Characterization of Grass Carp (Ctenopharyngodon idellus) Ovary Cell Line and Its Susceptibility to Spring Viremia of Carp Virus

Abstract:

Grass carp ovary cell lines (GCO) was used in the study of Grass Carp Hemorrhage and has been established by Chinese Academy of Sciences Institute of Aquatic Animal in 1970s. GCO has been cultured for more than 300 generations and plays an important role in fish virology research in China. In this study, we performed morphological observation, drawing of the growth curves, cell cycle analysis, chromosomal analysis, cytopathic effect assay (CPE), TCID50 assay, cell apoptosis detection, and electron microscopic observation to demonstrate the characteristics of GCO and the cell proliferation of spring viremia of carp virus (SVCV). It was observed that GCO cell line mainly consisted of epithelial-like cells. GCO grew at temperatures between 15℃ and 28℃, and the optimum was 25℃. The growth rate of GCO cells increased proportionally with the foetal bovine serum (FBS) concentration (5% to 20%), and the optimum concentration of FBS was 10%. There were 48 chromosomes in GCO cells. Four known fish cell lines were tested to determine the susceptibility of SVCV, and the results demonstrated that GCO was susceptible to SVCV. Moreover, GCO displayed higher sensitivity to SVCV and increased viral production than the control cell line, epithelioma papulosum cyprini (EPC), fathead minnow (FHM), and chinook salmon embryo (CHSE-214) cell lines. These results suggested that GCO cell line could be a useful diagnostic tool in SVCV isolation and diagnosis, and could serve as a suitable biological system in the pathogenicity study of SVCV. One advantage of this cell line is that it grows in a wide temperature range (15℃ to 28℃), and thus can be used in isolating both warm-water and cold-water fish viruses. These characteristics of the GCO make it a potential tool in the future study of other fish viruses.