Development and characterization of a new cell line from brain tissues of the rare minnow (Gobiocypris rarus)

A permanent epithelial-like cell line, named GrB, was established from brain tissues of the rare minnow (Gobiocypris rarus). GrB cells grow well at temperatures between 22celcius and 27celcius in L-15 medium supplemented with 10% FBS. Chromosome analysis revealed that GrB cells possessed a diploid chromosome number of 2n = 50 at passage 50, consistent with the number of chromosomes reported for G. rarus. Partial amplification and sequence analysis of the cytochrome oxidase subunit I (COI) confirmed that GrB cells are originated from G. rarus. The cell lines also successfully expressed green fluorescence protein from plasmid pEGFP-N1 and which makes them suitable for transfection studies. A cytolytic cytopathic effect was observed in the cells after infection with tilapia lake virus 2017A (TiLV-2017A). A large number of virus particles were detected by electron microscopy. Immunofluorescence and virus titration assays indicated that TiLV-2017A titres reached 10(5.67) TCID50/ml at 7 days post-infection (dpi). Healthy adult rare minnows were challenged with virus obtained from these cells showed that they can be infected by TiLV-2017A, which causes low mortality but clinical signs. The GrB cell line may represent a valuable model as basics for fish virology and fish immunology.