Kekarainen T, McCullough K, Fort M, Fossum C, Segalés J, Allan G M
Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
Vet Immunol Immunopathol. 2010 Aug 15;136(3-4):185-93. doi: 10.1016/j.vetimm.2010.03.025. Epub 2010 Apr 7.
Porcine circovirus type 2 (PCV2) is essential but not sufficient for postweaning multisystemic wasting syndrome (PMWS) occurrence in pigs. The outcome of PCV2 infection depends on the specific immune responses that are developing during the infection. Diseased pigs are immunosupressed and unable to mount effective immune responses to clear the virus from circulation. In the final stage, PMWS-affected pigs suffer from extensive lymphoid lesions and altered cytokine expression patterns in peripheral blood mononuclear cells (PBMCs) and lymphoid organs. PCV2 infection can also be asymptomatic, demonstrating that not every infection will guarantee the occurrence of severe immunopathological disturbances. Asymptomatic animals have higher virus specific and neutralising antibody titres than PMWS-affected animals. Recent results have pointed out that the mechanisms by which PCV2 can affect the immune responses involve the induction of IL-10, virus accumulation into and modulation of plasmacytoid dendritic cells and the role of viral DNA in regulation of immune cell functions. Fourteen years after the first description of PMWS in Canada, efficient commercial vaccines against PCV2 are available. The vaccine success is based on activated humoral and cellular immune responses against PCV2. This review focuses on the recent research on immunological aspects during PCV2 infections and summarizes what is currently known about the vaccine-induced immunity.
猪圆环病毒2型（PCV2）是仔猪断奶后多系统衰竭综合征（PMWS）发生的必要条件，但并非充分条件。PCV2感染的结果取决于感染期间所产生的特异性免疫反应。患病猪免疫功能受到抑制，无法产生有效的免疫反应以清除循环中的病毒。在疾病后期，受PMWS影响的猪会出现广泛的淋巴组织病变，外周血单核细胞（PBMC）和淋巴器官中的细胞因子表达模式也会发生改变。PCV2感染也可能无症状，这表明并非每次感染都会导致严重的免疫病理紊乱。无症状动物的病毒特异性中和抗体滴度高于受PMWS影响的动物。最近的研究结果指出，PCV2影响免疫反应的机制包括诱导白细胞介素-10、病毒在浆细胞样树突状细胞中的积累和调节，以及病毒DNA在免疫细胞功能调节中的作用。在加拿大首次描述PMWS十四年后，已有针对PCV2的高效商业疫苗。疫苗的成功基于针对PCV2激活的体液免疫和细胞免疫反应。本综述重点关注PCV2感染期间免疫方面的最新研究，并总结目前关于疫苗诱导免疫的已知情况。
