China.
Virol J. 2010 Dec 8;7:364. doi: 10.1186/1743-422X-7-364.
Cytokines are important mediators and regulators of host responses against foreign antigen, with their main function to orchestrate the functional activities of the cells of the immune system. However little is known about the role of cytokines in pathogenesis and immune responses caused by infectious bursa disease virus (IBDV). The aim of this study was to examine the transcripts of cell-mediated immune response-related cytokine genes in the bursal tissues of chickens infected with IBDVs of varying virulence to gain an understanding of pathological changes and mechanisms of immunosuppression caused by IBDV infection and the immune responses evoked.
Real-time quantitative PCR analysis revealed that the expression levels of both Th1 [interferon (IFN)-γ, interleukins (IL)-2 and IL-12p40] and Th2 (IL-4, IL-5, IL-13 and IL-10) cytokines were significantly up-regulated following challenge with the H strain (vvIBDV) and up to 2- and 30-fold, respectively (P < 0.05). Following infection with the Ts strain (cell-adapted virus) these cytokine transcripts were up-regulated at 5 days post-infection (dpi), 2- and 13-fold respectively (P < 0.05), while the expression levels of IL-2 and IL-4 were not significantly different (P > 0.05). A higher degree of cytokine expression was induced by the H strain compared with the Ts strain.
The results indicate that the expression of cell-mediated immune-related cytokine genes is strongly induced by IBDV, especially by the vvIBDV, H strain and reveal that these cytokines could play a crucial role in driving cellular immune responses during the acute phase of IBDV infection, and the cellular immune responses caused by IBDV of varying virulence are through different signaling pathways.
细胞因子是宿主对外来抗原反应的重要介质和调节剂，其主要功能是协调免疫系统细胞的功能活动。然而，关于细胞因子在传染性腔上囊病病毒（IBDV）引起的发病机制和免疫反应中的作用知之甚少。本研究旨在检测感染不同毒力 IBDV 的鸡法氏囊组织中细胞介导免疫反应相关细胞因子基因的转录本，以了解 IBDV 感染引起的病理变化和免疫抑制机制以及免疫反应。
实时定量 PCR 分析显示，感染 H 株（vvIBDV）后，Th1 [干扰素（IFN）-γ、白细胞介素（IL）-2 和 IL-12p40]和 Th2（IL-4、IL-5、IL-13 和 IL-10）细胞因子的表达水平均显著上调，分别上调了 2 倍和 30 倍（P < 0.05）。感染 Ts 株（细胞适应病毒）后，这些细胞因子转录物在感染后 5 天（dpi）上调，分别上调 2 倍和 13 倍（P < 0.05），而 IL-2 和 IL-4 的表达水平没有显著差异（P > 0.05）。与 Ts 株相比，H 株诱导的细胞因子表达水平更高。
结果表明，IBDV 强烈诱导细胞免疫相关细胞因子基因的表达，特别是 vvIBDV、H 株，表明这些细胞因子在 IBDV 感染的急性期可能发挥关键作用，不同毒力的 IBDV 引起的细胞免疫反应是通过不同的信号通路。
