Transcriptome analysis provides insights into the antiviral response in the spleen of gibel carp (Carassius auratus gibelio) after poly I: C treatment

Gibel carp (Carassius auratus gibelio) is an important commercial fish that has become one of the most cultured fishes in the region of Yangtze River in China. However, the fish faces increasing hazard due to cyprinid herpesvirus 2 (CyHV-2) infection, which has caused great economic losses. In this study, healthy gibel carp were intraperitoneally injected with different doses of poly I:C at 24 h before CyHV-2 challenge. Results showed that the mortality decreased and peak death time appeared later in the fish injected with poly I:C at a dose of 10 μg/g body weight. To explore what gene plays an important role after poly I:C treatment, the transcriptome analysis of the gibel carp spleen was further performed. Compared with the PBS group, 1286 differentially expressed genes (DEGs) were obtained in the poly I:C-treated fish, including 1006 up-regulated and 280 down-regulated DEGs. GO analysis revealed that the most enriched DEGs responded to “biological regulation”, “regulation of cellular process” and “regulation of biological process”. Meanwhile, KEGG enrichment analysis showed that the DEGs were mainly mapped on the immune pathways like “TNF signal pathway”, “p53 signal pathway” and “JAK-STAT signal pathway”, suggesting that these signal pathways may be responsible for the delayed peak of CyHV-2 infection in gibel carp after poly I:C treatment. Taken together, this study provides insights into the immune protection effect of poly I:C against CyHV-2 infection, as well as providing useful information for antiviral defense in gibel carp.