Department of Basic Veterinary, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China.
Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, China.
Front Immunol. 2023 Feb 27;14:1142830. doi: 10.3389/fimmu.2023.1142830. eCollection 2023.
Koi sleepy disease (KSD) is a high mortality and infection viral disease caused by carp edema virus (CEV), which was a serious threat to aquaculture of common carp and export trade of Koi worldwide. Asymptomatic infection is an important cause of the difficulty in preventing KSD and its worldwide spread, because asymptomatic infection can be activated under appropriate condition. However, the understanding of the molecular correlates of these infections is still unknown. The purpose of this study was to compare the pathology change, enzyme activity, immunoglobulin activity, host and viral gene expression differences in acutely infected and cohabiting asymptomatic Koi infected with CEV. Healthy Koi were used as a control. The gross pathology, histopathology and ultrastructural pathology showed the difference and characteristics damage to the tissues of Koi under different infection conditions. Periodic Acid-Schiff stain (PAS), enzyme activity and immunoglobulin activity revealed changes in the immune response of gill tissue between acutely infected, asymptomatic infected and healthy Koi. A total of 111 and 2484 upregulated genes and 257 and 4940 downregulated genes were founded in healthy Koi vs asymptomatic infected Koi and healthy Koi vs acutely infected Koi, respectively. Additionally, 878 upregulated genes and 1089 downregulated genes were identified in asymptomatic vs. acutely infected Koi. Immune gene categories and their corresponding genes in different comparison groups were revealed. A total of 3, 59 and 28 immune-related genes were identified in the group of healthy Koi vs asymptomatic infected Koi, healthy Koi vs acutely infected Koi and asymptomatic infected Koi vs acutely infected Koi, respectively. Nineteen immune-related genes have the same expression manner both in healthy Koi vs acutely infected Koi and asymptomatic Koi vs acutely infected Koi, while 9 immune-related genes were differentially expressed only in asymptomatic Koi vs acutely infected Koi, which may play a role in viral reactivation. In addition, 8 differentially expressed genes (DEGs) were validated by quantitative reverse transcription PCR (RT-qPCR), and the results were consistent with the RNA-Seq results. In conclusion, the data obtained in this study provide new evidence for further elucidating CEV-host interactions and the CEV infection mechanism and will facilitate the implementation of integrated strategies for controlling CEV infection and spread.
锦鲤昏睡病（Koi sleepy disease，KSD）是由鲤水肿病毒（carp edema virus，CEV）引起的一种高死亡率和感染性病毒病，对全球鲤鱼养殖和锦鲤出口贸易构成严重威胁。无症状感染是 KSD 难以预防和全球传播的一个重要原因，因为无症状感染在适当的条件下可以被激活。然而，对于这些感染的分子相关性的了解仍然未知。本研究旨在比较急性感染和同居无症状感染 CEV 的锦鲤的病理学变化、酶活性、免疫球蛋白活性、宿主和病毒基因表达差异。健康锦鲤被用作对照。大体病理学、组织病理学和超微结构病理学显示了不同感染条件下锦鲤组织的差异和特征性损伤。过碘酸雪夫氏染色（periodic acid-Schiff stain，PAS）、酶活性和免疫球蛋白活性揭示了急性感染、无症状感染和健康锦鲤之间鳃组织免疫反应的变化。在健康锦鲤与无症状感染锦鲤和健康锦鲤与急性感染锦鲤的比较中，分别发现了 111 个和 2484 个上调基因和 257 个和 4940 个下调基因。此外，在无症状感染与急性感染锦鲤的比较中，发现了 878 个上调基因和 1089 个下调基因。不同比较组中免疫基因类别及其相应基因被揭示。在健康锦鲤与无症状感染锦鲤、健康锦鲤与急性感染锦鲤和无症状感染与急性感染锦鲤的比较中，分别鉴定出 3、59 和 28 个免疫相关基因。在健康锦鲤与急性感染锦鲤和无症状感染与急性感染锦鲤的比较中，有 19 个免疫相关基因的表达方式相同，而只有 9 个免疫相关基因在无症状感染与急性感染锦鲤的比较中差异表达，这可能在病毒再激活中起作用。此外，通过定量逆转录 PCR（quantitative reverse transcription PCR，RT-qPCR）验证了 8 个差异表达基因（differentially expressed genes，DEGs），结果与 RNA-Seq 结果一致。综上所述，本研究获得的数据为进一步阐明 CEV-宿主相互作用和 CEV 感染机制提供了新的证据，并将有助于实施控制 CEV 感染和传播的综合策略。
