Barranco I, Gómez-Laguna J, Rodríguez-Gómez I M, Quereda J J, Salguero F J, Pallarés F J, Carrasco L
Department of Anatomy and Comparative Pathology, Faculty of Veterinary Medicine, Cordoba University, Agrifood Campus of International Excellence - CeiA3, 14071 Cordoba, Spain.
Vet Immunol Immunopathol. 2012 Oct 15;149(3-4):262-71. doi: 10.1016/j.vetimm.2012.07.011. Epub 2012 Jul 27.
Despite the numerous studies carried out, the mechanisms used by porcine reproductive and respiratory syndrome (PRRS) virus (PRRSV) to impair the host immune response are not yet clear. The aim of this study was to determine the expression of IL-12, IL-10, IFN-α and IFN-γ in lymphoid organs of PRRSV experimentally-infected pigs. Twenty eight piglets were inoculated with PRRSV field isolate 2982 and killed in batches of four at 3, 7, 10, 14, 17, 21 and 24 days post-inoculation (dpi). Control animals were mock-inoculated and killed at the end of the study. Samples from mediastinal and retropharyngeal lymph nodes and tonsil were collected and fixed for histopathological and immunohistochemical analyses. PRRSV antigen was mainly detected in the cytoplasm of macrophages, displaying a bimodal expression with a first peak at 3-7 dpi and a second peak at 14 dpi. The expression of IFN-α showed an early enhancement at 3 dpi, and both IL-12 and IFN-γ displayed a similar trend in all the lymphoid organs analysed, showing an increase at 3-7 dpi and at 14-17 dpi. On the other hand, the expression of IL-10 was lower than the one observed for the other cytokines. The expression of IL-10 compared with the higher expression of IL-12, IFN-α and IFN-γ detected in this study, indicates that other mechanisms besides the expression of IL-10 play a role in the inducement of an erratic host immune response. Taking into account the enhanced expression of IFNs together with the detection of PRRSV antigen until the end of the study in the examined lymphoid organs, further studies are being conducted to rule out a down-regulation in IFN signalling pathway.
尽管已经开展了大量研究，但猪繁殖与呼吸综合征（PRRS）病毒（PRRSV）损害宿主免疫反应的机制仍不清楚。本研究的目的是确定PRRSV实验感染猪的淋巴器官中白细胞介素-12（IL-12）、白细胞介素-10（IL-10）、α干扰素（IFN-α）和γ干扰素（IFN-γ）的表达情况。28头仔猪接种PRRSV野毒株2982，并在接种后3、7、10、14、17、21和24天（dpi）按每组4头分批处死。对照动物进行 mock 接种，并在研究结束时处死。收集纵隔和咽后淋巴结以及扁桃体的样本，固定后进行组织病理学和免疫组织化学分析。PRRSV抗原主要在巨噬细胞的细胞质中检测到，呈现双峰表达，第一个峰值出现在3 - 7 dpi，第二个峰值出现在14 dpi。IFN-α的表达在3 dpi时早期增强，IL-12和IFN-γ在所有分析的淋巴器官中呈现相似趋势，在3 - 7 dpi和14 - 17 dpi时增加。另一方面，IL-10的表达低于其他细胞因子。与本研究中检测到的IL-12、IFN-α和IFN-γ的较高表达相比，IL-10的表达表明，除了IL-10的表达外，其他机制在诱导不稳定的宿主免疫反应中起作用。考虑到IFN的表达增强以及在研究结束时在所检查的淋巴器官中检测到PRRSV抗原，正在进行进一步研究以排除IFN信号通路的下调。
