Establishment and characterization of a cell line from tilapia brain for detection of tilapia lake virus.

Tilapia lake virus (TiLV) is an emerging disease threatening tilapia culture in many parts of the world. A cell line from the brain of tilapia, which was named TiB, was established, characterized and subcultured with more than 100 passages. The TiB cell line was optimally maintained at 27°C using medium 199 (M199) supplemented with 10% foetal bovine serum (FBS). Chromosome analysis revealed that 60% of TiB cells at passage 5 maintained the modal chromosome number 2n = 44, while at passage 60, there were 43% of TiB cells with the diploid chromosome number 2n = 50. A significant cytopathic effect was observed in TiB cells after infection with tilapia lake virus (TiLV-2017A), and the viral replication in the cells was confirmed by transmission electron microscopy, immunofluorescence assays and viral titres, indicating the susceptibility of TiB cells to TiLV-2017A. The viral titres of TiLV-2017A in TiB cells reached 107.43 TCID50 /ml within 10 days. The stable growth and susceptibility to fish viruses make TiB cells a useful tool for fish virus-host cell interaction and for immune response of fish.