A novel cell line established from caudal fin tissue of Carassius auratus gibelio is susceptible to cyprinid herpesvirus 2 infection with the induction of apoptosis

Herpesviral haematopoietic necrosis induced by cyprinid herpesvirus 2 (CyHV-2) in Carassius auratus gibelio has caused huge economic losses in aquaculture. To better characterize this pathogen at molecular and cellular levels, it is necessary to study its pathogenesis in a sustainable cell line. In this study, a new cell line (GiCF) from the caudal fin of Carassius auratus gibelio (C. a. gibelio) was established and characterised. Typical cytopathic effect represented by characteristic morphological changes was induced in the cells at the 7th day post infection with CyHV-2, which was isolated from diseased C. a. gibeli. The susceptibility of GiCF to CyHV-2 was further demonstrated by the presence of viral assembling factory in the cytoplasm unveiled by transmission electron microscopy, and viral protein synthesis through immunofluorescence and Western blot assays. Sustainable propagation of CyHV-2 in GiCF had been demonstrated by virus infection and titration assays in a consecutive manner. The virus titer reached 104.9±0.22 TCID50/ml, and infectious CyHV-2 was produced from the GiCF cells over 30 subcultures from the established cell lines. In addition, apoptosis was observed in the GiCF cells upon CyHV-2 infection by DAPI staining, TUNEL and Annexin V staining, and quantitative expression patterns of caspase genes suggested that caspase activation might involve in CyHV-2 induced apoptosis. In summary, a new cell line, GiCF, susceptible to CyHV-2 infection was established from caudal fin tissue of C. a. gibelio, and it should serve as an ideal infection platform to characterize CyHV-2 and its pathogenic effect including apoptosis.