Study on the Optimal Scheme of Duck Circovirus Proliferation and Transcriptome Analysis of Infected PBMC

Duck circovirus disease (DuCVD) caused by duck circovirus (DuCV) is associated with developmental retardation, weight loss, loss of feather, etc., resulting in damage to lymphatic tissues, lymphocytopenia and immunosuppression in ducks. However, DuCV being characterized by a low viral titer clinically which hinders vaccine development and studies on DuCV pathogenesis. In order to improve this situation, culture of DuCV (SDDZ17) was conducted in vitro and in vivo , and the proliferation characteristics of SDDZ17 were optimized to obtain greater virus proliferation in cell culture and host tissues. The results showed that increasing the inoculation times of SDDZ17 and inoculating cyclophosphamide (CTX) could significantly increase the proliferation of SDDZ17 in vivo by about 1×10 4 times, and the addition of 5 mg/ml concanavalin A or 1% L-glutamine could significantly increase the proliferation of SDDZ17 in vitro by about 2.8 times. The results also showed that both in vivo and in vitro models of DuCV infection were shown to induce target cell death. To explore the pathogenesis of DuCV, RNA-sequencing was applied to duck peripheral blood mononuclear cells (PBMC) infected with SDDZ17 to determine differentially expressed genes (DEGs) and signaling pathways involved in cell death. In total, 1948 differently expressed genes (DEGs) were identified, among which 1053 were upregulated and 895 were downregulated. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway mapping showed that DEGs were related to the cellular processes lysosome and ferroptosis, apoptosis, necroptosis, and autophagy. This study not only contributes to accelerating the development of a DuCV vaccine, but also provides insights into the pathogenesis of DuCV, thus enabling a greater understanding of the mechanisms underlying immune evasion and immunosuppression triggered during DuCV infection.