Abstract:
Postweaning multisystemic wasting syndrome (PMWS) is caused by a systemic inflammation after porcine circovirus type 2 (PCV2) infection. It was one of the most economically important pathogens affecting pig production worldwide before PCV2 vaccine was first introduced in 2006. After the development of a vaccine against PCV2a type, pig farms gradually restored enormous economic losses from PMWS. However, vaccine against PCV2a type could not be fully effective against several different PCV2 genotypes (PCV2b - PCV2h). In addition, PCV2a vaccine itself could generate antigenic drift of PCV2 capsid. Therefore, PCV2 infection still threats pig industry worldwide. PCV2 infection was initially found in local tissues including reproductive, respiratory, and digestive tracks. However, PCV2 infection often leads to a systemic inflammation which can cause severe immunosuppression by depleting peripheral lymphocytes in secondary lymphoid tissues. Subsequently, a secondary infection with other microorganisms can cause PMWS. Eleven putative open reading frames (ORFs) have been predicted to encode PCV2 genome. Among them, gene products of six ORFs from ORF1 to ORF6 have been identified and characterized to estimate its functional role during PCV2 infection. Acquiring knowledge about the specific interaction between each PCV2 ORF protein and host protein might be a key to develop preventive or therapeutic tools to control PCV2 infection. In this article, we reviewed current understanding of how each ORF of PCV2 manipulates host cell signaling related to immune suppression caused by PCV2.
摘要:
断奶后多系统消耗综合征(PMWS)是由猪圆环病毒2型(PCV2)感染后的全身性炎症引起的。在2006年首次引入PCV2疫苗之前,它是影响全球猪生产的最重要的经济病原体之一。在开发针对PCV2a型的疫苗之后,猪场逐渐恢复了PMWS的巨大经济损失。然而,针对PCV2a型的疫苗对几种不同的PCV2基因型(PCV2b-PCV2h)不能完全有效。此外,PCV2a疫苗本身可产生PCV2衣壳的抗原漂移。因此,PCV2感染仍然威胁着全球养猪业。PCV2感染最初是在包括生殖在内的局部组织中发现的,呼吸,和消化道。然而,PCV2感染通常导致全身性炎症,其可通过耗尽次级淋巴组织中的外周淋巴细胞而引起严重的免疫抑制。随后,其他微生物的二次感染可引起PMWS。已预测11个推定的开放阅读框(ORF)编码PCV2基因组。其中,已鉴定并表征了从ORF1到ORF6的六个ORF的基因产物,以评估其在PCV2感染期间的功能作用。获得有关每种PCV20RF蛋白与宿主蛋白之间的特异性相互作用的知识可能是开发预防或治疗工具以控制PCV2感染的关键。在这篇文章中,我们回顾了目前对PCV2的每个ORF如何操纵与PCV2引起的免疫抑制相关的宿主细胞信号传导的理解.