Establishment and characterization of a brain cell line from sea perch, Lateolabrax japonicus

A continuous cell line, designated LJB, derived from the brain of sea perch (Lateolabrax japonicus) was established. LJB cells have been subcultured for more than 60 times in Dulbecco's modified Eagle's medium (DMEM) supplemented with 15% fetal bovine serum (FBS) since the initial primary culture. LJB cells exhibited maximum growth rate at 28°C in DMEM supplemented with 20% FBS. Cytogenetic analysis indicated that the modal chromosome number was 48, which was identical with the chromosome number of embryonic stem-like cells of sea perch. Comparison of the 18S ribosomal RNA gene sequences of LJB cells and sea perch confirmed that LJB cells originated from sea perch. After transfected with pEGFP-N3 plasmid, LJB cells showed a transfection efficiency of about 40% which was indicated by the percentage of cells expressing green fluorescence protein, indicating the potential application of LJB cells in gene expression studies. Cytopathic effect was clearly observed, and RNA-dependent RNA polymerase gene was also detected in LJB cells post red-spotted grouper nervous necrosis virus (RGNNV) infection. Furthermore, virus replication was confirmed by quantitative RT-PCR, virus titer, and transmission electron microscopy assay in RGNNV-infected LJB cells. The LJB cell line might be used as an ideal in vitro tool for analyzing and understanding the mechanisms of nervous necrosis virus-host interaction.