Establishment and Characterization of a Novel Kidney-cell Line from Orange-spotted Grouper, Epinephelus coioides, and its Susceptibility to Grouper Iridovirus

Abstract

A new continuous cell line, designated as GK-7, was developed from the kidney tissue of the marine grouper, Epinephelus coioides. The cell line grew well in Leibovitz's L-15 medium supplemented with 15% fetal bovine serum at a range of temperatures from 20 to 32℃, with optimal growth at 25℃. Morphologically, the GK-7 cell line is spindleshaped epithelial-like cell comfirmed by immunophenotyping with cytokeratin antibody. Chromosome number analysis showed that GK-7 cells of the 50th and 150th cell passages had a modal diploid chromosome number of 48 and 66, respectively. Replication of GIV with the cell line showed that the maximum virus yield reached up 10 8.4TCID 50 mL -1 with the cells of the 50th passage. Electron micrographs showed abundant cytoplasmic icosahedral virions with a mean diameter of 200 nm in virus-infected cells. Negative staining of ultrathin sections of infected cells showed three-layered membrane enveloped mature viral particles with a diameter about 240 nm. Green fluorescent protein can be expressed in both cell lines at 48 hr after the cell lines were transfected with a green fluorescent reporter gene driven by a cytomegalovirus promoter. Our results showed that the GK-7 cell line provided valuable tools for the isolation and investigation of fish iridovirus and for vaccine production.

Emergence of Decapod iridescent virus 1 in cultured shrimp from Taiwan in 2020

“…Phylogenetic analysis of DIV1s was performed by comparing the MCP gene fragment of DIV1s from Taiwan with reference sequences of the family Iridoviridae (Table 1 ) (Cano et al., 2010 ; Delhon et al., 2006 ; Holopainen et al., 2009 ; Huang et al., 2016 ; Jakob et al., 2001 ; Li et al., 2017 ; Marsh et al., 2002 ; Mazzoni et al., 2009 ; Piegu et al., 2014 ; Shinmoto et al., 2009 ; Tang et al., 2007 ; Zhang et al., 2004 ) using MEGA X (Kumar et al., 2018 ).…”