Two iridovirus-susceptible cell lines established front kidney and liver of grouper, Epinephelus awoara (Temminck & Schlegel), and partial characterization of grouper iridovirus

Two iridovirus-susceptible cell lines were established and characterized fr om grouper Epinephelus awoara kidney and liver tissues. These cell lines ha ve been designated GK and GL, respectively. The cells multiplied well in Le ibovitz's L-15 medium, supplemented with 10% foetal bovine serum, at temper atures between 20 and 32 degreesC, and have been subcultured more than 120 times, becoming continuous cell lines. The cell lines consist of a heteroge neous mixture of fibroblastic and epithelial cells. The viability of cells, stored frozen in liquid nitrogen (-196 degreesC), was 35% after 1 year. Ch romosome morphologies of GK and GL cells were homogeneous. Both cell lines were susceptible to grouper iridovirus, and yielded high titres of up to 10 (8) TCID50 mL(-1). In addition, both cell lines effectively replicated the virus, which could be purified to homogeneity by cesium chloride gradient c entrifugation. Electron microscopy studies showed that purified virus parti cles were 170 +/- 10 nm in diameter, and were hexagonal in shape. Virus-inf ected cells showed an abundance of virus particles inside the cytoplasm. Th ese results show that the GK and GL cell lines effectively replicate groupe r iridovirus, and can be used as a tool for studying fish iridoviruses.