Development of a New Marine Fish Continuous Cell Line Derived from Brain of Red Sea Bream () and Its Application to Fish Virology and Heavy Metal Toxicology.

Red sea bream () is one of the most popular farmed marine teleost fish species. Fish cell lines are becoming important research tool in the aquaculture field, and they are suitable models to study fish virology, immunology and toxicology. To obtain a cell line for biological studies, a continuous cell line from brain of red sea bream (designated as RSBB cell line) was established and has been successfully subcultured over 100 passages. The RSBB cell line predominantly consisted of fibroblast-like cells and multiplied well in M199 medium supplemented with 10% fetal bovine serum at 28 °C. Karyotyping analysis indicated that the modal chromosome numbers of RSBB cells was 48. After transfection with pEGFP-N1, RSBB cells showed bright green fluorescence with a transfection efficiency approaching 8%. For toxicology study, it was demonstrated that metal Cd could induce cytotoxic effects of RSBB cells, accompanied with a dose-dependent MTT conversion capacity. Morphologically, cells treated with metal Cd produced rounding, shrinking and detaching and induced both cell apoptosis and necrosis. For virology study, the RSBB cells were highly susceptible to Nervous necrosis virus (NNV) and Singapore grouper iridovirus (SGIV) with steady titers (i.e., 10 TCID mL and 10 TCID mL respectively). Furthermore, an obvious cytopathic effect (CPE) could be observed in RSBB cells infected with Infectious spleen and kidney necrosis virus (ISKNV) and rhabdoviruses (SCRV). Meanwhile, all the infections were confirmed by polymerase chain reaction. The new brain cell line developed and characterized from red sea bream in this study could be used as an in vitro model for fish studies in the fields of toxicology and virology.