Comparison of Immune Responses Induced in Gibel Carp, Carassius auratus gibelio Immersion, and Intraperitoneal Vaccinated With Live Attenuated Cyprinid Herpesvirus 2 (CyHV-2)

Abstract

This study investigated the immune responses induced in gibel carp, Carassius auratus gibelio, following immersion and intraperitoneal (i.p.) vaccination with live attenuated Cyprinid herpesvirus 2 (CyHV-2). Transcriptome sequencing analysis was performed on the kidney tissues of the experimental fish at 3, 7, and 14 days postvaccination. A staggering 948 million readings were assembled into 96,891 genes, with an average length of 1214 bp. We analyzed the KEGG enrichment, differentially expressed genes (DEGs), and DEGs temporal expression patterns between the immersion and i.p. injection groups. Our findings revealed that both i.p. injection and immersion vaccination significantly altered immune-related genes in gibel carp, suggesting that the prepared attenuated vaccine effectively stimulates the fish’s immune response. Generally, the injection group exhibited higher gene expression levels in the kidney tissue earlier and to a greater extent. In contrast, the immersion group showed delayed immune responses with lower expression levels. The differential expression of 12 immune-related genes in immunized gibel carp, as detected by real-time quantitative PCR. Significant differences were observed in the expression of 12 immune-related genes after vaccination, suggesting variations in the sensitivity of each gene to bodily stimuli and its involvement in immunity. The specific immune mechanisms require further research. These results provide essential data for evaluating vaccines’ immune pathways and efficacy, offering optimism for vaccine development in fish immunology.